Remove x11vnc subdir.

The new x11vnc repo is at https://github.com/LibVNC/x11vnc.

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-
-Copyright (C) 2002-2010 Karl J. Runge <runge@karlrunge.com>
-All rights reserved.
-
-x11vnc README file                         Date: Mon Dec 27 20:58:57 EST 2010
-
-The following information is taken from these URLs:
-
-	http://www.karlrunge.com/x11vnc/index.html
-	http://www.karlrunge.com/x11vnc/x11vnc_opts.html
-	...
-
-they contain the most up to date info.
-
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/index.html:
-
-
-     _________________________________________________________________
-
-x11vnc: a VNC server for real X displays
-                (to FAQ)    (to Downloads)    (to Building)    (to Beta Test)
-  (to Donations) [PayPal] 
-
-   x11vnc allows one to view remotely and interact with real X displays
-   (i.e. a display corresponding to a physical monitor, keyboard, and
-   mouse) with any VNC viewer. In this way it plays the role for Unix/X11
-   that WinVNC plays for Windows.
-
-   It has built-in SSL/TLS encryption and 2048 bit RSA authentication,
-   including VeNCrypt support; UNIX account and password login support;
-   server-side scaling; single port HTTPS/HTTP+VNC; Zeroconf service
-   advertising; and TightVNC and UltraVNC file-transfer. It has also been
-   extended to work with non-X devices: natively on Mac OS X Aqua/Quartz,
-   webcams and TV tuner capture devices, and embedded Linux systems such
-   as Qtopia Core. Full IPv6 support is provided. More features are
-   described here.
-
-   It also provides an encrypted Terminal Services mode (-create, -svc,
-   or -xdmsvc options) based on Unix usernames and Unix passwords where
-   the user does not need to memorize his VNC display/port number.
-   Normally a virtual X session (Xvfb) is created for each user, but it
-   also works with X sessions on physical hardware. See the tsvnc
-   terminal services mode of the SSVNC viewer for one way to take
-   advantage of this mode.
-
-   I wrote x11vnc back in 2002 because x0rfbserver was basically
-   impossible to build on Solaris and had poor performance. The primary
-   x0rfbserver build problems centered around esoteric C++ toolkits.
-   x11vnc is written in plain C and needs only standard libraries and so
-   should work on nearly all Unixes, even very old ones. I also created
-   enhancements to improve the interactive response, added many features,
-   and etc.
-
-   This page including the FAQ contains much information [*]; solutions
-   to many problems; and interesting applications, but nevertheless
-   please feel free to contact me if you have problems or questions (and
-   if I save you time or expense by giving you some of my time, please
-   consider a PayPal Donation.) Do check the FAQ and this page first; I
-   realize the pages are massive, but you can often use your browser's
-   find-in-page search action using a keyword to find the answer to your
-   problem or question.
-
-   SSVNC:  An x11vnc side-project provides an Enhanced TightVNC Viewer
-   package (SSVNC) for Unix, Windows, and Mac OS X with automatic SSL
-   and/or SSH tunnelling support, SSL Certificate creation, Saved
-   connection profiles, Zeroconf, VeNCrypt, and built-in Proxy support.
-   Added features for the TightVNC Unix viewer: NewFBSize, ZRLE encoding,
-   Viewer-side Scaling, cursor alphablending, low color modes, and
-   enhanced popup menu; UltraVNC extensions support for: File Transfer,
-   Text Chat, Single Window, Server Input, and 1/n Scaling extensions,
-   and UltraVNC DSM encryption. The SSVNC bundle could be placed on, say,
-   a USB memory stick for SSL/SSH VNC viewing from nearly any networked
-   computer.
-
-     _________________________________________________________________
-
-    Announcements:
-
-   Important: If you created any permanent SSL certificates (e.g. via
-   "x11vnc -ssl SAVE ...") on a Debian or Ubuntu system from Sept. 2006
-   through May 2008, then those keys are likely extremely weak and can be
-   easily cracked. The certificate files should be deleted and recreated
-   on a non-Debian system or an updated one. See
-   http://www.debian.org/security/2008/dsa-1571 for details. The same
-   applies to SSH keys (not used by x11vnc directly, but many people use
-   SSH tunnels for VNC access.)
-
-   FAQ moved: The huge FAQ has finally been moved to its own page. If you
-   are trying to follow someone's link to an FAQ once on this page it is
-   now a broken link. Try inserting the string "faq.html", e.g.:
-from:   http://www.karlrunge.com/x11vnc/#faq-singleclick
-to:     http://www.karlrunge.com/x11vnc/faq.html#faq-singleclick
-
-   Apologies for the inconvenience, unfortunately it is not possible to
-   automatically redirect to the new page since the '#' anchor is not
-   sent to the webserver.
-
-     _________________________________________________________________
-
-    Background:
-
-   VNC (Virtual Network Computing) is a very useful network graphics
-   protocol (applications running on one computer but displaying their
-   windows on another) in the spirit of X, however, unlike X, the
-   viewing-end is very simple and maintains no state. It is a remote
-   framebuffer (RFB) protocol.
-
-   Some VNC links:
-     * http://www.realvnc.com
-     * http://www.tightvnc.com
-     * http://www.ultravnc.com/
-     * http://www.testplant.com/products/vine_server/OS_X
-
-   For Unix, the traditional VNC implementation includes a "virtual" X11
-   server Xvnc (usually launched via the vncserver command) that is not
-   associated with a physical display, but provides a "fake" one X11
-   clients (xterm, firefox, etc.) can attach to. A remote user then
-   connects to Xvnc via the VNC client vncviewer from anywhere on the
-   network to view and interact with the whole virtual X11 desktop.
-
-   The VNC protocol is in most cases better suited for remote connections
-   with low bandwidth and high latency than is the X11 protocol because
-   it involves far fewer "roundtrips" (an exception is the cached pixmap
-   data on the viewing-end provided by X.) Also, with no state maintained
-   the viewing-end can crash, be rebooted, or relocated and the
-   applications and desktop continue running. Not so with X11.
-
-   So the standard Xvnc/vncserver program is very useful, I use it for
-   things like:
-     * Desktop conferencing with other users (e.g. code reviews.)
-     * Long running apps/tasks I want to be able to view from many places
-       (e.g. from home and work.)
-     * Motif, GNOME, and similar applications that would yield very poor
-       performance over a high latency link.
-
-   However, sometimes one wants to connect to a real X11 display (i.e.
-   one attached to a physical monitor, keyboard, and mouse: a Workstation
-   or a SunRay session) from far away. Maybe you want to close down an
-   application cleanly rather than using kill, or want to work a bit in
-   an already running application, or would like to help a distant
-   colleague solve a problem with their desktop, or would just like to
-   work out on the deck for a while. This is where x11vnc is useful.
-     _________________________________________________________________
-
-    How to use x11vnc:
-
-   In this basic example let's assume the remote machine with the X
-   display you wish to view is "far-away.east:0" and the workstation you
-   are presently working at is "sitting-here.west".
-
-   Step 0. Download x11vnc (see below) and have it available to run on
-   far-away.east (on some linux distros it is as easy as "apt-get install
-   x11vnc", "emerge x11vnc", etc.) Similarly, have a VNC viewer (e.g.
-   vncviewer) ready to run on sitting-here.west. We recommend TightVNC
-   Viewers (see also our SSVNC viewer.)
-
-   Step 1. By some means log in to far-away.east and get a command shell
-   running there. You can use ssh, or even rlogin, telnet, or any other
-   method to do this. We do this because the x11vnc process needs to be
-   run on the same machine the X server process is running on (otherwise
-   things would be extremely slow.)
-
-   Step 2. In that far-away.east shell (with command prompt "far-away>"
-   in this example) run x11vnc directed at the far-away.east X session
-   display:
-
-  far-away> x11vnc -display :0
-
-   You could have also set the environment variable DISPLAY=:0 instead of
-   using "-display :0". This step attaches x11vnc to the far-away.east:0
-   X display (i.e. no viewer clients yet.)
-
-   Common Gotcha: To get X11 permissions right, you may also need to set
-   the XAUTHORITY environment variable (or use the -auth option) to point
-   to the correct MIT-MAGIC-COOKIE file (e.g. /home/joe/.Xauthority.) If
-   x11vnc does not have the authority to connect to the display it exits
-   immediately. More on how to fix this below.
-
-   If you suspect an X11 permissions problem do this simple test: while
-   sitting at the physical X display open a terminal window
-   (gnome-terminal, xterm, etc.) You should be able to run x11vnc
-   successfully in that terminal without any need for command line
-   options. If that works OK then you know X11 permissions are the only
-   thing preventing it from working when you try to start x11vnc via a
-   remote shell. Then fix this with the tips below.
-
-   Note as of Feb/2007 you can also try the -find option instead of
-   "-display ..." and see if that finds your display and Xauthority. Note
-   as of Dec/2009 the -findauth and "-auth guess" options may be helpful
-   as well.
-   (End of Common Gotcha)
-
-   When x11vnc starts up there will then be much chatter printed out (use
-   "-q" to quiet it), until it finally says something like:
-  .
-  .
-  13/05/2004 14:59:54 Autoprobing selected port 5900
-  13/05/2004 14:59:54 screen setup finished.
-  13/05/2004 14:59:54
-  13/05/2004 14:59:54 The VNC desktop is far-away:0
-  PORT=5900
-
-   which means all is OK, and we are ready for the final step.
-
-   Step 3. At the place where you are sitting (sitting-here.west in this
-   example) you now want to run a VNC viewer program. There are VNC
-   viewers for Unix, Windows, MacOS, Java-enabled web browsers, and even
-   for PDA's like the Palm Pilot and Cell Phones! You can use any of them
-   to connect to x11vnc (see the above VNC links under "Background:" on
-   how to obtain a viewer for your platform or see this FAQ. For Solaris,
-   vncviewer is available in the Companion CD package SFWvnc.)
-
-   In this example we'll use the Unix vncviewer program on sitting-here
-   by typing the following command in a second terminal window:
-
-  sitting-here> vncviewer far-away.east:0
-
-   That should pop up a viewer window on sitting-here.west showing and
-   allowing interaction with the far-away.east:0  X11 desktop. Pretty
-   nifty! When finished, exit the viewer: the remote x11vnc process will
-   shutdown automatically (or you can use the -forever option to have it
-   wait for additional viewer connections.)
-
-   Common Gotcha: Nowadays there will likely be a host-level firewall on
-   the x11vnc side that is blocking remote access to the VNC port (e.g.
-   5900.) You will either have to open up that port (or a range of ports)
-   in your firewall administration tool, or try the SSH tunnelling method
-   below (even still the firewall must allow in the SSH port, 22.)
-
-
-   Shortcut: Of course if you left x11vnc running on far-away.east:0 in a
-   terminal window with the -forever option or as a service, you'd only
-   have to do Step 3 as you moved around. Be sure to use a VNC Password
-   or other measures if you do that.
-
-
-   Super Shortcut: Here is a potentially very easy way to get all of it
-   working.
-     * Have x11vnc (0.9.3 or later) available to run on the remote host
-       (i.e. in $PATH.)
-     * Download and unpack a SSVNC bundle (1.0.19 or later, e.g.
-       ssvnc_no_windows-1.0.28.tar.gz) on the Viewer-side machine.
-     * Start the SSVNC Terminal Services mode GUI: ./ssvnc/bin/tsvnc
-     * Enter your remote username@hostname (e.g. fred@far-away.east) in
-       the "VNC Terminal Server" entry.
-     * Click "Connect".
-
-   That will do an SSH to username@hostname and start up x11vnc and then
-   connect a VNC Viewer through the SSH encrypted tunnel.
-
-   There are a number of things assumed here, first that you are able to
-   SSH into the remote host; i.e. that you have a Unix account there and
-   the SSH server is running. On Unix and MacOS X it is assumed that the
-   ssh client command is available on the local machine (on Windows a
-   plink binary is included in the SSVNC bundle.) Finally, it is assumed
-   that you are already logged into an X session on the remote machine,
-   e.g. your workstation (otherwise, a virtual X server, e.g. Xvfb, will
-   be started for you.)
-
-   In some cases the remote SSH server will not run commands with the
-   same $PATH that you normally have in your shell there. In this case
-   click on Options -> Advanced -> X11VNC Options, and type in the
-   location of the x11vnc binary under "Full Path". (End of Super
-   Shortcut)
-
-
-   Desktop Sharing: The above more or less assumed nobody was sitting at
-   the workstation display "far-away.east:0". This is often the case: a
-   user wants to access her workstation remotely. Another usage pattern
-   has the user sitting at "far-away.east:0" and invites one or more
-   other people to view and interact with his desktop. Perhaps the user
-   gives a demo or presentation this way (using the telephone for vocal
-   communication.) A "Remote Help Desk" mode would be similar: a
-   technician connects remotely to the user's desktop to interactively
-   solve a problem the user is having.
-
-   For these cases it should be obvious how it is done. The above steps
-   will work, but more easily the user sitting at far-away.east:0 simply
-   starts up x11vnc from a terminal window, after which the guests would
-   start their VNC viewers. For this usage mode the "-connect
-   host1,host2" option may be of use to automatically connect to the
-   vncviewers in "-listen" mode on the list of hosts.
-     _________________________________________________________________
-
-    Tunnelling x11vnc via SSH:
-
-   The above example had no security or privacy at all. When logging into
-   remote machines (certainly when going over the internet) it is best to
-   use ssh, or use a VPN (for a VPN, Virtual Private Network, the above
-   example should be pretty safe.)
-
-   For x11vnc one can tunnel the VNC protocol through an encrypted ssh
-   channel. It would look something like running the following commands:
-  sitting-here> ssh -t -L 5900:localhost:5900 far-away.east 'x11vnc -localhost
--display :0'
-
-   (you will likely have to provide passwords/passphrases to login from
-   sitting-here into your far-away.east Unix account; we assume you have
-   a login account on far-away.east and it is running the SSH server)
-
-   And then in another terminal window on sitting-here run the command:
-  sitting-here> vncviewer -encodings "copyrect tight zrle hextile" localhost:0
-
-   Note: The -encodings option is very important: vncviewer will often
-   default to "raw" encoding if it thinks the connection is to the local
-   machine, and so vncviewer gets tricked this way by the ssh
-   redirection. "raw" encoding will be extremely slow over a networked
-   link, so you need to force the issue with -encodings "copyrect tight
-   ...". Nowadays, not all viewers use the -encodings option, try
-   "-PreferredEncoding=ZRLE" (although the newer viewers seem to
-   autodetect well when to use raw or not.)
-
-   Note that "x11vnc -localhost ..." limits incoming vncviewer
-   connections to only those from the same machine. This is very natural
-   for ssh tunnelling (the redirection appears to come from the same
-   machine.) Use of a VNC password is also strongly recommended.
-
-   Note also the -t we used above (force allocate pseudoterminal), it
-   actually seems to improve interactive typing response via VNC!
-
-   You may want to add the -C option to ssh to enable compression. The
-   VNC compression is not perfect, and so this may help a bit. However,
-   over a fast LAN you probably don't want to enable SSH compression
-   because it can slow things down. Try both and see which is faster.
-
-   If your username is different on the remote machine use something
-   like: "fred@far-away.east" in the above ssh command line.
-
-   Some VNC viewers will do the ssh tunnelling for you automatically, the
-   TightVNC Unix vncviewer does this when the "-via far-away.east" option
-   is supplied to it (this requires x11vnc to be already running on
-   far-away.east or having it started by inetd(8).) See the 3rd script
-   example below for more info.
-
-   SSVNC:  You may also want to look at the Enhanced TightVNC Viewer
-   (ssvnc) bundles because they contain scripts and GUIs to automatically
-   set up SSH tunnels (e.g. the GUI, "ssvnc", does it automatically and
-   so does this command: "ssvnc_cmd -ssh user@far-away.east:0") and can
-   even start up x11vnc as well.
-
-   The Terminal Services mode of SSVNC is perhaps the easiest way to use
-   x11vnc. You just need to have x11vnc available in $PATH on the remote
-   side (and can SSH to the host), and then on the viewer-side you type
-   something like:
-  tsvnc fred@far-away.east
-
-   everything else is done automatically for you. Normally this will
-   start a virtual Terminal Services X session (RAM-only), but if you
-   already have a real X session up on the physical hardware it will find
-   that one for you.
-
-   Gateways:  If the machine you SSH into is not the same machine with
-   the X display you wish to view (e.g. your company provides incoming
-   SSH access to a gateway machine), then you need to change the above
-   to, e.g.: "-L 5900:OtherHost:5900":
-  sitting-here> ssh -t -L 5900:OtherHost:5900 gateway.east
-
-   Where gateway.east is the internet hostname (or IP) of the gateway
-   machine (SSH server.) 'OtherHost' might be, e.g., freds-pc or
-   192.168.2.33 (it is OK for these to be private hostnames or private IP
-   addresses, the host in -L is relative to the remote server side.)
-
-   Once logged in, you'll need to do a second login (ssh, rsh, etc.) to
-   the workstation machine 'OtherHost' and then start up x11vnc on it (if
-   it isn't already running.) (The "-connect gateway:59xx" option may be
-   another alternative here with the viewer already in -listen mode.) For
-   an automatic way to use a gateway and have all the network traffic
-   encrypted (including inside the firewall) see Chaining SSH's.
-
-   These gateway access modes also can be done automatically for you via
-   the "Proxy/Gateway" setting in SSVNC (including the Chaining SSH's
-   case, "Double Proxy".)
-
-   Firewalls/Routers:
-
-   A lot of people have inexpensive devices for home or office that act
-   as a Firewall and Router to the machines inside on a private LAN. One
-   can usually configure the Firewall/Router from inside the LAN via a
-   web browser.
-
-   Often having a Firewall/Router sitting between the vncviewer and
-   x11vnc will make it impossible for the viewer to connect to x11vnc.
-
-   One thing that can be done is to redirect a port on the
-   Firewall/Router to, say, the SSH port (22) on an inside machine (how
-   to do this depends on your particular Firewall/Router, often the
-   router config URL is http://192.168.100.1 See www.portforward.com for
-   more info.) This way you reach these computers from anywhere on the
-   Internet and use x11vnc to view X sessions running on them.
-
-   Suppose you configured the Firewall/Router to redirect these ports to
-   two internal machines:
-  Port 12300 -> 192.168.1.3, Port 22 (SSH)
-  Port 12301 -> 192.168.1.4, Port 22 (SSH)
-
-   (where 192.168.1.3 is "jills-pc" and 192.168.1.4 is "freds-pc".) Then
-   the ssh's would look something like:
-  sitting-here> ssh -t -p 12300 -L 5900:localhost:5900 jill@far-away.east 'x11v
-nc -localhost -display :0'
-  sitting-here> ssh -t -p 12301 -L 5900:localhost:5900 fred@far-away.east 'x11v
-nc -localhost -display :0'
-
-   Where far-away.east means the hostname (or IP) that the
-   Router/Firewall is using (for home setups this is usually the IP
-   gotten from your ISP via DHCP, the site http://www.whatismyip.com/ is
-   a convenient way to determine what it is.)
-
-   It is a good idea to add some obscurity to accessing your system via
-   SSH by using some high random port (e.g. 12300 in the above example.)
-   If you can't remember it, or are otherwise not worried about port
-   scanners detecting the presence of your SSH server and there is just
-   one internal PC involved you could map 22:
-  Port 22 -> 192.168.1.3, Port 22 (SSH)
-
-   Again, this SSH gateway access can be done automatically for you via
-   the "Proxy/Gateway" setting in SSVNC. And under the "Remote SSH
-   Command" setting you can enter the x11vnc -localhost -display :0.
-
-   Host-Level-Firewalls: even with the hardware Firewall/Router problem
-   solved via a port redirection, most PC systems have their own Host
-   level "firewalls" enabled to protect users from themselves. I.e. the
-   system itself blocks all incoming connections. So you will need to see
-   what is needed to configure it to allow in the port (e.g. 22) that you
-   desire. E.g. Yast, Firestarter, iptables(1), etc..
-
-   VNC Ports and Firewalls: The above discussion was for configuring the
-   Firewall/Router to let in port 22 (SSH), but the same thing can be
-   done for the default VNC port 5900:
-  Port 5900 -> 192.168.1.3, Port 5900 (VNC)
-  Port 5901 -> 192.168.1.4, Port 5900 (VNC)
-
-   (where 192.168.1.3 is "jills-pc" and 192.168.1.4 is "freds-pc".) This
-   could be used for normal, unencrypted connections and also for SSL
-   encrypted ones.
-
-   The VNC displays to enter in the VNC viewer would be, say,
-   "far-away.east:0" to reach jills-pc and "far-away.east:1" to reach
-   freds-pc. We assume above that x11vnc is using port 5900 (and any
-   Host-Level-firewalls on jills-pc has been configured to let that port
-   in.) Use the "-rfbport" option to tell which port x11vnc should listen
-   on.
-
-   For a home system one likely does not have a hostname and would have
-   to use the IP address, say, "24.56.78.93:0". E.g.:
-  vncviewer 24.56.78.93:0
-
-   You may want to choose a more obscure port on the router side, e.g.
-   5944, to avoid a lot of port scans finding your VNC server. For 5944
-   you would tell the viewer to use:
-  vncviewer 24.56.78.93:44
-
-   The IP address would need to be communicated to the person running the
-   VNC Viewer. The site http://www.whatismyip.com/ can help here.
-
-     _________________________________________________________________
-
-   Scripts to automate ssh tunneling: As discussed below, there may be
-   some problems with port 5900 being available. If that happens, the
-   above port and display numbers may change a bit (e.g. -> 5901 and :1).
-   However, if you "know" port 5900 will be free on the local and remote
-   machines, you can easily automate the above two steps by using the
-   x11vnc option -bg (forks into background after connection to the
-   display is set up) or using the -f option of ssh. Some example scripts
-   are shown below. Feel free to try the ssh -C to enable its compression
-   and see if that speeds things up noticeably.
-     _________________________________________________________________
-
-   #1. A simple example script, assuming no problems with port 5900 being
-   taken on the local or remote sides, looks like:
-#!/bin/sh
-# usage: x11vnc_ssh <host>:<xdisplay>
-#  e.g.: x11vnc_ssh snoopy.peanuts.com:0
-#  (user@host:N also works)
-
-host=`echo $1 | awk -F: '{print $1}'`
-disp=`echo $1 | awk -F: '{print $2}'`
-if [ "x$disp" = "x" ]; then disp=0; fi
-
-cmd="x11vnc -display :$disp -localhost -rfbauth .vnc/passwd"
-enc="copyrect tight zrle hextile zlib corre rre raw"
-
-ssh -f -t -L 5900:localhost:5900 $host "$cmd"
-
-for i in 1 2 3
-do
-        sleep 2
-        if vncviewer -encodings "$enc" :0; then break; fi
-done
-
-   See also rx11vnc.pl below.
-     _________________________________________________________________
-
-   #2. Another method is to start the VNC viewer in listen mode
-   "vncviewer -listen" and have x11vnc initiate a reverse connection
-   using the -connect option:
-#!/bin/sh
-# usage: x11vnc_ssh <host>:<xdisplay>
-#  e.g.: x11vnc_ssh snoopy.peanuts.com:0
-#  (user@host:N also works)
-
-host=`echo $1 | awk -F: '{print $1}'`
-disp=`echo $1 | awk -F: '{print $2}'`
-if [ "x$disp" = "x" ]; then disp=0; fi
-
-cmd="x11vnc -display :$disp -localhost -connect localhost"   # <== note new opt
-ion
-enc="copyrect tight zrle hextile zlib corre rre raw"
-
-vncviewer -encodings "$enc" -listen &
-pid=$!
-ssh -t -R 5500:localhost:5500 $host "$cmd"
-kill $pid
-
-   Note the use of the ssh option "-R" instead of "-L" to set up a remote
-   port redirection.
-     _________________________________________________________________
-
-   #3. A third way is specific to the TightVNC vncviewer special option
-   -via for gateways. The only tricky part is we need to start up x11vnc
-   and give it some time (5 seconds in this example) to start listening
-   for connections (so we cannot use the TightVNC default setting for
-   VNC_VIA_CMD):
-#!/bin/sh
-# usage: x11vnc_ssh <host>:<xdisplay>
-#  e.g.: x11vnc_ssh snoopy.peanuts.com:0
-
-host=`echo $1 | awk -F: '{print $1}'`
-disp=`echo $1 | awk -F: '{print $2}'`
-if [ "x$disp" = "x" ]; then disp=0; fi
-
-VNC_VIA_CMD="ssh -f -t -L %L:%H:%R %G x11vnc -localhost -rfbport 5900 -display
-:$disp; sleep 5"
-export VNC_VIA_CMD
-
-vncviewer -via $host localhost:0      # must be TightVNC vncviewer.
-
-   Of course if you already have the x11vnc running waiting for
-   connections (or have it started out of inetd(8)), you can simply use
-   the TightVNC "vncviewer -via gateway host:port" in its default mode to
-   provide secure ssh tunnelling.
-     _________________________________________________________________
-
-
-
-   VNC password file: Also note in the #1. example script that the option
-   "-rfbauth .vnc/passwd" provides additional protection by requiring a
-   VNC password for every VNC viewer that connects. The vncpasswd or
-   storepasswd programs, or the x11vnc -storepasswd option can be used to
-   create the password file. x11vnc also has the slightly less secure
-   -passwdfile and "-passwd XXXXX" options to specify passwords.
-
-   Very Important: It is up to YOU to tell x11vnc to use password
-   protection (-rfbauth or -passwdfile), it will NOT do it for you
-   automatically or force you to (use -usepw if you want to be forced
-   to.) The same goes for encrypting the channel between the viewer and
-   x11vnc: it is up to you to use ssh, stunnel, -ssl mode, a VPN, etc.
-   (use the Enhanced TightVNC Viewer (SSVNC) GUI if you want to be forced
-   to use SSL or SSH.) For additional safety, also look into the -allow
-   and -localhost options and building x11vnc with tcp_wrappers support
-   to limit host access.
-
-     _________________________________________________________________
-
-    Tunnelling x11vnc via SSL/TLS:
-
-   One can also encrypt the VNC traffic using an SSL/TLS tunnel such as
-   stunnel.mirt.net (also stunnel.org) or using the built-in (Mar/2006)
-   -ssl openssl mode. A SSL-enabled Java applet VNC Viewer is also
-   provided in the x11vnc package (and https can be used to download it.)
-
-   Although not as ubiquitous as ssh, SSL tunnelling still provides a
-   useful alternative. See this FAQ on -ssl and -stunnel modes for
-   details and examples.
-
-   The Enhanced TightVNC Viewer (SSVNC) bundles contain some convenient
-   utilities to automatically set up an SSL tunnel from the viewer-side
-   (i.e. to connect to "x11vnc -ssl ...".) And many other enhancements
-   too.
-     _________________________________________________________________
-
-    Downloading x11vnc:
-
-   x11vnc is a contributed program to the LibVNCServer project at
-   SourceForge.net. I use libvncserver for all of the VNC aspects; I
-   couldn't have done without it. The full source code may be found and
-   downloaded (either file-release tarball or GIT tree) from the above
-   link. As of Sep 2010, the x11vnc-0.9.12.tar.gz source package is
-   released (recommended download). The x11vnc 0.9.12 release notes.
-
-   The x11vnc package is the subset of the libvncserver package needed to
-   build the x11vnc program. Also, you can get a copy of my latest,
-   bleeding edge x11vnc-0.9.13-dev.tar.gz tarball to build the most up to
-   date one.
-
-   Precompiled Binaries/Packages:  See the FAQ below for information
-   about where you might obtain a precompiled x11vnc binary from 3rd
-   parties and some ones I create.
-
-   VNC Viewers:  To obtain VNC viewers for the viewing side (Windows, Mac
-   OS, or Unix) try these links:
-     * http://www.tightvnc.com/download.html
-     * http://www.realvnc.com/download-free.html
-     * http://sourceforge.net/projects/cotvnc/
-     * http://www.ultravnc.com/
-     * Our Enhanced TightVNC Viewer (SSVNC)
-
-       [ssvnc.gif]
-
-
-   More tools: Here is a ssh/rsh wrapper script rx11vnc that attempts to
-   automatically do the above Steps 1-3 for you (provided you have
-   ssh/rsh login permission on the machine x11vnc is to be run on.) The
-   above example would be: "rx11vnc far-away.east:0" typed into a shell
-   on sitting-here.west. Also included is an experimental script
-   rx11vnc.pl that attempts to tunnel the vnc traffic through an ssh port
-   redirection (and does not assume port 5900 is free.) Have a look at
-   them to see what they do and customize as needed:
-     * rx11vnc wrapper script
-     * rx11vnc.pl wrapper script to tunnel traffic thru ssh
-
-     _________________________________________________________________
-
-    Building x11vnc:
-
-   Make sure you have all the needed build/compile/development packages
-   installed (e.g. Linux distributions foolishly don't install them by
-   default.) See this build FAQ for more details.
-
-   If your OS has libjpeg.so and libz.so in standard locations you can
-   build as follows (example given for the 0.9.12 release of x11vnc:
-   replace with the version you downloaded):
-(un-tar the x11vnc+libvncserver tarball)
-# gzip -dc x11vnc-0.9.12.tar.gz | tar -xvf -
-
-(cd to the source directory)
-# cd x11vnc-0.9.12
-
-(run configure and then run make)
-# ./configure
-# make
-
-(if all went OK, copy x11vnc to the desired destination, e.g. $HOME/bin)
-# cp ./x11vnc/x11vnc $HOME/bin
-
-   Or do make install, it will probably install to /usr/local/bin (run
-   ./configure --help for information on customizing your configuration,
-   e.g. --prefix=/my/place.) You can now run it via typing "x11vnc",
-   "x11vnc -help | more", "x11vnc -forever -shared -display :0", etc.
-
-
-   Note: Currently gcc is recommended to build libvncserver. In some
-   cases it will build with non-gcc compilers, but the resulting binary
-   sometimes fails to run properly. For Solaris pre-built gcc binaries
-   are at http://www.sunfreeware.com/. Some Solaris pre-built x11vnc
-   binaries are here.
-
-   However, one user reports it does work fine when built with Sun Studio
-   10, so YMMV. In fact, here is a little build script to do this on
-   Solaris 10:
-#!/bin/sh
-PATH=/usr/ccs/bin:/opt/SUNWspro/bin:$PATH; export PATH
-
-CC='cc' \
-CFLAGS='-xO4' \
-LDFLAGS='-L/usr/sfw/lib -L/usr/X11/lib -R/usr/sfw/lib -R/usr/X11/lib' \
-CPPFLAGS='-I /usr/sfw/include -I/usr/X11/include' \
-./configure
-
-MAKE="make -e"
-AM_CFLAGS=""
-export MAKE AM_CFLAGS
-$MAKE
-
-   In general you can use the "make -e" trick if you don't like
-   libvncserver's choice of AM_CFLAGS. See the build scripts below for
-   more ideas. Scripts similar to the above have been shown to work with
-   vendor C compilers on HP-UX (ccom: HP92453-01) and Tru64 (Compaq C
-   V6.5-011.)
-
-   You can find information on Misc. Build problems here.
-
-     _________________________________________________________________
-
-   Building on Solaris, FreeBSD, etc:   Depending on your version of
-   Solaris or other Unix OS the jpeg and/or zlib libraries may be in
-   non-standard places (e.g. /usr/local, /usr/sfw, /opt/sfw, etc.)
-
-   Note: If configure cannot find these two libraries then TightVNC and
-   ZRLE encoding support will be disabled, and you don't want that!!! The
-   TightVNC encoding gives very good compression and performance, it even
-   makes a noticeable difference over a fast LAN.
-
-
-   Shortcuts: On Solaris 10 you can pick up almost everything just by
-   insuring that your PATH has /usr/sfw/bin (for gcc) and /usr/ccs/bin
-   (for other build tools), e.g.:
-  env PATH=/usr/sfw/bin:/usr/ccs/bin:$PATH sh -c './configure; make'
-
-   (The only thing this misses is /usr/X11/lib/libXrandr.so.2, which is
-   for the little used -xrandr option, see the script below to pick it up
-   as well.)
-
-
-   libjpeg is included in Solaris 9 and later (/usr/sfw/include and
-   /usr/sfw/lib), and zlib in Solaris 8 and later (/usr/include and
-   /usr/lib.) So on Solaris 9 you can pick up everything with something
-   like this:
-  env PATH=/usr/local/bin:/usr/ccs/bin:$PATH sh -c './configure --with-jpeg=/us
-r/sfw; make'
-
-   assuming your gcc is in /usr/local/bin and x11vnc 0.7.1 or later.
-   These are getting pretty long, see those assignments split up in the
-   build script below.
-
-
-   If your system does not have these libraries at all you can get the
-   source for the libraries to build them: libjpeg is available at
-   ftp://ftp.uu.net/graphics/jpeg/ and zlib at http://www.gzip.org/zlib/.
-   See also http://www.sunfreeware.com/ for Solaris binary packages of
-   these libraries as well as for gcc. Normally they will install into
-   /usr/local but you can install them anywhere with the
-   --prefix=/path/to/anywhere, etc.
-
-
-   Here is a build script that indicates one way to pass the library
-   locations information to the libvncserver configuration via the
-   CPPFLAGS and LDFLAGS environment variables.
----8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8
-<---
-#!/bin/sh
-
-# Build script for Solaris, etc, with gcc, libjpeg and libz in
-# non-standard locations.
-
-# set to get your gcc, etc:
-#
-PATH=/path/to/gcc/bin:/usr/ccs/bin:/usr/sfw/bin:$PATH
-
-JPEG=/path/to/jpeg      # set to maybe "/usr/local", "/usr/sfw", or "/opt/sfw"
-ZLIB=/path/to/zlib      # set to maybe "/usr/local", "/usr/sfw", or "/opt/sfw"
-
-# Below we assume headers in $JPEG/include and $ZLIB/include and the
-# shared libraries are in $JPEG/lib and $ZLIB/lib.  If your situation
-# is different change the locations in the two lines below.
-#
-CPPFLAGS="-I $JPEG/include -I $ZLIB/include"
-LDFLAGS="-L$JPEG/lib -R $JPEG/lib -L$ZLIB/lib -R $ZLIB/lib"
-
-# These two lines may not be needed on more recent Solaris releases:
-#
-CPPFLAGS="$CPPFLAGS -I /usr/openwin/include"
-LDFLAGS="$LDFLAGS -L/usr/openwin/lib -R /usr/openwin/lib"
-
-# These are for libXrandr.so on Solaris 10:
-#
-CPPFLAGS="$CPPFLAGS -I /usr/X11/include"
-LDFLAGS="$LDFLAGS -L/usr/X11/lib -R /usr/X11/lib"
-
-# Everything needs to built with _REENTRANT for thread safe errno:
-#
-CPPFLAGS="$CPPFLAGS -D_REENTRANT"
-
-export PATH CPPFLAGS LDFLAGS
-
-./configure
-make
-
-ls -l ./x11vnc/x11vnc
-
----8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8
-<---
-
-   Then do make install or copy the x11vnc binary to your desired
-   destination.
-
-   BTW, To run a shell script, just cut-and-paste the above into a file,
-   say "myscript", then modify the "/path/to/..." items to correspond to
-   your system/environment, and then type: "sh myscript" to run it.
-
-   Note that on Solaris make is /usr/ccs/bin/make, so that is why the
-   above puts /usr/ccs/bin in PATH. Other important build utilities are
-   there too: ld, ar, etc. Also, it is probably a bad idea to have
-   /usr/ucb in your PATH while building.
-
-   Starting with the 0.7.1 x11vnc release the "configure --with-jpeg=DIR
-   --with-zlib=DIR" options are handy if you want to avoid making a
-   script.
-
-   If you need to link OpenSSL libssl.a on Solaris see this method.
-
-   If you need to build on Solaris 2.5.1 or earlier or other older Unix
-   OS's, see this workaround FAQ.
-
-
-   Building on FreeBSD, OpenBSD, ...:   The jpeg libraries seem to be in
-   /usr/local or /usr/pkg on these OS's. You won't need the openwin stuff
-   in the above script (but you may need /usr/X11R6/....) Also starting
-   with the 0.7.1 x11vnc release, this usually works:
-  ./configure --with-jpeg=/usr/local
-  make
-
-
-   Building on HP-UX:   For jpeg and zlib you will need to do the same
-   sort of thing as described above for Solaris. You set CPPFLAGS and
-   LDFLAGS to find them (see below for an example.) You do not need to do
-   any of the above /usr/openwin stuff. Also, HP-UX does not seem to
-   support -R, so get rid of the -R items in LDFLAGS. Because of this, at
-   runtime you may need to set LD_LIBRARY_PATH or SHLIB_PATH to indicate
-   the directory paths so the libraries can be found. It is a good idea
-   to have static archives, e.g. libz.a and libjpeg.a for the nonstandard
-   libraries so that they get bolted into the x11vnc binary (and so won't
-   get "lost".)
-
-   Here is what we recently did to build x11vnc 0.7.2 on HP-UX 11.11
-./configure --with-jpeg=$HOME/hpux/jpeg --with-zlib=$HOME/hpux/zlib
-make
-
-   Where we had static archives (libjpeg.a, libz.a) only and header files
-   in the $HOME/hpux/... directories as discussed for the build script.
-
-   On HP-UX 11.23 and 11.31 we have had problems compiling with gcc.
-   "/usr/include/rpc/auth.h:87: error: field 'syncaddr' has incomplete
-   type". As a workaround for x11vnc 0.9.4 and later set your CPPFLAGS to
-   include:
-  CPPFLAGS="-DIGNORE_GETSPNAM"
-  export CPPFLAGS
-
-   This disables a very rare usage mode for -unixpw_nis by not trying
-   getspnam(3).
-
-   Using HP-UX's C compiler on 11.23 and 11.31 we have some severe
-   compiler errors that have not been worked around yet. If you need to
-   do this, contact me and I will give you a drastic recipe that will
-   produce a working binary.
-
-
-   Building on AIX:   AIX: one user had to add the "X11.adt" package to
-   AIX 4.3.3 and 5.2 to get build header files like XShm.h, etc. You may
-   also want to make sure that /usr/lpp/X11/include, etc is being picked
-   up by the configure and make.
-
-   For a recent build on AIX 5.3 we needed to add these CFLAGS to be able
-   to build with gcc:
-  env CFLAGS='-maix64 -Xlinker -bbigtoc' ./configure ...
-
-   we also built our own libjpeg and libz using -maix64.
-
-   BTW, one way to run an Xvfb-like virtual X server for testing on AIX
-   is something like "/usr/bin/X11/X -force -vfb -ac :1".
-
-
-   Building on Mac OS X:   There is now native Mac OS X support for
-   x11vnc by using the raw framebuffer feature. This mode does not use or
-   need X11 at all. To build you may need to disable X11:
-./configure --without-x ...
-make
-
-   However, if your system has the Mac OS X build package for X11 apps
-   you will not need to supply the "--without-x" option (in this case the
-   resulting x11vnc would be able to export both the native Mac OS X
-   display and windows displayed in the XDarwin X server.) Be sure to
-   include the ./configure option to find libjpeg on your system.
-
-
-   OpenSSL:   Starting with version 0.8.3 x11vnc can now be built with
-   SSL/TLS support. For this to be enabled the libssl.so library needs to
-   be available at build time. So you may need to have additional
-   CPPFLAGS and LDFLAGS items if your libssl.so is in a non-standard
-   place. As of x11vnc 0.9.4 there is also the --with-ssl=DIR configure
-   option.
-
-   On Solaris using static archives libssl.a and libcrypto.a instead of
-   .so shared libraries (e.g. from www.sunfreeware.com), we found we
-   needed to also set LDFLAGS as follows to get the configure to work:
-env LDFLAGS='-lsocket -ldl' ./configure --with-ssl=/path/to/openssl ...
-make
-
-     _________________________________________________________________
-
-    Beta Testing:
-
-   I don't have any formal beta-testers for the releases of x11vnc, so
-   I'd appreciate any additional testing very much.
-
-   Thanks to those who suggested features and helped beta test x11vnc
-   0.9.12 released in Sep 2010!
-
-   Please help test and debug the 0.9.13 version for release sometime in
-   Winter 2010.
-
-   The version 0.9.13 beta tarball is kept here:
-   x11vnc-0.9.13-dev.tar.gz
-
-   There are also some Linux, Solaris, Mac OS X, and other OS test
-   binaries here. Please kick the tires and report bugs, performance
-   regressions, undesired behavior, etc. to me.
-
-   To aid testing of the built-in SSL/TLS support for x11vnc, a number of
-   VNC Viewer packages for Unix, Mac OS X, and Windows have been created
-   that provide SSL Support for the TightVNC Viewer (this is done by
-   wrapper scripts and a GUI that starts STUNNEL.) It should be pretty
-   convenient for automatic SSL and SSH connections. It is described in
-   detail at and can be downloaded from the Enhanced TightVNC Viewer
-   (SSVNC) page. The SSVNC Unix viewer also supports x11vnc's symmetric
-   key encryption ciphers (see the 'UltraVNC DSM Encryption Plugin'
-   settings panel.)
-
-
-   Here are some features that will appear in the 0.9.13 release:
-     * Improved support for non-X11 touchscreen devices (e.g. handheld or
-       cell phone) via Linux uinput input injection. Additional tuning
-       parameters are added. TSLIB touchscreen calibration is supported.
-       Tested on Qtmoko Neo Freerunner. A tool, misc/uinput.pl, is
-       provided to diagnose uinput behavior on new devices. The env.
-       vars. X11VNC_UINPUT_BUS and X11VNC_UINPUT_VERSION are available if
-       leaving them unset does not work.
-     * The Linux uinput non-X11 input injection can now be bypassed:
-       events can be directly written to the /dev/input/event devices
-       specified by the user (direct_abs=..., etc.) A -pipeinput input
-       injection helper script, misc/qt_tslib_inject.pl is provided as a
-       tweakable non-builtin direct input injection method.
-     * The list of new uinput parameters for the above two features is:
-       pressure, tslib_cal, touch_always, dragskip, btn_touch;
-       direct_rel, direct_abs, direct_btn, direct_key.
-     * The MacOSX native server can now use OpenGL for the screen
-       capture. In nearly all cases this is faster than the raw
-       framebuffer capture method. There are build and run time flags,
-       X11VNC_MACOSX_NO_DEPRECATED, etc. to disable use of deprecated
-       input injection and screen access interfaces. Cursor shape now
-       works for 64bit binaries.
-     * The included SSL enabled Java VNC Viewers now handle Mouse Wheel
-       events.
-     * miscellaneous new features and changes:
-     * In -reflect mode, the libvncclient connection can now have the
-       pixel format modified via the environment variables
-       X11VNC_REFLECT_bitsPerSample, X11VNC_REFLECT_samplesPerPixel, and
-       X11VNC_REFLECT_bytesPerPixel
-     * In -create mode the following environment variables are added to
-       fine tune the behavior: FIND_DISPLAY_NO_LSOF: do not use lsof(1)
-       to try to determine the Linux VT, FIND_DISPLAY_NO_VT_FIND: do not
-       try to determine the Linux VT at all, X11VNC_CREATE_LC_ALL_C_OK:
-       do not bother undoing the setting LC_ALL=C that the create_display
-       script sets. The performance of the -create script has been
-       improved for large installations (100's of user sessions on one
-       machine.)
-     * In -unixpw mode, one can now Tab from login: to Password.
-     * An environment variable, X11VNC_SB_FACTOR, allows one to scale the
-       -sb screenblank sleep time from the default 2 secs.
-     * An experimental option -unixsock is available for testing. Note,
-       however, that it requires a manual change to
-       libvncserver/rfbserver.c for it to work.
-     * Documented that -grabkbd is no longer working with some/most
-       window managers (it can prevent resizing and menu posting.)
-
-
-   Here are some features that appeared in the 0.9.12 release (Sep/2010):
-     * One can now specify the maximum number of displays that can be
-       created in -create mode via the env. var.
-       X11VNC_CREATE_MAX_DISPLAYS
-     * The X11VNC_NO_LIMIT_SHM env. var. is added to skip any automatic
-       shared memory reduction.
-     * The kdm display manager is now detected when trying not to get
-       killed by the display manager.
-     * A compile time bug is fixed so that configuring using
-       --with-system-libvncserver pointing to LibVNCServer 0.9.7 works
-       again. A bug from forced use of Xdefs.h is worked around.
-
-
-   Here are some features that appeared in the 0.9.11 release (Aug/2010):
-     * The source tree is synchronized with the most recent libvncclient
-       (this only affects -reflect mode.) Build is fixed for
-       incompatibilities when using an external LibVNCServer (e.g.
-       ./configure --with-system-libvncserver...) Please help test these
-       build and runtime aspects and report back what you find, thanks.
-     * The SSL enabled Java VNC Viewer Makefile has been modified so that
-       the jar files that are built are compatible back to Java 1.4.
-     * In -create/-unixpw mode, the env. var. FD_USERPREFS may be set to
-       a filename in the user's home directory that includes default
-       username:options values (so the options do not need to be typed
-       every time at the login prompt.)
-     * In -reflect mode cursor position updates are now handled
-       correctly.
-
-
-   Here are some features that appeared in the 0.9.10 release (May/2010):
-     * The included SSL enabled Java applet viewer now supports Chained
-       SSL Certificates. The debugCerts=yes applet parameter aids
-       troubleshooting certificate validation. The x11vnc -ssl mode has
-       always supported chained SSL certificates (simply put the
-       intermediate certificates, in order, after the server certificate
-       in the pem file.)
-     * A demo CGI script desktop.cgi shows how to create an SSL
-       encrypted, multi-user x11vnc web login desktop service. The script
-       requires x11vnc version 0.9.10. The user logs into a secure web
-       site and gets his/her own virtual desktop (Xvfb.) x11vnc's SSL
-       enabled Java Viewer Applet is launched by the web browser for
-       secure viewing (and so no software needs to be installed on the
-       viewer-side.) One can use the desktop.cgi script for ideas to
-       create their own fancier or customized web login desktop service
-       (e.g. user-creation, PHP, SQL, specialized desktop application,
-       etc.) More info here. There is also an optional 'port redirection'
-       mode that allows redirection to other SSL enabled VNC servers
-       running inside the firewall.
-     * Built-in support for IPv6 (128 bit internet addresses) is now
-       provided. See the -6 and -connect options for details.
-       Additionally, in case there are still problems with built-in IPv6
-       support, a transitional tool is provided in inet6to4 that allows
-       x11vnc (or any other IPv4 application) to receive connections over
-       IPv6.
-     * The Xdummy wrapper script for Xorg's dummy driver is updated and
-       no longer requires being run as root. New service options are
-       provided to select Xdummy over Xvfb as the virtual X server to be
-       created.
-     * The "%" unix password verification tricks for the -unixpw option
-       are now documented. They have also been extended to run a command
-       as the user if one sets the environment variable UNIXPW_CMD. The
-       desktop.cgi demo script takes advantage of this new feature.
-     * A bug has been fixed that would prevent the Java applet viewer
-       from being downloaded successfully in single-port HTTPS/VNC inetd
-       mode. The env. var. X11VNC_HTTPS_DOWNLOAD_WAIT_TIME can be used to
-       adjust for how many seconds a -inetd or -https httpd download is
-       waited for (default 15 seconds.) The applet will now autodetect
-       x11vnc and use GET=1 for faster connecting. Many other
-       improvements and fixes.
-     * The TightVNC security type (TightVNC features enabler) now works
-       for RFB version 3.8.
-     * The X property X11VNC_TRAP_XRANDR can be set on a desktop to force
-       x11vnc to use the -xrandr screen size change trapping code.
-     * New remote control query options: pointer_x, pointer_y,
-       pointer_same, pointer_root, and pointer_mask. A demo script using
-       them misc/panner.pl is provided.
-     * The -sslScripts option prints out the SSL certificate management
-       scripts.
-
-
-   Here are some features that appeared in the 0.9.9 release (Dec/2009):
-     * The -unixpw_system_greeter option, when used in combined unixpw
-       and XDMCP FINDCREATEDISPLAY mode (for example: -xdmsvc), enables
-       the user to press Escape to jump directly to the XDM/GDM/KDM login
-       greeter screen. This way the user avoids entering his unix
-       password twice at X session creation time. Also, the unixpw login
-       panel now has a short help displayed if the user presses 'F1'.
-     * x11vnc now tries to be a little bit more aggressive in keeping up
-       with VNC client's framebuffer update requests. Some broken VNC
-       clients like Eggplant and JollysFastVNC continuously spray these
-       requests at VNC servers (regardless of whether they have received
-       any updates or not.) Under some circumstances this could lead to
-       x11vnc falling behind. The -extra_fbur option allows one to fine
-       tune the setting. Additionally, one may also dial down delays:
-       e.g. "-defer 5" and "-wait 5" (or to 1 or even 0) or -nonap or
-       -allinput to keep up with these VNC clients at the expense of
-       increased system load.
-     * Heuristics are applied to try to determine if the X display is
-       currently in a Display Manager Greeter Login panel (e.g. GDM) If
-       so, x11vnc's creation of any windows and use of XFIXES are
-       delayed. This is to try to avoid x11vnc being killed after the
-       user logs in if the GDM KillInitClients=true is in effect. So one
-       does not need to set KillInitClients=false. Note that in recent
-       GDM the KillInitClients option has been removed. Also delayed is
-       the use of the XFIXES cursor fetching functionality; this avoids
-       an Xorg bug that causes Xorg to crash right after the user logs
-       in.
-     * A new option -findauth runs the FINDDISPLAY script that applies
-       heuristics that try to determine the XAUTHORITY file. The use of
-       '-auth guess' will use the XAUTHORITY that -findauth reveals. This
-       can be handy in with the lastest GDM where the ability to store
-       cookies in ~/.Xauthority has been removed. If x11vnc is running as
-       root (e.g. inetd) and you add -env FD_XDM=1 to the above -findauth
-       or -auth guess command lines, it will find the correct XAUTHORITY
-       for the given display (this works for XDM/GDM/KDM if the login
-       greeter panel is up or if someone has already logged into an X
-       session.)
-     * The FINDDISPLAY and FINDCREATEDISPLAY modes (i.e. "-display
-       WAIT:cmd=...", -find, -create) now work correctly for the
-       user-supplied login program scheme "-unixpw_cmd ...", as long as
-       the login program supports running commands specified in the
-       environment variable "RFB_UNIXPW_CMD_RUN" as the logged-in user.
-       The mode "-unixpw_nis ..." has also been made more consistent.
-     * The -stunnel option (like -ssl but uses stunnel as an external
-       helper program) now works with the -ssl "SAVE" and "TMP" special
-       certificate names. The -sslverify and -sslCRL options now work
-       correctly in -stunnel mode. Single port HTTPS connections are also
-       supported for this mode.
-     * There is an experimental Application Sharing mode that improves
-       upon the -id/-sid single window sharing: -appshare (run "x11vnc
-       -appshare -help" for more info.) It is still very primitive and
-       approximate, but at least it displays multiple top-level windows.
-     * The remote control command -R can be used to instruct x11vnc to
-       resend its most recent copy of the Clipboard, Primary, or
-       Cutbuffer selections: "x11vnc -R resend_clipboard", "x11vnc -R
-       resend_primary", and "x11vnc -R resend_cutbuffer".
-     * The fonts in the GUI (-gui) can now by set via environment
-       variables, e.g. -env X11VNC_FONT_BOLD='Helvetica -16 bold' and
-       -env X11VNC_FONT_FIXED='Courier -14'.
-     * The XDAMAGE mechanism is now automatically disabled for a period
-       of time if a game or screensaver generates too many XDAMAGE
-       rectangles per second. This avoids the X11 event queue from
-       soaking up too much memory.
-     * There is an experimental workaround: "-env X11VNC_WATCH_DX_DY=1"
-       that tries to avoid problems with poorly constructed menu themes
-       that place the initial position of the mouse cursor inside a menu
-       item's active zone. More information can be found here.
-
-
-   Here are some features that appeared in the 0.9.8 release (Jul/2009):
-     * Stability improvements to -threads mode. Running x11vnc this way
-       is more reliable now. Threaded operation sometimes gives better
-       interactive response and faster updates: try it out. The threaded
-       mode now supports multiple VNC viewers using the same VNC
-       encoding. The threaded mode can also yield a performance
-       enhancement in the many client case (e.g. class-room broadcast.)
-       We have tested with 30 to 50 simultaneous clients. See also
-       -reflect.
-       For simultaneous clients: the ZRLE encoding is thread safe on all
-       platforms, and the Tight and Zlib encodings are currently only
-       thread safe on Linux where thread local storage, __thread, is
-       used. If your non-Linux system and compiler support __thread one
-       can supply -DTLS=__thread to enable it. When there is only one
-       connected client, all encodings are safe on all platforms. Note
-       that some features (e.g. scroll detection and -ncache) may be
-       disabled or run with reduced functionality in -threads mode.
-     * Automatically tries to work around an Xorg server and GNOME bug
-       involving infinitely repeating keys when turning off key
-       repeating. Use -repeat if the automatic workaround fails.
-     * Improved reliability of the Single Port SSL VNC and HTTPS java
-       viewer applet delivery mechanism.
-     * The -clip mode works under -rawfb.
-
-
-   Here are some features that appeared in the 0.9.7 release (Mar/2009):
-     * Support for polling Linux Virtual Terminals (also called virtual
-       consoles) directly instead of using /dev/fb. The option to use is,
-       for example, "-rawfb vt2" for Virtual Terminal 2, etc. In this
-       case the special file /dev/vcsa2 is used to retrieve vt2's current
-       text. Text and colors are shown, but no graphics.
-     * Support for less than 8 bits per pixel framebuffers (e.g. 4 or 1
-       bpp) in the -rawfb mode.
-     * The SSL enabled UltraVNC Java viewer applet now has a [Home] entry
-       in the "drives" drop down menu. This menu can be configured with
-       the ftpDropDown applet parameter. All of the applet parameters are
-       documented in classes/ssl/README.
-     * Experimental support for VirtualGL's TurboVNC (an enhanced
-       TightVNC for fast LAN high framerate usage.)
-     * The CUPS Terminal Services helper mode has been improved.
-     * Improvements to the -ncache_cr that allows smooth opaque window
-       motions using the 'copyrect' encoding when using -ncache mode.
-     * The -rmflag option enables a way to indicate to other processes
-       x11vnc has exited.
-     * Reverse connections using anonymous Diffie Hellman SSL encryption
-       now work.
-
-
-   Here are some features that appeared in the 0.9.6 release (Dec/2008):
-     * Support for VeNCrypt SSL/TLS encrypted connections. It is enabled
-       by default in the -ssl mode. VNC Viewers like vinagre,
-       gvncviewer/gtk-vnc, the vencrypt package, SSVNC, and others
-       support this encryption mode. It can also be used with the -unixpw
-       option to enable Unix username and password authentication
-       (VeNCrypt's "*Plain" modes.) A similar but older VNC security type
-       "ANONTLS" (used by vino) is supported as well. See the -vencrypt
-       and -anontls options for additional control. The difference
-       between x11vnc's normal -ssl mode and VeNCrypt is that the former
-       wraps the entire VNC connection in SSL (like HTTPS does for HTTP,
-       i.e. "vncs://") while VeNCrypt switches on the SSL/TLS at a
-       certain point during the VNC handshake. Use -sslonly to disable
-       both VeNCrypt and ANONTLS (vino.)
-     * The "-ssl ANON" option enables Anonymous Diffie-Hellman (ADH) key
-       exchange for x11vnc's normal SSL/TLS operation. Note that
-       Anonymous Diffie-Hellman uses encryption for privacy, but provides
-       no authentication and so is susceptible to Man-In-The-Middle
-       attacks (and so we do not recommend it: we prefer you use "-ssl
-       SAVE", etc. and have the VNC viewer verify the cert.) The ANONTLS
-       mode (vino) only supports ADH. VeNCrypt mode supports both ADH and
-       regular X509 SSL certificates modes. For these ADH is enabled by
-       default. See -vencrypt and -anontls for how to disable ADH.
-     * For x11vnc's SSL/TLS modes, one can now specify a Certificate
-       Revocation List (CRL) with the -sslCRL option. This will only be
-       useful for wide deployments: say a company-wide x11vnc SSL access
-       deployment using a central Certificate Authority (CA) via
-       -sslGenCA and -sslGenCert. This way if a user has his laptop lost
-       or stolen, you only have to revoke his key instead of creating a
-       new Certificate Authority and redeploying new keys to all users.
-     * The default SSL/TLS mode, "-ssl" (no pem file parameter supplied),
-       is now the same as "-ssl SAVE" and will save the generated
-       self-signed cert in "~/.vnc/certs/server.pem". Previously "-ssl"
-       would create a temporary self-signed cert that was discarded when
-       x11vnc exited. The reason for the change is to at least give the
-       chance for the VNC Viewer side (e.g. SSVNC) to remember the cert
-       to authenticate subsequent connections to the same x11vnc server.
-       Use "-ssl TMP" to regain the previous behavior. Use "-ssl
-       SAVE_NOPROMPT" to avoid being prompted about using passphrase when
-       the certificate is created.
-     * The option -http_oneport enables single-port HTTP connections via
-       the Java VNC Viewer. So, for example, the web browser URL
-       "http://myhost.org:5900" works the same as
-       "http://myhost.org:5800", but with the convenience of only
-       involving one port instead of two. This works for both unencrypted
-       connections and for SSH tunnels (see -httpsredir if the tunnel
-       port differs.) Note that HTTPS single-port operation in -ssl SSL
-       encrypted mode has been available since x11vnc version 0.8.3.
-     * For the -avahi/-zeroconf Service Advertizing mode, if x11vnc was
-       not compiled with the avahi-client library, then an external
-       helper program, either avahi-publish(1) (on Unix) or dns-sd(1) (on
-       Mac OS X), is used instead.
-     * The "-rfbport PROMPT" option will prompt the user via the GUI to
-       select the VNC port (e.g. 5901) to listen on, and a few other
-       basic settings. This enables a handy GUI mode for naive users:
-   x11vnc -gui tray=setpass -rfbport PROMPT -logfile $HOME/.x11vnc.log.%VNCDISP
-LAY
-       suitable for putting in a launcher or menu, e.g. x11vnc.desktop.
-       The -logfile expansion is new too. In the GUI, the tray=setpass
-       Properties panel has been improved.
-     * The -solid solid background color option now works for the Mac OS
-       X console.
-     * The -reopen option instructs x11vnc to try to reopen the X display
-       if it is prematurely closed by, say, the display manager (e.g.
-       GDM.)
-
-
-   Here are some features that appeared in the 0.9.5 release (Oct/2008):
-     * Symmetric key encryption ciphers. ARC4, AES-128, AES-256,
-       blowfish, and 3des are supported. Salt and initialization vector
-       seeding is provided. These compliment the more widely used SSL and
-       SSH encryption access methods. SSVNC also supports these
-       encryption modes.
-     * Scaling differently along the X- and Y-directions. E.g. "-scale
-       1280x1024" or "-scale 0.8x0.75"    Also, "-geometry WxH" is an
-       alias for "-scale WxH"
-     * By having SSVNC version 1.0.21 or later available in your $PATH,
-       the -chatwindow option allows a UltraVNC Text Chat window to
-       appear on the local X11 console/display (this way the remote
-       viewer can chat with the person at the physical display; e.g.
-       helpdesk mode.) This also works on the Mac OS X console if the
-       Xquartz X11 server (enabled by default on leopard) is running for
-       the chatwindow.
-     * The HTTP Java viewer applet jar, classes/VncViewer.jar, has been
-       updated with an improved implementation based on the code used by
-       the classes/ssl applets.
-
-
-   Here are some features that appeared in the 0.9.4 release (Sep/2008):
-     * Improvements to the -find and -create X session finding or
-       creating modes: new desktop types and service redirection options.
-       Personal cupsd daemon and SSH port redirection helper for use with
-       SSVNC's Terminal Services feature.
-     * Reverse VNC connections via -connect work in the -find, -create
-       and related -display WAIT:... modes.
-     * Reverse VNC connections (either normal or SSL) can use a Web Proxy
-       or a SOCKS proxy, or a SSH connection, or even a CGI URL to make
-       the outgoing connection. See: -proxy. Forward connections can also
-       use: -ssh.
-     * Reverse VNC connections via the UltraVNC repeater proxy (either
-       normal or SSL) are supported. Use either the "-connect
-       repeater=ID:NNNN+host:port" or "-connect
-       repeater://host:port+ID:NNNN" notation. The SSVNC VNC viewer also
-       supports the UltraVNC repeater. Also, a perl repeater implemention
-       is here: ultravnc_repeater.pl
-     * Support for indexed colormaps (PseudoColor) with depths other than
-       8 (from 1 to 16 now work) for non-standard hardware. Option
-       "-advertise_truecolor" to handle some workaround in this mode.
-     * Support for the ZYWRLE encoding, this is the RealVNC ZRLE encoding
-       extended to do motion video and photo regions more efficiently by
-       way of a Wavelet based transformation.
-     * The -finddpy and -listdpy utilities help to debug and configure
-       the -find, -create, and -display WAIT:... modes.
-     * Some automatic detection of screen resizes are handled even if the
-       -xrandr option is not supplied.
-     * The -autoport options gives more control over the VNC port x11vnc
-       chooses.
-     * The -ping secs can be used to help keep idle connections alive.
-     * Pasting of the selection/clipboard into remote applications (e.g.
-       Java) has been improved.
-     * Fixed a bug if a client disconnects during the 'speed-estimation'
-       phase.
-     * To unset Caps_Lock, Num_Lock and raise all keys in the X server
-       use -clear_all.
-     * Usage with dvorak keyboards has been improved. See also: -xkb.
-     * The Java Viewer applet source code is now included in the
-       x11vnc-0.9.*.tar.gz tarball. This means you can now build the Java
-       viewer applet jar files from source. If you stopped shipping the
-       Java viewer applet jar files due to lack of source code, you can
-       start again.
-
-
-   Here are some features that appeared in the 0.9.3 release (Oct/2007):
-     * Viewer-side pixmap caching. A large area of pixels (at least 2-3
-       times as big as the framebuffer itself; the bigger the better...
-       default is 10X) is placed below the framebuffer to act as a
-       buffer/cache area for pixel data. The VNC CopyRect encoding is
-       used to move it around, so any viewer can take advantage of it.
-       Until we start modifying viewers you will be able to see the cache
-       area if you scroll down (this makes it easier to debug!) For
-       testing the default is "-ncache 10". The unix Enhanced TightVNC
-       Viewer ssvnc has a nice -ycrop option to help hide the pixel cache
-       area from view.
-
-
-   Here are some features that appeared in the 0.9.2 release (Jun/2007):
-     * Building with no OpenSSL libssl available (or with --without-ssl)
-       has been fixed.
-     * One can configure x11vnc via "./configure
-       --with-system-libvncserver" to use a system installed libvncserver
-       library instead of the one bundled in the release tarball.
-     * If UltraVNC file transfer or chat is detected, then VNC clients
-       are "pinged" more often to prevent these side channels from
-       becoming serviced too infrequently.
-     * In -unixpw mode in the username and password dialog no text will
-       be echoed if the first character sent is "Escape". This enables a
-       convenience feature in SSVNC to send the username and password
-       automatically.
-
-
-   Here are some features that appeared in the 0.9.1 release (May/2007):
-     * The UltraVNC Java viewer has been enhanced to support SSL (as the
-       TightVNC viewer had been previously.) The UltraVNC Java supports
-       ultravnc filetransfer, and so can be used as a VNC viewer on Unix
-       that supports ultravnc filetransfer. It is in the
-       classes/ssl/UltraViewerSSL.jar file (that is pointed to by
-       ultra.vnc.) The signed applet SignedUltraViewerSSL.jar version
-       (pointed to by ultrasigned.vnc) will be needed to access the local
-       drive if you are using it for file transfer via a Web browser.
-       Some other bugs in the UltraVNC Java viewer were fixed and a few
-       improvements to the UI made.
-     * A new Unix username login mode for VNC Viewers authenticated via a
-       Client SSL Certificate: "-users sslpeer=". The emailAddress
-       subject field is inspected for username@hostname and then acts as
-       though "-users +username" has been supplied. This way the Unix
-       username is identified by (i.e. simply extracted from) the Client
-       SSL Certificate. This could be useful with -find, -create and -svc
-       modes if you are also have set up and use VNC Client SSL
-       Certificate authentication.
-     * For external display finding/creating programs (e.g. WAIT:cmd=...)
-       if the VNC Viewer is authenticated via a Client SSL Certificate,
-       then that Certificate is available in the environment variable
-       RFB_SSL_CLIENT_CERT.
-
-
-   Here are some features that appeared in the 0.9 release (Apr/2007):
-     * VNC Service advertising via mDNS / ZeroConf / BonJour with the
-       Avahi client library. Enable via "-avahi" or "-zeroconf".
-     * Implementations of UltraVNC's TextChat, SingleWindow, and
-       ServerInput extensions (requires ultravnc viewer or ssvnc Unix
-       viewer.) They toggle the selection of a single window (-id), and
-       disable (friendly) user input and viewing (monitor blank) at the
-       VNC server.
-     * Short aliases "-find", "-create", "-svc", and "-xdmsvc" for
-       commonly used FINDCREATEDISPLAY usage modes.
-     * Reverse VNC connections (viewer listening) now work in SSL (-ssl)
-       mode.
-     * New options to control the Monitor power state and keyboard/mouse
-       grabbing: -forcedpms, -clientdpms, -noserverdpms, and -grabalways.
-     * A simple way to emulate inetd(8) to some degree via the "-loopbg"
-       option.
-     * Monitor the accuracy of XDAMAGE and apply "-noxdamage" if it is
-       not working well. OpenGL applications like like beryl and MythTv
-       have been shown to make XDAMAGE not work properly.
-     * For Java SSL connections involving a router/firewall port
-       redirection, an option -httpsredir to spare the user from needing
-       to include &PORT=NNN in the browser URL.
-
-
-   Here are some features that appeared in the 0.8.4 release (Feb/2007):
-     * Native Mac OS X Aqua/Quartz support. (i.e. OSXvnc alternative;
-       some activities are faster)
-     * A new login mode: "-display WAIT:cmd=FINDCREATEDISPLAY -unixpw
-       ..." that will Create a new X session (either virtual or real and
-       with or without a display manager, e.g. kdm) for the user if it
-       cannot find the user's X session display via the FINDDISPLAY
-       method. See the -svc and the -xdmsvc aliases.
-     * x11vnc can act as a VNC reflector/repeater using the "-reflect
-       host:N" option. Instead of polling an X display, the remote VNC
-       Server host:N is connected to and re-exported via VNC. This is
-       intended for use in broadcasting a display to many (e.g. > 16;
-       classroom or large demo) VNC viewers where bandwidth and other
-       resources are conserved by spreading the load over a number of
-       repeaters.
-     * Wireframe copyrect detection for local user activity (e.g. someone
-       sitting at the physical display moving windows) Use
-       -nowireframelocal to disable.
-     * The "-N" option couples the VNC Display number to the X Display
-       number. E.g. if your X DISPLAY is :2 then the VNC display will be
-       :2 (i.e. using port 5902.) If that port is taken x11vnc will exit.
-     * Option -nodpms to avoid problems with programs like KDE's
-       kdesktop_lock that keep restarting the screen saver every few
-       seconds.
-     * To automatically fix the common mouse motion problem on XINERAMA
-       (multi-headed) displays, the -xwarppointer option is enabled by
-       default when XINERAMA is active.
-
-   If you have a Mac please try out the native Mac OS X support, build
-   with "./configure --without-x", or download a binary mentioned above,
-   (even if you don't plan on ever using it in this mode!), and let me
-   know how it went. Thanks.
-
-
-   Here are some features that appeared in the 0.8.3 release (Nov/2006):
-     * The -ssl option provides SSL encryption and authentication
-       natively via the www.openssl.org library. One can use from a
-       simple self-signed certificate server certificate up to full CA
-       and client certificate authentication schemes.
-     * Similar to -ssl, the -stunnel option starts up a SSL tunnel server
-       stunnel (that must be installed separately on the system:
-       stunnel.mirt.net ) to allow only encrypted SSL connections from
-       the network.
-     * The -sslverify option allows for authenticating VNC clients via
-       their certificates in either -ssl or -stunnel modes.
-     * Certificate creation and management tools are provide in the
-       -sslGenCert, -sslGenCA, and related options.
-     * An SSL enabled Java applet VNC Viewer applet is provided by x11vnc
-       in classes/ssl/VncViewer.jar. In addition to normal HTTP, the
-       applet may be loaded into the web browser via HTTPS (HTTP over
-       SSL.) (one can use the VNC port, e.g. https://host:5900/, or also
-       the separate -https port option.) A wrapper shell script
-       ss_vncviewer is also provided that sets up a stunnel client-side
-       tunnel on Unix systems. See Enhanced TightVNC Viewer (SSVNC) for
-       other SSL/SSH viewer possibilities.
-     * The -unixpw option supports Unix username and password
-       authentication (a simpler variant is the -unixpw_nis option that
-       works in environments where the encrypted passwords are readable,
-       e.g. NIS.) The -ssl or -localhost + -stunnel options are enforced
-       in this mode to prevent password sniffing. As a convenience, these
-       requirements are lifted if a SSH tunnel can be deduced (but
-       -localhost still applies.)
-     * Coupling -unixpw with "-display WAIT:cmd=FINDDISPLAY" or "-display
-       WAIT:cmd=FINDCREATEDISPLAY" provides a way to allow a user to
-       login with their UNIX password and have their display connected to
-       automatically. See the -svc and the -xdmsvc aliases.
-     * Hooks are provided in the -unixpw_cmd and "-passwdfile
-       cmd:,custom:..." options to allow you to supply your own
-       authentication and password lookup programs.
-     * x11vnc can be configured and built to not depend on X11 libraries
-       "./configure --without-x" for -rawfb only operation (e.g. embedded
-       linux console devices.)
-     * The -rotate option enables you to rotate or reflect the screen
-       before exporting via VNC. This is intended for use on handhelds
-       and other devices where the rotation orientation is not "natural".
-     * The "-ultrafilexfer" alias is provided and improved UltraVNC
-       filetransfer rates have been achieved.
-     * Under the "-connect_or_exit host" option x11vnc will exit
-       immediately unless the reverse connection to host succeeds. The
-       "-rfbport 0" option disables TCP listening for connections (useful
-       for this mode.)
-     * The "-rawfb rand" and "-rawfb none" options are useful for testing
-       automation scripts, etc., without requiring a full desktop.
-     * Reduced spewing of information at startup, use "-verbose" (also
-       "-v") to turn it back on for debugging or if you are going to send
-       me a problem report.
-
-   Here are some Previous Release Notes
-     _________________________________________________________________
-
-    Some Notes:
-
-   Both a client and a server:   It is sometimes confusing to people that
-   x11vnc is both a client and a server at the same time. It is an X
-   client because it connects to the running X server to do the screen
-   polls. Think of it as a rather efficient "screenshot" program running
-   continuously. It is a server in the sense that it is a VNC server that
-   VNC viewers on the network can connect to and view the screen
-   framebuffer it manages.
-
-   When trying to debug problems, remember to think of both roles. E.g.
-   "how is x11vnc connecting to the X server?", "how is the vncviewer
-   connecting to x11vnc?", "what permits/restricts the connection?". Both
-   links may have reachability, permission, and other issues.
-
-   Network performance:   Whether you are using Xvnc or x11vnc it is
-   always a good idea to have a solid background color instead of a
-   pretty background image. Each and every re-exposure of the background
-   must be resent over the network: better to have that background be a
-   solid color that compresses very well compared to a photo image. (This
-   is one place where the X protocol has an advantage over the VNC
-   protocol.) I suggest using xsetroot, dtstyle or similar utility to set
-   a solid background while using x11vnc. You can turn the pretty
-   background image back on when you are using the display directly.
-   Update: As of Feb/2005 x11vnc has the -solid [color] option that works
-   on recent GNOME, KDE, and CDE and also on classic X (background image
-   is on the root window.) Update: As of Oct/2007 x11vnc has the -ncache
-   option that does a reasonable job caching the background (and other)
-   pixmap data on the viewer side.
-
-   I also find the TightVNC encoding gives the best response for my usage
-   (Unix <-> Unix over cable modem.) One needs a tightvnc-aware vncviewer
-   to take advantage of this encoding.
-
-   TCP port issues:   Notice the lines
-  18/07/2003 14:36:31 Autoprobing selected port 5900
-  PORT=5900
-
-   in the output. 5900 is the default VNC listening port (just like 6000
-   is X11's default listening port.) Had port 5900 been taken by some
-   other application, x11vnc would have next tried 5901. That would mean
-   the viewer command above should be changed to vncviewer
-   far-away.east:1. You can force the port with the "-rfbport NNNN"
-   option where NNNN is the desired port number. If that port is already
-   taken, x11vnc will exit immediately. The "-N" option will try to match
-   the VNC display number to the X display.   (also see the "SunRay
-   Gotcha" note below)
-
-   Options:   x11vnc has (far too) many features that may be activated
-   via its command line options. Useful options are, e.g., -scale to do
-   server-side scaling, and -rfbauth passwd-file to use VNC password
-   protection (the vncpasswd or storepasswd programs, or the x11vnc
-   -storepasswd option can be used to create the password file.)
-
-   Algorithm:   How does x11vnc do it? Rather brute-forcedly: it
-   continuously polls the X11 framebuffer for changes using
-   XShmGetImage(). When changes are discovered, it instructs libvncserver
-   which rectangular regions of the framebuffer have changed, and
-   libvncserver compresses the changes and sends them off to any
-   connected VNC viewers. A number of applications do similar things,
-   such as x0rfbserver, krfb, x0vncserver, vino. x11vnc uses a 32 x 32
-   pixel tile model (the desktop is decomposed into roughly 1000 such
-   tiles), where changed tiles are found by pseudo-randomly polling 1
-   pixel tall horizontal scanlines separated vertically by 32 pixels.
-   This is a surprisingly effective algorithm for finding changed
-   regions. For keyboard and mouse user input the XTEST extension is used
-   to pass the input events to the X server. To detect XBell "beeps" the
-   XKEYBOARD extension is used. If available, the XFIXES extension is
-   used to retrieve the current mouse cursor shape. Also, if available
-   the X DAMAGE extension is used to receive hints from the X server
-   where modified regions on the screen are. This greatly reduces the
-   system load when not much is changing on the screen and also improves
-   how quickly the screen is updated.
-
-   Barbershop mirrors effect:   What if x11vnc is started up, and
-   vncviewer is then started up on the same machine and displayed on the
-   same display x11vnc is polling? One might "accidentally" do this when
-   first testing out the programs. You get an interesting
-   recursive/feedback effect where vncviewer images keep popping up each
-   one contained in the previous one and slightly shifted a bit by the
-   window manager decorations. There will be an even more interesting
-   effect if -scale is used. Also, if the XKEYBOARD is supported and the
-   XBell "beeps" once, you get an infinite loop of beeps going off.
-   Although all of this is mildly exciting it is not much use: you will
-   normally run and display the viewer on a different machine!
-     _________________________________________________________________
-
-    Sun Ray Notes:
-
-   You can run x11vnc on your (connected or disconnected) SunRay session.
-   Here are some notes on SunRay usage with x11vnc.
-
-     _________________________________________________________________
-
-    Limitations:
-
-     * Due to the polling nature, some activities (opaque window moves,
-       scrolling), can be pretty choppy/ragged and others (exposures of
-       large areas) slow. Experiment with interacting a bit differently
-       than you normally do to minimize the effects (e.g. do fullpage
-       paging rather than line-by-line scrolling, and move windows in a
-       single, quick motion.) Recent work has provided the
-       -scrollcopyrect and -wireframe speedups using the CopyRect VNC
-       encoding and other things, but they only speed up some activities,
-       not all.
-     * A rate limiting factor for x11vnc performance is that graphics
-       hardware is optimized for writing, not reading (x11vnc reads the
-       video framebuffer for the screen image data.) The difference can
-       be a factor of 10 to 1000, and so it usually takes about 0.5-1 sec
-       to read in the whole video hardware framebuffer (e.g. 5MB for
-       1280x1024 at depth 24 with a read rate of 5-10MB/sec.) So whenever
-       activity changes most of the screen (e.g. moving or iconifying a
-       large window) there is a delay of 0.5-1 sec while x11vnc reads the
-       changed regions in.
-       A slow framebuffer read rate will often be the performance
-       bottleneck on a fast LAN (whereas on slower links the reduced
-       network bandwidth becomes the bottleneck.)
-       Note: A quick way to get a 2X speedup of this for x11vnc is to
-       switch your X server from depth 24 (32bpp) to depth 16 (16bpp.)
-       You get a 4X speedup going to 8bpp, but the lack of color cells is
-       usually unacceptable.
-       To get a sense of the read and write speeds of your video card,
-       you can run benchmarks like: "x11perf -getimage500",  "x11perf
-       -putimage500",  "x11perf -shmput500" and for XFree86 displays with
-       direct graphics access the "dga" command (press "b" to run the
-       benchmark and then after a few seconds press "q" to quit.) Even
-       this "dd if=/dev/fb0 of=/dev/null" often gives a good estimate.
-       x11vnc also prints out its estimate:
-  28/02/2009 11:11:07 Autoprobing TCP port
-  28/02/2009 11:11:07 Autoprobing selected port 5900
-  28/02/2009 11:11:08 fb read rate: 10 MB/sec
-  28/02/2009 11:11:08 screen setup finished.
-       We have seen a few cases where the hardware fb read speed is
-       greater than 65 MB/sec: on high end graphics workstations from SGI
-       and Sun, and also from a Linux user using nvidia proprietary
-       drivers for his nvidia video card. Update 2008: thankfully, these
-       sped up drivers are becoming more common on Linux and *BSD systems
-       and that makes x11vnc run somewhat more quickly. Sometimes they
-       have a read rate of over 400 MB/sec.
-       On XFree86/Xorg it is actually possible to increase the
-       framebuffer read speed considerably (10-100 times) by using the
-       Shadow Framebuffer (a copy of the framebuffer is kept in main
-       memory and this can be read much more quickly.) To do this one
-       puts the line Option "ShadowFB" "true" in the Device section of
-       the /etc/X11/XF86Config or /etc/X11/xorg.conf file. Note that this
-       disables 2D acceleration at the physical display and so that might
-       be unacceptable if one plays games, etc. on the machine's local
-       display. Nevertheless this could be handy in some circumstances,
-       e.g. if the slower speed while sitting at the physical display was
-       acceptable (this seems to be true for most video cards these
-       days.) Unfortunately it does not seem shadowfb can be turned on
-       and off dynamically...
-       Another amusing thing one can do is use Xvfb as the X server, e.g.
-       "xinit $HOME/.xinitrc -- /usr/X11R6/bin/Xvfb :1 -screen 0
-       1024x768x16" x11vnc can poll Xvfb efficiently via main memory.
-       It's not exactly clear why one would want to do this instead of
-       using vncserver/Xvnc, (perhaps to take advantage of an x11vnc
-       feature, such as framebuffer scaling or built-in SSL encryption),
-       but we mention it because it may be of use for special purpose
-       applications. You may need to use the "-cc 4" option to force Xvfb
-       to use a TrueColor visual instead of DirectColor. See also the
-       description of the -create option that does all of this
-       automatically for you (be sure to install the Xvfb package, e.g.
-       apt-get install xvfb.)
-       Also, a faster and more accurate way is to use the "dummy"
-       Xorg/XFree86 device driver (or our Xdummy wrapper script.) See
-       this FAQ for details.
-     * Somewhat surprisingly, the X11 mouse (cursor) shape is write-only
-       and cannot be queried from the X server. So traditionally in
-       x11vnc the cursor shape stays fixed at an arrow. (see the "-cursor
-       X" and "-cursor some" options, however, for a partial hack for the
-       root window, etc.) However, on Solaris using the SUN_OVL overlay
-       extension, x11vnc can show the correct mouse cursor when the
-       -overlay option is also supplied. A similar thing is done on IRIX
-       as well when -overlay is supplied.
-       More generally, as of Dec/2004 x11vnc supports the new XFIXES
-       extension (in Xorg and Solaris 10) to query the X server for the
-       exact cursor shape, this works pretty well except that cursors
-       with transparency (alpha channel) need to approximated to solid
-       RGB values (some cursors look worse than others.)
-     * Audio from applications is of course not redirected (separate
-       redirectors do exist, e.g. esd, see the FAQ on this below.) The
-       XBell() "beeps" will work if the X server supports the XKEYBOARD
-       extension. (Note that on Solaris XKEYBOARD is disabled by default.
-       Passing +kb to Xsun enables it.)
-     * The scroll detection algorithm for the -scrollcopyrect option can
-       give choppy or bunched up transient output and occasionally
-       painting errors.
-     * Using -threads can expose some bugs/crashes in libvncserver.
-
-   Please feel free to contact me if you have any questions, problems, or
-   comments about x11vnc, etc. Please be polite, thorough, and not
-   demanding (sadly, the number of people contacting me that are rude and
-   demanding is increasing dramatically.)
-   Also, some people ask if they can make a donation, see this link for
-   that.
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/faq.html:
-
-
-   x11vnc Home    Donations
-     _________________________________________________________________
-
-    x11vnc FAQ:
-
-
-   [Building and Starting]
-
-   Q-1: I can't get x11vnc to start up. It says "XOpenDisplay failed
-   (null)" or "Xlib: connection to ":0.0" refused by server Xlib: No
-   protocol specified" and then exits. What do I need to do? 
-
-   Q-2: I can't get x11vnc and/or libvncserver to compile. 
-
-   Q-3: I just built x11vnc successfully, but when I use it my keystrokes
-   and mouse button clicks are ignored  (I am able to move the mouse
-   though.) 
-
-   Q-4: Help, I need to run x11vnc on Solaris 2.5.1 (or other old
-   Unix/Linux) and it doesn't compile! 
-
-   Q-5: Where can I get a precompiled x11vnc binary for my Operating
-   System? 
-
-   Q-6: Where can I get a VNC Viewer binary (or source code) for the
-   Operating System I will be viewing from? 
-
-   Q-7: How can I see all of x11vnc's command line options and
-   documentation on how to use them? 
-
-   Q-8: I don't like typing arcane command line options every time I
-   start x11vnc. What can I do? Is there a config file? Or a GUI? 
-
-   Q-9: How can I get the GUI to run in the System Tray, or at least be a
-   smaller, simpler icon? 
-
-   Q-10: How can I get x11vnc to listen on a different port besides the
-   default VNC port (5900)? 
-
-   Q-11: My Firewall/Router doesn't allow VNC Viewers to connect to
-   x11vnc. 
-
-   Q-12: Is it possible for a VNC Viewer and a VNC Server to connect to
-   each other even though both are behind Firewalls that block all
-   incoming connections? 
-
-   Q-13: Can I make x11vnc more quiet and also go into the background
-   after starting up? 
-
-   Q-14: Sometimes when a VNC viewer dies abruptly, x11vnc also dies with
-   the error message like: "Broken pipe". I'm using the -forever mode and
-   I want x11vnc to keep running. 
-
-   Q-15: The Windows TightVNC 1.3.9 Viewer cannot connect to x11vnc. 
-
-   Q-16: KDE's krdc VNC viewer cannot connect to x11vnc. 
-
-   Q-17: When I start x11vnc on an Alpha Tru64 workstation the X server
-   crashes! 
-
-   Q-18: When running x11vnc on an IBM AIX workstation after a few
-   minutes the VNC connection freezes. 
-
-   Q-19: Are there any build-time customizations possible, e.g. change
-   defaults, create a smaller binary, etc? 
-
-   [Win2VNC Related]
-
-   Q-20: I have two separate machine displays in front of me, one Windows
-   the other X11: can I use x11vnc in combination with Win2VNC in
-   dual-screen mode to pass the keystrokes and mouse motions to the X11
-   display? 
-
-   Q-21: I am running Win2VNC on my Windows machine and "x11vnc -nofb" on
-   Unix to pass keyboard and mouse to the Unix monitor. Whenever I start
-   Win2VNC it quickly disconnects and x11vnc says:
-   rfbProcessClientNormalMessage: read: Connection reset by peer 
-
-   Q-22: Can I run "x11vnc -nofb" on a Mac OS X machine to redirect mouse
-   and keyboard input to it from Windows and X11 machines via Win2VNC and
-   x2vnc, respectively? 
-
-   [Color Issues]
-
-   Q-23: The X display I run x11vnc on is only 8 bits per pixel (bpp)
-   PseudoColor (i.e. only 256 distinct colors.) The x11vnc colors may
-   start out OK, but after a while they are incorrect in certain windows.
-   
-   Q-24: Color problems: Why are the colors for some windows incorrect in
-   x11vnc? BTW, my X display has nice overlay/multi-depth visuals of
-   different color depths: e.g. there are both depth 8 and 24 visuals
-   available at the same time. 
-
-   Q-25: I am on a high color system (depth >= 24) but I seem to have
-   colormap problems. They either flash or everything is very dark. 
-
-   Q-26: How do I figure out the window id to supply to the -id windowid
-   option? 
-
-   Q-27: Why don't menus or other transient windows come up when I am
-   using the -id windowid option to view a single application window? 
-
-   Q-28: My X display is depth 24 at 24bpp (instead of the normal depth
-   24 at 32bpp.) I'm having lots of color and visual problems with x11vnc
-   and/or vncviewer. What's up? 
-
-   [Xterminals]
-
-   Q-29: Can I use x11vnc to view and interact with an Xterminal (e.g.
-   NCD) that is not running UNIX and so x11vnc cannot be run on it
-   directly? 
-
-   Q-30: How do I get my X permissions (MIT-MAGIC-COOKIE file) correct
-   for a Unix/Linux machine acting as an Xterminal? 
-
-   [Sun Rays]
-
-   Q-31: I'm having trouble using x11vnc with my Sun Ray session. 
-
-   [Remote Control]
-
-   Q-32: How do I stop x11vnc once it is running in the background? 
-
-   Q-33: Can I change settings in x11vnc without having to restart it?
-   Can I remote control it? 
-
-   [Security and Permissions]
-
-   Q-34: How do I create a VNC password for use with x11vnc? 
-
-   Q-35: Can I make it so -storepasswd doesn't show my password on the
-   screen? 
-
-   Q-36: Can I have two passwords for VNC viewers, one for full access
-   and the other for view-only access to the display? 
-
-   Q-37: Can I have as many full-access and view-only passwords as I
-   like? 
-
-   Q-38: Does x11vnc support Unix usernames and passwords? Can I further
-   limit the set of Unix usernames who can connect to the VNC desktop? 
-
-   Q-39: Can I supply an external program to provide my own custom login
-   method (e.g. Dynamic/One-time passwords or non-Unix (LDAP) usernames
-   and passwords)? 
-
-   Q-40: Why does x11vnc exit as soon as the VNC viewer disconnects? And
-   why doesn't it allow more than one VNC viewer to connect at the same
-   time? 
-
-   Q-41: Can I limit which machines incoming VNC clients can connect
-   from? 
-
-   Q-42: How do I build x11vnc/libvncserver with libwrap (tcp_wrappers)
-   support? 
-
-   Q-43: Can I have x11vnc only listen on one network interface (e.g.
-   internal LAN) rather than having it listen on all network interfaces
-   and relying on -allow to filter unwanted connections out? 
-
-   Q-44: Now that -localhost implies listening only on the loopback
-   interface, how I can occasionally allow in a non-localhost via the -R
-   allowonce remote control command? 
-
-   Q-45: Can I fine tune what types of user input are allowed? E.g. have
-   some users just be able to move the mouse, but not click or type
-   anything? 
-
-   Q-46: Can I prompt the user at the local X display whether the
-   incoming VNC client should be accepted or not? Can I decide to make
-   some clients view-only? How about running an arbitrary program to make
-   the decisions? 
-
-   Q-47: I start x11vnc as root because it is launched via inetd(8) or a
-   display manager like gdm(1). Can I have x11vnc later switch to a
-   different user? 
-
-   Q-48: I use a screen-lock when I leave my workstation (e.g.
-   xscreensaver or xlock.) When I remotely access my workstation desktop
-   via x11vnc I can unlock the desktop fine, but I am worried people will
-   see my activities on the physical monitor. What can I do to prevent
-   this, or at least make it more difficult? 
-
-   Q-49: Can I have x11vnc automatically lock the screen when I
-   disconnect the VNC viewer? 
-
-   [Encrypted Connections]
-
-   Q-50: How can I tunnel my connection to x11vnc via an encrypted SSH
-   channel between two Unix machines? 
-
-   Q-51: How can I tunnel my connection to x11vnc via an encrypted SSH
-   channel from Windows using an SSH client like Putty? 
-
-   Q-52: How can I tunnel my connection to x11vnc via an encrypted SSL
-   channel using an external tool like stunnel? 
-
-   Q-53: Does x11vnc have built-in SSL tunneling? 
-
-   Q-54: How do I use VNC Viewers with built-in SSL tunneling? 
-
-   Q-55: How do I use the Java applet VNC Viewer with built-in SSL
-   tunneling when going through a Web Proxy? 
-
-   Q-56: Can Apache web server act as a gateway for users to connect via
-   SSL from the Internet with a Web browser to x11vnc running on their
-   workstations behind a firewall? 
-
-   Q-57: Can I create and use my own SSL Certificate Authority (CA) with
-   x11vnc? 
-
-   [Display Managers and Services]
-
-   Q-58: How can I run x11vnc as a "service" that is always available? 
-
-   Q-59: How can I use x11vnc to connect to an X login screen like xdm,
-   GNOME gdm, KDE kdm, or CDE dtlogin? (i.e. nobody is logged into an X
-   session yet.) 
-
-   Q-60: Can I run x11vnc out of inetd(8)? How about xinetd(8)? 
-
-   Q-61: Can I have x11vnc advertise its VNC service and port via mDNS /
-   Zeroconf (e.g. Avahi) so VNC viewers on the local network can detect
-   it automatically? 
-
-   Q-62: Can I have x11vnc allow a user to log in with her UNIX username
-   and password and then have it find her X session display on that
-   machine and then attach to it? How about starting an X session if one
-   cannot be found? 
-
-   Q-63: Can I have x11vnc restart itself after it terminates? 
-
-   Q-64: How do I make x11vnc work with the Java VNC viewer applet in a
-   web browser? 
-
-   Q-65: Are reverse connections (i.e. the VNC server connecting to the
-   VNC viewer) using "vncviewer -listen" and vncconnect(1) supported? 
-
-   Q-66: Can reverse connections be made to go through a Web or SOCKS
-   proxy or SSH? 
-
-   Q-67: Can x11vnc provide a multi-user desktop web login service as an
-   Apache CGI or PHP script? 
-
-   Q-68: Can I use x11vnc as a replacement for Xvnc? (i.e. not for a real
-   display, but for a virtual one I keep around.) 
-
-   Q-69: How can I use x11vnc on "headless" machines? Why might I want
-   to? 
-
-   [Resource Usage and Performance]
-
-   Q-70: I have lots of memory, but why does x11vnc fail with    shmget:
-   No space left on device    or    Minor opcode of failed request: 1
-   (X_ShmAttach)? 
-
-   Q-71: How can I make x11vnc use less system resources? 
-
-   Q-72: How can I make x11vnc use MORE system resources? 
-
-   Q-73: I use x11vnc over a slow link with high latency (e.g. dialup
-   modem or broadband), is there anything I can do to speed things up? 
-
-   Q-74: Does x11vnc support the X DAMAGE Xserver extension to find
-   modified regions of the screen quickly and efficiently? 
-
-   Q-75: My OpenGL application shows no screen updates unless I supply
-   the -noxdamage option to x11vnc. 
-
-   Q-76: When I drag windows around with the mouse or scroll up and down
-   things really bog down (unless I do the drag in a single, quick
-   motion.) Is there anything to do to improve things? 
-
-   Q-77: Why not do something like wireframe animations to avoid the
-   windows "lurching" when being moved or resized? 
-
-   Q-78: Can x11vnc try to apply heuristics to detect when a window is
-   scrolling its contents and use the CopyRect encoding for a speedup? 
-
-   Q-79: Can x11vnc do client-side caching of pixel data? I.e. so when
-   that pixel data is needed again it does not have to be retransmitted
-   over the network. 
-
-   Q-80: Does x11vnc support TurboVNC? 
-
-   [Mouse Cursor Shapes]
-
-   Q-81: Why isn't the mouse cursor shape (the little icon shape where
-   the mouse pointer is) correct as I move from window to window? 
-
-   Q-82: When using XFIXES cursorshape mode, some of the cursors look
-   really bad with extra black borders around the cursor and other cruft.
-   How can I improve their appearance? 
-
-   Q-83: In XFIXES mode, are there any hacks to handle cursor
-   transparency ("alpha channel") exactly? 
-
-   [Mouse Pointer]
-
-   Q-84: Why does the mouse arrow just stay in one corner in my
-   vncviewer, whereas my cursor (that does move) is just a dot? 
-
-   Q-85: Can I take advantage of the TightVNC extension to the VNC
-   protocol where Cursor Positions Updates are sent back to all connected
-   clients (i.e. passive viewers can see the mouse cursor being moved
-   around by another viewer)? 
-
-   Q-86: Is it possible to swap the mouse buttons (e.g. left-handed
-   operation), or arbitrarily remap them? How about mapping button clicks
-   to keystrokes, e.g. to partially emulate Mouse wheel scrolling? 
-
-   [Keyboard Issues]
-
-   Q-87: How can I get my AltGr and Shift modifiers to work between
-   keyboards for different languages? 
-
-   Q-88: When I try to type a "<" (i.e. less than) instead I get ">"
-   (i.e. greater than)! Strangely, typing ">" works OK!! 
-
-   Q-89: Extra Character Inserted, E.g.: When I try to type a "<" (i.e.
-   less than) instead I get "<," (i.e. an extra comma.) 
-
-   Q-90: I'm using an "international" keyboard (e.g. German "de", or
-   Danish "dk") and the -modtweak mode works well if the VNC viewer is
-   run on a Unix/Linux machine with a similar keyboard.   But if I run
-   the VNC viewer on Unix/Linux with a different keyboard (e.g. "us") or
-   Windows with any keyboard, I can't type some keys like:   "@", "$",
-   "<", ">", etc. How can I fix this? 
-
-   Q-91: When typing I sometimes get double, triple, or more of my
-   keystrokes repeated. I'm sure I only typed them once, what can I do? 
-
-   Q-92: The x11vnc -norepeat mode is in effect, but I still get repeated
-   keystrokes!! 
-
-   Q-93: After using x11vnc for a while, I find that I cannot type some
-   (or any) characters or my mouse clicks and drags no longer have any
-   effect, or they lead to strange effects. What happened? 
-
-   Q-94: The machine where I run x11vnc has an AltGr key, but the local
-   machine where I run the VNC viewer does not. Is there a way I can map
-   a local unused key to send an AltGr? How about a Compose key as well? 
-
-   Q-95: I have a Sun machine I run x11vnc on. Its Sun keyboard has just
-   one Alt key labelled "Alt" and two Meta keys labelled with little
-   diamonds. The machine where I run the VNC viewer only has Alt keys.
-   How can I send a Meta keypress? (e.g. emacs needs this) 
-
-   Q-96: Running x11vnc on HP-UX I cannot type "#" I just get a "3"
-   instead. 
-
-   Q-97: Can I map a keystroke to a mouse button click on the remote
-   machine? 
-
-   Q-98: How can I get Caps_Lock to work between my VNC viewer and
-   x11vnc? 
-
-   [Screen Related Issues and Features]
-
-   Q-99: The remote display is larger (in number of pixels) than the
-   local display I am running the vncviewer on. I don't like the
-   vncviewer scrollbars, what I can do? 
-
-   Q-100: Does x11vnc support server-side framebuffer scaling? (E.g. to
-   make the desktop smaller.) 
-
-   Q-101: Does x11vnc work with Xinerama? (i.e. multiple monitors joined
-   together to form one big, single screen.) 
-
-   Q-102: Can I use x11vnc on a multi-headed display that is not Xinerama
-   (i.e. separate screens :0.0, :0.1, ... for each monitor)? 
-
-   Q-103: Can x11vnc show only a portion of the display? (E.g. for a
-   special purpose application or a very large screen.) 
-
-   Q-104: Does x11vnc support the XRANDR (X Resize, Rotate and
-   Reflection) extension? Whenever I rotate or resize the screen x11vnc
-   just seems to crash. 
-
-   Q-105: Independent of any XRANDR, can I have x11vnc rotate and/or
-   reflect the screen that the VNC viewers see? (e.g. for a handheld
-   whose screen is rotated 90 degrees.) 
-
-   Q-106: Why is the view in my VNC viewer completely black? Or why is
-   everything flashing around randomly? 
-
-   Q-107: I use Linux Virtual Terminals (VT's) to implement 'Fast User
-   Switching' between users' sessions (e.g. Betty is on Ctrl-Alt-F7,
-   Bobby is on Ctrl-Alt-F8, and Sid is on Ctrl-Alt-F1: they use those
-   keystrokes to switch between their sessions.)   How come the view in a
-   VNC viewer connecting to x11vnc is either completely black or
-   otherwise all messed up unless the X session x11vnc is attached to is
-   in the active VT? 
-
-   Q-108: I am using x11vnc where my local machine has "popup/hidden
-   taskbars" and the remote display where x11vnc runs also has
-   "popup/hidden taskbars" and they interfere and fight with each other.
-   What can I do? 
-
-   Q-109: Help! x11vnc and my KDE screensaver keep switching each other
-   on and off every few seconds. 
-
-   Q-110: I am running the compiz 3D window manager (or beryl, MythTv,
-   Google Earth, or some other OpenGL app) and I do not get screen
-   updates in x11vnc. 
-
-   Q-111: Can I use x11vnc to view my VMWare session remotely? 
-
-   [Exporting non-X11 devices via VNC]
-
-   Q-112: Can non-X devices (e.g. a raw framebuffer) be viewed (and even
-   controlled) via VNC with x11vnc? 
-
-   Q-113: Can I export the Linux Console (Virtual Terminals) via VNC
-   using x11vnc? 
-
-   Q-114: Can I export via VNC a Webcam or TV tuner framebuffer using
-   x11vnc? 
-
-   Q-115: Can I connect via VNC to a Qt-embedded/Qt-enhanced/Qtopia
-   application running on my handheld, cell phone, or PC using the Linux
-   console framebuffer (i.e. not X11)? 
-
-   Q-116: How do I inject touch screen input into an
-   Qt-embedded/Qt-enhanced/Qtopia cell phone such as openmoko/qtmoko Neo
-   Freerunner? 
-
-   Q-117: Now that non-X11 devices can be exported via VNC using x11vnc,
-   can I build it with no dependencies on X11 header files and libraries?
-   
-   Q-118: How do I cross compile x11vnc for a different architecture than
-   my Linux i386 or amd64 PC? 
-
-   Q-119: Does x11vnc support Mac OS X Aqua/Quartz displays natively
-   (i.e. no X11 involved)? 
-
-   Q-120: Can x11vnc be used as a VNC reflector/repeater to improve
-   performance for the case of a large number of simultaneous VNC viewers
-   (e.g. classroom broadcasting or a large demo)? 
-
-   Q-121: Can x11vnc be used during a Linux, Solaris, etc. system
-   Installation so the Installation can be done remotely? 
-
-   [Misc: Clipboard, File Transfer/Sharing, Printing, Sound, Beeps,
-   Thanks, etc.]
-
-   Q-122: Does the Clipboard/Selection get transferred between the
-   vncviewer and the X display? 
-
-   Q-123: Can I use x11vnc to record a Shock Wave Flash (or other format)
-   video of my desktop, e.g. to record a tutorial or demo? 
-
-   Q-124: Can I transfer files back and forth with x11vnc? 
-
-   Q-125: Which UltraVNC extensions are supported? 
-
-   Q-126: Can x11vnc emulate UltraVNC's Single Click helpdesk mode for
-   Unix? I.e. something very simple for a naive user to initiate a
-   reverse vnc connection from their Unix desktop to a helpdesk
-   operator's VNC Viewer. 
-
-   Q-127: Can I (temporarily) mount my local (viewer-side) Windows/Samba
-   File share on the machine where x11vnc is running? 
-
-   Q-128: Can I redirect CUPS print jobs from the remote desktop where
-   x11vnc is running to a printer on my local (viewer-side) machine? 
-
-   Q-129: How can I hear the sound (audio) from the remote applications
-   on the desktop I am viewing via x11vnc? 
-
-   Q-130: Why don't I hear the "Beeps" in my X session (e.g. when typing
-   tput bel in an xterm)? 
-
-   Q-131: Does x11vnc work with IPv6? 
-
-   Q-132: Thanks for your program or for your help! Can I make a
-   donation? 
-     _________________________________________________________________
-
-
-   [Building and Starting]
-
-   Q-1: I can't get x11vnc to start up. It says "XOpenDisplay failed
-   (null)" or "Xlib: connection to ":0.0" refused by server Xlib: No
-   protocol specified" and then exits. What do I need to do?
-
-   For the former error, you need to specify the X display to connect to
-   (it also needs to be on the same machine the x11vnc process is to run
-   on.) Set your DISPLAY environment variable (or use the -display
-   option) to specify it. Nearly always the correct value will be ":0"
-   (in fact, x11vnc will now assume :0 if given no other information.)
-
-
-   For the latter error, you need to set up the X11 permissions
-   correctly.
-
-   To make sure X11 permissions are the problem do this simple test:
-   while sitting at the physical X display open a terminal window
-   (gnome-terminal, xterm, etc.) You should be able to run x11vnc
-   successfully without any need for special steps or command line
-   options in that terminal (i.e. just type "x11vnc".) If that works OK
-   then you know X11 permissions are the only thing preventing it from
-   working when you try to start x11vnc via, say, a remote shell.
-
-   How to Solve:  See the xauth(1), Xsecurity(7), and xhost(1) man pages
-   or this Howto for much info on X11 permissions. For example, you may
-   need to set your XAUTHORITY environment variable (or use the -auth
-   option) to point to the correct MIT-MAGIC-COOKIE file (e.g.
-   /home/joe/.Xauthority or /var/gdm/:0.Xauth or /var/lib/kdm/A:0-crWk72K
-   or /tmp/.gdmzndVlR, etc, etc.), or simply be sure you run x11vnc as
-   the correct user (i.e. the user who is logged into the X session you
-   wish to view.)
-
-   Note: The MIT cookie file contains the secret key that allows x11vnc
-   to connect to the desired X display.
-
-   If, say, sshd has set XAUTHORITY to point to a random file it has
-   created for X forwarding that will cause problems. (Under some
-   circumstances even su(1) and telnet(1) can set XAUTHORITY. See also
-   the gdm parameter NeverPlaceCookiesOnNFS that sets XAUTHORITY to a
-   random filename in /tmp for the whole X session.)
-
-   Running x11vnc as root is often not enough: you need to know where the
-   MIT-MAGIC-COOKIE file for the desired X display is.
-
-   Example solution:
-  x11vnc -display :0 -auth /var/gdm/:0.Xauth
-
-   (this is for the display manager gdm and requires root permission to
-   read the gdm cookie file, see this faq for other display manager
-   cookie file names.)
-
-   Note as of Feb/2007 you can also try the -find option instead of
-   "-display ..." and see if that finds your display and Xauthority.
-
-   Less safe, but to avoid figuring out where the correct XAUTHORITY file
-   is, if the person sitting at the physical X session types "xhost
-   +localhost" then one should be able to attach x11vnc to the session
-   (from the same machine.) The person could then type "xhost -localhost"
-   after x11vnc has connected to go back to the default permissions.
-   Also, for some situations the "-users lurk=" option may soon be of use
-   (please read the documentation on the -users option.)
-
-   To test out your X11 permissions from a remote shell, set DISPLAY and
-   possibly XAUTHORITY (see your shell's man page, bash(1), tcsh(1), on
-   how to set environment variables) and type xdpyinfo in the same place
-   you will be typing (or otherwise running) x11vnc. If information is
-   printed out about the X display (screen sizes, supported extensions,
-   color visuals info) that means the X11 permissions are set up
-   properly: xdpyinfo successfully connected to DISPLAY! You could also
-   type xclock and make sure no errors are reported (a clock should
-   appear on the X display, press Ctrl-C to stop it.) If these work, then
-   typing "x11vnc" in the same environment should also work.
-
-   Important: if you cannot get your X11 permissions so that the xdpyinfo
-   or xclock tests work, x11vnc also will not work (all of these X
-   clients must be allowed to connect to the X server to function
-   properly.)
-
-   Firewalls: Speaking of permissions, it should go without saying that
-   the host-level firewall will need to be configured to allow
-   connections in on a port. E.g. 5900 (default VNC port) or 22 (default
-   SSH port for tunnelling VNC.) Most systems these days have firewalls
-   turned on by default, so you will actively have to do something to
-   poke a hole in the firewall at the desired port number. See your
-   system administration tool for Firewall settings (Yast, Firestarter,
-   etc.)
-
-
-   Q-2: I can't get x11vnc and/or libvncserver to compile.
-
-   Make sure you have gcc (or other C compiler) and all of the required
-   libraries and the corresponding -dev/-devel packages installed. These
-   include Xorg/XFree86, libX11, libjpeg, libz, libssl, ... and don't
-   forget the devs: libjpeg-dev, libssl-dev ...
-
-   The most common build problem that people encounter is that the
-   necessary X11 libraries are installed on their system however it does
-   not have the corresponding -dev/-devel packages installed. These dev
-   packages include C header files and build-time .so symlink. It is a
-   shame the current trend in distros is to not install the dev package
-   by default when the the library runtime package is installed... (it
-   diminishes the power of open source)
-
-   As of Nov/2006 here is a list of libraries that x11vnc usually likes
-   to use:
-libc.so        libX11.so       libXtst.so       libXext.so
-libXfixes.so   libXdamage.so   libXinerama.so   libXrandr.so
-libz.so        libjpeg.so      libpthread.so
-libssl.so      libcrypto.so    libcrypt.so
-
-   although x11vnc will be pretty usable with the subset: libc.so,
-   libX11.so, libXtst.so, libXext.so, libz.so, and libjpeg.so.
-
-   After running the libvncserver configure, carefully examine the output
-   and the messages in the config.log file looking for missing
-   components. For example, if the configure output looks like:
-  checking how to run the C preprocessor... gcc -E
-  checking for X... no
-  checking for XkbSelectEvents in -lX11... no
-  checking for XineramaQueryScreens in -lXinerama... no
-  checking for XTestFakeKeyEvent in -lXtst... no
-
-   or even worse:
-  checking for C compiler default output file name... configure: error:
-  C compiler cannot create executables
-  See `config.log' for more details.
-
-   there is quite a bit wrong with the build environment. Hopefully
-   simply adding -dev packages and/or gcc or make will fix it.
-
-   For Debian the list seems to be:
-  gcc
-  make
-  libc6-dev
-  libjpeg8-dev           (formerly libjpeg62-dev)
-  libx11-dev
-  x11proto-core-dev      (formerly x-dev)
-  libxext-dev
-  libxtst-dev
-  libxdamage-dev
-  libxfixes-dev
-  libxrandr-dev
-  libxinerama-dev
-  libxss-dev             (formerly xlibs-static-dev)
-  zlib1g-dev
-  libssl-dev
-  libavahi-client-dev
-  linux-libc-dev         (only needed for linux console rawfb support)
-
-   Note that depending on your OS version the above names may have been
-   changed and/or additional packages may be needed.
-
-   For Redhat the list seems to be:
-  gcc
-  make
-  glibc-devel
-  libjpeg-devel
-  libX11-devel
-  xorg-x11-proto-devel
-  libXdamage-devel
-  libXfixes-devel
-  libXrandr-devel
-  zlib-devel
-  openssl-devel
-  avahi-devel
-  kernel-headers         (only needed for linux console rawfb support)
-
-   For other distros or OS's the package names may not be the same but
-   will look similar. Also, distros tend to rename packages as well so
-   the above list may be out of date. So only use the above lists as
-   hints for the package names that are needed.
-
-   Have a look at Misc. Build Problems for additional fixes.
-
-   Note: there is growing trend in Linux and other distros to slice up
-   core X11 software into more and smaller packages. So be prepared for
-   more headaches compiling software...
-
-
-   Q-3: I just built x11vnc successfully, but when I use it my keystrokes
-   and mouse button clicks are ignored  (I am able to move the mouse
-   though.)
-
-   This is most likely due to you not having a working build environment
-   for the XTEST client library libXtst.so. The library is probably
-   present on your system, but the package installing the build header
-   file is missing.
-
-   If you were watching carefully while configure was running you would
-   have seen:
-  checking for XTestFakeKeyEvent in -lXtst... no
-
-   The solution is to add the necessary build environment package (and
-   the library package if that is missing too.) On Debian the build
-   package is libxtst-dev. Other distros/OS's may have it in another
-   package.
-
-   x11vnc will build without support for this library (e.g. perhaps one
-   wants a view-only x11vnc on a stripped down or embedded system...) And
-   at runtime it will also continue to run even if the X server it
-   connects to does not support XTEST. In both cases it cannot inject
-   keystrokes or button clicks since XTEST is needed for that (it can
-   still move the mouse pointer using the X API XWarpPointer().)
-
-   You will see a warning message something like this at run time:
-  20/03/2005 22:33:09 WARNING: XTEST extension not available (either missing fr
-om
-  20/03/2005 22:33:09   display or client library libXtst missing at build time
-.)
-  20/03/2005 22:33:09   MOST user input (pointer and keyboard) will be DISCARDE
-D.
-  20/03/2005 22:33:09   If display does have XTEST, be sure to build x11vnc wit
-h
-  20/03/2005 22:33:09   a working libXtst build environment (e.g. libxtst-dev,
-  20/03/2005 22:33:09   or other packages.)
-  20/03/2005 22:33:09 No XTEST extension, switching to -xwarppointer mode for
-  20/03/2005 22:33:09   pointer motion input.
-
-   Also, as of Nov/2006 there will be a configure build time warning as
-   well:
-  ...
-  checking for XFixesGetCursorImage in -lXfixes... yes
-  checking for XDamageQueryExtension in -lXdamage... yes
-  configure: WARNING:
-  ==========================================================================
-  A working build environment for the XTEST extension was not found (libXtst).
-  An x11vnc built this way will be only barely usable.  You will be able to
-  move the mouse but not click or type.  There can also be deadlocks if an
-  application grabs the X server.
-
-  It is recommended that you install the necessary development packages
-  for XTEST (perhaps it is named something like libxtst-dev) and run
-  configure again.
-  ==========================================================================
-
-
-   Q-4: Help, I need to run x11vnc on Solaris 2.5.1 (or other old
-   Unix/Linux) and it doesn't compile!
-
-   We apologize that x11vnc does not build cleanly on older versions of
-   Solaris, Linux, etc.: very few users are on these old releases.
-
-   We have heard that since Dec/2004 a Solaris 2.6 built x11vnc will run
-   on Solaris Solaris 2.5 and 2.5.1 (since a workaround for XConvertCase
-   is provided.)
-
-   In any event, here is a workaround for Solaris 2.5.1 (and perhaps
-   earlier and perhaps non-Solaris):
-
-   First use the environment settings (CPPFLAGS, LDFLAGS, etc.) in the
-   above Solaris build script to run the configure command. That should
-   succeed without failure. Then you have to hand edit the autogenerated
-   rfb/rfbconfig.h file in the source tree, and just before the last
-   #endif at the bottom of that file insert these workaround lines:
-struct timeval _tmp_usleep_tv;
-#define usleep(x) \
-    _tmp_usleep_tv.tv_sec  = (x) / 1000000; \
-    _tmp_usleep_tv.tv_usec = (x) % 1000000; \
-    select(0, NULL, NULL, NULL, &_tmp_usleep_tv);
-int gethostname(char *name, int namelen);
-long random();
-int srandom(unsigned int seed);
-#undef LIBVNCSERVER_HAVE_LIBPTHREAD
-#define SHUT_RDWR 2
-typedef unsigned int in_addr_t;
-#define snprintf(a, n, args...) sprintf((a), ## args)
-
-   Then run make with the Solaris build script environment, everything
-   should compile without problems, and the resulting x11vnc binary
-   should work OK. If some non-x11vnc related programs fail (e.g. test
-   programs) and the x11vnc binary is not created try "make -k" to have
-   it keep going. Similar sorts of kludges in rfb/rfbconfig.h can be done
-   on other older OS (Solaris, Linux, ...) releases.
-
-   Here are some notes for similar steps that need to be done to build on
-   SunOS 4.x
-
-   Please let us know if you had to use the above workaround (and whether
-   it worked or not.) If there is enough demand we will try to push clean
-   compilations back to earlier Solaris, Linux, etc, releases.
-
-
-   Q-5: Where can I get a precompiled x11vnc binary for my Operating
-   System?
-
-   Hopefully the build steps above and FAQ provide enough info for a
-   painless compile for most environments. Please report problems with
-   the x11vnc configure, make, etc. on your system (if your system is
-   known to compile other GNU packages successfully.)
-
-   There are precompiled x11vnc binaries built by other groups that are
-   available at the following locations:
-    Slackware:      (.tgz)  http://www.linuxpackages.net/
-
-   SuSE: (.rpm) http:/software.opensuse.org/ Gentoo: (info)
-   http://gentoo-wiki.com/ and http://gentoo-portage.com/ FreeBSD: (.tbz)
-   http://www.freebsd.org/ http://www.freshports.org/net/x11vnc NetBSD:
-   (src) http://pkgsrc.se/x11/x11vnc OpenBSD: (.tgz) http://openports.se/
-   Arch Linux: (.tgz) http://www.archlinux.org/ Nokia 770 (.deb)
-   http://mike.saunby.googlepages.com/x11vncfornokia7702 Sharp Zaurus
-   http://www.focv.com/ Debian: (.deb) http://packages.debian.org/x11vnc
-   Redhat/Fedora: (.rpm) http://packages.sw.be/x11vnc RPMforge
-   http://dag.wieers.com/rpm/packages/x11vnc/ (N.B.: unmaintained after
-   0.9.3) Solaris: (pkg) http://www.sunfreeware.com/
-
-   If the above binaries don't work and building x11vnc on your OS fails
-   (and all else fails!) you can try one of My Collection of x11vnc
-   Binaries for various OS's and x11vnc releases.
-
-   As a general note, the x11vnc program is simple enough you don't
-   really need to install a package: the binary will in most cases work
-   as is and from any location (as long as your system libraries are not
-   too old, etc.) So, for Linux distributions that are not one of the
-   above, the x11vnc binary from the above packages has a good chance of
-   working. You can "install" it by just copying the x11vnc binary to the
-   desired directory in your PATH. Tip on extracting files from a Debian
-   package: extract the archive via a command like: "ar x
-   x11vnc_0.6-2_i386.deb" and then you can find the binary in the
-   resulting data.tar.gz tar file. Also, rpm2cpio(1) is useful in
-   extracting files from rpm packages.
-
-   If you use a standalone binary like this and also want x11vnc to serve
-   up the Java VNC Viewer jar file (either SSL enabled or regular one),
-   then you will need to extract the classes subdirectory from the source
-   tarball and point x11vnc to it via the -httpdir option. E.g.:
-    x11vnc -httpdir /path/to/x11vnc-0.9.9/classes/ssl ...
-
-
-   Q-6: Where can I get a VNC Viewer binary (or source code) for the
-   Operating System I will be viewing from?
-
-   To obtain VNC viewers for the viewing side (Windows, Mac OS, or Unix)
-   try here:
-     * http://www.tightvnc.com/download.html
-     * http://www.realvnc.com/download-free.html
-     * http://sourceforge.net/projects/cotvnc/
-     * http://www.ultravnc.com/
-     * Our Enhanced TightVNC Viewer (SSVNC)
-
-       [ssvnc.gif]
-
-
-   Q-7: How can I see all of x11vnc's command line options and
-   documentation on how to use them?
-
-   Run:  x11vnc -opts   to list just the option names or run:  x11vnc
-   -help   for long descriptions about each option. The output is listed
-   here as well. Yes, x11vnc does have a lot of options, doesn't it...
-
-
-   Q-8: I don't like typing arcane command line options every time I
-   start x11vnc. What can I do? Is there a config file? Or a GUI?
-
-   You could create a shell script that calls x11vnc with your options:
-#!/bin/sh
-#
-# filename: X11vnc  (i.e. not "x11vnc")
-# It resides in a directory in $PATH. "chmod 755 X11vnc" has been run on it.
-#
-x11vnc -wait 50 -localhost -rfbauth $HOME/.vnc/passwd -display :0 $*
-
-   a similar thing can be done via aliases in your shell (bash, tcsh,
-   csh, etc..)
-
-   Or as of Jun/2004 you can use the simple $HOME/.x11vncrc config file
-   support. If that file exists, each line is taken as a command line
-   option. E.g. the above would be:
-# this is a comment in my ~/.x11vncrc file
-wait 50        # this is a comment to the end of the line.
--localhost     # note: the leading "-" is optional.
-rfbauth  /home/fred/.vnc/passwd
-display :0
-
-   As of Dec/2004 there is now a simple Tcl/Tk GUI based on the
-   remote-control functionality ("-R") that was added. The /usr/bin/wish
-   program is needed for operation. The gui is not particularly
-   user-friendly, it just provides a point and click mode to set all the
-   many x11vnc parameters and obtain help on them. It is also very useful
-   for testing. See the -gui option for more info. Examples: "x11vnc ...
-   -gui" and "x11vnc ... -gui other:0" in the latter case the gui is
-   displayed on other:0, not the X display x11vnc is polling. There is
-   also a "-gui tray" system tray mode.
-
-   [tkx11vnc.gif]
-
-   NOTE: You may need to install the "wish" or "tk" or "tk8.4" package
-   for the gui mode to work (the package name depends on your OS/distro.)
-   The tcl/tk "wish" interpreter is used. In debian (and so ubuntu too)
-   one would run "apt-get install tk" or perhaps "apt-get install tk8.4"
-
-
-   Q-9: How can I get the GUI to run in the System Tray, or at least be a
-   smaller, simpler icon?
-
-   As of Jul/2005 the gui can run in a more friendly small icon mode
-   "-gui icon" or in the system tray: "-gui tray". It has balloon status,
-   a simple menu, and a Properities dialog. The full, complicated, gui is
-   only available under "Advanced". Other improvements were added as
-   well. Try "Misc -> simple_gui" for a gui with fewer esoteric menu
-   items.
-
-   If the gui fails to embed itself in the system tray, do a retry via
-   "Window View -> icon" followed by "Window View -> tray" with the popup
-   menu.
-
-   For inexperienced users starting up x11vnc and the GUI while sitting
-   at the physical X display (not remotely), using something like "x11vnc
-   -display :0 -gui tray=setpass" might be something for them that they
-   are accustomed to in a Desktop environment (it prompts for an initial
-   password, etc.) This is a basic "Share My Desktop" usage mode.
-
-   As of Nov/2008 in x11vnc 0.9.6 there is a desktop menu item
-   (x11vnc.desktop) that runs this command:
-   x11vnc -gui tray=setpass -rfbport PROMPT -logfile %HOME/.x11vnc.log.%VNCDISP
-LAY
-
-   which also prompts for which VNC port to use and a couple other
-   parameters.
-
-
-   Q-10: How can I get x11vnc to listen on a different port besides the
-   default VNC port (5900)?
-
-   Use something like, e.g., "x11vnc -rfbport 5901" to force it to use
-   port 5901 (this is VNC display :1.) If something else is using that
-   port x11vnc will exit immediately. If you do not supply the -rfbport
-   option, it will autoprobe starting at 5900 and work its way up to 5999
-   looking for a free port to listen on. In that case, watch for the
-   PORT=59xx line to see which port it found, then subtract 5900 from it
-   for the VNC display number to enter into the VNC Viewer(s).
-
-   The "-N" option will try to match the VNC display number to the X
-   display (e.g. X11 DISPLAY of :5 (port 6005) will have VNC display :5
-   (port 5905).)
-
-   Also see the "-autoport n" option to indicated at which value the auto
-   probing should start at.
-
-
-   Q-11: My Firewall/Router doesn't allow VNC Viewers to connect to
-   x11vnc.
-
-   See the Firewalls/Routers discussion.
-
-
-   Q-12: Is it possible for a VNC Viewer and a VNC Server to connect to
-   each other even though both are behind Firewalls that block all
-   incoming connections?
-
-   This is very difficult or impossible to do unless a third machine,
-   reachable by both, is used as a relay. So we assume a third machine is
-   somehow being used as a relay.
-
-   (Update: It may be possible to do "NAT-2-NAT" without a relay machine
-   by using a UDP tunnel such as http://samy.pl/pwnat/. All that is
-   required is that both NAT firewalls allow in UDP packets from an IP
-   address to which a UDP packet has recently been sent to. If you try it
-   out let us know how it went.)
-
-   In the following discussion, we will suppose port 5950 is being used
-   on the relay machine as the VNC port for the rendezvous.
-
-   A way to rendezvous is to have the VNC Server start a reverse
-   connection to the relay machine:
-   x11vnc -connect third-machine.net:5950 ...
-
-   and the VNC viewer forward connects as usual:
-   vncviewer third-machine.net:50
-
-   Or maybe two ports would be involved, e.g. the viewer goes to display
-   :51 (5951.) It depends on the relay software being used.
-
-   What software to run on third-machine? A TCP relay of some sort could
-   be used... Try a google search on "tcp relay" or "ip relay". However,
-   note that this isn't a simple redirection because it hooks up two
-   incoming connections. You can look at our UltraVNC repeater
-   implementation ultravnc_repeater.pl for ideas and possibly to
-   customize.
-
-   Also, if you are not the admin of third-machine you'd have to convince
-   the owner to allow you to install this software (and he would likely
-   need to open his server's firewall to allow the port through.)
-
-   It is recommended that SSL is used for encryption (e.g. "-ssl SAVE")
-   when going over the internet.
-
-   We have a prototype for performing a rendezvous via a Web Server
-   acting as the relay machine. Download the vncxfer CGI script and see
-   the instructions at the top.
-
-   Once that CGI script is set up on the website, both users go to, say,
-   http://somesite.com/vncxfer (or maybe a "/cgi-bin" directory or ".cgi"
-   suffix must be used.) Previously, both have agreed on the same session
-   name (say by phone or email) , e.g. "5cows", and put that into the
-   entry form on the vncxfer starting page (hopefully separated by a few
-   seconds, so the relay helper can fully start up at the first request.)
-
-   The page returned tells them the hostname and port number and possible
-   command to use for forward (VNC Viewer) and reverse (VNC Server, i.e.
-   x11vnc) connections as described above.
-
-   Also since Oct/2007, x11vnc can connect directly (no web browser),
-   like this:
-   x11vnc ... -connect localhost:0 -proxy 'http://somesite.com/vncxfer?session=
-5cows&'
-
-   Unfortunately the prototype requires that the Web server's firewall
-   allow in the port (e.g. 5950) used for the rendezvous. Most web
-   servers are not configured to do this, so you would need to ask the
-   admin to do this for you. Nearly all free webspace sites, e.g.
-   www.zendurl.com, will not allow your CGI script to be an open relay
-   like this. (If you find one that does allow this, let me know!)
-
-   Maybe someday a clever trick will be thought up to relax the listening
-   port requirement (e.g. use HTTP/CGI itself for the transfer... it is
-   difficult to emulate a full-duplex TCP connection with them.)
-
-   See also the Firewalls/Routers discussion and Reverse Connection Proxy
-   discussion.
-
-
-   SSH method: If both users (i.e. one on Viewer-side and the other on
-   x11vnc server side) have SSH access to a common machine on the
-   internet (or otherwise mutually reachable), then SSH plumbing can be
-   used to solve this problem. The users create SSH tunnels going through
-   the SSH login machine.
-
-   Instead of assuming port 5900 is free on the SSH machine, we will
-   assume both users agreed to use 5933. This will illustrate how to use
-   a different port for the redir. It could be any port, what matters is
-   that both parties refer to the same one.
-
-   Set up the Tunnel from the VNC Server side:
-   ssh -t -R 5933:localhost:5900 user@third-machine.net
-
-   Set up the Tunnel from the VNC Viewer side:
-   ssh -t -L 5900:localhost:5933 user@third-machine.net
-
-   Run Server on the VNC Server side:
-   x11vnc -rfbport 5900 -localhost ...
-
-   Run Viewer on the VNC Viewer side:
-   vncviewer -encodings "copyrect tight zrle hextile" localhost:0
-
-   (we assume the old-style -encodings option needs to be used. See here
-   for details.)
-
-   If the SSH machine has been configured (see sshd_config(5)) with the
-   option GatewayPorts=yes, then the tunnel set up by the VNC Server will
-   be reachable directly by the VNC viewer (as long as the SSH machine's
-   firewall does not block the port, 5933 in this example.) So in that
-   case the Viewer side does not need to run any ssh command, but rather
-   only runs:
-   vncviewer third-machine.net:33
-
-   In this case we recommend SSL be used for encryption.
-
-   The creation of both tunnels can be automated. As of Oct/2007 the -ssh
-   x11vnc option is available and so only this command needs to be run on
-   the VNC Server side:
-   x11vnc -ssh user@third-machine.net:33 ...
-
-   (the SSH passphrase may need to be supplied.)
-
-   To automate on the VNC Viewer side, the user can use the Enhanced
-   TightVNC Viewer (SSVNC) by:
-     * Clicking on 'Use SSH'
-     * Entering user@third-machine.net:33 into 'VNC Host:Display' entry
-       box
-     * Clicking on 'Connect'
-
-   As above, if the SSH GatewayPorts=yes setting is configured the Viewer
-   side doesn't need to create a SSH tunnel. In SSVNC the Viewer user
-   could instead select 'Use SSL' and then, e.g., on the Server side
-   supply "-ssl SAVE" to x11vnc. Then end-to-end SSL encryption would be
-   used (in addition to the SSH encryption on the Server-side leg.)
-
-
-   Q-13: Can I make x11vnc more quiet and also go into the background
-   after starting up?
-
-   Use the -q and -bg options, respectively.  (also: -quiet is an alias
-   for -q)
-
-   Note that under -bg the stderr messages will be lost unless you use
-   the "-o logfile" option.
-
-
-   Q-14: Sometimes when a VNC viewer dies abruptly, x11vnc also dies with
-   the error message like: "Broken pipe". I'm using the -forever mode and
-   I want x11vnc to keep running.
-
-   As of Jan/2004 the SIGPIPE signal is ignored. So if a viewer client
-   terminates abruptly, libvncserver will notice on the next I/O
-   operation and will close the connection and continue on.
-
-   Up until of Apr/2004 the above fix only works for BSD signal systems
-   (Linux, FreeBSD, ...) For SYSV systems there is a workaround in place
-   since about Jun/2004.
-
-
-   Q-15: The Windows TightVNC 1.3.9 Viewer cannot connect to x11vnc.
-
-   This appears to be fixed in x11vnc version 0.9 and later. If you need
-   to use an earlier version of x11vnc, try using the "-rfbversion 3.7"
-   option. In general sometimes one can get a misbehaving viewer to work
-   by supplying rfb versions 3.7 or 3.3.
-
-
-   Q-16: KDE's krdc VNC viewer cannot connect to x11vnc.
-
-   This has been fixed in x11vnc version 0.8.4. More info here, here, and
-   here.
-
-
-   Q-17: When I start x11vnc on an Alpha Tru64 workstation the X server
-   crashes!
-
-   This is a bug in the X server obviously; an X client should never be
-   able to crash it.
-
-   The problem seems to be with the RECORD X extension and so a
-   workaround is to use the "-noxrecord" x11vnc command line option.
-
-
-   Q-18: When running x11vnc on an IBM AIX workstation after a few
-   minutes the VNC connection freezes.
-
-   One user reports when running x11vnc on AIX 5.3 in his CDE session
-   after a few minutes or seconds x11vnc will "freeze" (no more updates
-   being sent, etc.) The freezing appeared to be worse for versions later
-   than 0.9.2.
-
-   The problem seems to be with the RECORD X extension on AIX and so a
-   workaround is to use the "-noxrecord" x11vnc command line option. The
-   user found no freezes occurred when using that option.
-
-
-   Q-19: Are there any build-time customizations possible, e.g. change
-   defaults, create a smaller binary, etc?
-
-   There are some options. They are enabled by adding something like
-   -Dxxxx=1 to the CPPFLAGS environment variable before running configure
-   (see the build notes for general background.)
-/*
- * Mar/2006
- * Build-time customization via CPPFLAGS.
- *
- * Summary of options to include in CPPFLAGS for custom builds:
- *
- * -DVNCSHARED  to have the vnc display shared by default.
- * -DFOREVER  to have -forever on by default.
- * -DNOREPEAT=0  to have -repeat on by default.
- * -DADDKEYSYMS=0  to have -noadd_keysyms the default.
- *
- * -DREMOTE_DEFAULT=0  to disable remote-control on by default (-yesremote.)
- * -DREMOTE_CONTROL=0  to disable remote-control mechanism completely.
- * -DEXTERNAL_COMMANDS=0  to disable the running of all external commands.
- * -DFILEXFER=0  disable filexfer.
- *
- * -DHARDWIRE_PASSWD=...      hardwired passwords, quoting necessary.
- * -DHARDWIRE_VIEWPASSWD=...
- * -DNOPW=1                   make -nopw the default (skip warning)
- * -DUSEPW=1                  make -usepw the default
- * -DPASSWD_REQUIRED=1        exit unless a password is supplied.
- * -DPASSWD_UNLESS_NOPW=1     exit unless a password is supplied and no -nopw.
- *
- * -DWIREFRAME=0  to have -nowireframe as the default.
- * -DWIREFRAME_COPYRECT=0  to have -nowirecopyrect as the default.
- * -DWIREFRAME_PARMS=...   set default -wirecopyrect parameters.
- * -DSCROLL_COPYRECT=0     to have -noscrollcopyrect as the default.
- * -DSCROLL_COPYRECT_PARMS=...  set default -scrollcopyrect parameters.
- * -DSCALING_COPYRECT=0
- * -DXDAMAGE=0    to have -noxdamage as the default.
- * -DSKIPDUPS=0   to have -noskip_dups as the default or vice versa.
- *
- * -DPOINTER_MODE_DEFAULT={0,1,2,3,4}  set default -pointer_mode.
- * -DBOLDLY_CLOSE_DISPLAY=0  to not close X DISPLAY under -rawfb.
- * -DSMALL_FOOTPRINT=1  for smaller binary size (no help, no gui, etc)
- *                      use 2 or 3 for even smaller footprint.
- * -DNOGUI  do not include the gui tkx11vnc.
- * -DPOLL_8TO24_DELAY=N
- * -DDEBUG_XEVENTS=1  enable printout for X events.
- *
- * Set these in CPPFLAGS before running configure. E.g.:
- *
- *   % env CPPFLAGS="-DFOREVER -DREMOTE_CONTROL=0" ./configure
- *   % make
- */
-
-   If other things (e.g. "-I ...") are needed in CPPFLAGS add them as
-   well.
-
-   On some systems is seems you need to set LC_ALL=C for configure to
-   work properly...
-
-   Be careful the following two variables: HARDWIRE_PASSWD and
-   HARDWIRE_VIEWPASSWD. If set (remember to include the double quotes
-   around the string), they will be used as default values for the
-   -passwd and -viewpasswd options. Of course the strings will exist
-   unobscured in the x11vnc binary: it better not be readable by
-   unintendeds. Perhaps this is of use in remote access for an embedded
-   application, etc...
-
-   Let us know if more build-time customizations would be useful.
-
-
-   [Win2VNC Related]
-
-   Q-20: I have two separate machine displays in front of me, one Windows
-   the other X11: can I use x11vnc in combination with Win2VNC in
-   dual-screen mode to pass the keystrokes and mouse motions to the X11
-   display?
-
-   Yes, for best response start up x11vnc with the "-nofb" option
-   (disables framebuffer polling, and does other optimizations) on the
-   secondary display (X11) machine. Then start up Win2VNC on the primary
-   display (Windows) referring it to the secondary display.
-
-   This will also work X11 to X11 using x2vnc, however you would probably
-   just want to avoid VNC and use x2x for that.
-
-   For reference, here are some links to Win2VNC-like programs for
-   multiple monitor setups:
-     * Original Win2VNC
-     * Enhanced Win2VNC (broken?) and sourceforge link
-     * x2vnc
-     * x2x
-     * zvnc (MorphOS)
-
-   All of them will work with x11vnc (except x2x where it is not needed.)
-
-
-   Q-21: I am running Win2VNC on my Windows machine and "x11vnc -nofb" on
-   Unix to pass keyboard and mouse to the Unix monitor. Whenever I start
-   Win2VNC it quickly disconnects and x11vnc says:
-   rfbProcessClientNormalMessage: read: Connection reset by peer
-
-   Is the default visual of the X display you run x11vnc on low color
-   (e.g. 8 bit per pixel PseudoColor)? (you can run xdpyinfo to check,
-   look in the "screen" section.) There seems to be a bug in Win2VNC in
-   that it cannot deal correctly with colormaps (PseudoColor is the most
-   common example of a visual with a colormap.)
-
-   If so, there are a couple options. 1) Can you set the default visual
-   on your display to be depth 24 TrueColor? Sun machines often have 8+24
-   overlay/multi-depth visuals, and you can make the default visual depth
-   24 TrueColor (see fbconfig(1) and Xsun(1).) 2) As of Feb/2004 x11vnc
-   has the -visual option to allow you to force the framebuffer visual to
-   whatever you want (this usually messes up the colors unless you are
-   very clever.) In this case, the option provides a convenient
-   workaround for the Win2VNC bug:
-  x11vnc -nofb -visual TrueColor -display :0 ...
-
-   So the visual will be set to 8bpp TrueColor and Win2VNC can handle
-   this. Since Win2VNC does not use the framebuffer data there should be
-   no problems in doing this.
-
-   Q-22: Can I run "x11vnc -nofb" on a Mac OS X machine to redirect mouse
-   and keyboard input to it from Windows and X11 machines via Win2VNC and
-   x2vnc, respectively?
-
-   Yes, as of Nov/2006 you can. There may be a trick or two you'll need
-   to do to get the Clipboard exchange between the machines to work.
-
-
-
-   [Color Issues]
-
-   Q-23: The X display I run x11vnc on is only 8 bits per pixel (bpp)
-   PseudoColor (i.e. only 256 distinct colors.) The x11vnc colors may
-   start out OK, but after a while they are incorrect in certain windows.
-
-   Use the -flashcmap option to have x11vnc watch for changes in the
-   colormap, and propagate those changes back to connected clients. This
-   can be slow (since the whole screen must be updated over the network
-   whenever the colormap changes.) This flashing colormap behavior often
-   happens if an application installs its own private colormap when the
-   mouse is in its window. "netscape -install" is a well-known historical
-   example of this. Consider reconfiguring the system to 16 bpp or depth
-   24 TrueColor if at all possible.
-
-   Also note the option -8to24 (Jan/2006) can often remove the need for
-   flashing the colormap. Everything is dynamically transformed to depth
-   24 at 32 bpp using the colormaps. There may be painting errors however
-   (see the following FAQ for tips on reducing and correcting them.)
-
-   In some rare cases (SCO unixware) the -notruecolor option has
-   corrected colors on 8bpp displays. The red, green, and blue masks were
-   non-zero in 8bpp PseudoColor on an obscure setup, and this option
-   corrected the problems.
-
-
-   Q-24: Color problems: Why are the colors for some windows incorrect in
-   x11vnc? BTW, my X display has nice overlay/multi-depth visuals of
-   different color depths: e.g. there are both depth 8 and 24 visuals
-   available at the same time.
-
-   You may want to review the previous question regarding 8 bpp
-   PseudoColor.
-
-   On some hardware (Sun/SPARC and SGI), the -overlay option discussed a
-   couple paragraphs down may solve this for you (you may want to skip to
-   it directly.) On other hardware the less robust -8to24 option may help
-   (also discussed below.)
-
-   Run xdpyinfo(1) to see what the default visual is and what the depths
-   of the other visuals are. Does the default visual have a depth of 8
-   but there are other visuals of depth 24? If it does, can you possibly
-   re-configure your X server to make a depth 24 visual the default? If
-   you can do it, this will save you a lot of grief WRT colors and x11vnc
-   (and for general usage too!) Here is how I do this on an old
-   Sparcstation 20 running Solaris 9 with SX graphics
-  xinit -- -dev /dev/fb defclass TrueColor defdepth 24
-
-   and it works nicely (note: to log into console from the dtlogin
-   window, select "Options -> Command Line Login", then login and enter
-   the above command.) See the -dev section of the Xsun(1) manpage for a
-   description of the above arguments. If you have root permission, a
-   more permanent and convenient thing to do is to record the arguments
-   in a line like:
-  :0  Local local_uid@console root /usr/openwin/bin/Xsun -dev /dev/fb defclass
-TrueColor defdepth 24
-
-   in /etc/dt/config/Xservers (copy /usr/dt/config/Xservers.) Also look
-   at the fbconfig(1) and related manpages (e.g. ffbconfig, m64config,
-   pgxconfig, SUNWjfb_config, etc ...) for hardware framebuffer settings
-   that may achieve the same effect.
-
-   In general for non-Sun machines, look at the "-cc class" and related
-   options in your X server manpage (perhaps Xserver(1)), it may allow
-   modifying the default visual (e.g. "-cc 4", see <X11/X.h> for the
-   visual class numbers.) On XFree86 some video card drivers (e.g. Matrox
-   mga) have settings like Option "Overlay" "24,8" to support multi-depth
-   overlays. For these, use the "-cc 4" X server command line option to
-   get a depth 24 default visual.
-
-
-   The -overlay mode: Another option is if the system with overlay
-   visuals is a Sun system running Solaris or SGI running IRIX you can
-   use the -overlay x11vnc option (Aug/2004) to have x11vnc use the
-   Solaris XReadScreen(3X11) function to poll the "true view" of the
-   whole screen at depth 24 TrueColor. XReadDisplay(3X11) is used on
-   IRIX. This is useful for Legacy applications (older versions of
-   Cadence CAD apps are mentioned by x11vnc users) that require the
-   default depth be 8bpp, or the app will use a 8bpp visual even if depth
-   24 visuals are available, and so the default depth workaround
-   described in the previous paragraph is not sufficient for these apps.
-
-   It seems that Xorg is working toward supporting XReadDisplay(3X11) as
-   part of the RENDER extension work. When it does support it and
-   provides a library API x11vnc will be modified to take advantage of
-   the feature to support -overlay on Linux, *BSD, etc. Until then see
-   the -8to24 mode below.
-
-   Misc. notes on -overlay mode: An amusing by-product of -overlay mode
-   is that the mouse cursor shape is correct! (i.e. XFIXES is not
-   needed.) The -overlay mode may be somewhat slower than normal mode due
-   to the extra framebuffer manipulations that must be performed. Also,
-   on Solaris there is a bug in that for some popup menus, the windows
-   they overlap will have painting errors (flashing colors) while the
-   popup is up (a workaround is to disable SaveUnders by passing -su to
-   Xsun, e.g. in your /etc/dt/config/Xservers file.)
-
-
-   The -8to24 mode: The -8to24 x11vnc option (Jan/2006) is a kludge to
-   try to dynamically rewrite the pixel values so that the 8bpp part of
-   the screen is mapped onto depth 24 TrueColor. This is less robust than
-   the -overlay mode because it is done by x11vnc outside of the X
-   server. So only use it on OS's that do not support -overlay. The
-   -8to24 mode will work if the default visual is depth 24 or depth 8. It
-   scans for any windows within 3 levels of the root window that are 8bpp
-   (i.e. legacy application), or in general ones that are not using the
-   default visual. For the windows it finds it uses XGetSubImage() to
-   retrieve the pixels values and uses the correct indexed colormap to
-   create a depth 24 TrueColor view of the whole screen. This depth 24,
-   32bpp view is exported via VNC.
-
-   Even on pure 8bpp displays it can be used as an alternative to
-   -flashcmap to avoid color flashing completely.
-
-   This scheme is approximate and can often lead to painting errors. You
-   can manually correct most painting errors by pressing 3 Alt_L's in a
-   row, or by using something like: -fixscreen V=3.0 to automatically
-   refresh the screen every 3 seconds. Also -fixscreen 8=3.0 has been
-   added to just refresh the non-default visual parts of the screen.
-
-   In general the scheme uses many resources and may give rise to
-   sluggish behavior. If multiple windows are using different 8bpp
-   indexed colormaps all but one window may need to be iconified for the
-   colors to be correct. There are a number of tunable parameters to try
-   to adjust performance and painting accuracy. The option -8to24
-   nogetimage can give a nice speedup if the default depth 24 X server
-   supports hiding the 8bpp bits in bits 25-32 of the framebuffer data.
-   On very slow machines -8to24 poll=0.2,cachewin=5.0 gives an useful
-   speedup. See the -8to24 help description for information on tunable
-   parameters, etc.
-
-
-   Colors still not working correctly? Run xwininfo on the application
-   with the incorrect colors to verify that the depth of its visual is
-   different from the default visual depth (gotten from xdpyinfo.) One
-   possible workaround in this case is to use the -id option to point
-   x11vnc at the application window itself. If the application is
-   complicated (lots of toplevel windows and popup menus) this may not be
-   acceptable, and may even crash x11vnc (but not the application.) See
-   also -appshare.
-
-   It is theoretically possible to solve this problem in general (see
-   xwd(1) for example), but it does not seem trivial or sufficiently fast
-   for x11vnc to be able to do so in real time. The -8to24 method does
-   this approximately and is somewhat usable. Fortunately the -overlay
-   option works for Solaris machines with overlay visuals where most of
-   this problem occurs.
-
-
-   Q-25: I am on a high color system (depth >= 24) but I seem to have
-   colormap problems. They either flash or everything is very dark.
-
-   This can happen if the default Visual (use xdpyinfo to list them) is
-   DirectColor instead of TrueColor. These are both usually used in high
-   color modes, but whereas TrueColor uses static ramps for the Red,
-   Green, and Blue components, DirectColor has arbitrary colormaps for
-   the Red, Green, and Blue Components. Currently x11vnc cannot decode
-   these colormaps and treats them just like TrueColor.
-
-   The only workaround so far is to restart the X server with the "-cc 4"
-   option to force TrueColor as the default visual (DirectColor is "-cc
-   5"; see /usr/include/X11/X.h.) The only place we have seen this is
-   with the virtual framebuffer server Xvfb on Xorg 7.2. So in that case
-   you probably should restart it with something like this: "Xvfb :1 -cc
-   4 -screen 0 1280x1024x24". It should be possible for x11vnc to handle
-   DirectColor, but this hasn't been implemented due to its rare usage.
-
-   You may also see this problem on an X display with a TrueColor default
-   visual where an application chooses a DirectColor visual for its
-   window(s). It seems the application also needs to install its own
-   colormap for the visual for the colors to be messed up in x11vnc. One
-   can make xwud do this for example.
-
-
-   Q-26: How do I figure out the window id to supply to the -id windowid
-   option?
-
-   Run the xwininfo program in a terminal. It will ask you to click on
-   the desired application window. After clicking, it will print out much
-   information, including the window id (e.g. 0x6000010.) Also, the
-   visual and depth of the window printed out is often useful in
-   debugging x11vnc color problems.
-
-   Also, as of Dec/2004 you can use "-id pick" to have x11vnc run
-   xwininfo(1) for you and after you click the window it extracts the
-   windowid. Besides "pick" there is also "id:root" to allow you to go
-   back to root window when doing remote-control.
-
-
-   Q-27: Why don't menus or other transient windows come up when I am
-   using the -id windowid option to view a single application window?
-
-   This is related to the behavior of the XGetImage(3X11) and
-   XShmGetImage() interfaces regarding backingstore, saveunders, etc. The
-   way the image is retrieved depends on some aspects of how the X server
-   maintains the display image data and whether other windows are
-   clipping or obscuring it. See the XGetImage(3X11) man page for more
-   details. If you disable BackingStore and SaveUnders in the X server
-   you should be able to see these transient windows.
-
-   If things are not working and you still want to do the single window
-   polling, try the -sid windowid option ("shifted" windowid.)
-
-   Update: as of Nov/2009 in the 0.9.9 x11vnc development tarball, there
-   is an experimental Application Sharing mode that improves upon the
-   -id/-sid single window sharing: -appshare (run "x11vnc -appshare
-   -help" for more info.) It is still very primitive and approximate, but
-   at least it displays multiple top-level windows.
-
-
-   Q-28: My X display is depth 24 at 24bpp (instead of the normal depth
-   24 at 32bpp.) I'm having lots of color and visual problems with x11vnc
-   and/or vncviewer. What's up?
-
-   First off, depth 24 at 24bpp (bpp=bits-per-pixel) is fairly uncommon
-   and can cause problems in general. It also can be slower than depth 24
-   at 32bpp. You might want to switch to 32bpp (for XFree86 see the
-   "-fbbpp 32", DefaultFbBpp, FbBpp and related options.) Perhaps you
-   have 24bpp because the video memory of the machine is low and the
-   screen wouldn't fit in video RAM at 32bpp. For this case depth 16 at
-   16bpp might be an acceptable option.
-
-   In any event x11vnc should handle depth 24 at 24bpp (although
-   performance may be slower, and you may need to use the ZRLE encoding
-   instead of Tight.) There are some caveats involving the viewer
-   however:
-
-   The RealVNC Unix viewer cannot handle 24bpp from the server, it will
-   say: "main: setPF: not 8, 16 or 32 bpp?" and exit. I have not checked
-   the RealVNC Windows viewer.
-
-   So you need to use the TightVNC Unix viewer. However there are some
-   problems with that too. It seems libvncserver does not do 24bpp
-   correctly with the Tight encoding. The colors and screen ultimately
-   get messed up. So you have to use a different encoding with the
-   TightVNC vncviewer, try "zlib", "hextile", or one of the other
-   encodings (e.g. vncviewer -encodings "zlib hextile" ....) I have not
-   checked the TightVNC or UltraVNC Windows viewers.
-
-   It appears the older RealVNC Unix viewers (e.g. 3.3.3 and 3.3.7) can
-   handle 24bpp from the server, so you may want to use those. They
-   evidently request 32 bpp and libvncserver obliges.
-
-   Update: as of Apr/2006 you can use the -24to32 option to have x11vnc
-   dynamically transform the 24bpp pixel data to 32bpp. This extra
-   transformation could slow things down further however.
-
-   Now coming the opposite direction if you are running the vncviewer on
-   the 24bpp display, TightVNC will fail with "Can't cope with 24
-   bits-per-pixel. Sorry." and RealVNC will fail with "main: Error:
-   couldn't find suitable pixmap format" so evidently you cannot use
-   24bpp for the vncviewers to work on that X display.
-
-   Note, however, that the Unix viewer in the Enhanced TightVNC Viewer
-   (SSVNC) project can handle 24bpp X displays. It does this by
-   requesting a 16bpp pixel format (or 8bpp if the -bgr233 option has
-   been supplied) from the VNC server, and translates that to 24bpp
-   locally.
-   [Xterminals]
-
-   Q-29: Can I use x11vnc to view and interact with an Xterminal (e.g.
-   NCD) that is not running UNIX and so x11vnc cannot be run on it
-   directly?
-
-   You can, but it will likely be very wasteful of network bandwidth
-   since you will be polling the X display over the network as opposed to
-   over the local hardware. To do this, run x11vnc on a UNIX machine as
-   close as possible network-wise (e.g. same switch) to the Xterminal
-   machine. Use the -display option to point the display to that of the
-   Xterminal (you'll of course need basic X11 permission to do that) and
-   finally supply the -noshm option (this enables the polling over the
-   network.)
-
-   If the Xterminal's X display is open to the network for connections,
-   you might use something like "-display xterm123:0". If you are trying
-   to do this via an SSH tunnel (assuming you can actually ssh into the
-   Xterminal) it will be a little tricky (either use the ssh "-R" option
-   or consider ssh-ing in the other direction.) In all cases the X11
-   permissions need to allow the connection.
-
-   The response will likely be sluggish (maybe only one "frame" per
-   second.) This mode is not recommended except for "quick checks" of
-   hard to get to X servers. Use something like "-wait 150" to cut down
-   on the polling rate. You may also need -flipbyteorder if the colors
-   get messed up due to endian byte order differences.
-
-   Q-30: How do I get my X permissions (MIT-MAGIC-COOKIE file) correct
-   for a Unix/Linux machine acting as an Xterminal?
-
-   If the X display machine is a traditional Xterminal (where the X
-   server process runs on the Xterminal box, but all of the X client
-   applications (firefox, etc) run on a central server (aka "terminal
-   server")), you will need to log into the Xterminal machine (i.e. get a
-   shell running there) and then start the x11vnc program. If the
-   Xterminal Linux/Unix machine is stripped down (e.g. no users besides
-   root) that may be difficult.
-
-   The next problem is the login Display Manager (e.g. gdm, kdm), and
-   hence the MIT-MAGIC-COOKIE auth files, are on the central server and
-   not on the Xterminal box where the X server and x11vnc processes are.
-
-   So unless X permissions are completely turned off (e.g. "xhost +"), to
-   run the x11vnc process on the Xterminal box the MIT-MAGIC-COOKIE auth
-   file data (XAUTHORITY or $HOME/.Xauthority) must be accessible by or
-   copied to the Xterminal. If $HOME/.Xauthority is exported via NFS
-   (this is insecure of course, but has been going on for decades), then
-   x11vnc can simply pick it up via NFS (you may need to use the -auth
-   option to point to the correct file.) Other options include copying
-   the auth file using scp, or something like:
-  central-server>  xauth nextract - xterm123:0 | ssh xterm123 xauth nmerge -
-
-   and then, say, ssh from central-server to xterm123 to start x11vnc.
-   Here "xterm123" refers to the computer acting as the Xterminal and
-   "central-server" is the terminal server. You can use "xauth -f
-   /path/to/cookie-file list" to examine the contents of the cookie(s) in
-   a file "/path/to/cookie-file". See the xauth(1) manpage for more
-   details.
-
-   If the display name in the cookie file needs to be changed between the
-   two hosts, see this note on the "xauth add ..." command.
-
-   A less secure option is to run something like "xhost +127.0.0.1" while
-   sitting at the Xterminal box to allow cookie-free local access for
-   x11vnc. You can run "xhost -127.0.0.1" after x11vnc connects if you
-   want to go back to the original permissions.
-
-   If the Xterminal is really stripped down and doesn't have any user
-   accounts, NFS, etc. you'll need to contact your system administrator
-   to set something up. It can be done!!!  Some Xterminal projects have
-   actually enabled "run locally" facilities for the running of an
-   occasional app more efficiently locally on the Xterminal box (e.g.
-   realplayer.)
-
-   Not recommended, but as a last resort, you could have x11vnc poll the
-   Xterminal Display over the network. For this you would run a "x11vnc
-   -noshm ..." process on the central-server (and hope the network admin
-   doesn't get angry...)
-
-   Note: use of Display Manager (gdm, kdm, ...) auth cookie files (i.e.
-   from /var/...,  /tmp/..., or elsewhere) may require modification via
-   xauth(1) to correctly include the display x11vnc refers to (e.g.
-   "xauth -f cookie-file add :0 . 45be51ae2ce9dfbacd882ab3ef8e96b1",
-   where the "45be51..." cookie value was found from an "xauth -f
-   /path/to/original/cookie-file list") or other reasons. See xauth(1)
-   manpage for full details on how to transfer an MIT-MAGIC-COOKIE
-   between machines and displays.
-
-   VNCviewer performance on Xterminals:  This isn't related to x11vnc on
-   Xterminals, but we mention it here anyway because of the similar
-   issues. If you are on an Xterminal and want to use vncviewer to
-   connect to a VNC server somewhere, then performance would be best if
-   you ran the viewer on the Xterminal box. Otherwise, (i.e. running the
-   viewer process on the central-server) all of the vncviewer screen
-   drawing is done more inefficiently over the network. Something to
-   consider, especially on a busy network. (BTW, this has all of the
-   above permission, etc, problems: both vncviewer and x11vnc are X
-   client apps desired to be run on the Xterminal box.)
-
-   [Sun Rays]
-
-   Q-31: I'm having trouble using x11vnc with my Sun Ray session.
-
-   The Sun Ray technology is a bit like "VNC done in hardware" (the Sun
-   Ray terminal device, DTU, playing the role of the vncviewer.)
-   Completely independent of that, the SunRay user's session is still an
-   X server that speaks the X11 protocol and so x11vnc simply talks to
-   the X server part to export the SunRay desktop to any place in the
-   world (i.e. not only to a Sun Ray terminal device), creating a sort of
-   "Soft Ray". Please see this discussion of Sun Ray issues for solutions
-   to problems.
-
-   Also see the Sun Ray Remote Control Toolkit that uses x11vnc.
-
-   [Remote Control]
-
-   Q-32: How do I stop x11vnc once it is running in the background?
-
-   As of Dec/2004 there is a remote control feature. It can change a huge
-   number of parameters on the fly: see the -remote and -query options.
-   To shut down the running x11vnc server just type "x11vnc -R stop". To
-   disconnect all clients do "x11vnc -R disconnect:all", etc.
-
-   If the -forever option has not been supplied, x11vnc will
-   automatically exit after the first client disconnects. In general if
-   you cannot use the remote control, then you will have to kill the
-   x11vnc process This can be done via: "kill NNNNN" (where NNNNN is the
-   x11vnc process id number found from ps(1)), or "pkill x11vnc", or
-   "killall x11vnc" (Linux only.)
-
-   If you have not put x11vnc in the background via the -bg option or
-   shell & operator, then simply press Ctrl-C in the shell where x11vnc
-   is running to stop it.
-
-   Potential Gotcha: If somehow your Keypress of Ctrl-C went through
-   x11vnc to the Xserver that then delivered it to x11vnc it is possible
-   one or both of the Ctrl or C keys will be left stuck in the pressed
-   down state in the Xserver. Tapping the stuck key (either via a new
-   x11vnc or at the physical console) will release it from the stuck
-   state. If the keyboard seems to be acting strangely it is often fixed
-   by tapping Ctrl, Shift, and Alt. Alternatively, the -clear_mods option
-   and -clear_keys option can be used to release pressed keys at startup
-   and exit. The option -clear_all will also try to unset Caps_Lock,
-   Num_Lock, etc.
-
-
-   Q-33: Can I change settings in x11vnc without having to restart it?
-   Can I remote control it?
-
-   Look at the -remote (an alias is -R) and -query (an alias is -Q)
-   options added in Dec/2004. They allow nearly everything to be changed
-   dynamically and settings to be queried. Examples: "x11vnc -R shared",
-   "x11vnc -R forever", "x11vnc -R scale:3/4", "x11vnc -Q modtweak",
-   "x11vnc -R stop", "x11vnc -R disconnect:all", etc..
-
-   These commands do not start a x11vnc server, but rather communicate
-   with one that is already running. The X display (X11VNC_REMOTE
-   property) is used as the communication channel, so the X permissions
-   and DISPLAY must be set up correctly for communication to be possible.
-
-   There is also a simple Tcl/Tk gui based on this remote control
-   mechanism. See the -gui option for more info. You will need to have
-   Tcl/Tk (i.e. /usr/bin/wish) installed for it to work. It can also run
-   in the system tray: "-gui tray" or as a standalone small icon window:
-   "-gui icon". Use "-gui tray=setpass" for a naive user "Share My
-   Desktop" mode.
-
-   [Security and Permissions]
-
-   Q-34: How do I create a VNC password for use with x11vnc?
-
-   You may already have one in $HOME/.vnc/passwd if you have used, say,
-   the vncserver program from the regular RealVNC or TightVNC packages
-   (i.e. launching the Xvnc server.) Otherwise, you could use the
-   vncpasswd(1) program from those packages.
-
-   As of Jun/2004 x11vnc supports the -storepasswd "pass" "file" option,
-   which is the same functionality of storepasswd. Be sure to quote the
-   "pass" if it contains shell meta characters, spaces, etc. Example:
-  x11vnc -storepasswd 'sword*fish' $HOME/myvncpasswd
-
-   You then use the password via the x11vnc option: "-rfbauth
-   $HOME/myvncpasswd"
-
-   As of Jan/2006 if you do not supply any arguments:
-  x11vnc -storepasswd
-
-   you will be prompted for a password to save to ~/.vnc/passwd (your
-   keystrokes when entering the password will not be echoed to the
-   screen.) If you supply one argument, e.g. "x11vnc -storepasswd
-   ~/.mypass", the password you are prompted for will be stored in that
-   file.
-
-   x11vnc also has the -passwdfile and -passwd/-viewpasswd plain text
-   (i.e. not obscured like the -rfbauth VNC passwords) password options.
-
-   You can use the -usepw option to automatically use any password file
-   you have in ~/.vnc/passwd or ~/.vnc/passwdfile (the latter is used
-   with the -passwdfile option.)
-
-  x11vnc -usepw -display :0 ...
-
-   If neither file exists you are prompted to store a password in
-   ~/.vnc/passwd. If a password file cannot be found or created x11vnc
-   exits immediately. An admin may want to set it up this way for users
-   who do not know better.
-
-
-   Q-35: Can I make it so -storepasswd doesn't show my password on the
-   screen?
-
-   You can use the vncpasswd program from RealVNC or TightVNC mentioned
-   above. As of Jan/2006 the -storepasswd option without any arguments
-   will not echo your password as you type it and save the file to
-   ~/.vnc/passwd:
-  # x11vnc -storepasswd
-  Enter VNC password:
-  Verify password:
-  Write password to /home/myname/.vnc/passwd?  [y]/n
-  Password written to: /home/myname/.vnc/passwd
-
-   You can also give it an alternate filename, e.g. "x11vnc -storepasswd
-   ~/.mypass"
-
-
-   Q-36: Can I have two passwords for VNC viewers, one for full access
-   and the other for view-only access to the display?
-
-   Yes, as of May/2004 there is the -viewpasswd option to supply the
-   view-only password. Note the full-access password option -passwd must
-   be supplied at the same time. E.g.: -passwd sword -viewpasswd fish.
-
-   To avoid specifying the passwords on the command line (where they
-   could be observed via the ps(1) command by any user) you can use the
-   -passwdfile option to specify a file containing plain text passwords.
-   Presumably this file is readable only by you, and ideally it is
-   located on the machine x11vnc is run on (to avoid being snooped on
-   over the network.) The first line of this file is the full-access
-   password. If there is a second line in the file and it is non-blank,
-   it is taken as the view-only password. (use "__EMPTY__" to supply an
-   empty one.)
-
-   View-only passwords currently do not work for the -rfbauth password
-   option (standard VNC password storing mechanism.) FWIW, note that
-   although the output (usually placed in $HOME/.vnc/passwd) by the
-   vncpasswd or storepasswd programs (or from x11vnc -storepasswd) looks
-   encrypted they are really just obscured to avoid "casual" password
-   stealing. It takes almost no skill to figure out how to extract the
-   plain text passwords from $HOME/.vnc/passwd since it is very
-   straight-forward to work out what to do from the VNC source code.
-
-
-   Q-37: Can I have as many full-access and view-only passwords as I
-   like?
-
-   Yes, as of Jan/2006 in the libvncserver CVS the -passwdfile option has
-   been extended to handle as many passwords as you like. You put the
-   view-only passwords after a line __BEGIN_VIEWONLY__.
-
-   You can also easily annotate and comment out passwords in the file.
-   You can have x11vnc re-read the file dynamically when it is modified.
-
-
-   Q-38: Does x11vnc support Unix usernames and passwords? Can I further
-   limit the set of Unix usernames who can connect to the VNC desktop?
-   Update: as of Feb/2006 x11vnc has the -unixpw option that does this
-   outside of the VNC protocol and libvncserver. The standard su(1)
-   program is used to validate the user's password. A familiar "login:"
-   and "Password:" dialog is presented to the user on a black screen
-   inside the vncviewer. The connection is dropped if the user fails to
-   supply the correct password in 3 tries or does not send one before a
-   25 second timeout. Existing clients are view-only during this period.
-   A list of allowed Unix usernames may also be supplied along with
-   per-user settings.
-
-   There is also the -unixpw_nis option for non-shadow-password
-   (typically NIS environments, hence the name) systems where the
-   traditional getpwnam() and crypt() functions are used instead of
-   su(1). The encrypted user passwords must be accessible to the user
-   running x11vnc in -unixpw_nis mode, otherwise the logins will always
-   fail even when the correct password is supplied. See ypcat(1) and
-   shadow(5).
-
-   Two settings are enforced in the -unixpw and -unixpw_nis modes to
-   provide extra security: the 1) -localhost and 2) -stunnel or -ssl
-   options. Without these one might send the Unix username and password
-   data in clear text over the network which is a very bad idea. They can
-   be relaxed if you want to provide encryption other than stunnel or
-   -ssl (the constraint is automatically relaxed if SSH_CONNECTION is set
-   and indicates you have ssh-ed in, however the -localhost requirement
-   is still enforced.)
-
-   The two -unixpw modes have been tested on Linux, Solaris, Mac OS X,
-   HP-UX, AIX, Tru64, FreeBSD, OpenBSD, and NetBSD. Additional testing is
-   appreciated. For the last 4 it appears that su(1) will not prompt for
-   a password if su-ing to oneself. Since x11vnc requires a password
-   prompt from su, x11vnc forces those logins to fail even when the
-   correct password is supplied. On *BSD it appears this can be corrected
-   by removing the pam_self.so entry in /etc/pam.d/su.
-
-
-   Previous older discussion (prior to the -unixpw option):
-
-   Until the VNC protocol and libvncserver support this things will be
-   approximate at best.
-
-   One approximate method involves starting x11vnc with the -localhost
-   option. This basically requires the viewer user to log into the
-   workstation where x11vnc is running via their Unix username and
-   password, and then somehow set up a port redirection of his vncviewer
-   connection to make it appear to emanate from the local machine. As
-   discussed above, ssh is useful for this: "ssh -L 5900:localhost:5900
-   user@hostname ..." See the ssh wrapper scripts mentioned elsewhere on
-   this page. stunnel does this as well.
-
-   Of course a malicious user could allow other users to get in through
-   his channel, but that is a problem with every method. Another thing to
-   watch out for is a malicious user on the viewer side (where ssh is
-   running) trying to sneak in through the ssh port redirection there.
-
-   Regarding limiting the set of Unix usernames who can connect, the
-   traditional way would be to further require a VNC password to supplied
-   (-rfbauth, -passwd, etc) and only tell the people allowed in what the
-   VNC password is. A scheme that avoids a second password involves using
-   the -accept option that runs a program to examine the connection
-   information to determine which user is connecting from the local
-   machine. That may be difficult to do, but, for example, the program
-   could use the ident service on the local machine (normally ident
-   should not be trusted over the network, but on the local machine it
-   should be accurate: otherwise root has been compromised and so there
-   are more serious problems! Unfortunately recent Linux distros seem to
-   provide a random string (MD5 hash?) instead of the username.) An
-   example script passed in via -accept scriptname that deduces the Unix
-   username and limits who can be accepted might look something like
-   this:
-#!/bin/sh
-if [ "$RFB_CLIENT_IP" != "127.0.0.1" -o "$RFB_SERVER_IP" != "127.0.0.1" ]; then
-        exit 1  # something fishy... reject it.
-fi
-user=`echo "$RFB_CLIENT_PORT, $RFB_SERVER_PORT" | nc -w 1 $RFB_CLIENT_IP 113 \
-        | grep 'USERID.*UNIX' | head -n 1 | sed -e 's/[\r ]//g' | awk -F: '{pri
-nt $4}'`
-
-for okuser in fred barney wilma betty
-do
-        if [ "X$user" = "X$okuser" ]; then
-                exit 0  # accept it
-        fi
-done
-exit 1  # reject it
-
-   For this to work with ssh port redirection, the ssh option
-   UsePrivilegeSeparation must be enabled otherwise the userid will
-   always be "root".
-
-   Here is a similar example based on Linux netstat(1) output:
-#!/bin/sh
-#
-# accept_local_netstat:  x11vnc -accept command to accept a local
-# vncviewer connection from acceptable users.  Linux netstat -nte is used.
-
-PATH=/bin:/usr/bin:$PATH; export PATH;  # set to get system utils
-
-allowed="`id -u fred`";                 # add more user numbers if desired.
-
-# check required settings
-ok=1
-if [ "X$allowed" = "X" ]; then
-        ok=0;   # something wrong with allowed list
-fi
-if [ "X$RFB_CLIENT_IP" != "X127.0.0.1" -o "X$RFB_SERVER_IP" != "X127.0.0.1" ];
-then
-        ok=0;   # connection not over localhost
-fi
-if [ "$RFB_CLIENT_PORT" -le 0 -o "$RFB_SERVER_PORT" -le 0 ]; then
-        ok=0;   # something wrong with tcp port numbers
-fi
-if [ "$ok" = 0 ]; then
-        echo "$0: invalid setting:" 1>&2
-        env | grep ^RFB | sort 1>&2
-        exit 1
-fi
-
-# Linux netstat -nte:
-# Proto Recv-Q Send-Q Local Address           Foreign Address         State
-   User       Inode
-# 0     0      0      RFB_CLIENT              RFB_SERVER           ESTABLISHED
-   nnnn       ....
-#
-user=`netstat -nte | grep ESTABLISHED \
-        | grep " $RFB_CLIENT_IP:$RFB_CLIENT_PORT  *$RFB_SERVER_IP:$RFB_SERVER_P
-ORT "`
-
-echo "netstat match: $user" 1>&2
-user=`echo "$user" | head -n 1 | sed -e 's/^.*ESTABLISHED/ /' | awk '{print $1}
-'`
-
-ok=0
-for u in $allowed
-do
-        if [ "X$user" = "X$u" ]; then
-                ok=1
-                break
-        fi
-done
-
-if [ "X$ok" = "X1" ]; then
-        echo "$0: user accepted: '$user'" 1>&2
-        exit 0
-else
-        echo "$0: user '$user' invalid:" 1>&2
-        echo "$0: allowed: $allowed" 1>&2
-        env | grep ^RFB | sort 1>&2
-        exit 1
-fi
-
-
-   Q-39: Can I supply an external program to provide my own custom login
-   method (e.g. Dynamic/One-time passwords or non-Unix (LDAP) usernames
-   and passwords)?
-   Yes, there are several possibilities. For background see the FAQ on
-   the -accept where an external program may be run to decide if a VNC
-   client should be allowed to try to connect and log in. If the program
-   (or local user prompted by a popup) answers "yes", then -accept
-   proceeds to the normal VNC and x11vnc authentication methods,
-   otherwise the connection is dropped.
-
-   To provide more direct coupling to the VNC client's username and/or
-   supplied password the following options were added in Sep/2006:
-     * -unixpw_cmd command
-     * -passwdfile cmd:command
-     * -passwdfile custom:command
-
-   In each case "command" is an external command run by x11vnc. You
-   supply it. For example, it may couple to your LDAP system or other
-   servers you set up.
-
-   For -unixpw_cmd the normal -unixpw Login: and Password: prompts are
-   supplied to the VNC viewer and the strings the client returns are then
-   piped into "command" as the first two lines of its standard input. If
-   the command returns success, i.e. exit(0), the VNC client is accepted,
-   otherwise it is rejected.
-
-   For "-passwdfile cmd:command" the command is run and it returns a
-   password list (like a password file, see the -passwdfile read:filename
-   mode.) Perhaps a dynamic, one-time password is retrieved from a server
-   this way.
-
-   For "-passwdfile custom:command" one gets complete control over the
-   VNC challenge-response dialog with the VNC client. x11vnc sends out a
-   string of random bytes (16 by the VNC spec) and the client returns the
-   same number of bytes in a way the server can verify only the
-   authorized user could have created. The VNC protocol specifies DES
-   encryption with a password. If you are willing to modify the VNC
-   viewers, you can have it be anything you want, perhaps a less
-   crackable MD5 hash scheme or one-time pad. Your program will read from
-   its standard input the size of the challenge-response followed by a
-   newline, then the challenge bytes followed by the response bytes. If
-   your command then returns success, i.e. exit(0), the VNC client is
-   accepted, otherwise it is rejected.
-
-   In all cases the "RFB_*" environment variables are set as under
-   -accept. These variables can provide useful information for the
-   externally supplied program to use.
-
-
-   Q-40: Why does x11vnc exit as soon as the VNC viewer disconnects? And
-   why doesn't it allow more than one VNC viewer to connect at the same
-   time?
-
-   These defaults are simple safety measures to avoid someone unknowingly
-   leaving his X11 desktop exposed (to the internet, say) for long
-   periods of time. Use the -forever option (aka -many) to have x11vnc
-   wait for more connections after the first client disconnects. Use the
-   -shared option to have x11vnc allow multiple clients to connect
-   simultaneously.
-
-   Recommended additional safety measures include using ssh (see above),
-   stunnel, -ssl, or a VPN to authenticate and encrypt the viewer
-   connections or to at least use the -rfbauth passwd-file option to use
-   VNC password protection (or -passwdfile) It is up to YOU to apply
-   these security measures, they will not be done for you automatically.
-
-
-   Q-41: Can I limit which machines incoming VNC clients can connect
-   from?
-
-   Yes, look at the -allow and -localhost options to limit connections by
-   hostname or IP address. E.g.
-  x11vnc -allow 192.168.0.1,192.168.0.2
-
-   for those two hosts or
-  x11vnc -allow 192.168.0.
-
-   for a subnet. For individual hosts you can use the hostname instead of
-   the IP number, e.g.: "-allow snoopy", and "-allow darkstar,wombat".
-   Note that -localhost achieves the same thing as "-allow 127.0.0.1"
-
-   For more control, build libvncserver with libwrap support
-   (tcp_wrappers) and then use /etc/hosts.allow See hosts_access(5) for
-   complete details.
-
-
-   Q-42: How do I build x11vnc/libvncserver with libwrap (tcp_wrappers)
-   support?
-
-   Here is one way to pass this information to the configure script:
-  env CPPFLAGS=-DUSE_LIBWRAP LDFLAGS=-lwrap ./configure
-
-   then run make as usual. This requires libwrap and its development
-   package (tcpd.h) to be installed on the build machine. If additional
-   CPPFLAGS or LDFLAGS options are needed supply them as well using
-   quotes.
-
-   The resulting x11vnc then uses libwrap/tcp_wrappers for connections.
-   The service name you will use in /etc/hosts.allow and /etc/hosts.deny
-   is "vnc", e.g.:
-  vnc: 192.168.100.3 .example.com
-
-   Note that if you run x11vnc out of inetd you do not need to build
-   x11vnc with libwrap support because the /usr/sbin/tcpd reference in
-   /etc/inetd.conf handles the tcp_wrappers stuff.
-
-
-   Q-43: Can I have x11vnc only listen on one network interface (e.g.
-   internal LAN) rather than having it listen on all network interfaces
-   and relying on -allow to filter unwanted connections out?
-
-   As of Mar/2005 there is the "-listen ipaddr" option that enables this.
-   For ipaddr either supply the desired network interface's IP address
-   (or use a hostname that resolves to it) or use the string "localhost".
-   For additional filtering simultaneously use the "-allow host1,..."
-   option to allow only specific hosts in.
-
-   This option is useful if you want to insure that no one can even begin
-   a dialog with x11vnc from untrusted network interfaces (e.g. ppp0.)
-   The option -localhost now implies "-listen localhost" since that is
-   what most people expect it to do.
-
-
-   Q-44: Now that -localhost implies listening only on the loopback
-   interface, how I can occasionally allow in a non-localhost via the -R
-   allowonce remote control command?
-
-   To do this specify "-allow localhost". Unlike -localhost this will
-   leave x11vnc listening on all interfaces (but of course only allowing
-   in local connections, e.g. ssh redirs.) Then you can later run "x11vnc
-   -R allowonce:somehost" or use to gui to permit a one-shot connection
-   from a remote host.
-
-
-   Q-45: Can I fine tune what types of user input are allowed? E.g. have
-   some users just be able to move the mouse, but not click or type
-   anything?
-
-   As of Feb/2005, the -input option allows you to do this. "K", "M",
-   "B", "C", and "F" stand for Keystroke, Mouse-motion, Button-clicks,
-   Clipboard, and File-Transfer, respectively. The setting: "-input M"
-   makes attached viewers only able to move the mouse. "-input KMBC,M"
-   lets normal clients do everything and enables view-only clients to
-   move the mouse.
-
-   These settings can also be applied on a per-viewer basis via the
-   remote control mechanism or the GUI. E.g. x11vnc -R input:hostname:M
-
-
-   Q-46: Can I prompt the user at the local X display whether the
-   incoming VNC client should be accepted or not? Can I decide to make
-   some clients view-only? How about running an arbitrary program to make
-   the decisions?
-
-   Yes, look at the "-accept command" option, it allows you to specify an
-   external command that is run for each new client. (use quotes around
-   the command if it contains spaces, etc.) If the external command
-   returns 0 (success) the client is accepted, otherwise with any other
-   return code the client is rejected. See below how to also accept
-   clients view-only.
-
-   The external command will have the RFB_CLIENT_IP environment variable
-   set to the client's numerical IP address, RFB_CLIENT_PORT its port
-   number. Similarly for RFB_SERVER_IP and RFB_SERVER_PORT to allow
-   identification of the tcp virtual circuit. DISPLAY will be set to that
-   of the X11 display being polled. Also, RFB_X11VNC_PID is set to the
-   x11vnc process id (e.g. in case you decided to kill it), RFB_CLIENT_ID
-   will be an id number, and RFB_CLIENT_COUNT the number of other clients
-   currently connected. RFB_MODE will be "accept".
-
-   Built-in Popup Window: As a special case, "-accept popup" will
-   instruct x11vnc to create its own simple popup window. To accept the
-   client press "y" or click mouse on the "Yes" button. To reject the
-   client press "n" or click mouse on the "No" button. To accept the
-   client View-only, press "v" or click mouse on the "View" button. If
-   the -viewonly option has been supplied, the "View" action will not be
-   present: the whole display is view only in that case.
-
-   The popup window times out after 120 seconds, to change this behavior
-   use "-accept popup:N" where N is the number of seconds (use 0 for no
-   timeout.) More tricks: "-accept popupmouse" will only take mouse click
-   responses, while "-accept popupkey" will only take keystroke responses
-   (popup takes both.) After any of the 3 popup keywords you can supply a
-   position of the window: +N+M, (the default is to center the window)
-   e.g. -accept popupmouse+10+10.
-
-   Also as a special case "-accept xmessage" will run the xmessage(1)
-   program to prompt the user whether the client should be accepted or
-   not. This requires that you have xmessage installed and available via
-   PATH. In case it is not already on your system, the xmessage program
-   is available at ftp://ftp.x.org/
-   (End of Built-in Popup Window:)
-
-   To include view-only decisions for the external commands, prefix the
-   command something like this: "yes:0,no:*,view:3 mycommand ..." This
-   associates the three actions: yes(accept), no(reject), and
-   view(accept-view-only), with the numerical return (i.e. exit()) codes.
-   Use "*" instead of a number to set the default action (e.g. in case
-   the external command returns an unexpected return code.)
-
-   Here is an example -accept script called accept_or_lock. It uses
-   xmessage and xlock (replace with your screen lock command, maybe it is
-   "xscreensaver-command -lock", or kdesktop_lock, or "dtaction
-   LockDisplay".) It will prompt the user at the X display whether to
-   accept, reject, or accept view-only the client, but if the prompt
-   times out after 60 seconds the screen is locked and the VNC client is
-   accepted. This allows the remote access when no one is at the display.
-#!/bin/sh
-#
-# accept_or_lock: prompt user at X display whether to accept an incoming
-#                 VNC connection.  If timeout expires, screen is locked
-#                 and the VNC viewer is accepted (allows remote access
-#                 when no one is sitting at the display.)
-#
-# usage: x11vnc ... -forever -accept 'yes:0,no:*,view:4 accept_or_lock'
-#
-xmessage -buttons yes:2,no:3,view-only:4 -center \
-         -timeout 60 "x11vnc: accept connection from $RFB_CLIENT_IP?"
-rc=$?
-if [ $rc = 0 ]; then
-        xlock & # or "xlock -mode blank" for no animations.
-        sleep 5
-        exit 0
-elif [ $rc = 2 ]; then
-        exit 0
-elif [ $rc = 4 ]; then
-        exit 4
-fi
-exit 1
-
-   Stefan Radman has written a nice dtksh script dtVncPopup for use in
-   CDE environments to do the same sort of thing. Information on how to
-   use it is found at the top of the file. He encourages you to provide
-   feedback to him to help improve the script.
-
-   Note that in all cases x11vnc will block while the external command or
-   popup is being run, so attached clients will not receive screen
-   updates, etc during this period.
-
-   To run a command when a client disconnects, use the "-gone command"
-   option. This is for the user's convenience only: the return code of
-   the command is not interpreted by x11vnc. The same environment
-   variables are set as in "-accept command" (except that RFB_MODE will
-   be "gone".)
-
-   As of Jan/2006 the "-afteraccept command" option will run the command
-   only after the VNC client has been accepted and authenticated. Like
-   -gone the return code is not interpreted. RFB_MODE will be
-   "afteraccept".)
-
-
-   Q-47: I start x11vnc as root because it is launched via inetd(8) or a
-   display manager like gdm(1). Can I have x11vnc later switch to a
-   different user?
-
-   As of Feb/2005 x11vnc has the -users option that allows things like
-   this. Please read the documentation on it (also in the x11vnc -help
-   output) carefully for features and caveats. It's use can often
-   decrease security unless care is taken.
-
-   BTW, a nice use of it is "-users +nobody" that switches to the Unix
-   user nobody right after connections to the X display are established.
-
-   In any event, while running x11vnc as root, remember it comes with no
-   warranty ;-).
-
-
-   Q-48: I use a screen-lock when I leave my workstation (e.g.
-   xscreensaver or xlock.) When I remotely access my workstation desktop
-   via x11vnc I can unlock the desktop fine, but I am worried people will
-   see my activities on the physical monitor. What can I do to prevent
-   this, or at least make it more difficult?
-
-   Probably most work environments would respect your privacy if you
-   powered off the monitor. Also remember if people have physical access
-   to your workstation they basically can do anything they want with it
-   (e.g. install a backdoor for later use, etc.)
-
-   In any event, as of Jun/2004 there is an experimental utility to make
-   it more difficult for nosey people to see your x11vnc activities. The
-   source for it is blockdpy.c The idea behind it is simple (but
-   obviously not bulletproof): when a VNC client attaches to x11vnc put
-   the display monitor in the DPMS "off" state, if the DPMS state ever
-   changes immediately start up the screen-lock program. The x11vnc user
-   will notice something is happening and think about what to do next
-   (while the screen is in a locked state.)
-
-   This works (or at least has a chance of working) because if the
-   intruder moves the mouse or presses a key on the keyboard, the monitor
-   wakes up out of the DPMS off state, and this induces the screen lock
-   program to activate as soon as possible. Of course there are cracks in
-   this, the eavesdropper could detach your monitor and insert a non-DPMS
-   one, and there are race conditions. As mentioned above this is not
-   bulletproof. A really robust solution would likely require X server
-   and perhaps even video hardware support.
-
-   The blockdpy utility is launched by the -accept option and told to
-   exit via the -gone option (the vnc client user should obviously
-   re-lock the screen before disconnecting!) Instructions can be found in
-   the source code for the utility at the above link. Roughly it is
-   something like this:
-  x11vnc ... -accept "blockdpy -bg -f $HOME/.bdpy" -gone "touch $HOME/.bdpy"
-
-   but please read the top of the file.
-
-   Update: As of Feb/2007 there is some builtin support for this:
-   -forcedpms and -clientdpms however, they are probably less robust than
-   the above blockdpy.c scheme, since if the person floods the physical
-   machine with mouse or pointer input he can usually see flashes of the
-   screen before the monitor is powered off again. See also the -grabkbd,
-   -grabptr, and -grabalways options.
-
-
-   Q-49: Can I have x11vnc automatically lock the screen when I
-   disconnect the VNC viewer?
-
-   Yes, a user mentions he uses the -gone option under CDE to run a
-   screen lock program:
-  x11vnc -display :0 -forever -gone 'dtaction LockDisplay'
-
-   Other possibilities are:
-  x11vnc -display :0 -forever -gone 'xscreensaver-command -lock'
-  x11vnc -display :0 -forever -gone 'kdesktop_lock'
-  x11vnc -display :0 -forever -gone 'xlock &'
-  x11vnc -display :0 -forever -gone 'xlock -mode blank &'
-
-   Here is a scheme using the -afteraccept option (in version 0.8) to
-   unlock the screen after the first valid VNC login and to lock the
-   screen after the last valid VNC login disconnects:
-  x11vnc -display :0 -forever -shared -afteraccept ./myxlocker -gone ./myxlocke
-r
-
-   Where the script ./myxlocker is:
-#!/bin/sh
-
-#/usr/bin/env | grep RFB_ | sort        # for viewing RFB_* settings.
-
-if [ "X$RFB_MODE" = "Xafteraccept" ]; then
-        if [ "X$RFB_STATE" = "XNORMAL" ]; then  # require valid login
-                if [ "X$RFB_CLIENT_COUNT" = "X1" ]; then
-                        killall xlock   # Linux only.
-                fi
-        fi
-elif [ "X$RFB_MODE" = "Xgone" ]; then
-        if [ "X$RFB_STATE" = "XNORMAL" ]; then  # require valid login
-                if [ "X$RFB_CLIENT_COUNT" = "X0" ]; then
-                        xlock -mode blank &
-                fi
-        fi
-fi
-
-   Note the xlock option "-mode blank" to avoid animations.
-
-   There is a problem if you have x11vnc running this way in -forever
-   mode and you hit Ctrl-C to stop it. The xlock (or other program) will
-   get killed too. To work around this make a little script called
-   setpgrp that looks like:
-#!/usr/bin/perl
-setpgrp(0, 0);
-exec @ARGV;
-
-   then use -gone "setpgrp xlock &", etc.
-   [Encrypted Connections]
-
-   Q-50: How can I tunnel my connection to x11vnc via an encrypted SSH
-   channel between two Unix machines?
-
-   See the description earlier on this page on how to tunnel VNC via SSH
-   from Unix to Unix. A number of ways are described along with some
-   issues you may encounter.
-
-   Other secure encrypted methods exists, e.g. stunnel, IPSEC, various
-   VPNs, etc.
-
-   See also the Enhanced TightVNC Viewer (SSVNC) page where much of this
-   is now automated.
-
-
-   Q-51: How can I tunnel my connection to x11vnc via an encrypted SSH
-   channel from Windows using an SSH client like Putty?
-
-   Above we described how to tunnel VNC via SSH from Unix to Unix, you
-   may want to review it. To do this from Windows using Putty it would go
-   something like this:
-     * In the Putty dialog window under 'Session' enter the hostname or
-       IP number of the Unix machine with display to be viewed.
-     * Make sure the SSH protocol is selected and the server port is
-       correct.
-     * Under 'Connections/SSH/Tunnels' Add a Local connection with
-       'Source port:  5900' and 'Destination:  localhost:5900'
-     * Log into the remote machine by pressing 'Open' and supplying
-       username, password, etc.
-     * In that SSH shell, start up x11vnc by typing the command: x11vnc
-       -display :0 plus any other desired options (e.g. -localhost.)
-     * Finally, start up your VNC Viewer in Windows and enter
-       'localhost:0' as the VNC server.
-
-   You can keep all of the settings in a Putty 'Saved Session'. Also,
-   once everything is working, you can consider putting x11vnc -display
-   :0 (plus other cmdline options) in the 'Remote command' Putty setting
-   under 'Connections/SSH'.
-
-   See also the Enhanced TightVNC Viewer (SSVNC) page where much of this
-   is now automated via the Putty plink utility.
-
-   For extra protection feel free to run x11vnc with the -localhost and
-   -rfbauth/-passwdfile options.
-
-   If the machine you SSH into via Putty is not the same machine with the
-   X display you wish to view (e.g. your company provides incoming SSH
-   access to a gateway machine), then you need to change the above Putty
-   dialog setting to: 'Destination: otherhost:5900', Once logged in,
-   you'll need to do a second login (ssh or rsh) to the workstation
-   machine 'otherhost' and then start up x11vnc on it. This can also be
-   automated by Chaining SSH's.
-
-   As discussed above another option is to first start the VNC viewer in
-   "listen" mode, and then launch x11vnc with the "-connect localhost"
-   option to establish the reverse connection. In this case a Remote port
-   redirection (not Local) is needed for port 5500 instead of 5900 (i.e.
-   'Source port:  5500' and 'Destination:  localhost:5500' for a Remote
-   connection.)
-
-
-   Q-52: How can I tunnel my connection to x11vnc via an encrypted SSL
-   channel using an external tool like stunnel?
-
-   It is possible to use a "lighter weight" encryption setup than SSH or
-   IPSEC. SSL tunnels such as stunnel (also stunnel.org) provide an
-   encrypted channel without the need for Unix users, passwords, and key
-   passphrases required for ssh (and at the other extreme SSL can also
-   provide a complete signed certificate chain of trust.) On the other
-   hand, since SSH is usually installed everywhere and firewalls often
-   let its port through, ssh is frequently the path of least resistance
-   (it also nicely manages public keys for you.)
-
-   Update: As of Feb/2006 x11vnc has the options -ssl, -stunnel, and
-   -sslverify to provide integrated SSL schemes. They are discussed in
-   the Next FAQ (you probably want to skip to it now.)
-
-   We include these non-built-in method descriptions below for historical
-   reference. They are handy because can be used to create SSL tunnels to
-   any VNC (or other type of) server.
-
-
-   Here are some basic examples using stunnel but the general idea for
-   any SSL tunnel utility is the same:
-     * Start up x11vnc and constrain it to listen on localhost.
-     * Then start up the SSL tunnel running on the same machine to
-       forward incoming connections to that x11vnc.
-     * Set up and run a similar SSL tunnel for the outgoing connection on
-       the VNC viewer machine pointing it to the SSL/x11vnc server.
-     * Optionally, set up server (or even client) public/private keys for
-       use in authenticating one side to the other.
-     * Finally, start the VNC Viewer and tell it to connect to the local
-       port (e.g. a vnc display localhost:0) where its outgoing SSL
-       tunnel is listening.
-
-   We'll first use the stunnel version 3 syntax since it is the most
-   concise and Unixy.
-
-   Start up x11vnc listening on port 5900:
-  x11vnc -display :0 -rfbport 5900 -localhost -bg -passwdfile ~/mypass
-
-   Then start stunnel (version 3, not 4) with this command:
-  stunnel -d 5901 -r 5900 -p /path/to/stunnel.pem
-
-   The above two commands are run on host "far-away.east". The
-   stunnel.pem is the self-signed PEM file certificate created when
-   stunnel is built. One can also create certificates signed by
-   Certificate Authorities or self-signed if desired using the x11vnc
-   utilities described there.
-
-   SSL Viewers:  Next, on the VNC viewer side we need an SSL tunnel to
-   encrypt the outgoing connection. The nice thing is any SSL tunnel can
-   be used because the protocol is a standard. For this example we'll
-   also use stunnel on the viewer side on Unix. First start up the
-   client-side stunnel (version 3, not 4):
-  stunnel -c -d localhost:5902 -r far-away.east:5901
-
-   Then point the viewer to the local tunnel on port 5902:
-  vncviewer -encodings "copyrect tight zrle hextile" localhost:2
-
-   That's it.  Note that the ss_vncviewer script can automate this
-   easily, and so can the Enhanced TightVNC Viewer (SSVNC) package.
-
-   Be sure to use a VNC password because unlike ssh by default the
-   encrypted SSL channel provides no authentication (only privacy.) With
-   some extra configuration one could also set up certificates to provide
-   authentication of either or both sides as well (and hence avoid
-   man-in-the-middle attacks.) See the stunnel and openssl documentation
-   and also the key management section for details.
-
-   stunnel has also been ported to Windows, and there are likely others
-   to choose from for that OS. Much info for using it on Windows can be
-   found at the stunnel site and in this article The article also shows
-   the detailed steps to set up all the authentication certificates. (for
-   both server and clients, see also the x11vnc utilities that do this.)
-   The default Windows client setup (no certs) is simpler and only 4
-   files are needed in a folder: stunnel.exe, stunnel.conf, libssl32.dll,
-   libeay32.dll. We used an stunnel.conf containing:
-# stunnel.conf:
-client = yes
-options = ALL
-[myvncssl]
-accept = localhost:5902
-connect = far-away.east:5901
-
-   then double click on the stunnel.exe icon to launch it (followed by
-   pointing the VNC viewer to localhost:2).
-
-
-   stunnel inetd-like mode:
-
-   As an aside, if you don't like the little "gap" of unencrypted TCP
-   traffic (and a localhost listening socket) on the local machine
-   between stunnel and x11vnc it can actually be closed by having stunnel
-   start up x11vnc in -inetd mode:
-  stunnel -p /path/to/stunnel.pem -P none -d 5900 -l ./x11vnc_sh
-
-   Where the script x11vnc_sh starts up x11vnc:
-#!/bin/sh
-x11vnc -q -inetd -display :0 -passwdfile ~/mypass
-
-   Note that this creates a separate x11vnc process for each incoming
-   connection (as any inetd x11vnc usage would), but for the case of
-   normally just one viewer at a time it should not be a big problem.
-
-
-   stunnel 4 syntax:
-
-   Somewhat sadly, the stunnel version 4 syntax is not so amenable to the
-   command line or scripts. You need to create a config file with the
-   parameters. E.g.:
-  stunnel x11vnc.cfg
-
-   Where the file x11vnc.cfg contains:
-foreground = yes
-pid =
-cert = /path/to/stunnel.pem
-[x11vnc_stunnel]
-accept  = 5901
-connect = 5900
-
-   One nice thing about version 4 is often the PEM file does not need to
-   be specified because stunnel finds it in its installed area. One other
-   gotcha the PEM file is usually only readable by root (it has the
-   private key afterall), so you'll need to relax the permissions or make
-   a copy that the user running x11vnc/stunnel can read.
-
-
-   SSL VNC Viewers:
-
-   Regarding VNC viewers that "natively" do SSL unfortunately there do
-   not seem to be many. The SingleClick UltraVNC Java Viewer is SSL and
-   is compatible with x11vnc's -ssl option and stunnel.) Commercial
-   versions of VNC seem to have some SSL-like encryption built in, but we
-   haven't tried those either and they probably wouldn't work since their
-   (proprietary) SSL-like negotiation is likely embedded in the VNC
-   protocol unlike our case where it is external.
-
-   Note: as of Mar/2006 libvncserver/x11vnc provides a SSL-enabled Java
-   applet that can be served up via the -httpdir or -http options when
-   -ssl is enabled. It will also be served via HTTPS via either the VNC
-   port (e.g. https://host:5900/) or a 2nd port via the -https option.
-
-   In general current SSL VNC solutions are not particularly "seemless".
-   But it can be done, and with a wrapper script on the viewer side and
-   the -stunnel or -ssl option on the server side it works well and is
-   convenient. Here is a simple script ss_vncviewer that automates
-   running stunnel on the VNC viewer side on Unix a little more carefully
-   than the commands printed above. (One could probably do a similar
-   thing with a .BAT file on Windows in the stunnel folder.)
-
-   Update Jul/2006: we now provide an Enhanced TightVNC Viewer (SSVNC)
-   package that starts up STUNNEL automatically along with some other
-   features. All binaries (stunnel, vncviewer, and some utilities) are
-   provided in the package. It works on Unix, Mac OS X, and Windows.
-
-
-   Q-53: Does x11vnc have built-in SSL tunneling?
-
-   You can read about non-built-in methods in the Previous FAQ for
-   background.
-
-   SSL tunnels provide an encrypted channel without the need for Unix
-   users, passwords, and key passphrases required for ssh (and at the
-   other extreme SSL can also provide a complete signed certificate chain
-   of trust.) On the other hand, since SSH is usually installed
-   everywhere and firewalls often let its port through, ssh is frequently
-   the path of least resistance.
-
-   Built-in SSL x11vnc options:
-
-   As of Feb/2006 the x11vnc -ssl option automates the SSL tunnel
-   creation on the x11vnc server side. An SSL-enabled Java Viewer applet
-   is also provided that can be served via HTTP or HTTPS to automate SSL
-   on the client side.
-
-   The -ssl mode uses the www.openssl.org library if available at build
-   time.
-
-   The mode requires an SSL certificate and key (i.e. .pem file.) These
-   are usually created via the openssl(1) program (in fact in for "-ssl"
-   (same as "-ssl SAVE") it will run openssl for you automatically.) So
-   the SSL is not completely "built-in" since this external tool needs to
-   be installed, but at least x11vnc runs it for you automatically.
-
-   An -ssl example:
-  x11vnc -display :0 -ssl -passwdfile ~/mypass
-
-   You'll get output like this:
-  09/04/2006 19:27:35 Creating a self-signed PEM certificate...
-  09/04/2006 19:27:35
-  ...
-
-  The SSL VNC desktop is:  far-away.east:0
-  PORT=5900
-  SSLPORT=5900
-
-   In this case openssl(1) was used to create a PEM automatically. It
-   will prompt you if you want to protect it with with a passphrase. Use
-   "-ssl SAVE_NOPROMPT" to not be prompted. Use "-ssl TMP" to create a
-   temporary self-signed cert that will be discarded when x11vnc exits.
-
-   Update: As of Nov/2008 x11vnc also supports the VeNCrypt SSL/TLS
-   tunnel extension to the VNC protocol. The older ANONTLS method (vino)
-   is also supported. This support is on by default when the -ssl option
-   is in use and can be fine-tuned using these options: -vencrypt,
-   -anontls, and -sslonly.
-
-   The normal x11vnc -ssl operation is somewhat like a URL method
-   vncs://hostname if vnc://hostname indicates a standard unencrypted VNC
-   connection. Just as https://hostname is an SSL encrypted version of
-   http://hostname. The entire VNC session goes through the SSL tunnel.
-   VeNCrypt, on the other hand, switches to SSL/TLS early in the VNC
-   protocol handshake. x11vnc 0.9.6 supports both simultaneously when
-   -ssl is active.
-
-
-   SSL VNC Viewers:. Viewer-side will need to use SSL as well. See the
-   next FAQ and here for SSL enabled VNC Viewers, including SSVNC, to
-   connect to the above x11vnc via SSL.
-
-
-   As seen above, the PEM (privacy enhanced mail) file does not need to
-   be supplied if the openssl(1) command is available in PATH, in that
-   case a self-signed, certificate good the current and subsequent x11vnc
-   sessions is created (this may take a while on very slow machines.)
-
-   In general, the PEM file contains both the Certificate (i.e. public
-   key) and the Private Key. Because of the latter, the file should be
-   protected from being read by untrusted users. The best way to do this
-   is to encrypt the key with a passphrase (note however this requires
-   supplying the passphrase each time x11vnc is started up.)
-
-   See the discussion on x11vnc Key Management for some utilities
-   provided for creating and managing certificates and keys and even for
-   creating your own Certificate Authority (CA) for signing VNC server
-   and client certificates. This may be done by importing the certificate
-   into Web Browser or Java plugin keystores, or pointing stunnel to it.
-   The wrapper script ss_vncviewer provides an example on unix (see the
-   -verify option.)
-
-   Here are some notes on the simpler default (non-CA) operation. To have
-   x11vnc save the generated certificate and key, use the "SAVE" keyword
-   like this:
-  x11vnc -ssl SAVE -display :0 ...
-
-   (this is the same as the default: "-ssl".) This way it will be saved
-   in the default directory ~/.vnc/certs/ as server.crt (the certificate
-   only) and server.pem (both certificate and private key.) This opens up
-   the possibility of copying the server.crt to machines where the VNC
-   Viewer will be run to enable authenticating the x11vnc SSL VNC server
-   to the clients. When authentication takes place this way (or via the
-   more sophisticated CA signing described here), then
-   Man-In-The-Middle-Attacks are prevented. Otherwise, the SSL encryption
-   only provides protection against passive network traffic "sniffing"
-   (i.e. you are not protected against M-I-T-M attacks.) Nowadays, most
-   people seem mostly concerned mainly about passive sniffing (and the
-   default x11vnc SSL mode protects against it.) Note that there are
-   hacker tools like dsniff/webmitm and cain that implement SSL
-   Man-In-The-Middle attacks. They rely on the client not bothering to
-   check the cert.
-
-
-   One can test to some degree that SSL is working after starting x11vnc
-   with the -stunnel or -ssl option. From another machine one can use the
-   openssl command something like this:
- openssl s_client -debug -msg -showcerts -connect far-away.east:5900
-
-   After all of the debugging output and informational messages you'll
-   see the string "RFB 003.008" that came from x11vnc. Pointing a web
-   browser connecting to: https://far-away.east:5900/ and then viewing
-   the SSL certificate information about the connection in the panels
-   will also work.
-
-   Note: If you serve up the SSL enabled Java VNC Viewer via something
-   like:
- x11vnc -ssl -httpdir /usr/local/share/x11vnc/classes/ssl
-
-   (or just the -http option), you can test it out completely using that,
-   including using https to download it into the browser and connect to
-   x11vnc.
-
-
-   The older -stunnel option: Before the -ssl option there was a
-   convenience option -stunnel that would start an external SSL tunnel
-   for you using stunnel. The -ssl method is the preferred way, but for
-   historical reference we keep the -stunnel info here.
-
-   The -stunnel mode requires the stunnel.mirt.net command stunnel(8) to
-   be installed on the system.
-
-   Some -stunnel examples:
-  x11vnc -display :0 -stunnel /path/to/stunnel.pem -passwdfile ~/mypass
-
-  x11vnc -display :0 -stunnel SAVE ...
-
-   You'll get output like this:
-  The VNC desktop is:      localhost:50
-  The SSL VNC desktop is:  far-away.east:0
-  PORT=5950
-  SSLPORT=5900
-
-   That indicates stunnel is listening on port 5900 for incoming
-   SSL-wrapped VNC connections from viewers. x11vnc is listening for
-   local connections on port 5950 in this case (remote viewers cannot
-   connect to it directly.) For -stunnel to work the stunnel command must
-   be installed on the machine and available in PATH (note stunnel is
-   often installed in sbin directories rather than bin.) Note that the
-   default "-stunnel" by itself creates a temporary cert (as in "-ssl
-   TMP".)
-
-
-   Q-54: How do I use VNC Viewers with built-in SSL tunneling?
-
-   Notes on using "native" VNC Viewers with SSL:
-
-   There aren't any native VNC Viewers that do SSL (ask your VNC viewer
-   developer to add the feature.) So a tunnel must be setup that you
-   point the VNC Viewer to. This is often STUNNEL. You can do this
-   manually, or use the ss_vncviewer script on Unix, or our Enhanced
-   TightVNC Viewer (SSVNC) package on Unix, Windows, or MacOSX. See the
-   next section for Java Web browser SSL VNC Viewers (you only need a
-   Java-enabled Web browser for it to work.)
-
-   Notes on the SSL enabled Java VNC Viewer provided in x11vnc
-   classes/ssl/VncViewer.jar:
-
-   A Java applet VNC Viewer allows you to connect to a VNC Server from a
-   Java-enabled Web browser.
-
-   The SSL enabled Java VNC Viewer (VncViewer.jar) in the x11vnc package
-   supports only SSL based connections by default. As mentioned above the
-   -httpdir can be used to specify the path to .../classes/ssl. A typical
-   location might be /usr/local/share/x11vnc/classes/ssl. Or -http can be
-   used to try to have it find the directory automatically.
-
-   Also note that the SingleClick UltraVNC Java Viewer is compatible with
-   x11vnc's -ssl SSL mode. (We tested it this way: "java -cp
-   ./VncViewer.jar VncViewer HOST far-away.east PORT 5900 USESSL 1
-   TRUSTALL 1")
-
-   The Java viewer uses SSL to communicate securely with x11vnc. Note
-   that the applet can optionally also be downloaded into your web
-   browser via HTTPS (which is HTTP over SSL.) This way the HTML page and
-   the Java applet itself are also delivered securely with SSL (as
-   opposed to only the VNC traffic being encrypted with SSL.)
-
-   For this case the output will be something like this:
-  x11vnc -ssl SAVE -http
-  ...
-  The SSL VNC desktop is:  far-away.east:0
-  Java SSL viewer URL:     https://far-away.east:5900/
-  Java SSL viewer URL:     http://far-away.east:5800/
-  PORT=5900
-  SSLPORT=5900
-
-   Indicating the two URLs (the first one encrypted, the second not) one
-   could point the web browser at to get the VNC viewer applet. E.g. put
-   this
-   http://far-away.east:5800/
-
-   or:
-   https://far-away.east:5900/
-
-   into your Java-enabled Web browser.
-
-   Note that KDE's Konqueror web browser seems to have problems with
-   https Java applets, so you'll have to use the http/5800 with it (if
-   you get https/5900 working let us know how you did it.)
-
-   If you are using a router/firewall with port-redirection, and you are
-   redirecting ports other than the default ones (5800, 5900) listed
-   above see here.
-
-   The https service provided thru the actual VNC port (5900 in the above
-   example) can occasionally be slow or unreliable (it has to read some
-   input and try to guess if the connection is VNC or HTTP.) If it is
-   unreliable for you and you still want to serve the Java applet via
-   https, use the -https option to get an additional port dedicated to
-   https (its URL will also be printed in the output.)
-
-   Another possibility is to add the GET applet parameter:
-  https://far-away.east:5900/?GET=1
-
-   This will have the VNC Viewer send a special HTTP GET string "GET
-   /request.https.vnc.connection HTTP/1.0" that x11vnc will notice more
-   quickly as a request for a VNC connection. Otherwise it must wait for
-   a timeout to expire before it assumes a VNC connection.
-
-   You may also use "urlPrefix=somestring" to have /somestring prepended
-   to /request.https.vnc.connection". Perhaps you are using a web server
-   proxy scheme to enter a firewall or otherwise have rules applied to
-   the URL. If you need to have any slashes "/" in "somestring" use
-   "_2F_" (a deficiency in libvncserver prevents using the more natural
-   "%2F".)
-
-   You apply multiple applet parameters in the regular URL way, e.g.:
-  https://far-away.east:5900/?GET=1&urlPrefix=mysubdir&...
-
-   All of the x11vnc Java Viewer applet parameters are described in the
-   file classes/ssl/README
-
-
-   Tips on Getting the SSL Java Applet Working the First Time:
-   Unfortunately, it can be a little tricky getting the SSL VNC Java
-   Viewer working with x11vnc. Here are some tips to getting working the
-   first time (afterwards you can incrementally customize with more
-   complex settings.)
-     * First try it on the LAN: Do NOT try to have it work the first time
-       going through firewalls, Web proxies, home router port
-       redirections, or Apache portal. Just try a direct connection over
-       your LAN first (if you only have 1 machine and no LAN, just do a
-       direct connection to the same machine: localhost.) If the LAN
-       machine you run x11vnc on has its own host-level firewall (most
-       linux machine come with that on by default), disable it or at
-       least let tcp ports 5800-6000 through.
-     * First try HTTP to download the Java Applet: x11vnc can serve both
-       the Java Applet jar file and VNC out of the same port (both
-       tunneled through SSL, see below.) But it can lead to timing and
-       other problems. So first try HTTP instead of HTTPS to download the
-       Applet jar file (VncViewer.jar.) That is to say try
-       http://hostname:5800 in your web browser first before trying
-       https://hostname:5900. x11vnc will print out the ports and URLs it
-       is using, so use the HTTP one it prints out.
-     * Always Restart the Browser: If you are having failures and have to
-       repeatedly retry things ALWAYS restart the browser (i.e.
-       completely exit it and then start a new browser process) each
-       time. Otherwise as you are changing things the browser may
-       "remember" failed applet downloads, etc. and just add to the
-       confusion and irreproducibility. If you see it trying to download
-       VncViewer.class (instead of VncViewer.jar) you know it is really
-       confused and needs to be restarted.
-     * Step Lively: If you get Browser or Java VM or VNC Viewer applet
-       dialog boxes saying things like "Do you want to trust this
-       certificate?" or "The hostname does not match the one on the
-       certificate", etc. just go through them as quickly as possible.
-       x11vnc cannot wait forever for each SSL connection, and so if you
-       dawdle too long inspecting the certs, etc it can lead to problems.
-       Get it working first before taking your time to read the details
-       in the dialogs, etc.
-     * No inetd, Please: Even if you intend to deploy via inetd or xinetd
-       eventually, get that working later (and remember do not use
-       something like "-ssl TMP" that creates a new temporary SSL
-       certificate for every new socket connection.)
-     * Nothing Fancy: Do not try fancy stuff like -svc, -create, -unixpw,
-       "-users unixpw=", "-users sslpeer=", -sslverify, etc. Just get the
-       simplest connection working first and then incrementally add what
-       you need.
-
-   So the recommended test command lines are:
-   x11vnc -ssl SAVE -http
-   x11vnc -ssl SAVE -httpdir /path/to/x11vnc/classes/ssl
-
-   Use the latter if x11vnc cannot automatically find the classes/ssl
-   directory (this what the -http option instructs it to do.) Then point
-   your browser to the HTTP (not HTTPS) URL it prints out.
-
-   Following the above guidelines, did it work? If so, Congratulations!!
-   you created an SSL encrypted connection between the SSL Java applet
-   running in your web browser and x11vnc. The fact that you used HTTP
-   instead of HTTPS to download the applet is not the end of the world
-   (some users do it this way), the main thing is that the VNC traffic is
-   encrypted with SSL. If you are having trouble even with the above
-   baseline test case feel free to contact me (please send the Full
-   x11vnc output, not just part of it; the complete x11vnc command line;
-   the URL(s) entered in the browser; the full Java Console output; and
-   anything else you can think of.)
-
-   Next, you can add the features you want one by one testing it still
-   works each time. I suggest first turning on the HTTPS applet download
-   (https://hostname:5900) if that is what you intend to use. That one
-   gives the most trouble because of the ambiguity of passing two
-   different protocols (HTTP and VNC) through the same SSL service port.
-
-   Next, turn on inetd if you intend to use that (this can be tricky too,
-   be sure to use -oa logfile and inspect it carefully if there are
-   problems.) If you are going to use non-standard ports (e.g. "-rfbport
-   443" as root), work on that next. Then enable the firewall, router
-   port redirection channel (you will somehow need to be outside to do
-   that, maybe test that through another VNC session.)
-
-   Then, if you plan to use them, enable "fancy stuff" like "-svc" or
-   "-unixpw", etc, etc. Be sure to add a password either "-rfbauth" or
-   "-unixpw" or both. If you need to have the web browser use a corporate
-   Web Proxy (i.e. it cannot connect directly) work on that last. Ditto
-   for the Apache portal.
-
-
-   Router/Firewall port redirs:  If you are doing port redirection at
-   your router to an internal machine running x11vnc AND the internet
-   facing port is different from the internal machine's VNC port, you
-   will need to apply the PORT applet parameter to indicate to the applet
-   the Internet facing port number (otherwise by default the internal
-   machine's port, say 5900, is sent and that of course is rejected at
-   the firewall/router.) For example:
-  https://far-away.east:443/?GET=1&PORT=443
-
-   So in this example the user configures his router to redirect
-   connections to port 443 on his Internet side to, say, port 5900 on the
-   internal machine running x11vnc. See also the -httpsredir option that
-   will try to automate this for you.
-
-   To configure your router to do port redirection, see its instructions.
-   Typically, from the inside you point a web browser to a special URL
-   (e.g. http://192.168.1.1) and you get a web interface to configure it.
-   Look for something like "Port Redirection" or "Port Forwarding",
-   probably under "Advanced" or something like that. If you have a Linux
-   or Unix system acting as your firewall/router, see its firewall
-   configuration.
-
-   You can also use x11vnc options -rfbport NNNNN and -httpport NNNNN to
-   match the ports that your firewall will be redirecting to the machine
-   where x11vnc is run.
-
-
-   Tedious Dialogs: If you do serve the SSL enabled Java viewer via https
-   be prepared for quite a number of "are you sure you trust this site?"
-   dialogs:
-     * First from the Web browser that cannot verify the self-signed
-       certificate when it downloads index.vnc.
-     * From the Web browser again noting that the common name on the
-       certificate does not match the hostname of the remote machine.
-     * Next from the Java VM that cannot verify the self-signed
-       certificate when it downloads VncViewer.jar.
-     * And also from the Java VM again noting that the common name on the
-       certificate does not match the hostname of the remote machine.
-     * Finally from the Java VncViewer applet itself saying it cannot
-       verify the certificate! (or a popup asking you if you want to see
-       the certificate.)
-
-   Note that sometimes if you pause too long at one of the above dialogs
-   then x11vnc may exceed a timeout and assume the current socket
-   connection is VNC instead of the HTTPS it actually is (but since you
-   have paused too long at the dialog the GET request comes too late.)
-   Often hitting Reload and going through the dialogs more quickly will
-   let you connect. The Java VM dialogs are the most important ones to
-   NOT linger at. If you see in the x11vnc output a request for
-   VncViewer.class instead of VncViewer.jar it is too late... you will
-   need to completely restart the Web browser to get it to try for the
-   jar again. You can use the -https option if you want a dedicated port
-   for HTTPS connections instead of sharing the VNC port.
-
-   To see example x11vnc output for a successful https://host:5900/
-   connection with the Java Applet see This Page. And here is a newer
-   example including the Java Console output.
-
-   All of the x11vnc Java Viewer applet parameters are described in the
-   file classes/ssl/README
-
-
-   Notes on the VNC Viewer ss_vncviewer wrapper script:
-
-   If you want to use a native VNC Viewer with the SSL enabled x11vnc you
-   will need to run an external SSL tunnel on the Viewer side. There do
-   not seem to be any native SSL VNC Viewers outside of our x11vnc and
-   SSVNC packages. The basic ideas of doing this were discussed for
-   external tunnel utilities here.
-
-   The ss_vncviewer script provided with x11vnc and SSVNC can set up the
-   stunnel tunnel automatically on unix as long as the stunnel command is
-   installed on the Viewer machine and available in PATH (and vncviewer
-   too of course.) Note that on a Debian based system you will need to
-   install the package stunnel4 not stunnel. You can set the environment
-   variables STUNNEL and VNCVIEWERCMD to point to the correct programs if
-   you want to override the defaults.
-
-   Here are some examples:
-  1)  ss_vncviewer far-away.east:0
-
-  2)  ss_vncviewer far-away.east:0 -encodings "copyrect tight zrle hextile"
-
-  3)  ss_vncviewer -verify ./server.crt far-away.east:0
-
-  4)  ss_vncviewer -mycert ./client.pem far-away.east:0
-
-  5)  ss_vncviewer -proxy far-away.east:8080 myworkstation:0
-
-   The first one is the default mode and accepts the x11vnc certificate
-   without question. The second one is as the first, but adds the
-   -encodings options to the vncviewer command line.
-
-   The third one requires that the x11vnc server authenticate itself to
-   the client against the certificate in the file ./server.crt (e.g. one
-   created by "x11vnc -ssl SAVE" and safely copied to the VNC viewer
-   machine.)
-
-   The fourth one is for VNC Viewer authentication, it uses ./client.pem
-   to authenticate itself to x11vnc. One can supply both -verify and
-   -mycert simultaneously.
-
-   The fifth one shows that Web proxies can be used if that is the only
-   way to get out of the firewall. If the "double proxy" situation arises
-   separate the two by commas. See this page for more information on how
-   Web proxies come into play.
-
-   If one uses a Certificate Authority (CA) scheme described here, the
-   wrapper script would use the CA cert instead of the server cert:
-  3')  ss_vncviewer -verify ./cacert.crt far-away.east:0
-
-   Update Jul/2006: we now provide an Enhanced TightVNC Viewer (SSVNC)
-   package that starts up STUNNEL automatically along with some other
-   features. All binaries (stunnel, vncviewer, and some utilities) are
-   provided in the package. It works on Unix, Mac OS X, and Windows.
-
-
-   Q-55: How do I use the Java applet VNC Viewer with built-in SSL
-   tunneling when going through a Web Proxy?
-   The SSL enabled Java VNC Viewer and firewall Proxies:
-
-   SSL and HTTPS aside, there is a general problem with Firewall Proxies
-   and Java Applets that open sockets. The applet is downloaded
-   successfully (through the browser) using HTTP and the proxy, but when
-   the applet tries to reconnect to the originating host (the only one
-   allowed by security) it does not use the proxy channel. So it cannot
-   reconnect to the server the applet came from!
-
-   We have found a convenient workaround: in the directory where
-   VncViewer.jar resides there is a digitally signed version of the same
-   applet called SignedVncViewer.jar. Since the applet is digitally
-   signed, there will be an additional dialog from the Java VM plugin
-   asking you if you want to trust the applet fully.
-
-   You should say "Yes". If you do, the applet will be run in a mode
-   where it can try to determine the firewall proxy host name and port
-   (it will ask you for them if it cannot find them.) This way it can
-   connect directly to the Proxy and then request the CONNECT method to
-   be redirected to the originating host (the x11vnc VNC Server.) SSL is
-   then layered over this socket.
-
-   To do this you should use the proxy.vnc HTML file like via this URL in
-   your browser:
-  https://yourmachine.com:5900/proxy.vnc
-
-   (instead of the unsigned one in https://yourmachine.com:5900/ that
-   gives the default index.vnc)
-
-   Proxies that limit CONNECT to ports 443 and 563:
-
-   Things become trickier if the Web proxy restricts which CONNECT ports
-   can be redirected to. For security, some (most?) proxies only allow
-   port 443 (HTTPS) and 563 (SNEWS) by default. In this case, the only
-   thing to do is run x11vnc on that low port, e.g. "-rfbport 443", (or
-   use a port redirection on, say, a firewall or router port 443 to the
-   internal machine.)
-
-   If you do such a redirection to an internal machine and x11vnc is not
-   listening on port 443, you will probably need to edit proxy.vnc.
-   Suppose the SSL x11vnc server was listening on port 5901. You should
-   change the line in proxy.vnc from:
-  <param name=PORT value=$PORT>
-
-   to:
-  <param name=PORT value=443>
-
-   Since otherwise $PORT will be expanded to 5901 by x11vnc and the
-   viewer applet will fail to connect to that port on the firewall.
-
-   Another way to achieve the same thing is to use the applet PORT
-   parameter:
-  https://yourmachine.com/proxy.vnc?PORT=443
-
-   this is cleaner because it avoids editing the file, but requires more
-   parameters in the URL. See also the -httpsredir x11vnc option that
-   will try to automate this for you. To use the GET trick discussed
-   above, do:
-  https://yourmachine.com/proxy.vnc?GET=1&PORT=443
-
-   All of the x11vnc Java Viewer applet parameters are described in the
-   file classes/ssl/README
-
-   Here is an example of Java Console and x11vnc output for the Web proxy
-   case.
-
-
-   Note that both the ss_vncviewer stunnel Unix wrapper script and
-   Enhanced TightVNC Viewer (SSVNC) can use Web proxies as well even
-   though they do not involve a Web browser.
-
-
-   Q-56: Can Apache web server act as a gateway for users to connect via
-   SSL from the Internet with a Web browser to x11vnc running on their
-   workstations behind a firewall?
-   Yes. You will need to configure apache to forward these connections.
-   It is discussed here. This SSL VNC portal provides a clean alternative
-   to the traditional method where the user uses SSH to log in through
-   the gateway to create the encrypted port redirection to x11vnc running
-   on her desktop.
-
-   Also see the desktop.cgi CGI script method that achieves much of what
-   this Apache VNC SSL portal method does (as long as desktop.cgi's 'port
-   redirection' mode is enabled.)
-
-
-   Q-57: Can I create and use my own SSL Certificate Authority (CA) with
-   x11vnc?
-   Yes, see this page for how to do this and the utility commands x11vnc
-   provides to create and manage many types of certificates and private
-   keys.
-
-
-
-   [Display Managers and Services]
-
-   Q-58: How can I run x11vnc as a "service" that is always available?
-
-   There are a number of ways to do this. The primary thing you need to
-   decide is whether you want x11vnc to connect to the X session on the
-   machine 1) regardless of who (or if anyone) has the X session, or 2)
-   only if a certain user has the X session. Because X sessions are
-   protected by X permissions (MIT-MAGIC-COOKIE files XAUTHORITY and
-   $HOME/.Xauthority) the automatically started x11vnc will of course
-   need to have sufficient permissions to connect to the X display.
-
-   Here are some ideas:
-     * Use the description under "Continuously" in the FAQ on x11vnc and
-       Display Managers
-     * Use the description in the FAQ on x11vnc and inetd(8)
-     * Use the description in the FAQ on Unix user logins and inetd(8)
-     * Start x11vnc from your $HOME/.xsession (or $HOME/.xinitrc or
-       autostart script or ...)
-     * Although less reliable, see the x11vnc_loop rc.local hack below.
-
-   The display manager scheme will not be specific to which user has the
-   X session unless a test is specifically put into the display startup
-   script (often named Xsetup.) The inetd(8) scheme may or may not be
-   specific to which user has the X session (and it may not be able to do
-   all users via the XAUTHORITY permission issues.)
-
-   The .xsession/.xinitrc scheme is obviously is specific to a particular
-   user and only when they are logged into X. If you do not know what a
-   $HOME/.xsession script is or how to use one, perhaps your desktop has
-   a "session startup commands" configuration option. The command to be
-   run in the .xsession or .xinitrc file may look like this:
-x11vnc -logfile $HOME/.x11vnc.log -rfbauth $HOME/.vnc/passwd -forever -bg
-
-   plus any other options you desire.
-
-   Depending on your desktop and/or OS/distribution the automatically run
-   X startup scripts (traditionally .xsession/.xinitrc) may have to be in
-   a different directory or have a different basename. One user
-   recommends the description under 'Running Scripts Automatically' at
-   this link.
-
-   Firewalls: note all methods will require the host-level firewall to be
-   configured to allow connections in on a port. E.g. 5900 (default VNC
-   port) or 22 (default SSH port for tunnelling VNC.) Most systems these
-   days have firewalls turned on by default, so you will actively have to
-   do something to poke a hole in the firewall at the desired port
-   number. See your system administration tool for Firewall settings
-   (Yast, Firestarter, etc.)
-
-
-   Q-59: How can I use x11vnc to connect to an X login screen like xdm,
-   GNOME gdm, KDE kdm, or CDE dtlogin? (i.e. nobody is logged into an X
-   session yet.)
-
-   We describe two scenarios here. The first is called 'One time only'
-   meaning you just need to do it quickly once and don't want to repeat;
-   and the second is called 'Continuously' meaning you want the access to
-   be available after every reboot and after every desktop logout.
-     _________________________________________________________________
-
-   One time only:   If the X login screen is running and you just want to
-   connect to it once (i.e. a one-shot):
-
-   It is usually possible to do this by just adjusting the XAUTHORITY
-   environment variable to point to the correct MIT-COOKIE auth file
-   while running x11vnc as root, e.g. for the gnome display manager, GDM:
-  x11vnc -auth /var/gdm/:0.Xauth -display :0
-
-   (the -auth option sets the XAUTHORITY variable for you.)
-
-   There will be a similar thing to do for xdm using however a different
-   auth directory path (perhaps something like
-   /var/lib/xdm/authdir/authfiles/A:0-XQvaJk) for the xdm greeter or
-   /var/lib/kdm/A:0-crWk72 (or /var/run/xauth/A:0-qQPftr, etc. etc) for
-   the kdm greeter. Of course, the random characters in the file basename
-   will vary and you will need to use the actual filename on your system.
-   Read your system docs to find out where the display manager cookie
-   files are kept.
-
-   Trick: sometimes ps(1) can reveal the X server process -auth argument
-   (e.g. "ps wwaux | grep auth") and hence the path to the auth file.
-
-   x11vnc must be run as root for this because the /var/gdm/:0.Xauth,
-   /var/lib/kdm/A:0-crWk72, etc. auth files are only readable by root. If
-   you do not want to run x11vnc as root, you can copy (as root or sudo)
-   the auth file to some location and make it readable by your userid.
-   Then run x11vnc as your userid with -auth pointed to the copied file.
-
-   Update Dec/2009: use "-auth guess" to have x11vnc try to guess the
-   location of the auth file for you.
-
-   You next connect to x11vnc with a VNC viewer, give your username and
-   password to the X login prompt to start your session.
-
-   Note:  GDM: gdm seems to have an annoying setting that causes x11vnc
-   (and any other X clients) to be killed after the user logs in. Setting
-   KillInitClients=false in the [daemon] section of /etc/X11/gdm/gdm.conf
-   (or /etc/gdm/gdm.conf, etc.) avoids this. Otherwise, just restart
-   x11vnc and then reconnect your viewer. Other display managers (kdm,
-   etc) may also have a similar problem. One user reports having to alter
-   "gdm.conf-custom" as well.
-
-   Note:  Solaris: For dtlogin in addition to the above sort of trick
-   (BTW, the auth file should be in /var/dt), you'll also need to add
-   something like Dtlogin*grabServer:False to the Xconfig file
-   (/etc/dt/config/Xconfig or /usr/dt/config/Xconfig on Solaris, see the
-   example at the end of this FAQ.) Then restart dtlogin, e.g.:
-   /etc/init.d/dtlogin stop; /etc/init.d/dtlogin start or reboot.
-
-   Update Nov/2008: Regarding GDM KillInitClients: see the -reopen option
-   for another possible workaround.
-
-   Update Oct/2009: Regarding GDM KillInitClients: starting with x11vnc
-   0.9.9 it will try to apply heuristics to detect if a window manager is
-   not running (i.e. whether the Display Manager Greeter Login panel is
-   still up.) If it thinks the display manager login is still up it will
-   delay creating windows or using XFIXES. The former is what GDM uses to
-   kill the initial clients, use of the latter can cause a different
-   problem: an Xorg server crash. So with 0.9.9 and later it should all
-   work without needing to set KillInitClients=false (which is a good
-   because recent GDM, v2.24, has removed this option) or use -noxfixes.
-   To disable the heuristics and delaying set X11VNC_AVOID_WINDOWS=never;
-   to set the delay time explicitly use, e.g., X11VNC_AVOID_WINDOWS=120
-   (delays for 120 seconds after the VNC connection; you have that long
-   to log in.)
-     _________________________________________________________________
-
-   Continuously:   Have x11vnc reattach each time the X server is
-   restarted (i.e. after each logout and reboot):
-
-   To make x11vnc always attached to the X server including the login
-   screen you will need to add a command to a display manager startup
-   script.
-
-   Please consider the security implications of this! The VNC display for
-   the X session always accessible (but hopefully password protected.)
-   Add -localhost if you only plan to access via a SSH tunnel.
-
-   The name of the display manager startup script file depends on desktop
-   used and seem to be:
-     GDM (GNOME)  /etc/X11/gdm/Init/Default
-                  /etc/gdm/Init/Default
-     KDM (KDE)    /etc/kde*/kdm/Xsetup
-     XDM          /etc/X11/xdm/Xsetup          (or sometimes xdm/Xsetup_0)
-     CDE          /etc/dt/config/Xsetup
-
-   although the exact location can be operating system, distribution, and
-   time dependent. See the documentation for your display manager:
-   gdm(1), kdm(1), xdm(1), dtlogin(1) for additional details. There may
-   also be display number specific scripts: e.g. Xsetup_0 vs. Xsetup, you
-   need to watch out for.
-
-   Note:  You should read and understand all of the Note's and Update's
-   in the 'One time only' section above. All of the GDM topics apply here
-   as well:
-
-   Note:  GDM: The above (in 'One time only') gdm setting of
-   KillInitClients=false in /etc/X11/gdm/gdm.conf (or /etc/gdm/gdm.conf,
-   etc.) for GDM is needed here as well. Other display managers (KDM,
-   etc) may also have a similar problem.
-
-   Also see the Update Oct/2009 above where x11vnc 0.9.9 and later
-   automatically avoids being killed.
-
-   Note:  DtLogin: The above (in 'One time only')
-   Dtlogin*grabServer:False step for Solaris will be needed for dtlogin
-   here as well.
-
-   In any event, the line you will add to the display manager script
-   (Xsetup, Default, or whatever) will look something like:
-  /usr/local/bin/x11vnc -rfbauth /path/to/the/vnc/passwd -o /var/log/x11vnc.log
- -forever -bg
-
-   where you should customize the exact command to your needs (e.g.
-   -localhost for SSH tunnel-only access; -ssl SAVE for SSL access; etc.)
-
-   Happy, happy, joy, joy:  Note that we do not need to specify -display
-   or -auth because happily they are already set for us in the DISPLAY
-   and XAUTHORITY environment variables for the Xsetup script!!!
-
-   You may also want to force the VNC port with something like "-rfbport
-   5900" (or -N) to avoid autoselecting one if 5900 is already taken.
-     _________________________________________________________________
-
-   Fedora/gdm: Here is an example of what we did on a vanilla install of
-   Fedora-C3 (seems to use gdm by default.) Add a line like this to
-   /etc/X11/gdm/Init/:0
-  /usr/local/bin/x11vnc -rfbauth /etc/x11vnc.passwd -forever -bg -o /var/log/x1
-1vnc.log
-
-   And then add this line to /etc/X11/gdm/gdm.conf (or /etc/gdm/gdm.conf,
-   etc.) in the [daemon] section:
-  KillInitClients=false
-
-   Then restart: /usr/sbin/gdm-restart (or reboot.) The
-   KillInitClients=false setting is important: without it x11vnc will be
-   killed immediately after the user logs in. Here are full details on
-   how to configure gdm
-     _________________________________________________________________
-
-   Solaris/dtlogin: Here is an example of what we did on a vanilla
-   install of Solaris:
-   Make the directory /etc/dt/config:
-  mkdir -p /etc/dt/config
-
-   Copy over the Xconfig file for customization:
-  cp /usr/dt/config/Xconfig /etc/dt/config/Xconfig
-
-   Edit /etc/dt/config/Xconfig and uncomment the line:
-  Dtlogin*grabServer:        False
-
-   Next, copy over Xsetup for customization:
-  cp /usr/dt/config/Xsetup /etc/dt/config/Xsetup
-
-   Edit /etc/dt/config/Xsetup and at the bottom put a line like:
-  /usr/local/bin/x11vnc -forever -o /var/log/x11vnc.log -bg
-
-   (tweaked to your local setup and preferences, a password via -rfbauth,
-   etc. would be a very good idea.)
-
-   Restart the X server and dtlogin:
-  /etc/init.d/dtlogin stop
-  /etc/init.d/dtlogin start
-
-   (or reboot or maybe just restart the X session.)
-     _________________________________________________________________
-
-   KDM: One user running the kdm display manager reports putting this
-   line:
-  x11vnc -forever -rfbauth /home/xyz/.vnc/passwd -bg -o /var/log/x11vnc.log
-
-   in /etc/kde/kdm/Xsetup. After rebooting the system it all seemed to
-   work fine.
-     _________________________________________________________________
-
-
-   If you do not want to deal with any display manager startup scripts,
-   here is a kludgey script that can be run manually or out of a boot
-   file like rc.local: x11vnc_loop It will need some local customization
-   before running. Because the XAUTHORITY auth file must be guessed by
-   this script, use of the display manager script method described above
-   is greatly preferred. There is also the -loop option that does
-   something similar.
-
-   If the machine is a traditional Xterminal you may want to read this
-   FAQ.
-
-   Firewalls: note all methods will require the host-level firewall to be
-   configured to allow connections in on a port. E.g. 5900 (default VNC
-   port) or 22 (default SSH port for tunnelling VNC.) Most systems these
-   days have firewalls turned on by default, so you will actively have to
-   do something to poke a hole in the firewall at the desired port
-   number. See your system administration tool for Firewall settings
-   (Yast, Firestarter, etc.)
-
-
-   Q-60: Can I run x11vnc out of inetd(8)? How about xinetd(8)?
-
-   Yes, perhaps a line something like this in /etc/inetd.conf will do it
-   for you:
-
-  5900 stream tcp nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc_sh
-
-   where the shell script /usr/local/bin/x11vnc_sh uses the -inetd option
-   and looks something like (you'll need to customize to your settings.)
-#!/bin/sh
-/usr/local/bin/x11vnc -inetd -display :0 -auth /home/fred/.Xauthority \
-        -rfbauth /home/fred/.vnc/passwd -o /var/log/x11vnc_sh.log
-
-   Important:  Note that you must redirect the standard error output to a
-   log file (e.g. -o logfile) or "2>/dev/null" for proper operation via
-   inetd (otherwise the standard error also goes to the VNC vncviewer,
-   and that confuses it greatly, causing it to abort.) If you do not use
-   a wrapper script as above but rather call x11vnc directly in
-   /etc/inetd.conf and do not redirect stderr to a file, then you must
-   specify the -q (aka -quiet) option: "/usr/local/bin/x11vnc -q -inetd
-   ...". When you supply both -q and -inet and no "-o logfile" then
-   stderr will automatically be closed (to prevent, e.g. library stderr
-   messages leaking out to the viewer.) The recommended practice is to
-   use "-o logfile" to collect the output in a file or wrapper script
-   with "2>logfile" redirection because the errors and warnings printed
-   out are very useful in troubleshooting problems.
-
-   Note also the need to set XAUTHORITY via -auth to point to the
-   MIT-COOKIE auth file to get permission to connect to the X display
-   (setting and exporting the XAUTHORITY variable accomplishes the same
-   thing.) See the x11vnc_loop file in the previous question for more
-   ideas on what that auth file may be, etc. The scheme described in the
-   FAQ on Unix user logins and inetd(8) works around the XAUTHORITY issue
-   nicely.
-
-   Note:  On Solaris you cannot have the bare number 5900 in
-   /etc/inetd.conf, you'll need to replace it with a word like x11vnc an
-   then put something like "x11vnc 5900/tcp" in /etc/services.
-
-   Since the process runs as root, it might be a bad idea to have the
-   logfile in a world-writable area like /tmp if there are untrustworthy
-   users on the machine. Perhaps /var/log is a better place.
-
-   Be sure to look at your /etc/hosts.allow and /etc/hosts.deny settings
-   to limit the machines that can connect to this service (your desktop!)
-   For the above example with /etc/hosts.allow:
-  x11vnc_sh : 123.45.67.89
-
-   A really safe way to do things is to limit the above inetd to
-   localhost only (via /etc/hosts.allow) and use ssh to tunnel the
-   incoming connection. Using inetd for this prevents there being a tiny
-   window of opportunity between x11vnc starting up and your vncviewer
-   connecting to it. Always use a VNC password to further protect against
-   unwanted access.
-
-   For xinetd(8), one user reports he created the file
-   /etc/xinetd.d/x11vncservice containing the following:
-# default: off
-# description:
-service x11vncservice
-{
-        flags           = REUSE NAMEINARGS
-        port            = 5900
-        type            = UNLISTED
-        socket_type     = stream
-        protocol        = tcp
-        wait            = no
-        user            = root
-        server          = /usr/sbin/tcpd
-        server_args     = /usr/local/bin/x11vnc_sh
-        disable         = no
-}
-
-   With the contents of /usr/local/bin/x11vnc_sh similar to the example
-   given above. One user reports this works with avoiding the wrapper
-   script:
-service x11vncservice
-{
-        port            = 5900
-        type            = UNLISTED
-        socket_type     = stream
-        protocol        = tcp
-        wait            = no
-        user            = root
-        server          = /usr/local/bin/x11vnc
-        server_args     = -inetd -q -display :0 -auth /var/gdm/:0.Xauth
-        disable         = no
-}
-
-   (or one can replace the -q with say "-o /var/log/x11vnc.log" to
-   capture a log)
-
-   The above works nicely for GDM because the -auth file is a fixed name.
-   For KDM or XDM the filename varies. Here is one idea for a x11vnc_sh
-   wrapper to try to guess the name:
-#!/bin/sh
-COLUMNS=256
-export COLUMNS
-authfile=`ps wwaux | grep '/X.*-auth' | grep -v grep | sed -e 's/^.*-auth *//'
--e 's/ .*$//' | head -n 1`
-
-if [ -r "$authfile" ]; then
-        exec /usr/local/bin/x11vnc -inetd -o /var/log/x11vnc.log -display :0 -a
-uth "$authfile"
-fi
-exit 1
-
-   Starting with x11vnc 0.9.3 this can be automated by:
-#!/bin/sh
-exec /usr/local/bin/x11vnc -inetd -o /var/log/x11vnc.log -find -env FD_XDM=1
-
-
-   Q-61: Can I have x11vnc advertise its VNC service and port via mDNS /
-   Zeroconf (e.g. Avahi) so VNC viewers on the local network can detect
-   it automatically?
-
-   Yes, as of Feb/2007 x11vnc supports mDNS / Zeroconf advertising of its
-   service via the Avahi client library. Use the option -avahi (same as
-   -mdns or -zeroconf) to enable it. Depending on your setup you may need
-   to install Avahi (including the development/build packages), enable
-   the server: avahi-daemon and avahi-dnsconfd, and possibly open up UDP
-   port 5353 on your firewall.
-
-   If the Avahi client library or build environment is not available at
-   build-time, then at run-time x11vnc will try to look for external
-   helper programs, avahi-browse(1) or dns-sd(1), to do the work.
-
-   The service was tested with Chicken of the VNC ("Use Bonjour"
-   selected) on a Mac on the same network and the service was noted and
-   listed in the servers list. Clicking on it and then "Connect"
-   connected automatically w/o having to enter any hostnames or port
-   numbers.
-
-   It appears SuSE 10.1 comes with avahi (or you can add packages, e.g.
-   avahi-0.6.5-27) but not the development package (you can use the
-   OpenSuSE avahi-devel rpm.) Unfortunately, you may need to disable
-   another Zeroconf daemon "/etc/init.d/mdnsd stop", before doing
-   "/etc/init.d/avahi-daemon start" and "/etc/init.d/avahi-dnsconfd
-   start". We also had to comment out the browse-domains line in
-   /etc/avahi/avahi-daemon.conf. Hopefully there is "LessConf" to do on
-   other distros/OS's...
-
-
-   Q-62: Can I have x11vnc allow a user to log in with her UNIX username
-   and password and then have it find her X session display on that
-   machine and then attach to it? How about starting an X session if one
-   cannot be found?
-
-   The easiest way to do this is via inetd(8) using the -unixpw and
-   -display WAIT options. The reason inetd(8) makes this easier is that
-   it starts a new x11vnc process for each new user connection. Otherwise
-   a wrapper would have to listen for connections and spawn new x11vnc's
-   (see this example and also the -loopbg option.) inetd(8) is not
-   required for this, but it makes some aspects more general.
-
-   Also with inetd(8) users always connect to a fixed VNC display, say
-   hostname:0, and do not need to memorize a special VNC display number
-   just for their personal use, etc.
-
-   Update: Use the -find, -create, -svc, and -xdmsvc options that are
-   shorthand for common FINDCREATEDISPLAY usage modes (e.g. terminal
-   services) described below. (i.e. simply use "-svc" instead of the
-   cumbersome "-display WAIT:cmd=FINDCREATEDISPLAY-Xvfb -unixpw -users
-   unixpw= -ssl SAVE")
-
-   The -display WAIT option makes x11vnc wait until a VNC viewer is
-   connected before attaching to the X display.
-
-   Additionally it can be used to run an external command that returns
-   the DISPLAY and XAUTHORITY data. We provide some useful builtin ones
-   (FINDDISPLAY and FINDCREATEDISPLAY below), but in principle one could
-   supply his own script: "-display WAIT:cmd=/path/to/find_display" where
-   the script find_display might look something like this.
-
-   A default script somewhat like the above is used under "-display
-   WAIT:cmd=FINDDISPLAY" (same as -find) The format for any such command
-   is that it returns DISPLAY=:disp as the first line and any remaining
-   lines are either XAUTHORITY=file or raw xauth data (the above example
-   does the latter.) If applicable (-unixpw mode), the program is run as
-   the Unix user name who logged in.
-
-   On Linux if the virtual terminal is known the program appends ",VT=n"
-   to the DISPLAY line; a chvt n will be attempted automatically. Or if
-   only the X server process ID is known it appends ",XPID=n" (a chvt
-   will be attempted by x11vnc.)
-
-   Tip: Note that the -find option is an alias for "-display
-   WAIT:cmd=FINDDISPLAY". Use it!
-
-   The -unixpw option allows UNIX password logins. It conveniently knows
-   the Unix username whose X display should be found. Here are a couple
-   /etc/inetd.conf examples of this usage:
-5900  stream  tcp  nowait  nobody  /usr/sbin/tcpd /usr/local/bin/x11vnc -inetd
--unixpw \
-      -find -o /var/log/x11vnc.log -ssl SAVE -ssldir /usr/local/certs
-5900  stream  tcp  nowait  root    /usr/sbin/tcpd /usr/local/bin/x11vnc -inetd
--unixpw \
-      -find -o /var/log/x11vnc.log -ssl SAVE -users unixpw=
-
-   Note we have used the -find alias and the very long lines have been
-   split. An alternative is to use a wrapper script, e.g.
-   /usr/local/bin/x11vnc.sh that has all of the options. (see also the
-   -svc alias.)
-
-   In the first inetd line x11vnc is run as user "nobody" and stays user
-   nobody during the whole session. The permissions of the log files and
-   certs directory will need to be set up to allow "nobody" to use them.
-
-   In the second one x11vnc is run as root and switches to the user that
-   logs in due to the "-users unixpw=" option.
-
-   Note that SSL is required for this mode because otherwise the Unix
-   password would be passed in clear text over the network. In general
-   -unixpw is not required for this sort of scheme, but it is convenient
-   because it determines exactly who the Unix user is whose display
-   should be sought. Otherwise the find_display script would have to use
-   some method to work out DISPLAY, XAUTHORITY, etc (perhaps you use
-   multiple inetd ports and hardwire usernames for different ports.)
-
-   If you really want to disable the SSL or SSH -localhost constraints
-   (this is not recommended unless you really know what you are doing:
-   Unix passwords sent in clear text is a very bad idea...) read the
-   -unixpw documentation.
-
-   A inetd(8) scheme for a fixed user that doesn't use SSL or unix
-   passwds could be:
-  /usr/local/bin/x11vnc -inetd -users =fred -find -rfbauth /home/fred/.vnc/pass
-wd -o /var/log/x11vnc.log
-
-   The "-users =fred" option will cause x11vnc to switch to user fred and
-   then find his X display. The VNC password (-rfbauth) as opposed to
-   Unix password (-unixpw) is used to authenticate the VNC client.
-
-   Similar looking commands to the above examples can be run directly and
-   do not use inetd (just remove the -inetd option and run from the
-   cmdline, etc.)
-
-
-   X Session Creation: An added (Nov/2006) extension to FINDDISPLAY is
-   FINDCREATEDISPLAY where if it does not find an X display via the
-   FINDDISPLAY method it will create an X server session for the user
-   (i.e. desktop/terminal server.) This is the only time x11vnc actually
-   tries to start up an X server (normally it just attaches to an
-   existing one.)
-
-   For virtual sessions you will need to install the Xvfb program (e.g.
-   apt-get install xvfb) or our Xdummy program (see below.)
-
-   By default it will only try to start up virtual (non-hardware) X
-   servers: first Xvfb and if that is not available then Xdummy (included
-   in the x11vnc source code.) Note that Xdummy only works on Linux
-   whereas Xvfb works just about everywhere (and in some situations
-   Xdummy must be run as root.) An advantage of Xdummy over Xvfb is that
-   Xdummy supports RANDR dynamic screen resizing, which can be handy if
-   the user accesses the desktop from different sized screens (e.g.
-   workstation and laptop.)
-
-   So an inetd(8) example might look like:
-5900 stream tcp nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc -inetd \
-      -o /var/log/x11vnc.log -http -prog /usr/local/bin/x11vnc \
-      -ssl SAVE -unixpw -users unixpw= -display WAIT:cmd=FINDCREATEDISPLAY
-
-   Where the very long lines have been split. See below where that long
-   and cumbersome last line is replaced by the -svc alias.
-
-   The above mode will allow direct SSL (e.g. ss_vncviewer or SSVNC)
-   access and also Java Web browers access via: https://hostname:5900/.
-
-   Tip: Note that the -create option is an alias for "-display
-   WAIT:cmd=FINDCREATEDISPLAY-Xvfb".
-
-   Tip: Note that -svc is a short hand for the long "-ssl SAVE -unixpw
-   -users unixpw= -display WAIT:cmd=FINDCREATEDISPLAY" part. Unlike
-   -create, this alias also sets up SSL encryption and Unix password
-   login.
-
-   The above inetd example then simplifies to:
-5900 stream tcp nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc -inetd \
-      -o /var/log/x11vnc.log -http -prog /usr/local/bin/x11vnc \
-      -svc
-
-   Tip: In addition to the usual unixpw parameters, inside the VNC viewer
-   the user can specify after his username (following a ":" see -display
-   WAIT for details) for FINDCREATEDISPLAY they can add "geom=WxH" or
-   "geom=WxHxD" to specify the width, height, and optionally the color
-   depth. E.g. "fred:geom=800x600" at the login: prompt. Also if the env.
-   var X11VNC_CREATE_GEOM is set to the desired WxH or WxHxD that will be
-   used by x11vnc.
-
-   You can set the env. var X11VNC_SKIP_DISPLAY to a comma separated list
-   of displays to ignore in the FINDDISPLAY process (to force creation of
-   new displays in some cases.) The user logging in via the vncviewer can
-   also set this via username:nodisplay=...)
-
-   If you do not plan on using the Java Web browser applet you can remove
-   the -http (and -prog) option since this will speed up logging-in by a
-   few seconds (x11vnc will not have to wait to see if a connection is
-   HTTPS or VNC.)
-
-   For reference, xinetd format in the file, say, /etc/xinetd.d/x11vnc:
-service x11vnc
-{
-        type            = UNLISTED
-        port            = 5900
-        socket_type     = stream
-        protocol        = tcp
-        wait            = no
-        user            = root
-        server          = /usr/local/bin/x11vnc
-        server_args     = -inetd -o /var/log/x11vnc.log -http -prog /usr/local/
-bin/x11vnc -svc
-        disable         = no
-}
-
-   To print out the script in this case use "-display
-   WAIT:cmd=FINDCREATEDISPLAY-print". To change the preference of
-   Xservers and which to try list them, e.g.: "-display
-   WAIT:cmd=FINDCREATEDISPLAY-X,Xvfb,Xdummy" or use "-create_xsrv
-   X,Xvfb,Xdummy". The "X" one means to try to start up a real, hardware
-   X server, e.g. startx(1) (if there is already a real X server running
-   this may only work on Linux and the chvt program may need to be run to
-   switch to the correct Linux virtual terminal.) x11vnc will try to run
-   chvt automatically if it can determine which VT should be switched to.
-
-   XDM/GDM/KDM Login Greeter Panel: If you want to present the user with
-   a xdm/gdm/kdm display manager "greeter" login you can use Xvfb.xdmcp
-   instead of Xvfb, etc in the above list. However, you need to configure
-   xdm/gdm/kdm to accept localhost XDMCP messages, this can be done by
-   (from -help output):
-      If you want the FINDCREATEDISPLAY session to contact an XDMCP login
-      manager (xdm/gdm/kdm) on the same machine, then use "Xvfb.xdmcp"
-      instead of "Xvfb", etc.  The user will have to supply his username
-      and password one more time (but he gets to select his desktop
-      type so that can be useful.)  For this to work, you will need to
-      enable localhost XDMCP (udp port 177) for the display manager.
-      This seems to be:
-
-       for gdm in gdm.conf:   Enable=true in section [xdmcp]
-       for kdm in kdmrc:      Enable=true in section [Xdmcp]
-       for xdm in xdm-config: DisplayManager.requestPort: 177
-
-   Unless you are also providing XDMCP service to xterminals or other
-   machines, make sure that the host access list only allows local
-   connections (the name of this file is often Xaccess and it is usually
-   setup by default to do just that.) Nowadays, host level firewalling
-   will also typically block UDP (port 177 for XDMCP) by default
-   effectively limiting the UDP connections to localhost.
-
-   Tip: Note that -xdmsvc is a short hand alias for the long "-ssl SAVE
-   -unixpw -users unixpw= -display
-   WAIT:cmd=FINDCREATEDISPLAY-Xvfb.xdmcp". So we simply use:
-service x11vnc
-{
-        type            = UNLISTED
-        port            = 5900
-        socket_type     = stream
-        protocol        = tcp
-        wait            = no
-        user            = root
-        server          = /usr/local/bin/x11vnc
-        server_args     = -inetd -o /var/log/x11vnc.log -xdmsvc
-        disable         = no
-}
-
-   (Note: use "-svc" instead of "-xdmsvc" for no XDMCP login greeter.)
-
-
-   Local access (VNC Server and VNC Viewer on the same machine): To
-   access your virtual X display session locally (i.e. while sitting at
-   the same machine it is running on) one can perhaps have something like
-   this in their $HOME/.xinitrc
-#!/bin/sh
-x11vnc -create -rfbport 5905 -env WAITBG=1
-vncviewer -geometry +0+0 -encodings raw -passwd $HOME/.vnc/passwd localhost:5
-
-   You may not need the -passwd. Recent RealVNC viewers might be this:
-#!/bin/sh
-x11vnc -create -rfbport 5905 -env WAITBG=1
-vncviewer -FullScreen -PreferredEncoding raw -passwd $HOME/.vnc/passwd localhos
-t:5
-
-   This way a bare X server is run with no window manager or desktop; it
-   simply runs only the VNC Viewer on the real X server. The Viewer then
-   draws the virtual X session on to the real one. On your system it
-   might not be $HOME/.xinitrc, but rather .xsession, .Xclients, or
-   something else. You will need to figure out what it is for your system
-   and configuration.
-
-   There may be a problem if the resolution (WxH) of the virtual X
-   display does not match that of the physical X display.
-
-   If you do not want to or cannot figure out the X startup script name
-   (.xinitrc, etc) you could save the above commands to a shell script,
-   say "vnclocal", and the log in via the normal KDM or GDM greeter
-   program using the "Failsafe" option. Then in the lone xterm that comes
-   up type "vnclocal" to connect to your virtual X display via x11vnc and
-   vncviewer.
-
-     _________________________________________________________________
-
-   Summary: The "-display WAIT:cmd=FINDCREATEDISPLAY" scheme can be used
-   to provide a "desktop service" (i.e. terminal service) on the server
-   machine: you always get some desktop there, either a real hardware X
-   server or a virtual one (depending on how you set things up.)
-
-   So it provides simple "terminal services" based on Unix username and
-   password. The created X server sessions (virtual or real hardware)
-   will remain running after you disconnect the VNC viewer and will be
-   found again on reconnecting via VNC and logging in. To terminate them
-   use the normal way to Exit/LogOut from inside your X session. The user
-   does not have to memorize which VNC display number is his. They all go
-   the same one (e.g. hostname:0) and it switches based on username.
-
-
-   Q-63: Can I have x11vnc restart itself after it terminates?
-
-   One could do this in a shell script, but now there is an option -loop
-   that makes it easier. Of course when x11vnc restarts it needs to have
-   permissions to connect to the (potentially new) X display. This mode
-   could be useful if the X server restarts often. Use e.g. "-loop5000"
-   to sleep 5000 ms between restarts. Also "-loop2000,5" to sleep 2000 ms
-   and only restart 5 times.
-
-   One can also use the -loopbg to emulate inetd(8) to some degree, where
-   each connected process runs in the background. It could be combined,
-   say, with the -svc option to provide simple terminal services without
-   using inetd(8).
-
-
-   Q-64: How do I make x11vnc work with the Java VNC viewer applet in a
-   web browser?
-
-   To have x11vnc serve up a Java VNC viewer applet to any web browsers
-   that connect to it, run x11vnc with this option:
-  -httpdir /path/to/the/java/classes/dir
-
-   (this directory will contain the files index.vnc and, for example,
-   VncViewer.jar) Note that libvncserver contains the TightVNC Java
-   classes jar file for your convenience. (it is the file
-   classes/VncViewer.jar in the source tree.)
-
-   You will see output something like this:
-  14/05/2004 11:13:56 Autoprobing selected port 5900
-  14/05/2004 11:13:56 Listening for HTTP connections on TCP port 5800
-  14/05/2004 11:13:56   URL http://walnut:5800
-  14/05/2004 11:13:56 screen setup finished.
-  14/05/2004 11:13:56 The VNC desktop is walnut:0
-  PORT=5900
-
-   then you can connect to that URL with any Java enabled browser. Feel
-   free to customize the default index.vnc file in the classes directory.
-
-   As of May/2005 the -http option will try to guess where the Java
-   classes jar file is by looking in expected locations and ones relative
-   to the x11vnc binary.
-
-   Also note that if you wanted to, you could also start the Java viewer
-   entirely from the viewer-side by having the jar file there and using
-   either the java or appletviewer commands to run the program.
-  java -cp ./VncViewer.jar VncViewer HOST far-away.east PORT 5900
-
-   Proxies: See the discussion here if the web browser must use a web
-   proxy to connect to the internet. It is tricky to get Java applets to
-   work in this case: a signed applet must be used so it can connect to
-   the proxy and ask for the redirection to the VNC server. One way to do
-   this is to use the signed SSL one referred to in classes/ssl/proxy.vnc
-   and set disableSSL=yes (note that this has no encryption; please use
-   SSL or SSH as discuss elsewhere on this page) in the URL or the file.
-
-
-   Q-65: Are reverse connections (i.e. the VNC server connecting to the
-   VNC viewer) using "vncviewer -listen" and vncconnect(1) supported?
-
-   As of Mar/2004 x11vnc supports reverse connections. On Unix one starts
-   the VNC viewer in listen mode: "vncviewer -listen" (see your
-   documentation for Windows, etc), and then starts up x11vnc with the
-   -connect option. To connect immediately at x11vnc startup time use the
-   "-connect host:port" option (use commas for a list of hosts to connect
-   to.) The ":port" is optional (default is VNC listening port is 5500.)
-
-   If a file is specified instead: -connect /path/to/some/file then that
-   file is checked periodically (about once a second) for new hosts to
-   connect to.
-
-   The -remote control option (aka -R) can also be used to do this during
-   an active x11vnc session, e.g.:
-x11vnc -display :0 -R connect:hostname.domain
-
-   Use the "-connect_or_exit" option to have x11vnc exit if the reverse
-   connection fails. Also, note the "-rfbport 0" option disables TCP
-   listening for connections (potentially useful for reverse connection
-   mode, assuming you do not want any "forward" connections.)
-
-   Note that as of Mar/2006 x11vnc requires password authentication for
-   reverse connections as well as for forward ones (assuming password
-   auth has been enabled, e.g. via -rfbauth, -passwdfile, etc.) Many VNC
-   servers do not require any password for reverse connections. To regain
-   the old behavior supply this option "-env
-   X11VNC_REVERSE_CONNECTION_NO_AUTH=1" to x11vnc.
-
-   Vncconnect command: To use the vncconnect(1) program (from the core
-   VNC package at www.realvnc.com) specify the -vncconnect option to
-   x11vnc (Note: as of Dec/2004 -vncconnect is now the default.)
-   vncconnect(1) must be pointed to the same X11 DISPLAY as x11vnc (since
-   it uses X properties to communicate with x11vnc.) If you do not have
-   or do not want to get the vncconnect(1) program, the following script
-   (named "Vncconnect") may work if your xprop(1) supports the -set
-   option:
-#!/bin/sh
-# usage: Vncconnect <host>
-#        Vncconnect <host:port>
-# note: not all xprop(1) support -set.
-#
-xprop -root -f VNC_CONNECT 8s -set VNC_CONNECT "$1"
-
-
-   Q-66: Can reverse connections be made to go through a Web or SOCKS
-   proxy or SSH?
-
-   Yes, as of Oct/2007 x11vnc supports reverse connections through
-   proxies: use the "-proxy host:port" option. The default is to assume
-   the proxy is a Web proxy. Note that most Web proxies only allow proxy
-   destination connections to ports 443 (HTTPS) and 563 (SNEWS) and so
-   this might not be too useful unless the proxy has been modified
-   (AllowCONNECT apache setting) or the VNC viewer listens on one of
-   those ports (or the router does a port redir.) A web proxy may also be
-   specified via "-proxy http://host:port"
-
-   For SOCKS4 and SOCKS4a proxies use this format "-proxy
-   socks://host:port". If the reverse connection hostname is a numerical
-   IP or "localhost" then SOCKS4 (no host lookup) is used, otherwise
-   SOCKS4a will be used. For SOCKS5 (proxy will do lookup and many other
-   things) use "-proxy socks5://host:port". Note that the SSH builtin
-   SOCKS proxy "ssh -D port" only does SOCKS4 or SOCKS5, so use socks5://
-   for a ssh -D proxy.
-
-   The proxying works for both SSL encrypted and normal reverse
-   connections.
-
-   An experimental mode is "-proxy http://host:port/..." where the URL
-   (e.g. a CGI script) is retrieved via the GET method. See -proxy for
-   more info.
-
-   Another experimental mode is "-proxy ssh://user@host" in which case a
-   SSH tunnel is used for the proxying. See -proxy for more info.
-
-   Up to 3 proxies may be chained together by listing them by commas
-   e.g.: "-proxy http://host1:port1,socks5://host2:port2" in case one
-   needs to ricochet off of several machines to ultimately reach the
-   listening viewer.
-
-
-   Q-67: Can x11vnc provide a multi-user desktop web login service as an
-   Apache CGI or PHP script?
-   Yes. See the example script desktop.cgi for ideas. It is in the source
-   tree in the directory x11vnc/misc. It serves x11vnc's SSL enabled Java
-   Applet to the web browser with the correct connection information for
-   the user's virtual desktop (an Xvfb session via -create; be sure to
-   add the Xvfb package.) HTTPS/SSL enabled Apache should be used to
-   serve the script to avoid unix and vnc passwords from being sent in
-   cleartext and sniffed.
-
-   By default it uses a separate VNC port for each user desktop (either
-   by autoprobing in a range of ports or using a port based on the userid
-   number.) The web server's firewall must allow incoming connections to
-   these ports.
-
-   It is somewhat difficult to do all of this with x11vnc listening on a
-   single port, however there is also a 'fixed port' scheme described in
-   the script based on -loopbg that works fairly well (but more
-   experience is needed to see what problems contention for the same port
-   causes; however at worst one user may need to re-login.)
-
-   There is also an optional 'port redirection' mode for desktop.cgi that
-   allows redirection to other machines inside the firewall already
-   running SSL enabled VNC servers. This provides much of the
-   functionality as the SSL Portal and is easier to set up.
-
-
-   Q-68: Can I use x11vnc as a replacement for Xvnc? (i.e. not for a real
-   display, but for a virtual one I keep around.)
-
-   You can, but you would not be doing this for performance reasons (for
-   virtual X sessions via VNC, Xvnc should give the fastest response.)
-   You may want to do this because Xvnc is buggy and crashes, does not
-   support an X server extension you desire, or you want to take
-   advantage of one of x11vnc's unending number of options and features.
-
-   One way to achieve this is to have a Xvfb(1) virtual framebuffer X
-   server running in the background and have x11vnc attached to it.
-   Another method, faster and more accurate, is to use the "dummy" Device
-   Driver in XFree86/Xorg (see below.)
-
-   For these virtual sessions you will need to install the Xvfb program
-   (e.g. apt-get install xvfb) or our Xdummy program (see below.)
-
-   In either case, one can view this desktop both remotely and also
-   locally using vncviewer. Make sure vncviewer's "-encodings raw" is in
-   effect for local viewing (compression seems to slow things down
-   locally.) For local viewing you set up a "bare" window manager that
-   just starts up vncviewer and nothing else (See how below.)
-
-   Here is one way to start up Xvfb:
-  xinit -- /usr/bin/Xvfb :1 -cc 4 -screen 0 1024x768x16
-
-   This starts up a 16bpp virtual display. To export it via VNC use
-  x11vnc -display :1 ...
-
-   Then have the remote vncviewer attach to x11vnc's VNC display (e.g. :0
-   which is port 5900.)
-
-   The "-cc 4" Xvfb option is to force it to use a TrueColor visual
-   instead of DirectColor (this works around a recent bug in the Xorg
-   Xvfb server.)
-
-   One good thing about Xvfb is that the virtual framebuffer exists in
-   main memory (rather than in the video hardware), and so x11vnc can
-   "screen scrape" it very efficiently (more than, say, 100X faster than
-   normal video hardware.)
-
-   Update Nov/2006: See the FINDCREATEDISPLAY discussion of the "-display
-   WAIT:cmd=FINDDISPLAY" option where virtual (Xvfb or Xdummy, or even
-   real ones by changing an option) X servers are started automatically
-   for new users connecting. This provides a "desktop service" for the
-   machine. You either get your real X session or your virtual
-   (Xvfb/Xdummy) one whenever you connect to the machine (inetd(8) is a
-   nice way to provide this service.) The -find, -create, -svc, and
-   -xdmsvc aliases can also come in handy here.
-
-   There are some annoyances WRT Xvfb however. The default keyboard
-   mapping seems to be very poor. One should run x11vnc with -add_keysyms
-   option to have keysyms added automatically. Also, to add the Shift_R
-   and Control_R modifiers something like this is needed:
-#!/bin/sh
-xmodmap -e "keycode any = Shift_R"
-xmodmap -e "add Shift = Shift_L Shift_R"
-xmodmap -e "keycode any = Control_R"
-xmodmap -e "add Control = Control_L Control_R"
-xmodmap -e "keycode any = Alt_L"
-xmodmap -e "keycode any = Alt_R"
-xmodmap -e "keycode any = Meta_L"
-xmodmap -e "add Mod1 = Alt_L Alt_R Meta_L"
-
-   (note: these are applied automatically in the FINDCREATEDISPLAY mode
-   of x11vnc.) Perhaps the Xvfb options -xkbdb or -xkbmap could be used
-   to get a better default keyboard mapping...
-
-   Dummy Driver:  A user points out a faster and more accurate method is
-   to use the "dummy" Device Driver of XFree86/Xorg instead of Xvfb. He
-   uses this to create a persistent and resizable desktop accessible from
-   anywhere. In the Device Section of the config file set Driver "dummy".
-   You may also need to set VideoRam NNN to be large enough to hold the
-   framebuffer. The framebuffer is kept in main memory like Xvfb except
-   that the server code is closely correlated with the real XFree86/Xorg
-   Xserver unlike Xvfb.
-
-   The main drawback to this method (besides requiring extra
-   configuration and possibly root permission) is that it also does the
-   Linux Virtual Console/Terminal (VC/VT) switching even though it does
-   not need to (since it doesn't use a real framebuffer.) There are some
-   "dual headed" (actually multi-headed/multi-user) patches to the X
-   server that turn off the VT usage in the X server. Update: As of
-   Jul/2005 we have an LD_PRELOAD script Xdummy that allows you to use a
-   stock (i.e. unpatched) Xorg or XFree86 server with the "dummy" driver
-   and not have any VT switching problems! An advantage of Xdummy over
-   Xvfb is that Xdummy supports RANDR dynamic screen resizing.
-
-   The standard way to start the "dummy" driver would be:
-startx -- :1 -config /etc/X11/xorg.conf.dummy
-
-   where the file /etc/X11/xorg.conf.dummy has its Device Section
-   modified as described above. To use the LD_PRELOAD wrapper script:
-startx -- /path/to/Xdummy :1
-
-   An xdm(1) example is also provided.
-
-   In general, one can use these sorts of schemes to use x11vnc to export
-   other virtual X sessions, say Xnest or even Xvnc itself (useful for
-   testing x11vnc.)
-
-   Local access (VNC Server and VNC Viewer on the same machine): You use
-   a VNC viewer to access the display remotely; to access your virtual X
-   display locally (i.e. while sitting at the same machine it is running
-   on) one can perhaps have something like this in their $HOME/.xinitrc
-#!/bin/sh
-x11vnc -display :5 -rfbport 5905 -bg
-vncviewer -geometry +0+0 -encodings raw -passwd $HOME/.vnc/passwd localhost:5
-
-   The display numbers (VNC and X) will likely be different (you could
-   also try -find), and you may not need the -passwd. Recent RealVNC
-   viewers might be this:
-#!/bin/sh
-x11vnc -display :5 -rfbport 5905 -bg
-vncviewer -FullScreen -PreferredEncoding raw -passwd $HOME/.vnc/passwd localhos
-t:5
-
-   This way a bare X server is run with no window manager or desktop; it
-   simply runs only the VNC Viewer on the real X server. The Viewer then
-   draws the virtual X session on to the real one. On your system it
-   might not be $HOME/.xinitrc, but rather .xsession, .Xclients, or
-   something else. You will need to figure out what it is for your system
-   and configuration.
-
-
-   XDM/GDM/KDM One-Shot X sessions: For the general replacement of Xvnc
-   by Xvfb+x11vnc, one user describes a similar setup he created where
-   the X sessions are one-shot's (destroyed after the vncviewer
-   disconnects) and it uses the XDM/GDM/KDM login greeter here.
-
-
-   Q-69: How can I use x11vnc on "headless" machines? Why might I want
-   to?
-
-   An interesting application of x11vnc is to let it export displays of
-   "headless" machines. For example, you may have some lab or server
-   machines with no keyboard, mouse, or monitor, but each one still has a
-   video card. One can use x11vnc to provide a simple "desktop service"
-   from these server machines.
-
-   An X server can be started on the headless machine (sometimes this
-   requires configuring the X server to not fail if it cannot detect a
-   keyboard or mouse, see the next paragraph.) Then you can export that X
-   display via x11vnc (e.g. see this FAQ) and access it from anywhere on
-   the network via a VNC viewer.
-
-   Some tips on getting X servers to start on machines without keyboard
-   or mouse: For XFree86/Xorg the Option "AllowMouseOpenFail" "true"
-   "ServerFlags" config file option is useful. On Solaris Xsun the
-   +nkeyboard and +nmouse options are useful (put them in the server
-   command line args in /etc/dt/config/Xservers.) There are patches
-   available for Xsun at lease back to Solaris 8 that support this. See
-   Xserver(1) for more info.
-
-   Although this usage may sound strange it can be quite useful for a GUI
-   (or other) testing or QA setups: the engineers do not need to walk to
-   lab machines running different hardware, OS's, versions, etc (or have
-   many different machines in their office.) They just connect to the
-   various test machines over the network via VNC. The advantage to
-   testing this way instead of using Xvnc or even Xvfb is that the test
-   is done using the real X server, fonts, video hardware, etc. that will
-   be used in the field.
-
-   One can imagine a single server machine crammed with as many video
-   cards as it can hold to provide multiple simultaneous access or
-   testing on different kinds of video hardware.
-
-   See also the FINDCREATEDISPLAY discussion of the "-display
-   WAIT:cmd=FINDDISPLAY" option where virtual Xvfb or Xdummy, or real X
-   servers are started automatically for new users connecting. The -find,
-   -create, -svc, and -xdmsvc aliases can also come in handy here.
-
-   [Resource Usage and Performance]
-
-   Q-70: I have lots of memory, but why does x11vnc fail with    shmget:
-   No space left on device    or    Minor opcode of failed request: 1
-   (X_ShmAttach)?
-
-   It is not a matter of free memory, but rather free shared memory (shm)
-   slots, also known as shm segments. This often occurs on a public
-   Solaris machine using the default of only 100 slots. You (or the owner
-   or root) can clean them out with ipcrm(1). x11vnc tries hard to
-   release its slots, but it, and other programs, are not always able to
-   (e.g. if kill -9'd.)
-
-   Sometimes x11vnc will notice the problem with shm segments and tries
-   to get by with fewer, only giving a warning like this:
-  19/03/2004 10:10:58 shmat(tile_row) failed.
-  shmat: Too many open files
-  19/03/2004 10:10:58 error creating tile-row shm for len=4
-  19/03/2004 10:10:58 reverting to single_copytile mode
-
-   Here is a shell script shm_clear to list and prompt for removal of
-   your unattached shm segments (attached ones are skipped.) I use it
-   while debugging x11vnc (I use "shm_clear -y" to assume "yes" for each
-   prompt.) If x11vnc is regularly not cleaning up its shm segments,
-   please contact me so we can work to improve the situation.
-
-   Longer term, on Solaris you can put something like this in
-   /etc/system:
-  set shmsys:shminfo_shmmax = 0x2000000
-  set shmsys:shminfo_shmmni = 0x1000
-
-   to sweep the problem under the rug (4096 slots.) On Linux, examine
-   /proc/sys/kernel/shmmni; you can modify the value by writing to that
-   file.
-
-   Things are even more tight on Solaris 8 and earlier, there is a
-   default maximum number of shm segments per process of 6. The error is
-   the X server (not x11vnc) being unable to attach to the segments, and
-   looks something like this:
-  30/04/2004 14:04:26 Got connection from client 192.168.1.23
-  30/04/2004 14:04:26   other clients:
-  X Error of failed request:  BadAccess (attempt to access private resource den
-ied)
-     Major opcode of failed request:  131 (MIT-SHM)
-     Minor opcode of failed request:  1 (X_ShmAttach)
-     Serial number of failed request:  14
-     Current serial number in output stream:  17
-
-   This tight limit on Solaris 8 can be increased via:
-  set shmsys:shminfo_shmseg = 100
-
-   in /etc/system. See the next paragraph for more workarounds.
-
-   To minimize the number of shm segments used by x11vnc try using the
-   -onetile option (corresponds to only 3 shm segments used, and adding
-   -fs 1.0 knocks it down to 2.) If you are having much trouble with shm
-   segments, consider disabling shm completely via the -noshm option.
-   Performance will be somewhat degraded but when done over local machine
-   sockets it should be acceptable (see an earlier question discussing
-   -noshm.)
-
-
-   Q-71: How can I make x11vnc use less system resources?
-
-   The -nap (now on by default; use -nonap to disable) and "-wait n"
-   (where n is the sleep between polls in milliseconds, the default is 30
-   or so) option are good places to start. In addition, something like
-   "-sb 15" will cause x11vnc to go into a deep-sleep mode after 15
-   seconds of no activity (instead of the default 60.)
-
-   Reducing the X server bits per pixel depth (e.g. to 16bpp or even
-   8bpp) will further decrease memory I/O and network I/O. The ShadowFB X
-   server setting will make x11vnc's screen polling less severe. Using
-   the -onetile option will use less memory and use fewer shared memory
-   slots (add -fs 1.0 for one less slot.)
-
-
-   Q-72: How can I make x11vnc use MORE system resources?
-
-   You can try -threads (note this mode can be unstable and/or crash; and
-   as of May/2008 is strongly discouraged, see the option description) or
-   dial down the wait time (e.g. -wait 1) and possibly dial down -defer
-   as well. Note that if you try to increase the "frame rate" too much
-   you can bog down the server end with the extra work it needs to do
-   compressing the framebuffer data, etc.
-
-   That said, it is possible to "stream" video via x11vnc if the video
-   window is small enough. E.g. a 256x192 xawtv TV capture window (using
-   the x11vnc -id option) can be streamed over a LAN or wireless at a
-   reasonable frame rate. If the graphics card's framebuffer read rate is
-   faster than normal then the video window size and frame rate can be
-   much higher. The use of TurboVNC and/or TurboJPEG can make the frame
-   rate somewhat higher still (but most of this hinges on the graphics
-   card's read rate.)
-
-
-   Q-73: I use x11vnc over a slow link with high latency (e.g. dialup
-   modem or broadband), is there anything I can do to speed things up?
-
-   Some things you might want to experiment with (many of which will help
-   performance on faster links as well):
-
-     X server/session parameters:
-     * Configure the X server bits per pixel to be 16bpp or even 8bpp.
-       (reduces amount of data needed to be polled, compressed, and sent)
-     * Use a smaller desktop size (e.g. 1024x768 instead of 1280x1024)
-     * Make sure the desktop background is a solid color (the background
-       is resent every time it is re-exposed.) Consider using the -solid
-       [color] option to try to do this automatically.
-     * Configure your window manager or desktop "theme" to not use fancy
-       images, shading, and gradients for the window decorations, etc.
-       Disable window animations, etc. Maybe your desktop has a "low
-       bandwidth" theme you can easily switch into and out of. Also in
-       Firefox disable eye-candy, e.g.: Edit -> Preferences -> Advanced
-       -> Use Smooth Scrolling (deselect it.)
-     * Avoid small scrolls of large windows using the Arrow keys or
-       scrollbar. Try to use PageUp/PageDown instead. (not so much of a
-       problem in x11vnc 0.7.2 if -scrollcopyrect is active and detecting
-       scrolls for the application.)
-     * If the -wireframe option is not available (earlier than x11vnc
-       0.7.2 or you have disabled it via -nowireframe) then Disable
-       Opaque Moves and Resizes in the window manager/desktop.
-     * However if -wireframe is active (on by default in x11vnc 0.7.2)
-       then you should Enable Opaque Moves and Resizes in the window
-       manager! This seems counter-intuitive, but because x11vnc detects
-       the move/resize events early there is a huge speedup over a slow
-       link when Opaque Moves and Resizes are enabled. (e.g. CopyRect
-       encoding will be used.)
-     * Turn off Anti-aliased fonts on your system, web browser, terminal
-       windows, etc. AA fonts do not compress as well as traditional
-       fonts (sometimes 10X less.)
-     * On Firefox/Mozilla (and anything else) turn off "Smooth Scroll"
-       animations. In Firefox put in the URL "about:config" and set
-       general.smoothScroll to false.
-     * On Xorg/XFree86 turn on the Shadow Framebuffer to speed up
-       reading. (Option "ShadowFB" "true" in the Device section of
-       /etc/X11/XF86Config) This disables 2D acceleration on the physical
-       display and so may not be worth it (if you play games, etc), but
-       could be of use in some situations. Note: If the network link is
-       very slow, this speedup may not be noticed.
-
-     VNC viewer parameters:
-     * Use a TightVNC enabled viewer! (Actually, RealVNC 4.x viewer with
-       ZRLE encoding is not too bad either; some claim it is faster.)
-     * Make sure the tight (or zrle) encoding is being used (look at
-       vncviewer and x11vnc outputs)
-     * Request 8 bits per pixel using -bgr233 (up to 4X speedup over
-       depth 24 TrueColor (32bpp), but colors will be off)
-     * RealVNC 4.x viewer has some extremely low color modes (only 64 and
-       even 8 colors.) SSVNC does too. The colors are poor, but it is
-       usually noticeably faster than bgr233 (256 colors.)
-     * Try increasing the TightVNC -compresslevel (compresses more on
-       server side before sending, but uses more CPU)
-     * Try reducing the TightVNC -quality (increases JPEG compression,
-       but is lossy with painting artifacts)
-     * Try other VNC encodings via -encodings (tight may be the fastest,
-       but you should compare it to zrle and maybe some of the others)
-     * On the machine where vncviewer is run, make sure Backing Store is
-       enabled (Xorg/XFree86 disables it by default causing re-exposures
-       of vncviewer to be very slow) Option "backingstore" in config
-       file.
-
-     x11vnc parameters:
-     * Make sure the -wireframe option is active (it should be on by
-       default) and you have Opaque Moves/Resizes Enabled in the window
-       manager.
-     * Make sure the -scrollcopyrect option is active (it should be on by
-       default.) This detects scrolls in many (but not all) applications
-       an applies the CopyRect encoding for a big speedup.
-     * Enforce a solid background when VNC viewers are connected via
-       -solid
-     * Try x11vnc's client-side caching client-side caching scheme:
-       -ncache
-     * Specify -speeds modem to force the wireframe and scrollcopyrect
-       heuristic parameters (and any future ones) to those of a dialup
-       modem connection (or supply the rd,bw,lat numerical values that
-       characterize your link.)
-     * If wireframe and scrollcopyrect aren't working, try using the more
-       drastic -nodragging (no screen updates when dragging mouse, but
-       sometimes you miss visual feedback)
-     * Set -fs 1.0 (disables fullscreen updates)
-     * Try increasing -wait or -defer (reduces the maximum "frame rate",
-       but won't help much for large screen changes)
-     * Try the -progressive pixelheight mode with the block pixelheight
-       100 or so (delays sending vertical blocks since they may change
-       while viewer is receiving earlier ones)
-     * If you just want to watch one (simple) window use -id or -appshare
-       (cuts down extraneous polling and updates, but can be buggy or
-       insufficient)
-     * Set -nosel (disables all clipboard selection exchange)
-     * Use -nocursor and -nocursorpos (repainting the remote cursor
-       position and shape takes resources and round trips)
-     * On very slow links (e.g. <= 28.8) you may need to increase the
-       -readtimeout n setting if it sometimes takes more than 20sec to
-       paint the full screen, etc.
-     * Do not use -fixscreen to automatically refresh the whole screen,
-       tap three Alt_L's then the screen has painting errors (rare
-       problem.)
-
-
-   Example for the KDE desktop:
-
-   Launch the "KDE Control Center" utility. Sometimes this is called
-   "Personal Settings".
-
-   Select "Desktop".
-
-    Then Select "Window Behavior". In the "Moving" Tab set these:
-     * YES - Display content in moving windows
-     * YES - Display content in resizing windows
-     * NO   - Display window geometry when moving or resizing
-     * NO   - Animate minimize and restore
-
-    In the "Translucency" Tab set:
-     * NO   - Use translucency/shadows
-
-   Next hit "Back" and then select "Panels".
-
-    In the "Appearance" Tab set:
-     * NO   - Enable icon mouseover effects
-     * NO   - Enable transparency
-
-   Now go all the way back up to the top and Select "Appearance &
-   Themes".
-
-    Select "Background" and set:
-     * YES - No picture
-     * Colors: Single Color
-
-    Select "Fonts" and disable anti-aliased fonts if you are bold enough.
-
-    Select "Launch Feedback" and set:
-     * Busy Cursor: No Busy Cursor
-     * NO   - Enable taskbar notification
-
-    Select "Screen Saver" and set:
-     * Screen Saver: Blank Screen
-
-    Select "Style" and in the "Effects" Tab set:
-     * NO   - Enable GUI effects
-
-
-   Example for the GNOME desktop:
-     * TBD.
-
-
-   Q-74: Does x11vnc support the X DAMAGE Xserver extension to find
-   modified regions of the screen quickly and efficiently?
-
-   Yes, as of Mar/2005 x11vnc will use the X DAMAGE extension by default
-   if it is available on the display. This requires libXdamage to be
-   available in the build environment as well (recent Linux distros and
-   Solaris 10 have it.)
-
-   The DAMAGE extension enables the X server to report changed regions of
-   the screen back to x11vnc. So x11vnc doesn't have to guess where the
-   changes are (by polling every pixel of the entire screen every 2-4
-   seconds.) The use of X DAMAGE dramatically reduces the load when the
-   screen is not changing very much (i.e. most of the time.) It also
-   noticeably improves updates, especially for very small changed areas
-   (e.g. clock ticking, cursor flashing, typing, etc.)
-
-   Note that the DAMAGE extension does not speed up the actual reading of
-   pixels from the video card framebuffer memory, by, say, mirroring them
-   in main memory. So reading the fb is still painfully slow (e.g.
-   5MB/sec), and so even using X DAMAGE when large changes occur on the
-   screen the bulk of the time is still spent retrieving them. Not ideal,
-   but use of the ShadowFB XFree86/Xorg option speeds up the reading
-   considerably (at the cost of h/w acceleration.)
-
-   Unfortunately the current Xorg DAMAGE extension implementation can at
-   times be overly conservative and report very large rectangles as
-   "damaged" even though only a small portion of the pixels have actually
-   been modified. This behavior is often the fault of the window manager
-   (e.g. it redraws the entire, unseen, frame window underneath the
-   application window when it gains focus), or the application itself
-   (e.g. does large, unnecessary repaints.)
-
-   To work around this deficiency, x11vnc currently only trusts small
-   DAMAGE rectangles to contain real damage. The larger rectangles are
-   only used as hints to focus the traditional scanline polling (i.e. if
-   a scanline doesn't intersect a recent DAMAGE rectangle, the scan is
-   skipped.) You can use the "-xd_area A" option to adjust the size of
-   the trusted DAMAGE rectangles. The default is 20000 pixels (e.g. a
-   140x140 square, etc.) Use "-xd_area 0" to disable the cutoff and trust
-   all DAMAGE rectangles.
-
-   The option "-xd_mem f" may also be of use in tuning the algorithm. To
-   disable using DAMAGE entirely use "-noxdamage".
-
-
-   Q-75: My OpenGL application shows no screen updates unless I supply
-   the -noxdamage option to x11vnc.
-   One user reports in his environment (MythTV using the NVIDIA OpenGL
-   drivers) he gets no updates after the initial screen is drawn unless
-   he uses the "-noxdamage" option.
-
-   This seems to be a bug in the X DAMAGE implementation of that driver.
-   You may have to use -noxdamage as well. A way to autodetect this will
-   be tried, probably the best it will do is automatically stop using X
-   DAMAGE.
-
-   A developer for MiniMyth reports that the 'alphapulse' tag of the
-   theme G.A.N.T. can also cause problems, and should be avoided when
-   using VNC.
-
-   Update: see this FAQ too.
-
-
-   Q-76: When I drag windows around with the mouse or scroll up and down
-   things really bog down (unless I do the drag in a single, quick
-   motion.) Is there anything to do to improve things?
-
-   This problem is primarily due to slow hardware read rates from video
-   cards: as you scroll or move a large window around the screen changes
-   are much too rapid for x11vnc to keep up them (it can usually only
-   read the video card at about 5-10 MB/sec, so it can take a good
-   fraction of a second to read the changes induce from moving a large
-   window, if this to be done a number of times in succession the window
-   or scroll appears to "lurch" forward.) See the description in the
-   -pointer_mode option for more info. The next bottleneck is compressing
-   all of these changes and sending them out to connected viewers,
-   however the VNC protocol is pretty much self-adapting with respect to
-   that (updates are only packaged and sent when viewers ask for them.)
-
-   As of Jan/2004 there are some improvements to libvncserver. The
-   default should now be much better than before and dragging small
-   windows around should no longer be a huge pain. If for some reason
-   these changes make matters worse, you can go back to the old way via
-   the "-pointer_mode 1" option.
-
-   Also added was the -nodragging option that disables all screen updates
-   while dragging with the mouse (i.e. mouse motion with a button held
-   down.) This gives the snappiest response, but might be undesired in
-   some circumstances when you want to see the visual feedback while
-   dragging (e.g. menu traversal or text selection.)
-
-   As of Dec/2004 the -pointer_mode n option was introduced. n=1 is the
-   original mode, n=2 an improvement, etc.. See the -pointer_mode n help
-   for more info.
-
-   Also, in some circumstances the -threads option can improve response
-   considerably. Be forewarned that if more than one vncviewer is
-   connected at the same time then libvncserver may not be thread safe
-   (try to get the viewers to use different VNC encodings, e.g. tight and
-   ZRLE.) This option can be unstable and so as of Feb/2008 it is
-   disabled by default. Set env. X11VNC_THREADED=1 to re-enable.
-
-   As of Apr/2005 two new options (see the wireframe FAQ and
-   scrollcopyrect FAQ below) provide schemes to sweep this problem under
-   the rug for window moves or resizes and for some (but not all) window
-   scrolls. These are the preferred way of avoiding the "lurching"
-   problem, contact me if they are not working. Note on SuSE and some
-   other distros the RECORD X extension used by scrollcopyrect is not
-   enabled by default, turn it on in xorg.conf:
-Section "Module"
-        ...
-        Load  "record"
-        ...
-EndSection
-
-
-   Q-77: Why not do something like wireframe animations to avoid the
-   windows "lurching" when being moved or resized?
-
-   Nice idea for a hack! As of Apr/2005 x11vnc by default will apply
-   heuristics to try to guess if a window is being (opaquely) moved or
-   resized. If such a change is detected framebuffer polling and updates
-   will be suspended and only an animated "wireframe" (a rectangle
-   outline drawn where the moved/resized window would be) is shown. When
-   the window move/resize stops, it returns to normal processing: you
-   should only see the window appear in the new position. This spares you
-   from interacting with a "lurching" window between all of the
-   intermediate steps. BTW the lurching is due to slow video card read
-   rates (see here too.) A displacement, even a small one, of a large
-   window requires a non-negligible amount of time, a good fraction of a
-   second, to read in from the hardware framebuffer.
-
-   Note that Opaque Moves/Resizes must be Enabled by your window manager
-   for -wireframe to do any good.
-
-   The mode is currently on by default because most people are afflicted
-   with the problem. It can be disabled with the -nowireframe option (aka
-   -nowf.) Why might one want to turn off the wireframing? Since x11vnc
-   is merely guessing when windows are being moved/resized, it may guess
-   poorly for your window-manager or desktop, or even for the way you
-   move the pointer. If your window-manager or desktop already does its
-   own wireframing then this mode is a waste of time and could do the
-   wrong thing occasionally. There may be other reasons the new mode
-   feels unnatural. If you have very expensive video hardware (SGI, well
-   now even proprietary Xorg drivers are fast at reading) or are using an
-   in-RAM video framebuffer (SunRay, ShadowFB, Xvfb), the read rate from
-   that framebuffer may be very fast (100's of MB/sec) and so you don't
-   really see much lurching (at least over a fast LAN): opaque moves look
-   smooth in x11vnc. Note: ShadowFB is often turned on when you are using
-   the vesafb or fbdev XFree86 video driver instead of a native one so
-   you might be using it already and not know.
-
-   The heuristics used to guess window motion or resizing are simple, but
-   are not fool proof: x11vnc is sometimes tricked and so you'll
-   occasionally see the lurching opaque move and rarely something even
-   worse.
-
-   First it assumes that the move/resize will occur with a mouse button
-   pressed, held down and dragged (of course this is only mostly true.)
-   Next it will only consider a window for wireframing if the mouse
-   pointer is initially "close enough" to the edges of the window frame,
-   e.g. you have grabbed the title bar or a resizer edge (this
-   requirement can be disabled and it also not applied if a modifier key,
-   e.g. Alt, is pressed.) If these are true, it will wait an amount of
-   time to see if the window starts moving or resizing. If it does, it
-   starts drawing the wireframe "outline" of where the window would be.
-   When the mouse button is released, or a timeout occurs, it goes back
-   to the standard mode to allow the actual framebuffer changes to
-   propagate to the viewers.
-
-   These parameters can be tweaked:
-     * Color/Shade of the wireframe.
-     * Linewidth of the outline frame.
-     * Cutoff size of windows to not apply wireframing to.
-     * Cutoffs for closeness to Top, Bottom, Left, and Right edges of
-       window.
-     * Modifier keys to enable interior window grabbing.
-     * Maximum time to wait for dragging pointer events.
-     * Maximum time to wait for the window to start moving/resizing.
-     * Maximum time to show a wireframe animation.
-     * Minimum time between sending wireframe outlines.
-
-   See the "-wireframe tweaks" option for more details. On a slow link,
-   e.g. dialup modem, the parameters may be automatically adjusted for
-   better response.
-
-
-   CopyRect encoding:  In addition to the above there is the
-   "-wirecopyrect mode" option. It is also on by default. This instructs
-   x11vnc to not only show the wireframe animation, but to also instruct
-   all connected VNC viewers to locally translate the window image data
-   from the original position to the new position on the screen when the
-   animation is done. This speedup is the VNC CopyRect encoding: the
-   framebuffer update doesn't need to send the actual new image data.
-   This is nice in general, and very convenient over a slow link, but
-   since it is based on heuristics you may need to disable it with the
-   -nowirecopyrect option (aka -nowcr) if it works incorrectly or
-   unnaturally for you.
-
-   The -wirecopyrect modes are: "never" (same as -nowirecopyrect); "top",
-   only apply the CopyRect if the window is appears to be on the top of
-   the window stack and is not obstructed by other windows; and "always"
-   to always try to apply the CopyRect (obstructed regions are usually
-   clipped off and not translated.)
-
-   Note that some desktops (KDE and xfce) appear to mess with the window
-   stacking in ways that are not yet clear. In these cases x11vnc works
-   around the problem by applying the CopyRect even if obscuring windows'
-   data is translated! Use -nowirecopyrect if this yields undesirable
-   effects for your desktop.
-
-   Also, the CopyRect encoding may give incorrect results under -scale
-   (depending on the scale factor the CopyRect operation is often only
-   approximate: the correctly scaled framebuffer will be slightly
-   different from the translated one.) x11vnc will try to push a
-   "cleanup" update after the CopyRect if -scale is in effect. Use
-   -nowirecopyrect if this or other painting errors are unacceptable.
-
-
-   Q-78: Can x11vnc try to apply heuristics to detect when a window is
-   scrolling its contents and use the CopyRect encoding for a speedup?
-
-   Another nice idea for a hack! As of May/2005 x11vnc will by default
-   apply heuristics to try to detect if the window that has the input
-   focus is scrolling its contents (but only when x11vnc is feeding user
-   input, keystroke or pointer, to the X server.) So, when detected,
-   scrolls induced by dragging on a scrollbar or by typing (e.g. Up or
-   Down arrows, hitting Return in a terminal window, etc), will show up
-   much more quickly than via the standard x11vnc screen polling update
-   mechanism.
-
-   There will be a speedup for both slow and fast links to viewers. For
-   slow links the speedup is mostly due to the CopyRect encoding not
-   requiring the image data to be transmitted over the network. For fast
-   links the speedup is primarily due to x11vnc not having to read the
-   scrolled framebuffer data from the X server (recall that reading from
-   the hardware framebuffer is slow.)
-
-   To do this x11vnc uses the RECORD X extension to snoop the X11
-   protocol between the X client with the focus window and the X server.
-   This extension is usually present on most X servers (but SuSE disables
-   it for some reason.) On XFree86/Xorg it can be enabled via Load
-   "record" in the Module section of the config file if it isn't already:
-Section "Module"
-        ...
-        Load  "record"
-        ...
-EndSection
-
-   Currently the RECORD extension is used as little as possible so as to
-   not slow down regular use. Only simple heuristics are applied to
-   detect XCopyArea and XConfigureWindow calls from the application.
-   These catch a lot of scrolls, e.g. in mozilla/firefox and in terminal
-   windows like gnome-terminal and xterm. Unfortunately the toolkits KDE
-   applications use make scroll detection less effective (only rarely are
-   they detected: i.e. Konqueror and Konsole don't work.) An interesting
-   project, that may be the direction x11vnc takes, is to record all of
-   the X11 protocol from all clients and try to "tee" the stream into a
-   modified Xvfb watching for CopyRect and other VNC speedups. A
-   potential issue is the RECORD stream is delayed from actual view on
-   the X server display: if one falls too far behind it could become a
-   mess...
-
-   The initial implementation of -scrollcopyrect option is useful in that
-   it detects many scrolls and thus gives a much nicer working
-   environment (especially when combined with the -wireframe
-   -wirecopyrect options, which are also on by default; and if you are
-   willing to enable the ShadowFB things are very fast.) The fact that
-   there aren't long delays or lurches during scrolling is the primary
-   improvement.
-
-   But there are some drawbacks:
-     * Not all scrolls are detected. Some apps scroll windows in ways
-       that cannot currently be detected, and other times x11vnc "misses"
-       the scroll due to timeouts, etc. Sometimes it is more distracting
-       that a speedup occasionally doesn't work as opposed to being
-       consistently slow!
-     * For rapid scrolling (i.e. sequence of many scrolls over a short
-       period) there can be painting errors (tearing, bunching up, etc.)
-       during the scroll. These will repair themselves after the scroll
-       is over, but when they are severe it can be distracting. Try to
-       think of the approximate window contents as a quicker and more
-       useful "animation" compared to the slower polling scheme...
-     * Scrolling inside shells in terminal windows (gnome-terminal,
-       xterm), can lead to odd painting errors. This is because x11vnc
-       did not have time to detect a screen change just before the scroll
-       (most common is the terminal undraws the block cursor before
-       scrolling the text up: in the viewer you temporarily see multiple
-       block cursors.) Another issue is with things like more(1): scroll
-       detection for 5-6 lines happens nicely, but then it can't keep up
-       and so there is a long pause for the standard polling method to
-       deliver the remaining updates.
-     * More rarely sometimes painting errors are not repaired after the
-       scroll is over. This may be a bug in x11vnc or libvncserver, or it
-       may be an inescapable fact of the CopyRect encoding and the delay
-       between RECORD callbacks and what is actually on the X display.
-       One can tap the Alt_L key (Left "Alt" key) 3 times in a row to
-       signal x11vnc to refresh the screen to all viewers. Your
-       VNC-viewer may have its own screen refresh hot-key or button. See
-       also: -fixscreen
-     * Some applications, notably OpenOffice, do XCopyArea scrolls in
-       weird ways that assume ancestor window clipping is taking place.
-       See the -scr_skip option for ways to tweak this on a
-       per-application basis.
-     * Selecting text while dragging the mouse may be slower, especially
-       if the Button-down event happens near the window's edge. This is
-       because the scrollcopyrect scheme is watching for scrolls via
-       RECORD and has to wait for a timeout to occur before it does the
-       update.
-     * For reasons not yet understood the RECORD extension can stop
-       responding (and hence scrolls are missed.) As a workaround x11vnc
-       attempts to reset the RECORD connection every 60 seconds or so.
-       Another workaround is to type 4 Super_L (Left Super/Windows-Flag
-       key) in a row to reset RECORD. Work is in progress to try to fix
-       this bug.
-     * Sometimes you need to "retrain" x11vnc for a certain window
-       because it fails to detect scrolls in it. Sometimes clicking
-       inside the application window or selecting some text in it to
-       force the focus helps.
-     * When using the -scale option there will be a quick CopyRect
-       scroll, but it needs to be followed by a slower "cleanup" update.
-       This is because for a fixed finite screen resolution (e.g. 75 dpi)
-       scaling and copyrect-ing are not exactly independent. Scaling
-       involves a blending of nearby pixels and if you translate a pixel
-       the neighbor pixel weighting may be different. So you have to wait
-       a bit for the cleanup update to finish. On slow links x11vnc may
-       automatically decide to not detect scrolls when -scale is in
-       effect. In general it will also try to defer the cleanup update if
-       possible.
-
-   If you find the -scrollcopyrect behavior too approximate or
-   distracting you can go back to the standard polling-only update method
-   with the -noscrollcopyrect (or -noscr for short.) If you find some
-   extremely bad and repeatable behavior for -scrollcopyrect please
-   report a bug.
-
-   Alternatively, as with -wireframe, there are many tuning parameters to
-   try to improve the situation. You can also access these parameters
-   inside the gui under "Tuning". These parameters can be tweaked:
-     * The minimum pixel area of a rectangle to be watched for scrolls.
-     * A list if application names to skip scroll detection.
-     * Which keystrokes should trigger scroll detection.
-     * Which applications should have a "terminal" tweak applied to them.
-     * When repeating keys (e.g. Up arrow) should be discarded to
-       preserve a scroll.
-     * Cutoffs for closeness to Top, Bottom, Left, and Right edges of
-       window for mouse induced scrolls.
-     * Set timeout parameters for keystroke induced scrolls.
-     * Set timeout parameters for mouse pointer induced scrolls.
-     * Have the full screen be periodically refreshed to fix painting
-       errors.
-
-
-   Q-79: Can x11vnc do client-side caching of pixel data? I.e. so when
-   that pixel data is needed again it does not have to be retransmitted
-   over the network.
-
-   As of Dec/2006 in the 0.9 development tarball there is an experimental
-   client-side caching implementation enabled by the "-ncache n" option.
-   In fact, during the test period it was on by default with n set to 10.
-   To disable it use "-noncache".
-
-   It is a simple scheme where a (very large) lower portion of the
-   framebuffer (i.e. starting just below the user's actual desktop
-   display) is used for storing pixel data. CopyRect; a fast, essentially
-   local viewer-side VNC encoding; is used to swap the pixel data in and
-   out of the actual display area. It gives an excellent speedup for
-   iconifying/deiconifying and moving windows and re-posting of menus
-   (often it doesn't feel like VNC at all: there is no delay waiting for
-   the pixel data to fill in.)
-
-   This scheme is nice because it does all of this within the existing
-   VNC protocol, and so it works with all VNC viewers.
-
-   A challenge to doing more sophisticated (e.g. compressed and/or
-   shared) client-side caching is that one needs to extend the VNC
-   protocol, modify a viewer and then also convince users to adopt your
-   modified VNC Viewer (or get the new features to be folded into the
-   main VNC viewers, patches accepted, etc... likely takes many years
-   before they might be deployed in the field.) So it is convenient that
-   the "-ncache n" works with any unaltered VNC viewer.
-
-   A drawback of the "-ncache n" method is that in the VNC Viewer you can
-   scroll down and actually see the cached pixel data. So it looks like
-   there is a bug: you can scroll down in your viewer and see a strange
-   "history" of windows on your desktop. This is working as intended. One
-   will need to try to adjust the size of his VNC Viewer window so the
-   cache area cannot be seen. SSVNC (see below) can do this
-   automatically.
-
-   At some point LibVNCServer may implement a "rfbFBCrop" pseudoencoding
-   that viewers can use to learn which portion of the framebuffer to
-   actually show to the users (with the hidden part used for caching, or
-   perhaps something else, maybe double buffering or other offscreen
-   rendering...)
-
-   The Enhanced TightVNC Viewer (SSVNC) Unix viewer has a nice -ycrop
-   option to help hide the pixel cache area from view. It will turn on
-   automatically if the framebuffer appears to be very tall (height more
-   than twice the width), or you can supply the actual value for the
-   height. If the screen is resized by scaling, etc, the ycrop value is
-   scaled as well. In fullscreen mode you cannot scroll past the end of
-   the actual screen, and in non-fullscreen mode the window manager frame
-   is adjusted to fit the actual display (so you don't see the pixel
-   cache region) and the scrollbars are very thin to avoid distraction
-   and trouble fitting inside your display. Use the "-sbwidth n" viewer
-   option to make the scrollbars thicker if you like.
-
-   Another drawback of the scheme is that it is VERY memory intensive,
-   the n in "-ncache n" is the factor of increase over the base
-   framebuffer size to use for caching. It is an even integer and should
-   be fairly large, 6-12, to achieve good response. This usually requires
-   about 50-100MB of additional RAM on both the client and server sides.
-   For example with n=6 a 1280x1024 display will use a framebuffer that
-   is 1280x7168: everything below row 1024 is the pixel buffer cache. If
-   you are running on low memory machines or memory is tight because of
-   other running applications you should not use -ncache.
-
-   The reason for so much memory is because the pixel data is not
-   compressed and so the whole window to be saved must be stored
-   "offscreen". E.g. for a large web browser window this can be nearly 1
-   million pixels, and that is only for a single window! One typically
-   wants to cycle between 5-10 large active windows. Also because both
-   backing-store (the window's actual contents) and save-unders (the
-   pixels covered up by the window) are cached offscreen that introduces
-   an additional factor of 2 in memory use.
-
-   However, even in the smallest usage mode with n equal 2 and
-   -ncache_no_rootpixmap set (this requires only 2X additional
-   framebuffer memory) there is still a noticable improvement for many
-   activities, although it is not as dramatic as with, say n equal 12 and
-   rootpixmap (desktop background) caching enabled.
-
-   The large memory consumption of the current implementation can be
-   thought of as a tradeoff to providing caching and being compatible
-   with all VNC viewers and also ease of implementing. Hopefully it can
-   be tuned to use less, or the VNC community will extend the protocol to
-   allow caching and replaying of compressed blobs of data.
-
-   Another option to experiment with is "-ncache_cr". By specifying it,
-   x11vnc will try to do smooth opaque window moves instead of its
-   wireframe. This can give a very nice effect (note: on Unix the realvnc
-   viewer seems to be smoother than the tightvnc viewer), but can lead to
-   some painting problems, and can be jerky in some circumstances.
-
-   Surprisingly, for very slow connections, e.g. modem, the -ncache_cr
-   option can actually improve window drags. This is probably because no
-   pixel data (only CopyRect instructions) are sent when dragging a
-   window. Normally, the wireframe must be sent and this involves
-   compressing and sending the lines that give rise to the moving box
-   effect (note that real framebuffer data is sent to "erase" the white
-   lines of the box.)
-
-   If you experience painting errors you can can tap the Alt_L key (Left
-   "Alt" key) 3 times in a row to signal x11vnc to refresh the screen to
-   all viewers. You may also need to iconify and then deiconify any
-   damaged windows to correct their cache data as well. Note that if you
-   change color viewer depth (e.g. 8bpp to full color) dynamically that
-   will usually lead to the entire extended framebuffer being resent
-   which can take a long time over very slow links: it may be better to
-   reconnect and reset the format right after doing so. x11vnc will try
-   to detect the format change and clear (make completely black) the
-   cache region.
-
-   Gotcha for older Unix VNC Viewers: The older Unix VNC viewers (e.g.
-   current TightVNC Unix Viewer) require X server backingstore to keep
-   off-viewer screen data local. If the viewer-side X server has
-   backingstore disabled (sadly, currently the default on Linux, etc),
-   then to get the offscreen pixels the viewer has to ask for a refresh
-   over the network, thereby defeating the caching. Use something like
-   this in your viewer-side /etc/X11/xorg.conf file (or otherwise get
-   your viewer-side system to do it)
-Section "Device"
-        ...
-        Option  "backingstore"
-        ...
-EndSection
-
-   No problems like this have been observed with Windows VNC Viewers:
-   they all seem to keep their entire framebuffer in local memory.
-
-   Gotcha for KDE krdc VNC Viewer: One user found that KDE's krdc viewer
-   has some sort of hardwired limit on the maximum size of the
-   framebuffer (64MB?). It fails quickly saying "The connection to the
-   host has been interrupted." The workaround for his 1280x1024
-   x11vnc-side display was to run with "-ncache 10", i.e. a smaller value
-   to be under the krdc threshold.
-
-   Although this scheme is not as quick (nor as compressed) as
-   nx/nomachine, say, it does provide a good step in the direction of
-   improving VNC performance by client side caching.
-
-
-   Q-80: Does x11vnc support TurboVNC?
-
-   As of Feb/2009 (development tarball) there is an experimental kludge
-   to let you build x11vnc using TurboVNC's modified TightVNC encoding.
-   TurboVNC is part of the VirtualGL project. It does two main things to
-   speed up the TightVNC encoding:
-     * It eliminates bottlenecks, overheads, wait-times in the TightVNC
-       encoding implementation and instead only worries about sending
-       very well (and quickly) compressed JPEG data.
-     * A fast proprietary JPEG implemention is used (Intel IPP on x86)
-       instead of the usual libjpeg implementation. TurboJPEG is an
-       interface library, libturbojpeg, provided by the project that
-       achieves this.
-
-   TurboVNC works very well over LAN and evidently fast Broadband too.
-   When using it with x11vnc in such a situation you may want to dial
-   down the delays, e.g. "-wait 5" and "-defer 5" (or even a smaller
-   setting) to poll and pump things out more quickly.
-
-   See the instructions in "x11vnc/misc/turbovnc/README" for how to build
-   x11vnc with TurboVNC support. You will also need to download the
-   TurboJPEG software.
-
-   In brief, the steps look like this:
-  cd x11vnc-x.y.z/x11vnc/misc/turbovnc
-  ./apply_turbovnc
-  cd ../../..
-  env LDFLAGS='-L/DIR -Xlinker --rpath=/DIR' ./configure
-  make AM_LDFLAGS='-lturbojpeg'
-
-   where you replace "/DIR" with the directory containing libturbojpeg.so
-   you downloaded separately. If it works out well enough TurboVNC
-   support will be integrated into x11vnc and more of its tuning features
-   will be implemented. Support for TurboVNC in SSVNC viewer has been
-   added as an experiment as well. If you try either one, let us know how
-   it went.
-
-   There also may be some Linux.i686 and Darwin.i386 x11vnc binaries with
-   TurboVNC support in the misc. bins directory. For other platforms you
-   will need to compile yourself.
-
-   On relatively cheap and old hardware (Althon64 X2 5000+ / GeForce
-   6200) x11vnc and SSVNC, both TurboVNC enabled, were able to sustain
-   13.5 frames/sec (fps) and 15 Megapixels/sec using the VirtualGL
-   supplied OpenGL benchmark program glxspheres. VirtualGL on higher-end
-   hardware can sustain 20-30 fps with the glxspheres benchmark.
-
-   Potential Slowdown: As we describe elsewhere, unless you use x11vnc
-   with an X server using, say, NVidia proprietary drivers (or a virtual
-   X server like Xvfb or Xdummy, or in ShadowFB mode), then the read rate
-   from the graphics card can be rather slow (e.g. 10 MB/sec) and becomes
-   the bottleneck when using x11vnc over fast networks. Note that all of
-   Xorg's drivers currently (2009) have slow read rates (only proprietary
-   drivers appear to have optimized reads.)
-
-   So under these (more or less typical) conditions, the speed
-   improvement provided by TurboVNC may only be marginal. Look for this
-   output to see your read rate:
-  28/02/2009 11:11:07 Autoprobing TCP port
-  28/02/2009 11:11:07 Autoprobing selected port 5900
-  28/02/2009 11:11:08 fb read rate: 10 MB/sec
-  28/02/2009 11:11:08 screen setup finished.
-
-   A rate of 10 MB/sec means a 1280x1024x24 screen takes 0.5 seconds to
-   read in. TurboVNC compresses that to JPEG in a much shorter time. On
-   the other hand, an NVidia driver may have a read rate of 250 MB/sec
-   and so only takes 0.02 seconds to read the entire screen in.
-
-
-
-   [Mouse Cursor Shapes]
-
-   Q-81: Why isn't the mouse cursor shape (the little icon shape where
-   the mouse pointer is) correct as I move from window to window?
-
-   On X servers supporting XFIXES or Solaris/IRIX Overlay extensions it
-   is possible for x11vnc to do this correctly. See a few paragraphs down
-   for the answer.
-
-   Historically, the X11 mouse cursor shape (i.e. little picture: an
-   arrow, X, I-beam, resizer, etc) is one of the few WRITE-only objects
-   in X11. That is, an application can tell the X server what the cursor
-   shape should be when the pointer is in a given window, but a program
-   (like x11vnc) unfortunately cannot read this information. I believe
-   this is because the cursor shape is often downloaded to the graphics
-   hardware (video card), but I could be mistaken.
-
-   A simple kludge is provided by the "-cursor X" option that changes the
-   cursor when the mouse is on the root background (or any window has the
-   same cursor as the root background.) Note that desktops like GNOME or
-   KDE often cover up the root background, so this won't work for those
-   cases. Also see the "-cursor some" option for additional kludges.
-
-   Note that as of Aug/2004 on Solaris using the SUN_OVL overlay
-   extension and IRIX, x11vnc can show the correct mouse cursor when the
-   -overlay option is supplied. See this FAQ for more info.
-
-   Also as of Dec/2004 XFIXES X extension support has been added to allow
-   exact extraction of the mouse cursor shape. XFIXES fixes the problem
-   of the cursor-shape being write-only: x11vnc can now query the X
-   server for the current shape and send it back to the connected
-   viewers. XFIXES is available on recent Linux Xorg based distros and
-   Solaris 10.
-
-   The only XFIXES issue is the handling of alpha channel transparency in
-   cursors. If a cursor has any translucency then in general it must be
-   approximated to opaque RGB values for use in VNC. There are some
-   situations where the cursor transparency can also handled exactly:
-   when the VNC Viewer requires the cursor shape be drawn into the VNC
-   framebuffer or if you apply a patch to your VNC Viewer to extract
-   hidden alpha channel data under 32bpp. Details can be found here.
-
-
-   Q-82: When using XFIXES cursorshape mode, some of the cursors look
-   really bad with extra black borders around the cursor and other cruft.
-   How can I improve their appearance?
-
-   This happens for cursors with transparency ("alpha channel"); regular
-   X cursors (bitmaps) should be correct. Unfortunately x11vnc 0.7 was
-   released with a very poor algorithm for approximating the
-   transparency, which led to the ugly black borders.
-
-   The problem is as follows: XFIXES allows x11vnc to retrieve the
-   current X server cursor shape, including the alpha channel for
-   transparency. For traditional bitmap cursors the alpha value will be 0
-   for completely transparent pixels and 255 for completely opaque
-   pixels; whereas for modern, eye-candy cursors an alpha value between 0
-   and 255 means to blend in the background colors to that degree with
-   the cursor colors. The pixel color blending formula is something like
-   this: Red = Red_cursor * a + Red_background * (1 - a), (where here 0
-   =< a =< 1), with similar for Green and Blue. The VNC protocol does not
-   currently support an alpha channel in cursors: it only supports
-   regular X bitmap cursors and Rich Cursors that have RGB (Red, Green,
-   Blue) color data, but no "A" = alpha data. So in general x11vnc has to
-   approximate a cursor with transparency to create a Rich Cursor. This
-   is easier said than done: some cursor themes have cursors with
-   complicated drop shadows and other forms of translucency.
-
-   Anyway, for the x11vnc 0.7.1 release the algorithm for approximating
-   transparency is much improved and hopefully gives decent cursor shapes
-   for most cursor themes and you don't have to worry about it.
-
-   In case it still looks bad for your cursor theme, there are (of
-   course!) some tunable parameters. The "-alphacut n" option lets you
-   set the threshold "n" (between 0 and 255): cursor pixels with alpha
-   values below n will be considered completely transparent while values
-   equal to or above n will be completely opaque. The default is 240. The
-   "-alphafrac f" option tries to correct individual cursors that did not
-   fare well with the default -alphacut value: if a cursor has less than
-   fraction f (between 0.0 and 1.0) of its pixels selected by the default
-   -alphacut, the threshold is lowered until f of its pixels are
-   selected. The default fraction is 0.33.
-
-   Finally, there is an option -alpharemove that is useful for themes
-   where many cursors are light colored (e.g. "whiteglass".) XFIXES
-   returns the cursor data with the RGB values pre-multiplied by the
-   alpha value. If the white cursors look too grey, specify -alpharemove
-   to brighten them by having x11vnc divide out the alpha value.
-
-   One user played with these parameters and reported back:
- Of the cursor themes present on my system:
-
-   gentoo and gentoo-blue:   alphacut:192 - noalpharemove
-
-   gentoo-silver:            alphacut:127 and alpharemove
-
-   whiteglass and redglass (presumably also handhelds, which is based
-   heavily on redglass) look fine with the apparent default of alphacut:255.
-
-
-   Q-83: In XFIXES mode, are there any hacks to handle cursor
-   transparency ("alpha channel") exactly?
-
-   As of Jan/2005 libvncserver has been modified to allow an alpha
-   channel (i.e. RGBA data) for Rich Cursors. So x11vnc can now send the
-   alpha channel data to libvncserver. However, this data will only be
-   used for VNC clients that do not support the CursorShapeUpdates VNC
-   extension (or have disabled it.) It can be disabled for all clients
-   with the -nocursorshape x11vnc option. In this case the cursor is
-   drawn, correctly blended with the background, into the VNC framebuffer
-   before being sent out to the client. So the alpha blending is done on
-   the x11vnc side. Use the -noalphablend option to disable this behavior
-   (always approximate transparent cursors with opaque RGB values.)
-
-   The CursorShapeUpdates VNC extension complicates matters because the
-   cursor shape is sent to the VNC viewers supporting it, and the viewers
-   draw the cursor locally. This improves response over slow links. Alpha
-   channel data for these locally drawn cursors is not supported by the
-   VNC protocol.
-
-   However, in the libvncserver CVS there is a patch to the TightVNC
-   viewer to make this work for CursorShapeUpdates under some
-   circumstances. This hack is outside of the VNC protocol. It requires
-   the screens on both sides to be depth 24 at 32bpp (it uses the extra 8
-   bits to secretly hide the cursor alpha channel data.) Not only does it
-   require depth 24 at 32bpp, but it also currently requires the client
-   and server to be of the same endianness (otherwise the hidden alpha
-   data gets reset to zero by a libvncserver translation function; we can
-   fix this at some point if there is interest.) The patch is for the
-   TightVNC 1.3dev5 Unix vncviewer and it enables the TightVNC viewer to
-   do the cursor alpha blending locally. The patch code should give an
-   example on how to change the Windows TightVNC viewer to achieve the
-   same thing (send me the patch if you get that working.)
-
-   This patch is applied to the Enhanced TightVNC Viewer (SSVNC) package
-   we provide.
-
-   [Mouse Pointer]
-
-   Q-84: Why does the mouse arrow just stay in one corner in my
-   vncviewer, whereas my cursor (that does move) is just a dot?
-
-   This default takes advantage of a tightvnc extension
-   (CursorShapeUpdates) that allows specifying a cursor image shape for
-   the local VNC viewer. You may disable it with the -nocursor option to
-   x11vnc if your viewer does not have this extension.
-
-   Note: as of Aug/2004 this should be fixed: the default for
-   non-tightvnc viewers (or ones that do not support CursorShapeUpdates)
-   will be to draw the moving cursor into the x11vnc framebuffer. This
-   can also be disabled via -nocursor.
-
-
-   Q-85: Can I take advantage of the TightVNC extension to the VNC
-   protocol where Cursor Positions Updates are sent back to all connected
-   clients (i.e. passive viewers can see the mouse cursor being moved
-   around by another viewer)?
-
-   Use the -cursorpos option when starting x11vnc. A VNC viewer must
-   support the Cursor Positions Updates for the user to see the mouse
-   motions (the TightVNC viewers support this.) As of Aug/2004 -cursorpos
-   is the default. See also -nocursorpos and -nocursorshape.
-
-
-   Q-86: Is it possible to swap the mouse buttons (e.g. left-handed
-   operation), or arbitrarily remap them? How about mapping button clicks
-   to keystrokes, e.g. to partially emulate Mouse wheel scrolling?
-
-   You can remap the mouse buttons via something like: -buttonmap 13-31
-   (or perhaps 12-21.) Also, note that xmodmap(1) lets you directly
-   adjust the X server's button mappings, but in some circumstances it
-   might be more desirable to have x11vnc do it.
-
-   One user had an X server with only one mouse button(!) and was able to
-   map all of the VNC client mouse buttons to it via: -buttonmap 123-111.
-
-   Note that the -debug_pointer option prints out much info for every
-   mouse/pointer event and is handy in solving problems.
-
-   To map mouse button clicks to keystrokes you can use the alternate
-   format where the keystrokes are enclosed between colons like this
-   :<KeySym>: in place of the mouse button digit. For a sequence of
-   keysyms separate them with "+" signs. Look in the include file
-   <X11/keysymdef.h>, or use xev(1), or -debug_keyboard to find the
-   keysym names. Button clicks can also be included in the sequence via
-   the fake keysyms Button1, etc.
-
-   As an example, suppose the VNC viewer machine has a mouse wheel (these
-   generate button 4 and 5 events), but the machine that x11vnc is run on
-   only has the 3 regular buttons. In normal operation x11vnc will
-   discard the button 4 and 5 events. However, either of the following
-   button maps could possibly be of use emulating the mouse wheel events
-   in this case:
-  -buttonmap 12345-123:Prior::Next:
-  -buttonmap 12345-123:Up+Up+Up::Down+Down+Down:
-
-   Exactly what keystroke "scrolling" events they should be bound to
-   depends on one's taste. If this method is too approximate, one could
-   consider not using -buttonmap but rather configuring the X server to
-   think it has a mouse with 5 buttons even though the physical mouse
-   does not. (e.g. 'Option "ZAxisMapping" "4 5"'.)
-
-   Note that when a keysym-mapped mouse button is clicked down this
-   immediately generates the key-press and key-release events (for each
-   keysym in turn if the mapping has a sequence of keysyms.) When the
-   mouse button goes back up nothing is generated.
-
-   If you include modifier keys like Shift_L instead of key-press
-   immediately followed by key-release the state of the modifier key is
-   toggled (however the initial state of the modifier key is ignored.) So
-   to map the right button to type my name 'Karl Runge' I could use this:
-  -buttonmap 3-:Shift_L+k+Shift_L+a+r+l+space+Shift_L+r+Shift_L+u+n+g+e:
-
-   (yes, this is getting a little silly.)
-
-   BTW, Coming the other way around, if the machine you are sitting at
-   does not have a mouse wheel, but the remote machine does (or at least
-   has 5 buttons configured), this key remapping can be useful:
-  -remap Super_R-Button4,Menu-Button5
-
-   you just tap those two keys to get the mouse wheel scrolls (this is
-   more useful than the Up and Down arrow keys because a mouse wheel
-   "click" usually gives a multi-line scroll.)
-   [Keyboard Issues]
-
-   Q-87: How can I get my AltGr and Shift modifiers to work between
-   keyboards for different languages?
-
-   The option -modtweak should help here. It is a mode that monitors the
-   state of the Shift and AltGr Modifiers and tries to deduce the correct
-   keycode to send, possibly by sending fake modifier key presses and
-   releases in addition to the actual keystroke.
-
-   Update:  As of Jul/2004 -modtweak is now the default (use -nomodtweak
-   to get the old behavior.) This was done because it was noticed on
-   newer XFree86 setups even on bland "us" keyboards like "pc104 us"
-   XFree86 included a "ghost" key with both "<" and ">" it. This key does
-   not exist on the keyboard (see this FAQ for more info.) Without
-   -modtweak there was then an ambiguity in the reverse map keysym =>
-   keycode, making it so the "<" symbol could not be typed.
-
-   Also see the FAQ about the -xkb option for a more powerful method of
-   modifier tweaking for use on X servers with the XKEYBOARD extension.
-
-   When trying to resolve keyboard mapping problems, note that the
-   -debug_keyboard option prints out much info for every keystroke and so
-   can be useful debugging things.
-
-   Note that one user had a strange setup and none of the above helped.
-   His solution was to disable all of the above and use -nomodtweak. This
-   is the simplest form of keystroke insertion and it actually solved the
-   problem. Try it if the other options don't help.
-
-
-   Q-88: When I try to type a "<" (i.e. less than) instead I get ">"
-   (i.e. greater than)! Strangely, typing ">" works OK!!
-
-   Does your keyboard have a single key with both "<" and ">" on it? Even
-   if it doesn't, your X server may think your keyboard has such a key
-   (e.g. pc105 in the XF86Config file when it should be something else,
-   say pc104.)
-
-   Short Cut: Try the -xkb or -sloppy_keys options and see if that helps
-   the situation. The discussion below is a bit outdated (e.g. -modtweak
-   is now the default) but it is useful reference for various tricks and
-   so is kept.
-
-
-   The problem here is that on the Xserver where x11vnc is run there are
-   two keycodes that correspond to the "<" keysym. Run something like
-   this to see:
-
-  xmodmap -pk | egrep -i 'KeyCode|less|greater'
-  There are 4 KeySyms per KeyCode; KeyCodes range from 8 to 255.
-      KeyCode     Keysym (Keysym) ...
-       59         0x002c (comma)  0x003c (less)
-       60         0x002e (period) 0x003e (greater)
-       94         0x003c (less)   0x003e (greater)
-
-   That keycode 94 is the special key with both "<" and ">". When x11vnc
-   receives the "<" keysym over the wire from the remote VNC client, it
-   unfortunately maps it to keycode 94 instead of 59, and sends 94 to the
-   X server. Since Shift is down (i.e. you are Shifting the comma key),
-   the X server interprets this as Shifted-94, which is ">".
-
-   A workaround in the X server configuration is to "deaden" that special
-   key:
-
-  xmodmap -e "keycode 94 = "
-
-   However, one user said he had to do this:
-
-  xmodmap -e "keycode 94 = 0x002c 0x003c"
-
-   (If the numerical values are different for your setup, substitute the
-   ones that correspond to your display. The above xmodmap scheme can
-   often be used to work around other ambiguous keysym to keycode
-   mappings.)
-
-   Alternatively, here are some x11vnc options to try to work around the
-   problem:
-   -modtweak
-
-   and
-   -remap less-comma
-
-   These are convenient in that they do not modify the actual X server
-   settings. The former (-modtweak) is a mode that monitors the state of
-   the Shift and AltGr modifiers and tries to deduce the correct keycode
-   sequence to send. Since Jul/2004 -modtweak is now the default. The
-   latter (-remap less-comma) is an immediate remapping of the keysym
-   less to the keysym comma when it comes in from a client (so when Shift
-   is down the comma press will yield "<".)
-
-   See also the FAQ about the -xkb option as a possible workaround using
-   the XKEYBOARD extension.
-
-   Note that the -debug_keyboard option prints out much info for every
-   keystroke to aid debugging keyboard problems.
-
-
-   Q-89: Extra Character Inserted, E.g.: When I try to type a "<" (i.e.
-   less than) instead I get "<," (i.e. an extra comma.)
-
-   This is likely because you press "Shift" then "<" but then released
-   the Shift key before releasing the "<". Because of a keymapping
-   ambiguity the last event "< up" is interpreted as "," because that key
-   unshifted is the comma.
-
-   This extra character insertion will happen for other combinations of
-   characters: in general it can happen whenever the Shift key is
-   released early.
-
-   This should not happen in -xkb mode, because it works hard to resolve
-   the ambiguities. If you do not want to use -xkb, try the option
-   -sloppy_keys to attempt a similar type of algorithm.
-
-   One user had this problem for Italian and German keyboards with the
-   key containing ":" and "." When he typed ":" he would get an extra "."
-   inserted after the ":". The solution was -sloppy_keys.
-
-
-   Q-90: I'm using an "international" keyboard (e.g. German "de", or
-   Danish "dk") and the -modtweak mode works well if the VNC viewer is
-   run on a Unix/Linux machine with a similar keyboard.   But if I run
-   the VNC viewer on Unix/Linux with a different keyboard (e.g. "us") or
-   Windows with any keyboard, I can't type some keys like:   "@", "$",
-   "<", ">", etc. How can I fix this?
-
-   The problem with Windows is it does not seem to handle AltGr well. It
-   seems to fake it up by sending Control_L+Alt_R to applications. The
-   Windows VNC viewer sends those two down keystrokes out on the wire to
-   the VNC server, but when the user types the next key to get, e.g., "@"
-   the Windows VNC viewer sends events bringing the up the
-   Control_L+Alt_R keys, and then sends the "@" keysym by itself.
-
-   The Unix/Linux VNC viewer on a "us" keyboard does a similar thing
-   since "@" is the Shift of the "2" key. The keysyms Shift and "@" are
-   sent to the VNC server.
-
-   In both cases no AltGr is sent to the VNC server, but we know AltGr is
-   needed on the physical international keyboard to type a "@".
-
-   This all worked fine with x11vnc running with the -modtweak option (it
-   figures out how to adjust the Modifier keys (Shift or AltGr) to get
-   the "@".) However it fails under recent versions of XFree86 (and the
-   X.org fork.) These run the XKEYBOARD extension by default and make
-   heavy use of it to handle international keyboards.
-
-   To make a long story short, on these newer XFree86 setups the
-   traditional X keymap lookup x11vnc uses is no longer accurate. x11vnc
-   can't find the keysym "@" anywhere in the keymapping! (even though it
-   is in the XKEYBOARD extended keymapping.)
-
-   How to Solve: As of Jul/2004 x11vnc has two changes:
-     * -modtweak (tweak Modifier keys) is now the default (use
-       -nomodtweak to go back to the old way)
-     * there is a new option -xkb to use the XKEYBOARD extension API to
-       do the Modifier key tweaking.
-
-   The -xkb option seems to fix all of the missing keys: "@", "<", ">",
-   etc.: it is recommended that you try it if you have this sort of
-   problem. Let us know if there are any remaining problems (see the next
-   paragraph for some known problems.) If you specify the -debug_keyboard
-   (aka -dk) option twice you will get a huge amount of keystroke
-   debugging output (send it along with any problems you report.)
-
-   Update: as of Jun/2005 x11vnc will try to automatically enable -xkb if
-   it appears that would be beneficial (e.g. if it sees any of "@", "<",
-   ">", "[" and similar keys are mapped in a way that needs the -xkb to
-   access them.) To disable this automatic check use -noxkb.
-
-   Known problems:
-     * One user had to disable a "ghost" Mode_switch key that was causing
-       problems under -xkb. His physical AltGr key was bound to
-       ISO_Level3_Shift (which seems to be the XKEYBOARD way of doing
-       things), while there was a ghost key Mode_switch (which seems to
-       be obsolete) in the mapping as well. Both of these keysyms were
-       bound to Mod5 and x11vnc was unfortunately choosing Mode_switch.
-       From the x11vnc -xkb -dk -dk output it was noted that Mode_switch
-       was attached to keycode 93 (no physical key generates this
-       keycode) while ISO_Level3_Shift was attached to keycode 113. The
-       keycode skipping option was used to disable the ghost key:
-       -skip_keycodes 93
-     * In implementing -xkb we noticed that some characters were still
-       not getting through, e.g. "~" and "^". This is not really an
-       XKEYBOARD problem. What was happening was the VNC viewer was
-       sending the keysyms asciitilde and asciicircum to x11vnc, but on
-       the X server with the international keyboard those keysyms were
-       not mapped to any keys. So x11vnc had to skip them (Note: as of
-       May/2005 they are added by default see -add_keysyms below.)
-       The way these characters are typically entered on international
-       keyboards is by "dead" (aka "mute") keys. E.g. to enter "~" at the
-       physical display the keysym dead_tilde is pressed and released
-       (this usually involves holding AltGr down while another key is
-       pressed) and then space is pressed. (this can also be used get
-       characters with the "~" symbol on top, e.g. "ã" by typing "a"
-       instead of space.)
-       What to do? In general the VNC protocol has not really solved this
-       problem: what should be done if the VNC viewer sends a keysym not
-       recognized by the VNC server side? Workarounds can possibly be
-       created using the -remap x11vnc option:
-  -remap asciitilde-dead_tilde,asciicircum-dead_circumflex
-       etc. Use -remap filename if the list is long. Please send us your
-       workarounds for this problem on your keyboard. Perhaps we can have
-       x11vnc adjust automatically at some point. Also see the
-       -add_keysyms option in the next paragraph.
-       Update: for convenience "-remap DEAD" does many of these mappings
-       at once.
-     * To complement the above workaround using the -remap, an option
-       -add_keysyms was added. This option instructs x11vnc to bind any
-       unknown Keysyms coming in from VNC viewers to unused Keycodes in
-       the X server. This modifies the global state of the X server. When
-       x11vnc exits it removes the extra keymappings it created. Note
-       that the -remap mappings are applied first, right when the Keysym
-       is received from a VNC viewer, and only after that would
-       -add_keysyms, or anything else, come into play.
-       Update: -add_keysyms is now on by default. Use -noadd_keysyms to
-       disable.
-
-
-   Q-91: When typing I sometimes get double, triple, or more of my
-   keystrokes repeated. I'm sure I only typed them once, what can I do?
-
-   This may be due to an interplay between your X server's key autorepeat
-   delay and the extra time delays caused by x11vnc processing.
-
-   Short answer: disable key autorepeating by running the command "xset r
-   off" on the Xserver where x11vnc is run (restore via "xset r on") or
-   use the new (Jul/2004) -norepeat x11vnc option. You will still have
-   autorepeating because that is taken care of on your VNC viewer side.
-
-   Update: as of Dec/2004 -norepeat is now the default. Use -repeat to
-   disable it.
-
-   Details:
-   suppose you press a key DOWN and it generates changes in large regions
-   of the screen. The CPU and I/O work x11vnc does for the large screen
-   change could be longer than your X server's key autorepeat delay.
-   x11vnc may not get to processing the key UP event until after the
-   screen work is completed. The X server believes the key has been held
-   down all this time, and applies its autorepeat rules.
-
-   Even without inducing changes in large regions of the screen, this
-   problem could arise when accessing x11vnc via a dialup modem or
-   otherwise high latency link (e.g. > 250 ms latency.)
-
-   Look at the output of "xset q" for the "auto repeat delay" setting. Is
-   it low (e.g. < 300 ms)? If you turn off autorepeat completely: "xset r
-   off", does the problem go away?
-
-   The workaround is to manually apply "xset r off" and "xset r on" as
-   needed, or to use the -norepeat (which has since Dec/2004 been made
-   the default.) Note that with X server autorepeat turned off the VNC
-   viewer side of the connection will (nearly always) do its own
-   autorepeating so there is no big loss here, unless someone is also
-   working at the physical display and misses his autorepeating.
-
-
-   Q-92: The x11vnc -norepeat mode is in effect, but I still get repeated
-   keystrokes!!
-
-   Are you using x11vnc to log in to an X session via display manager?
-   (as described in this FAQ) If so, x11vnc is starting before your
-   session and it disables autorepeat when you connect, but then after
-   you log in your session startup (GNOME, KDE, ...) could be resetting
-   the autorepeat to be on. Or it could be something inside your desktop
-   trying to be helpful that decides to turn it back on.
-
-   x11vnc in -norepeat mode will by default reset autorepeat to off 2
-   times (to help get thru the session startup problem), but it will not
-   continue to battle with things turning autorepeat back on. It will
-   also turn autorepeat off whenever it goes from a state of zero clients
-   to one client. You can adjust the number of resets via "-norepeat N",
-   or use "-norepeat -1" to have it keep resetting it whenever autorepeat
-   gets turned back on when clients are connected.
-
-   In general you can manually turn autorepeating off by typing "xset r
-   off", or a using desktop utility/menu, or "x11vnc -R norepeat". If
-   something in your desktop is automatically turning it back on you
-   should figure out how to disable that somehow.
-
-
-   Q-93: After using x11vnc for a while, I find that I cannot type some
-   (or any) characters or my mouse clicks and drags no longer have any
-   effect, or they lead to strange effects. What happened?
-
-   Probably a modifier key, e.g. Control or Alt is "stuck" in a pressed
-   down state.
-
-   This happens for VNC in general by the following mechanism. Suppose on
-   the Viewer side desktop there is some hot-key to switch
-   desktops/rooms/spaces, etc. E.g. suppose Alt+LeftArrow moves to the
-   left desktop/room/space. Or suppose an Alt+hotkey combination
-   iconifies a window. This can leave the Alt key pressed down on the
-   remote side.
-
-   Consider the sequence that happens. The Alt_L key and then the
-   LeftArrow key go down. Since you are inside the viewer the Alt_L key
-   press is sent to the other side (x11vnc) and so it is pressed down in
-   the remote desktop as well. (by "Alt_L" we mean the Alt key on the
-   left-hand side of the keyboard.) Your local desktop (where the VNC
-   Viewer is running) then warps to the new desktop/room/space: Leaving
-   the Alt_L key still pressed down in the remote desktop.
-
-   If someone is sitting at the desktop, or when you return in the viewer
-   it may be very confusing because the Alt_L is still pressed down but
-   you (or the person sitting at the desktop) do not realize this.
-   Depending on which remote desktop (x11vnc side) is used, it can act
-   very strangely.
-
-   A quick workaround when you notice this is to press and release all of
-   the Alt, Shift, Control, Windows-Flag, modifier keys to free the
-   pressed one. You need to do this for both the left and right Shift,
-   Alt, Control, etc. keys to be sure.
-
-   Note that many VNC Viewers try to guard against this when they are
-   notified by the window system that the viewer app has "lost focus".
-   When it receives the "lost focus" event, the viewer sends VNC
-   Key-Release events for all modifier keys that are currently pressed
-   down. This does not always work, however, since it depends on how the
-   desktop manages these "warps". If the viewer is not notified it cannot
-   know it needs to release the modifiers.
-
-   You can also use the -clear_mods option to try to clear all of the
-   modifier keys at x11vnc startup. You will still have to be careful
-   that you do not leave the modifier key pressed down during your
-   session. It is difficult to prevent this problem from occurring (short
-   of using -remap to prevent sending all of the problem modifier keys,
-   which would make the destkop pretty unusable.)
-
-   During a session these x11vnc remote control commands can also help:
-   x11vnc -R clear_mods
-   x11vnc -R clear_keys
-   x11vnc -R clear_locks
-   x11vnc -R clear_all
-
-   A similar problem can occur if you accidentally press the Caps_Lock or
-   Num_Lock down. When these are locked on the remote side it can
-   sometimes lead to strange desktop behavior (e.g. cannot drag or click
-   on windows.) As above you may not notice this because the lock isn't
-   down on the local (Viewer) side. See this FAQ on lock keys problem.
-   These options may help avoid the problem: -skip_lockkeys and
-   -capslock. See also -clear_all.
-
-
-   Q-94: The machine where I run x11vnc has an AltGr key, but the local
-   machine where I run the VNC viewer does not. Is there a way I can map
-   a local unused key to send an AltGr? How about a Compose key as well?
-
-   Something like "-remap Super_R-Mode_switch" x11vnc option may work.
-   Note that Super_R is the "Right Windoze(tm) Flaggie" key; you may want
-   to choose another. The -debug_keyboard option comes in handy in
-   finding keysym names (so does xev(1).)
-
-   For Compose how about "-remap Menu-Multi_key" (note that Multi_key is
-   the official name for Compose.) To do both at the same time: "-remap
-   Super_R-Mode_switch,Menu-Multi_key" or use "-remap filename" to
-   specify remappings from a file.
-
-
-   Q-95: I have a Sun machine I run x11vnc on. Its Sun keyboard has just
-   one Alt key labelled "Alt" and two Meta keys labelled with little
-   diamonds. The machine where I run the VNC viewer only has Alt keys.
-   How can I send a Meta keypress? (e.g. emacs needs this)
-
-   Here are a couple ideas. The first one is to simply use xmodmap(1) to
-   adjust the Sun X server. Perhaps xmodmap -e "keysym Alt_L = Meta_L
-   Alt_L" will do the trick. (there are other ways to do it, one user
-   used: xmodmap -e "keycode 26 = Meta_L" for his setup.)
-
-   Since xmodmap(1) modifies the X server mappings you may not want to do
-   this (because it affects local work on that machine.) Something like
-   the -remap Alt_L-Meta_L to x11vnc may be sufficient for ones needs,
-   and does not modify the X server environment. Note that you cannot
-   send Alt_L in this case, maybe -remap Super_L-Meta_L would be a better
-   choice if the Super_L key is typically unused in Unix.
-
-
-   Q-96: Running x11vnc on HP-UX I cannot type "#" I just get a "3"
-   instead.
-
-   One user reports this problem on HP-UX Rel_B.11.23. The problem was
-   traced to a strange keyboard mapping for the machine (e.g. xmodmap -pk
-   output) that looked like:
-  ...
-  039  2                  at                 at               at
-  ...
-  047  3                  numbersign         numbersign       numbersign
-
-   and similar triple mappings (with two in the AltGr/Mode_switch group)
-   of a keysum to a single keycode.
-
-   Use the -nomodtweak option as a workaround. You can also use xmodmap
-   to correct these mappings in the server, e.g.:
-  xmodmap -e "keycode 47 = 3 numbersign"
-
-   Also, as of Feb/2007, set the environment variable MODTWEAK_LOWEST=1
-   (either in your shell or via "-env MODTWEAK_LOWEST=1" option) to
-   handle these mappings better.
-
-
-   Q-97: Can I map a keystroke to a mouse button click on the remote
-   machine?
-
-   This can be done directly in some X servers using AccessX and
-   Pointer_EnableKeys, but is a bit awkward. It may be more convenient to
-   have x11vnc do the remapping. This can be done via the -remap option
-   using the fake "keysyms" Button1, Button2, etc. as the "to" keys (i.e.
-   the ones after the "-")
-
-   As an example, consider a laptop where the VNC viewer is run that has
-   a touchpad with only two buttons. It is difficult to do a middle
-   button "paste" because (using XFree86/Xorg Emulate3Buttons) you have
-   to click both buttons on the touch pad at the same time. This
-   remapping:
-  -remap Super_R-Button2
-
-   maps the Super_R "flag" key press to the Button2 click, thereby making
-   X pasting a bit easier.
-
-   Note that once the key goes down, the button down and button up events
-   are generated immediately on the x11vnc side. When the key is released
-   (i.e. goes up) no events are generated.
-
-   Q-98: How can I get Caps_Lock to work between my VNC viewer and
-   x11vnc?
-
-   This is a little tricky because it is possible to get the Caps_Lock
-   state out of sync between your viewer-side machine and the x11vnc-side
-   X server. For best results, we recommend not ever letting the
-   Caps_Lock keypresses be processed by x11vnc. That way when you press
-   Caps_Lock in the viewer your local machine goes into the Caps_Lock on
-   state and sends keysym "A" say when you press "a". x11vnc will then
-   fake things up so that Shift is held down to generate "A". The
-   -skip_lockkeys option should help to accomplish this. For finer grain
-   control use something like: "-remap Caps_Lock-None".
-
-   Also try the -nomodtweak and -capslock options.
-
-   Another useful option that turns off any Lock keys on the remote side
-   at startup and end is the -clear_all option. During a session you can
-   run these remote control commands to modify the Lock keys:
-   x11vnc -R clear_locks
-   x11vnc -R clear_all
-
-   the former will try to unset any Lock keys, the latter will do same
-   and also try to make it so no key is pressed down (e.g. "stuck" Alt_L,
-   etc.)
-   [Screen Related Issues and Features]
-
-   Q-99: The remote display is larger (in number of pixels) than the
-   local display I am running the vncviewer on. I don't like the
-   vncviewer scrollbars, what I can do?
-
-   vncviewer has a option (usually accessible via F8 key or -fullscreen
-   option) for vncviewer to run in full screen, where it will
-   automatically scroll when the mouse is near the edge of the current
-   view. For quick scrolling, also make sure Backing Store is enabled on
-   the machine vncviewer is run on. (XFree86/Xorg disables it by default
-   for some reason, add Option "backingstore" to XF86Config on the
-   vncviewer side.)
-
-   BTW, contact me if you are having problems with vncviewer in
-   fullscreen mode with your window manager (i.e. no keyboard response.)
-   I have a workaround for vncviewer using XGrabServer().
-
-   There may also be scaling viewers out there (e.g. TightVNC or UltraVNC
-   on Windows) that automatically shrink or expand the remote framebuffer
-   to fit the local display. Especially for hand-held devices. See also
-   the next FAQ on x11vnc scaling.
-
-
-   Q-100: Does x11vnc support server-side framebuffer scaling? (E.g. to
-   make the desktop smaller.)
-
-   As of Jun/2004 x11vnc provides basic server-side scaling. It is a
-   global scaling of the desktop, not a per-client setting. To enable it
-   use the "-scale fraction" option. "fraction" can either be a floating
-   point number (e.g. -scale 0.75) or the alternative m/n fraction
-   notation (e.g. -scale 3/4.) Note that if fraction is greater than one
-   the display is magnified.
-
-   Extra resources (CPU, memory I/O, and memory) are required to do the
-   scaling. If the machine is slow where x11vnc is run with scaling
-   enabled, the interactive response can be unacceptable. OTOH, if run
-   with scaling on a fast machine the performance degradation is usually
-   not a big issue or even noticeable.
-
-   It may help to compile x11vnc with compiler option -O3 or -O4 to speed
-   up the scaling code. Set the CFLAGS env. var. before running
-   configure.
-
-   Also, if you just want a quick, rough "thumbnail" of the display you
-   can append ":nb" to the fraction to turn on "no blending" mode. E.g.:
-   "-scale 1/3:nb" Fonts will be difficult to read, but the larger
-   features will be recognizable. BTW, "no blending" mode is forced on
-   when scaling 8bpp PseudoColor displays (because blending an indexed
-   colormap is a bad idea and leads to random colors, use :fb to force it
-   on.)
-
-   One can also use the ":nb" with an integer scale factor (say "-scale
-   2:nb") to use x11vnc as a screen magnifier for vision impaired
-   applications. Since with integer scale factors the framebuffers become
-   huge and scaling operations time consuming, be sure to use ":nb" for
-   the fastest response.
-
-   In general for a scaled display if you are using a TightVNC viewer you
-   may want to turn off jpeg encoding (e.g. vncviewer -nojpeg host:0.)
-   There appears to be a noise enhancement effect, especially for regions
-   containing font/text: the scaling can introduce some pixel artifacts
-   that evidently causes the tight encoding algorithm to incorrectly
-   detect the regions as image data and thereby introduce additional
-   pixel artifacts due to the lossiness of the jpeg compression
-   algorithm. Experiment to see if -nojpeg vncviewer option improves the
-   readability of text when using -scale to shrink the display size. Also
-   note that scaling may actually slow down the transfer of text regions
-   because after being scaled they do not compress as well. (this can
-   often be a significant slowdown, e.g. 10X.)
-
-   Another issue is that it appears VNC viewers require the screen width
-   to be a multiple of 4. When scaling x11vnc will round the width to the
-   nearest multiple of 4. To disable this use the ":n4" sub option (like
-   ":nb" in the previous paragraph; to specify both use a comma:
-   ":nb,n4", etc.)
-
-   If one desires per-client scaling for something like 1:1 from a
-   workstation and 1:2 from a smaller device (e.g. handheld), currently
-   the only option is to run two (or more) x11vnc processes with
-   different scalings listening on separate ports (-rfbport option, etc.)
-
-   Update: As of May/2006 x11vnc also supports the UltraVNC server-side
-   scaling. This is a per-client scaling by factors 1/2, 1/3, ... and so
-   may be useful for PDA's ("-scale 1/2", etc. will give similar results
-   except that it applies to all clients.) You may need to supply
-   "-rfbversion 3.6" for this to be recognized by UltraVNC viewers.
-
-   BTW, whenever you run two or more x11vnc's on the same X display and
-   use the GUI, then to avoid all of the x11vnc's simultaneously
-   answering the gui you will need to use something like "-connect file1
-   -gui ..." with different connect files for each x11vnc you want to
-   control via the gui (or remote-control.) The "-connect file1" usage
-   gives separate communication channels between a x11vnc process and the
-   gui process. Otherwise they all share the same X property channels:
-   VNC_CONNECT and X11VNC_REMOTE.
-
-   Update: As of Mar/2005 x11vnc now scales the mouse cursor with the
-   same scale factor as the screen. If you don't want that, use the
-   "-scale_cursor frac" option to set the cursor scaling to a different
-   factor (e.g. use "-scale_cursor 1" to keep the cursor at its natural
-   unscaled size.)
-
-
-   Q-101: Does x11vnc work with Xinerama? (i.e. multiple monitors joined
-   together to form one big, single screen.)
-
-   Yes, it should generally work because it simply polls the big
-   effective screen.
-
-   If the viewing-end monitor is not as big as the remote Xinerama
-   display, then the vncviewer scrollbars, etc, will have to be used to
-   pan across the large area. However one user started two x11vnc's, one
-   with "-clip 1280x1024+0+0" and the other with "-clip 1280x1024+1280+0"
-   to split the big screen into two and used two VNC viewers to access
-   them.
-
-   As of Jun/2008: Use "-clip xinerama0" to clip to the first xinerama
-   sub-screen (if xinerama is active.) xinerama1 for the 2nd sub-screen,
-   etc. This way you don't need to figure out the WxH+X+Y of the desired
-   xinerama sub-screen. screens are sorted in increasing distance from
-   the (0,0) origin (I.e. not the Xserver's order.)
-
-   There are a couple potential issues with Xinerama however. If the
-   screen is not rectangular (e.g. 1280x1024 and 1024x768 monitors joined
-   together), then there will be "non-existent" areas on the screen. The
-   X server will return "garbage" image data for these areas and so they
-   may be distracting to the viewer. The -blackout x11vnc option allows
-   you to blacken-out rectangles by manually specifying their WxH+X+Y
-   geometries. If your system has the libXinerama library, the -xinerama
-   x11vnc option can be used to have it automatically determine the
-   rectangles to be blackened out. (Note on 8bpp PseudoColor displays the
-   fill color may not be black.) Update: -xinerama is now on by default.
-
-   Some users have reported that the mouse does not behave properly for
-   their Xinerama display: i.e. the mouse cannot be moved to all regions
-   of the large display. If this happens try using the -xwarppointer
-   option. This instructs x11vnc to fake mouse pointer motions using the
-   XWarpPointer function instead of the XTestFakeMotionEvent XTEST
-   function. (This may be due to a bug in the X server for XTEST when
-   Xinerama is enabled.) Update: As of Dec/2006 -xwarppointer will be
-   applied automatically if Xinerama is detected. To disable use:
-   -noxwarppointer
-
-
-   Q-102: Can I use x11vnc on a multi-headed display that is not Xinerama
-   (i.e. separate screens :0.0, :0.1, ... for each monitor)?
-
-   You can, but it is a little bit awkward: you must start separate
-   x11vnc processes for each screen, and on the viewing end start up
-   separate VNC viewer processes connecting to them. e.g. on the remote
-   end:
-  x11vnc -display :0.0 -bg -q -rfbport 5900
-  x11vnc -display :0.1 -bg -q -rfbport 5901
-
-   (this could be automated in the display manager Xsetup for example)
-   and then on the local machine where you are sitting:
-  vncviewer somehost:0 &
-  vncviewer somehost:1 &
-
-   Note: if you are running on Solaris 8 or earlier you can easily hit up
-   against the maximum of 6 shm segments per process (for Xsun in this
-   case) from running multiple x11vnc processes. You should modify
-   /etc/system as mentioned in another FAQ to increase the limit. It is
-   probably also a good idea to run with the -onetile option in this case
-   (to limit each x11vnc to 3 shm segments), or even -noshm to use no shm
-   segments.
-
-
-   Q-103: Can x11vnc show only a portion of the display? (E.g. for a
-   special purpose application or a very large screen.)
-
-   As of Mar/2005 x11vnc has the "-clip WxH+X+Y" option to select a
-   rectangle of width W, height H and offset (X, Y). Thus the VNC screen
-   will be the clipped sub-region of the display and be only WxH in size.
-   One user used -clip to split up a large Xinerama screen into two more
-   managable smaller screens.
-
-   This also works to view a sub-region of a single application window if
-   the -id or -sid options are used. The offset is measured from the
-   upper left corner of the selected window.
-
-
-   Q-104: Does x11vnc support the XRANDR (X Resize, Rotate and
-   Reflection) extension? Whenever I rotate or resize the screen x11vnc
-   just seems to crash.
-
-   As of Dec/2004 x11vnc supports XRANDR. You enable it with the -xrandr
-   option to make x11vnc monitor XRANDR events and also trap X server
-   errors if the screen change occurred in the middle of an X call like
-   XGetImage. Once it traps the screen change it will create a new
-   framebuffer using the new screen.
-
-   If the connected vnc viewers support the NewFBSize VNC extension
-   (Windows TightVNC viewer and RealVNC 4.0 windows and Unix viewers do)
-   then the viewer will automatically resize. Otherwise, the new
-   framebuffer is fit as best as possible into the original viewer size
-   (portions of the screen may be clipped, unused, etc.) For these
-   viewers you can try the -padgeom option to make the region big enough
-   to hold all resizes and rotations. We have fixed this problem for the
-   TightVNC Viewer on Unix: SSVNC
-
-   If you specify "-xrandr newfbsize" then vnc viewers that do not
-   support NewFBSize will be disconnected before the resize. If you
-   specify "-xrandr exit" then all will be disconnected and x11vnc will
-   terminate.
-
-
-   Q-105: Independent of any XRANDR, can I have x11vnc rotate and/or
-   reflect the screen that the VNC viewers see? (e.g. for a handheld
-   whose screen is rotated 90 degrees.)
-
-   As of Jul/2006 there is the -rotate option allow this. E.g's: "-rotate
-   +90", "-rotate -90", "-rotate x", etc.
-
-
-   Q-106: Why is the view in my VNC viewer completely black? Or why is
-   everything flashing around randomly?
-
-   See the next FAQ for a possible explanation.
-
-
-   Q-107: I use Linux Virtual Terminals (VT's) to implement 'Fast User
-   Switching' between users' sessions (e.g. Betty is on Ctrl-Alt-F7,
-   Bobby is on Ctrl-Alt-F8, and Sid is on Ctrl-Alt-F1: they use those
-   keystrokes to switch between their sessions.)   How come the view in a
-   VNC viewer connecting to x11vnc is either completely black or
-   otherwise all messed up unless the X session x11vnc is attached to is
-   in the active VT?
-
-   This seems to have to do with how applications (the X server processes
-   in this case) must "play nicely" if they are not on the active VT
-   (sometimes called VC for virtual console.) That is, they should not
-   read from the keyboard or mouse or manage the video display unless
-   they have the active VT. Given that it appears the XGetImage() call
-   must ultimately retrieve the framebuffer data from the video hardware
-   itself, it would make sense x11vnc's polling wouldn't work unless the
-   X session had active control of the VT.
-
-   There does not seem to be an easy way to work around this. Even xwd(1)
-   doesn't work in this case (try it.) Something would need to be done at
-   a lower level, say in the XFree86/Xorg X server. Also, using the
-   Shadow Framebuffer (a copy of the video framebuffer is kept in main
-   memory) does not appear to fix the problem.
-
-   If no one is sitting at the workstation and you just want to remotely
-   switch the VT over to the one associated with your X session (so
-   x11vnc can poll it correctly), one can use the chvt(1) command, e.g.
-   "chvt 7" for VT #7.
-
-
-   Q-108: I am using x11vnc where my local machine has "popup/hidden
-   taskbars" and the remote display where x11vnc runs also has
-   "popup/hidden taskbars" and they interfere and fight with each other.
-   What can I do?
-
-   When you move the mouse to the edge of the screen where the popups
-   happen, the taskbars interfere with each other in strange ways. This
-   sometimes happens where the local machine is GNOME or Mac OS X and the
-   remote machine is GNOME. Is there a way to temporarily disable one or
-   both of these magic desktop taskbars?
-
-   One x11vnc user suggests: it should be straightforward to right mouse
-   click on the task bar panel, and uncheck "enable auto-hide" from the
-   panel properties dialog box. This will make the panel always visible.
-
-   Q-109: Help! x11vnc and my KDE screensaver keep switching each other
-   on and off every few seconds.
-
-   This is a new (Jul/2006) problem seen, say, on the version of KDE that
-   is shipped with SuSE 10.1. It is not yet clear what is causing this...
-   If you move the mouse through x11vnc the screensaver shuts off like it
-   should but then a second or two after you stop moving the mouse the
-   screensaver snaps back on.
-
-   This may be a bug in kdesktop_lock. For now the only workaround is to
-   disable the screensaver. You can try using another one such as
-   straight xscreensaver (see the instructions here for how to disable
-   kdesktop_lock.) If you have more info on this or see it outside of KDE
-   please let us know.
-
-   Update: It appears this is due to kdesktop_lock enabling the screen
-   saver when the Monitor is in DPMS low-power state (e.g. standby,
-   suspend, or off.) In Nov/2006 the x11vnc -nodpms option was added as a
-   workaround. Normally it is a good thing that the monitor powers down
-   (since x11vnc can still poll the framebuffer in this state), but if
-   you experience the kdesktop_lock problem you can specify the "-nodpms"
-   option to keep the Monitor out of low power state while VNC clients
-   are connected. This is basically the same as typing "xset dpms force
-   on" periodically. (if you don't want to do these things just disable
-   the screensaver.) Feel free to file a bug against kdesktop_lock with
-   KDE.
-
-   Q-110: I am running the compiz 3D window manager (or beryl, MythTv,
-   Google Earth, or some other OpenGL app) and I do not get screen
-   updates in x11vnc.
-
-   This appears to be because the 3D OpenGL/GLX hardware screen updates
-   do not get reported via the XDAMAGE mechanism. So this is a bug in
-   compiz/beryl or XDAMAGE/Xorg or the (possibly 3rd party) video card
-   driver.
-
-   As a workaround apply the -noxdamage option. As of Feb/2007 x11vnc
-   will try to autodetect the problem and disable XDAMAGE if is appears
-   to be missing a lot of updates. But if you know you are using compiz
-   you might as well always supply -noxdamage. Thanks to this user who
-   reported the problem and discovered the workaround.
-
-   A developer for MiniMyth reports that the 'alphapulse' tag of the
-   theme G.A.N.T. can also cause problems, and should be avoided when
-   using VNC.
-
-   Please report a bug or complaint to Beryl/Compiz and/or Xorg about
-   this: running x11vnc with -noxdamage disables a nice improvement in
-   responsiveness (especially for typing) and also leads to unnecessary
-   CPU and memory I/O load due to the extra polling.
-
-   Update: as of May/2010 NVIDIA may have fixed this problem in their
-   proprietary drivers. See the NVIDIA Release Notes. (look for
-   'x11vnc'.)
-
-   Q-111: Can I use x11vnc to view my VMWare session remotely?
-
-   Yes, since VMWare usually runs as an X application you can view it via
-   x11vnc in the normal way.
-
-   Note that VMWare has several viewing modes:
-     * Normal X application window  (with window manager frame)
-     * Quick-Switch mode  (with no window manager frame)
-     * Fullscreen mode
-
-   The way VMWare does Fullscreen mode on Linux is to display the Guest
-   desktop in a separate Virtual Terminal (e.g. VT 8) (see this FAQ on
-   VT's for background.) Unfortunately, this Fullscreen VT is not an X
-   server. So x11vnc cannot access it (however, see this discussion of
-   -rawfb for a possible workaround.) x11vnc works fine with "Normal X
-   application window" and "Quick-Switch mode" because these use X.
-
-   Update: It appears the in VMWare 5.x the Fullscreen mode is X, so
-   x11vnc access does work.
-
-   One user reports he left his machine with VMWare in the Fullscreen
-   mode, and even though his X session wasn't in the active VT, he could
-   still connect x11vnc to the X session and pass the keystrokes Ctrl-Alt
-   (typing "blind") to the VMWare X app. This induced VMWare to switch
-   out of Fullscreen into Normal X mode and he could continue working in
-   the Guest desktop remotely.
-
-
-   Aside: Sometimes it is convenient (for performance, etc.) to start
-   VMWare in its own X session using startx(1). This can be used to have
-   a minimal window manger (e.g. twm or even no window manager), to
-   improve response. One can also cut the display depth (e.g. to 16bpp)
-   in this 2nd X session to improve video performance. This 2nd X session
-   emulates Fullscreen mode to some degree and can be viewed via x11vnc
-   as long as the VMWare X session is in the active VT.
-
-   Also note that with a little bit of playing with "xwininfo -all
-   -children" output one can extract the (non-toplevel) window-id of the
-   of the Guest desktop only when VMWare is running as a normal X
-   application. Then one can export just the guest desktop (i.e. without
-   the VMWare menu buttons) by use of the -id windowid option. The
-   caveats are the X session VMWare is in must be in the active VT and
-   the window must be fully visible, so this mode is not terribly
-   convenient, but could be useful in some circumstances (e.g. running
-   VMWare on a very powerful server machine in a server room that happens
-   to have a video card, (but need not have a monitor, Keyboard or
-   mouse).)
-
-
-
-   [Exporting non-X11 devices via VNC]
-
-   Q-112: Can non-X devices (e.g. a raw framebuffer) be viewed (and even
-   controlled) via VNC with x11vnc?
-
-   As of Apr/2005 there is support for this. Two options were added:
-   "-rawfb string" (to indicate the raw frame buffer device, file, etc.
-   and its parameters) and "-pipeinput command" (to provide an external
-   program that will inject or otherwise process mouse and keystroke
-   input.) Some useful -pipeinput schemes, VID, CONSOLE, and UINPUT, have
-   since been built into x11vnc for convenience.
-
-   This non-X mode for x11vnc is somewhat experimental because it is so
-   removed in scope from the intended usage of the tool. Incomplete
-   attempt is made to make all of the other options consistent with non-X
-   framebuffer polling. So all of the X-related options (e.g.
-   -add_keysyms, -xkb) are just ignored or may cause an error if used. Be
-   careful applying such an option via remote control.
-
-   The format for the -rawfb string is:
-    -rawfb <type>:<object>@<W>x<H>x<bpp>[-<BPL>][:<R>/<G>/<B>][+<offset>]
-
-   There are also some useful aliases (e.g. "console".) Some examples:
-    -rawfb shm:210337933@800x600x32:ff/ff00/ff0000
-
-    -rawfb map:/dev/fb0@1024x768x16
-
-    -rawfb map:/tmp/Xvfb_screen0@640x480x8+3232
-
-    -rawfb file:/tmp/my.pnm@250x200x24+37
-
-    -rawfb file:/dev/urandom@128x128x8
-
-    -rawfb snap:/dev/video0@320x240x24 -24to32
-
-    -rawfb console
-
-    -rawfb vt2
-
-    -rawfb video
-
-    -rawfb setup:mycmd.sh
-
-   So the type can be "shm" for shared memory objects, and "map" or
-   "file" for file objects. "map" uses mmap(2) to map the file into
-   memory and is preferred over "file" (that uses the slower lseek(2)
-   access method.) Only use file if map isn't working. BTW, "mmap" is an
-   alias for "map" and if you do not supply a type and the file exists,
-   map is assumed (see the -help output and below for some exceptions to
-   this.) The "snap:" setting applies the -snapfb option with "file:"
-   type reading (this is useful for exporting webcams or TV tuner video;
-   see the next FAQ for more info.)
-
-   Also, if the string is of the form "setup:cmd" then cmd is run and the
-   first line of its output retrieved and used as the rawfb string. This
-   allows initializing the device, determining WxHxB, etc.
-
-   The object will be the numerical shared memory id for the case of shm.
-   The idea here is some other program has created this shared memory
-   segment and periodically updates it with new framebuffer data. x11vnc
-   polls the area for changes. See shmat(2) and ipcs(8) for more info.
-   The ipcs command will list current shared memory segments on the
-   system. Sometimes you can snoop on a program's framebuffer it did not
-   expect you would be polling!
-
-   The object will be the path to the regular or character special file
-   for the cases of map and file. The idea here is that in the case of a
-   regular file some other program is writing/updating framebuffer image
-   data to it. In the case of a character special (e.g. /dev/fb0) it is
-   the kernel that is "updating" the framebuffer data.
-
-   In most cases x11vnc needs to be told the width, height, and number of
-   bits per pixel (bpp) of the framebuffer. This is the @WxHxB field. For
-   the case of the Linux framebuffer device, /dev/fb0, the fbset(8) may
-   be of use (but may not always be accurate for what is currently
-   viewable.) In general some guessing may be required, especially for
-   the bpp. Update: in "-rawfb console" mode x11vnc will use the linuxfb
-   API to try to guess (it is still not always accurate.) Also try
-   "-rawfb vtN" (on x11vnc 0.9.7 and later) for the N-th Linux text
-   console (aka virtual terminal.) If the number of Bytes Per Line is not
-   WxHxB/8 (i.e. the framebuffer lines are padded) you can specify this
-   information after WxHxB via "-BPL", e.g. @800x600x16-2048
-
-   Based on the bpp x11vnc will try to guess the red, green, and blue
-   masks (these indicate which bits correspond to each color.) It if gets
-   it wrong you can specify them manually via the optional ":R/G/B"
-   field. E.g. ":0xff0000/0x00ff00/0x0000ff" (this is the default for
-   32bpp.)
-
-   Finally, the framebuffer may not begin at the beginning of the memory
-   object, so use the optional "+offset" parameter to indicate where the
-   framebuffer information starts. So as an example, the Xvfb virtual
-   framebuffer has options -shmem and -fbdir for exporting its virtual
-   screen to either shm or a mapped file. The format of these is XWD and
-   so the initial header should be skipped. BTW, since XWD is not
-   strictly RGB the view will only be approximate, but usable. Of course
-   for the case of Xvfb x11vnc can poll it much better via the X API, but
-   you get the idea.
-
-   By default in -rawfb mode x11vnc will actually close any X display it
-   happened to open. This is basically to shake out bugs (e.g it will
-   crash rather than mysteriously interacting with the X display.) If you
-   want x11vnc to keep the X display open while polling the raw
-   framebuffer prefix a "+" sign at the beginning of the string (e.g.
-   +file:/dev/urandom@64x64x8) This could be convenient for keeping the
-   remote control channel active (it uses X properties.) The "-connect
-   /path/to/file" mechanism could also be used for remote control to
-   avoid the X property channel. Rare usage, but if you also supply
-   -noviewonly in this "+" mode then the mouse and keyboard input are
-   still sent to the X display, presumably for doing something amusing
-   with /dev/fb...
-
-   Interesting Devices:. Here are some aliases for interesting device
-   files that can be polled via -rawfb:
-   -rawfb console               /dev/fb0        Linux Console
-   -rawfb vt2                   /dev/vcsa2      Linux Console (e.g. virtual ter
-minal #2)
-   -rawfb video                 /dev/video0     Video4Linux Capture device
-   -rawfb rand                  /dev/urandom    Random Bytes
-   -rawfb null                  /dev/zero       Zero Bytes (black screen)
-
-   The Linux console, /dev/fb0, etc needs to have its driver enabled in
-   the kernel. Some of the drivers are video card specific and
-   accelerated. The console is either the Text consoles (usually
-   tty1-tty6), or X graphical display (usually starting at tty7.) In
-   addition to the text console other graphical ones may be viewed and
-   interacted with as well, e.g. DirectFB or SVGAlib apps, VMWare non-X
-   fullscreen, or Qt-embedded apps (PDAs/Handhelds.) By default the
-   pipeinput mechanisms UINPUT and CONSOLE (keystrokes only) are
-   automatically attempted in this mode under "-rawfb console".
-
-   The Video4Linux Capture device, /dev/video0, etc is either a Webcam or
-   a TV capture device and needs to have its driver enabled in the
-   kernel. See this FAQ for details. If specified via "-rawfb Video" then
-   the pipeinput method "VID" is applied (it lets you change video
-   parameters dynamically via keystrokes.)
-
-   The last two, /dev/urandom and /dev/zero are just for fun, but are
-   also useful in testing.
-
-
-   All of the above -rawfb options are just for viewing the raw
-   framebuffer (although some of the aliases do imply keystroke and mouse
-   pipeinput methods.) That may be enough for certain applications of
-   this feature (e.g. suppose a video camera mapped its framebuffer into
-   memory and you just wanted to look at it via VNC.)
-   To handle the pointer and keyboard input from the viewer users the
-   "-pipeinput cmd" option was added to indicate a helper program to
-   process the user input. The input is streamed to it and looks
-   something like this:
-   Pointer 1 205 257 0 None
-   Pointer 1 198 253 0 None
-   Pointer 1 198 253 1 ButtonPress-1
-   Pointer 1 198 253 0 ButtonRelease-1
-   Pointer 1 198 252 0 None
-   Keysym 1 1 119 w KeyPress
-   Keysym 1 0 119 w KeyRelease
-   Keysym 1 1 65288 BackSpace KeyPress
-   Keysym 1 0 65288 BackSpace KeyRelease
-   Keysym 1 1 112 p KeyPress
-   Keysym 1 0 112 p KeyRelease
-
-   Run "-pipeinput tee:/bin/cat" to get a description of the format. Note
-   that the -pipeinput option is independent of -rawfb mode and so may
-   have some other interesting uses. The "tee:" prefix means x11vnc will
-   both process the user input and pipe it to the command. The default is
-   to just pipe it to the -pipeinput command.
-
-   Note the -pipeinput helper program could actually control the raw
-   framebuffer. In the libvncserver CVS a simple example program
-   x11vnc/misc/slide.pl is provided that demonstrates a simple jpeg
-   "slideshow" application. Also the builtin "-pipeinput VID" mode does
-   this for webcams and TV capture devices (/dev/video0.)
-
-   The -pipeinput program is run with these environment variables set:
-   X11VNC_PID, X11VNC_PROG, X11VNC_CMDLINE, X11VNC_RAWFB_STR to aid its
-   knowing what is up.
-
-   Another example provided in libvncserver CVS is a script to inject
-   keystrokes into the Linux console (e.g. the virtual consoles:
-   /dev/tty1, /dev/tty2, etc) in x11vnc/misc/vcinject.pl. It is based on
-   the vncterm/LinuxVNC.c program also in the libvncserver CVS. So to
-   view and interact with VT #2 (assuming it is the active VT) one can
-   run something like:
-  x11vnc -rawfb map:/dev/fb0@1024x768x16 -pipeinput './vcinject.pl 2'
-
-   This assumes your Linux framebuffer device (/dev/fb0) is properly
-   configured. See fbset(8) and other documentation. Try
-   "file:/dev/fb0@WxHxB" as a last resort. Starting with x11vnc 0.8.1,
-   the above VT injection is built in, as well as WxHxB determination.
-   Just use something like:
-  x11vnc -rawfb console
-
-   this will try to guess the active virtual console (via /dev/tty0) and
-   also the /dev/fb0 WxHxB and rgb masks automatically. Use, e.g.,
-   "-rawfb console3" to force the VT number. This input method can be
-   used generally via "-pipeinput CONSOLE". Also starting with x11vnc
-   0.8.2 the "-pipeinput UINPUT" mode is tried first (it does both
-   keyboard and mouse input) and then falls back to CONSOLE mode if it is
-   not available. Here is the -help output for this mode:
-
-     If the rawfb string begins with "console" the framebuffer device
-     /dev/fb0 is opened (this requires the appropriate kernel modules to
-     be installed) and so is /dev/tty0. The latter is used to inject
-     keystrokes (not all are supported, but the basic ones are.) You
-     will need to be root to inject keystrokes. /dev/tty0 refers to the
-     active VT, to indicate one explicitly, use "console2", etc. using
-     the VT number.
-
-     If the Linux version seems to be 2.6 or later and the "uinput"
-     module appears to be present, then the uinput method will be used
-     instead of /dev/ttyN. uinput allows insertion of BOTH keystrokes
-     and mouse input and so it preferred when accessing graphical (e.g.
-     Qt-embedded) linux console apps. See -pipeinput UINPUT below for
-     more information on this mode (you may want to also use the
-     -nodragging and -cursor none options.) Use "console0", etc or
-     -pipeinput CONSOLE to force the /dev/ttyN method.
-
-     Note you can change VT remotely using the chvt(1) command.
-     Sometimes switching out and back corrects the framebuffer state.
-
-     To skip input injecting entirely use "consolex".
-
-     The string "/dev/fb0" (1, etc) can be used instead of "console".
-     This can be used to specify a different framebuffer device, e.g.
-     /dev/fb1. As a shortcut the "/dev/" can be dropped. If the name is
-     something nonstandard, use "console:/dev/foofb"
-
-     If you do not want x11vnc to guess the framebuffer's WxHxB and
-     masks automatically (sometimes the kernel gives inaccurate
-     information), specify them with a @WxHxB at the end of the string.
-
-   The above is just an example of what can be done. Note that if you
-   really want to view and interact with the Linux Text console it is
-   better to use the more accurate and faster LinuxVNC program. The
-   advantage x11vnc -rawfb might have is that it can allow interaction
-   with a non-text application, e.g. one based on SVGAlib or Qt-embedded
-   Also, for example the VMWare Fullscreen mode is actually viewable
-   under -rawfb and can be interacted with if uinput is enabled.
-
-   If the Linux uinput driver is available then full keystroke and mouse
-   input into the Linux console can be performed. You may be able to
-   enable uinput via commands like these:
-  modprobe uinput
-  mknod /dev/input/uinput c 10 223
-
-   The -rawfb and -pipeinput features are intended to help one creatively
-   "get out of a jam" (say on a legacy or embedded device) where X is
-   absent or doesn't work properly. Feedback and bug reports are welcome.
-   For more control and less overhead use libvncserver in your own C
-   program that passes the framebuffer to libvncserver.
-
-
-   Q-113: Can I export the Linux Console (Virtual Terminals) via VNC
-   using x11vnc?
-
-   Yes, you may need to be root to access the devices that make up the
-   linux console.
-
-   To access the active Linux console via the computer's framebuffer try
-   something like:
-  x11vnc -rawfb console
-  x11vnc -rawfb console2
-
-   These will try to access the framebuffer through /dev/fb (or /dev/fb0,
-   etc.) and if it succeeds it will show any text or graphics that is
-   currently displayed. Keystrokes will be injected via the device
-   /dev/tty0 (to force an explicit virtual terminal append a number, e.g.
-   "console2" to select /dev/tty2.)
-
-   If your Linux system does not have a framebuffer device (/dev/fb) you
-   can get one by adding, e.g., vga=0x31B boot parameter. This enables
-   the VGA framebuffer device at 1280x1024x24. 0x317 gives 1024x768x16,
-   etc. You can also enable a Linux framebuffer device by modprobing a
-   framebuffer driver specific to your video card.
-
-   Note that this "-rawfb console" mode shows the contents of the
-   hardware framebuffer, and so will show whatever is on the screen. It
-   has no concept of Virtual Terminals WRT what there is to view, it
-   always shows the active virtual terminal.
-
-   Another mode is specific to the Linux text Virtual Terminals, it shows
-   their text and colors (but no graphics) regardless of whether it is
-   the active VT or not. It is available on x11vnc 0.9.7 and later.
-   Enable this mode like this:
-  x11vnc -rawfb vt
-  x11vnc -rawfb vt2
-
-   The former will select the active one, the latter the 2nd VT. x11vnc
-   implements this mode by opening the current console text file
-   "/dev/vcsa2" instead of "/dev/fb". In this way it provides the basic
-   functionality of the LibVNCServer LinuxVNC program.
-
-   The vt mode can be a useful way to try to get a machine's X server
-   working remotely, e.g. you edit /etc/X11/xorg.conf and then type
-   startx (or similar, e.g. gdm) in the virtual terminal. A 2nd x11vnc
-   could be used to see if the X server is now working correctly.
-
-   Q-114: Can I export via VNC a Webcam or TV tuner framebuffer using
-   x11vnc?
-
-   Yes, this is possible to some degree with the -rawfb option. There is
-   no X11 involved: snapshots from the video capture device are used for
-   the screen image data. See the previous FAQ on -rawfb for background.
-   For best results, use x11vnc version 0.8.1 or later.
-
-   Roughly, one would do something like this:
-  x11vnc -rawfb snap:/dev/video@320x240x32
-
-   This requires that the system allows simple read(2) access to the
-   video device. This is true for video4Linux on Linux kernel 2.6 and
-   later (it won't work for 2.4, you'll need a separate program to
-   snapshot to a file that you point -rawfb to; ask me if it is not clear
-   what to do.)
-
-   The "snap:" enforces -snapfb mode which appears to be necessary. The
-   read pointer for video capture devices cannot be repositioned (which
-   would be needed for scanline polling), but you can read a full frame
-   of data from the device.
-
-   On Linux, if the Video4Linux API is present or the v4l-info(1) program
-   (related to xawtv) exists in in PATH, then x11vnc can be instructed to
-   try it to determine the -rawfb WxHxB parameters for you automatically.
-   In this case one would just type:
-  x11vnc -rawfb video
-
-   or "-rawfb video1" for the 2nd video device, etc.
-
-   x11vnc has also been extended to use the Video4Linux API over v4l-info
-   if it is available at build time. This enables setting parameters
-   (e.g. size and brightness) via x11vnc. See the description below.
-   Without Video4Linux you will need to initialize the settings of the
-   video device using something like xawtv or spcaview (and then hope the
-   settings persist until x11vnc reopens the device.)
-
-   Many video4linux drivers tend to set the framebuffer to be 24bpp (as
-   opposed to 32bpp.) Since this can cause problems with VNC viewers,
-   etc, the -24to32 option will be automatically imposed when in 24bpp.
-
-   Note that by its very nature, video capture involves rapid change in
-   the framebuffer. This is especially true for cameras where slight
-   wavering in brightness is always happening. This can lead to much
-   network bandwidth consumption for the VNC traffic and also local CPU
-   and I/O resource usage. You may want to experiment with "dialing down"
-   the framerate via the -wait, -slow_fb, or -defer options. Decreasing
-   the window size and bpp also helps.
-
-
-   Setting Camera/Tuner parameters via x11vnc:
-
-   There is also some support for setting parameters of the capture
-   device. This is done via "-rawfb video:<settings>". This could be
-   useful for unattended startup at boottime, etc. Here is the -help
-   description:
-
-     A more sophisticated video device scheme allows initializing the
-     device's settings using:
-
-           -rawfb video:<settings>
-
-     The prefix could also be, as above, e.g. "video1:" to specify the
-     device file. The v4l API must be available for this to work.
-     Otherwise, you will need to try to initialize the device with an
-     external program, e.g. xawtv, spcaview, and hope they persist when
-     x11vnc re-opens the device.
-
-     <settings> is a comma separated list of key=value pairs. The
-     device's brightness, color, contrast, and hue can be set to
-     percentages, e.g. br=80,co=50,cn=44,hu=60.
-
-     The device filename can be set too if needed (if it does not start
-     with "video"), e.g. fn=/dev/qcam.
-
-     The width, height and bpp of the framebuffer can be set via, e.g.,
-     w=160,h=120,bpp=16.
-
-     Related to the bpp above, the pixel format can be set via the
-     fmt=XXX, where XXX can be one of: GREY, HI240, RGB555, RGB565,
-     RGB24, and RGB32 (with bpp 8, 8, 16, 16, 24, and 32 respectively.)
-     See http://www.linuxtv.org for more info (V4L api.)
-
-     For TV/rf tuner cards one can set the tuning mode via tun=XXX where
-     XXX can be one of PAL, NTSC, SECAM, or AUTO.
-
-     One can switch the input channel by the inp=XXX setting, where XXX
-     is the name of the input channel (Television, Composite1, S-Video,
-     etc.) Use the name that is in the information about the device that
-     is printed at startup.
-
-     For input channels with tuners (e.g. Television) one can change
-     which station is selected by the sta=XXX setting. XXX is the
-     station number. Currently only the ntsc-cable-us (US cable)
-     channels are built into x11vnc. See the -freqtab option below to
-     supply one from xawtv. If XXX is greater than 500, then it is
-     interpreted as a raw frequency in KHz.
-
-     Example:
-
-     -rawfb video:br=80,w=320,h=240,fmt=RGB32,tun=NTSC,sta=47
-
-     one might need to add inp=Television too for the input channel to
-     be TV if the card doesn't come up by default in that one.
-
-     Note that not all video capture devices will support all of the
-     above settings.
-
-     See the -pipeinput VID option below for a way to control the
-     settings through the VNC Viewer via keystrokes.
-
-     As above, if you specify a "@WxHxB..." after the <settings> string
-     they are used verbatim: the device is not queried for the current
-     values. Otherwise the device will be queried.
-
-   Also, if you supply the "-pipeinput VID" (or use "-rawfb Video")
-   option you can control the settings to some degree via keystroke
-   mappings, e.g. B to increase the brightness or Up arrow to change the
-   TV station:
-
-     For "-pipeinput VID" and you are using the -rawfb for a video
-     capture device, then an internal list of keyboard mappings is used
-     to set parameters of the video. The mappings are:
-
-         "B" and "b" adjust the brightness up and down.
-         "H" and "h" adjust the hue.
-         "C" and "c" adjust the colour.
-         "N" and "n" adjust the contrast.
-         "S" and "s" adjust the size of the capture screen.
-         "I" and "i" cycle through input channels.
-         Up and Down arrows adjust the station (if a tuner)
-         F1, F2, ..., F6 will switch the video capture pixel
-         format to HI240, RGB565, RGB24, RGB32, RGB555, and
-         GREY respectively. See -rawfb video for details.
-
-   See also the -freqtab option to supply your own xawtv channel to
-   frequency mappings for your country (only ntsc-cable-us is built into
-   x11vnc.)
-
-
-   Q-115: Can I connect via VNC to a Qt-embedded/Qt-enhanced/Qtopia
-   application running on my handheld, cell phone, or PC using the Linux
-   console framebuffer (i.e. not X11)?
-
-   Yes, the basic method for this is the -rawfb scheme where the Linux
-   console framebuffer (usually /dev/fb0) is polled and the uinput driver
-   is used to inject keystrokes and mouse input. Often you will just have
-   to type:
-  x11vnc -rawfb console
-
-   (you may need to enable the uinput driver on the system via "modprobe
-   uinput; mknod /dev/input/uinput c 10 223") If this does not find the
-   correct frame buffer properties figure them out or guess them and use
-   something like:
-  x11vnc -rawfb /dev/fb0@640x480x16
-
-   Also, to force usage of the uinput injection method use "-pipeinput
-   UINPUT". See the -pipeinput description for tunable parameters, etc.
-
-   One problem with the x11vnc uinput scheme is that it cannot guess the
-   mouse motion "acceleration" used by the windowing application (e.g.
-   QWS or X11.) For X11 and Qt-embedded the acceleration is usually 2
-   (i.e. a dx of 1 from the mouse yields a 2 pixel displacement of the
-   mouse cursor.) The default x11vnc uses is 2, since that is often used.
-   However for one Qt-embedded system we needed to do:
-  x11vnc -rawfb console  -pipeinput UINPUT:accel=4.0
-
-   to get reasonable positioning of the mouse.
-
-   Even with the correct acceleration setting there is still some drift
-   (probably because of the mouse threshold where the acceleration kicks
-   in) and so x11vnc needs to reposition the cursor from 0,0 about 5
-   times a second. See the -pipeinput UINPUT option for tuning parameters
-   that can be set (there are some experimental thresh=N tuning
-   parameters as well)
-
-   Currently, one can expect mouse input to be a little flakey. All in
-   all, the Linux framebuffer input mechanism for Qt-embedded framebuffer
-   apps is not perfect, but it is usable.
-
-   If you need to create a smaller x11vnc binary for a handheld
-   environment be sure to run strip(1) on it and also consider
-   configuring with, e.g. "env CPPFLAGS='-DSMALL_FOOTPRINT=1' ./configure
-   ..." to remove rarely used features and large texts (use 2 or 3
-   instead of 1 to remove more.) Currently (Jul/2006) this can lower the
-   size of the x11vnc from 1.1MB to 0.6-0.7MB.
-
-   The x11vnc uinput method applies to nearly anything on the Linux
-   framebuffer console, not just Qt-embedded/Qtopia. DirectFB, SDL using
-   fbcon driver, SVGAlib applications can also be viewed and interacted
-   with. Even a Linux X session can be viewed and interacted with without
-   using X11 (and x11vnc does not have to terminate when the X server
-   restarts!) The Linux Text consoles (F1-F6) also work.
-
-   Note that Qt-embedded supplies its own VNC graphics driver, but it
-   cannot do both the Linux console framebuffer and VNC at the same time,
-   which is often what is desired from VNC.
-
-   Update: We are finding some setups like Qtopia on the IPAQ do not
-   allow mouse input via uinput. Please help us debug this problem by
-   trying x11vnc on your device and letting us know what does and does
-   not work. See the next FAQ for a possible workaround for touchscreens.
-
-
-   Q-116: How do I inject touch screen input into an
-   Qt-embedded/Qt-enhanced/Qtopia cell phone such as openmoko/qtmoko Neo
-   Freerunner?
-
-   The qtmoko project does not use X11 for the graphical display.
-   Unfortunately the Linux uinput method described in the previous FAQ
-   does not work because Qt is using TSLIB (touch screen library) to
-   process the input and it only reads from one device (often
-   /dev/input/event1) and not from the new UINPUT device that x11vnc
-   creates (under -pipeinput UINPUT)
-
-   So something else needs to be done. It was discovered that by simply
-   writing the touchscreen events directly to /dev/input/event1 then
-   input can be injected into the system. There is no x11vnc builtin mode
-   for this yet (until we understand it better), but there is a working
-   script provided in x11vnc/misc/qt_tslib_inject.pl. So one could use it
-   this way for example:
-  x11vnc ... -rawfb console -pipeinput path/to/qt_tslib_inject.pl -env INJECT_O
-PTIONS=clickonly,cal=/etc/pointercal
-
-   Read the script for how to enable other options and what the above
-   options mean (e.g. /etc/pointercal contains TSLIB's calibration
-   parameters and are necessary to achieve accurate pointing.)
-
-   The x11vnc/misc/qt_tslib_inject.pl script can potentially be modified
-   to handle other devices where the uinput method fails. It could also
-   be modified to create 'hot keys', etc.
-
-   Please let us know how things go if you try this out; there is much to
-   learn about synthetic input injection in handhelds and cell phones. As
-   we learn more we can develop a builtin x11vnc mode for this sort of
-   injection.
-
-   Update Dec/2010: There is experimental built-in UINPUT support in the
-   x11vnc development tarball for qtmoko with touchpad managed by tslib.
-   See -pipeinput UINPUT for more info. Here is an example:
-   x11vnc -rawfb console -pipeinput UINPUT:touch,tslib_cal=/etc/pointercal,dire
-ct_abs=/dev/input/event1,nouinput,dragskip=3
-
-
-   Q-117: Now that non-X11 devices can be exported via VNC using x11vnc,
-   can I build it with no dependencies on X11 header files and libraries?
-
-   Yes, as of Jul/2006 x11vnc enables building for -rawfb only support.
-   Just do something like when building:
-  ./configure --without-x    (plus any other flags)
-  make
-
-   You can then test via "ldd x11vnc" that the binary does not depend on
-   libX11.so, etc. See the previous FAQ's for non-X11 framebuffer usage.
-   If you use this for an interesting non-X11 application please let us
-   know what you did.
-
-
-   Q-118: How do I cross compile x11vnc for a different architecture than
-   my Linux i386 or amd64 PC?
-
-   You will need a cross-compiling toolchain. Perhaps your distro
-   provides these or you can find a HOWTO for your distro. We found a
-   nice one at qtmoko.org for building armel binaries on Debian Linux
-   i386 machines. It includes most of the libraries that x11vnc needs. We
-   use that example here.
-
-   We ran this script to set PATH, configure, and build:
-#!/bin/sh
-
-# toolchain from: qtmoko-debian-toolchain-armv4t-eabi.tar.gz
-
-export PATH=/opt/toolchains/arm920t-eabi/bin:$PATH
-
-env CC=arm-linux-gcc ./configure --host=arm-linux --without-avahi
-
-make
-
-arm-linux-strip ./x11vnc/x11vnc
-ls -l ./x11vnc/x11vnc
-
-   Note we had to include --without-avahi due to lack of
-   libavahi-client.so.3 supplied by the toolchain we used. One would need
-   to add it if it was desired on the target machine. We also stripped
-   the binary to make it smaller.
-
-   For an embedded system one may also want to add --without-x if the
-   embedded system does not use X11 and the -rawfb mechanism must be
-   used.
-
-
-   Q-119: Does x11vnc support Mac OS X Aqua/Quartz displays natively
-   (i.e. no X11 involved)?
-
-   Yes, since Nov/2006 in the development tree (x11vnc-0.8.4 tarball)
-   there is support for native Mac OS X Aqua/Quartz displays using the
-   -rawfb mechanism described above. The mouse and keyboard input is
-   achieved via Mac OS X API's.
-
-   So you can use x11vnc as an alternative to OSXvnc (aka Vine Server),
-   or Apple Remote Desktop (ARD). Perhaps there is some x11vnc feature
-   you'd like to use on Mac OS X, etc. For a number of activities (e.g.
-   window drags) it seems to be faster than OSXvnc.
-
-   Notes:
-
-   X11:  x11vnc will also work (as it has for years) with a X11 server
-   (XDarwin) running on Mac OS X (people often install this software to
-   display remote X11 apps on their Mac OS X system, or use some old
-   favorites locally such as xterm.) However in this case x11vnc will
-   only work reasonably in single window -id windowid mode (and the
-   window may need to have mouse focus.)
-
-   If you do not have the DISPLAY env. variable set, x11vnc will assume
-   native Aqua/Quartz on Mac OS X, however if DISPLAY is set it will
-   assume an X11 connection. Use "-rawfb console" to force the native
-   display (or unset DISPLAY.)
-
-   Update: Leopard sets DISPLAY by default in all sessions. Since it
-   starts with the string "/tmp/" x11vnc will use that to know if it
-   should ignore it. Use "-display :0.0" to force it.
-
-   Building:  If you don't have the X11 build and runtime packages
-   installed you will need to build it like this:
-   (cd to the e.g. x11vnc-0.9, source directory)
-   ./configure --without-x
-   make
-
-   Win2VNC/x2vnc:  One handy use is to use the -nofb mode to redirect
-   mouse and keyboard input to a nearby Mac (i.e. one to the side of your
-   desk) via x2vnc or Win2VNC. See this FAQ for more info.
-
-   Options:  Here are the Mac OS X specific x11vnc options:
-   -macnodim              For the native Mac OS X server, disable dimming.
-   -macnosleep            For the native Mac OS X server, disable display sleep
-.
-   -macnosaver            For the native Mac OS X server, disable screensaver.
-   -macnowait             For the native Mac OS X server, do not wait for the
-                          user to switch back to his display.
-   -macwheel n            For the native Mac OS X server, set the mouse wheel
-                          speed to n (default 5.)
-   -macnoswap             For the native Mac OS X server, do not swap mouse
-                          buttons 2 and 3.
-   -macnoresize           For the native Mac OS X server, do not resize or rese
-t
-                          the framebuffer even if it is detected that the scree
-n
-                          resolution or depth has changed.
-   -maciconanim n         For the native Mac OS X server, set n to the number
-                          of milliseconds that the window iconify/deiconify
-                          animation takes.  In -ncache mode this value will be
-                          used to skip the animation if possible. (default 400)
-   -macmenu               For the native Mac OS X server, in -ncache client-sid
-e
-                          caching mode, try to cache pull down menus (not perfe
-ct
-                          because they have animated fades, etc.)
-
-   PasteBoard/Clipboard:   There is a bug that the Clipboard (called
-   PasteBoard on Mac it appears) exchange will not take place unless
-   x11vnc was started from inside the Aqua display (e.g. started inside a
-   Terminal app window.) Otherwise it cannot connect to the PasteBoard
-   server. So Clipboard exchange won't work for our standard "ssh in"
-   startup scheme.
-
-   Hopefully this deficiency can be removed, but until then for Clipboard
-   exchange to work you will need to start x11vnc inside the desktop
-   session (i.e. either start it running before you leave, or start up a
-   2nd x11vnc inside from a 1st one started outside, or use the apple
-   script below)
-
-   Here also is a osascript trick that seems to work (it opens the
-   Terminal app and instructs it to start x11vnc):
-
-#!/bin/sh
-#
-# start_x11vnc: start x11vnc in a Terminal window
-# (this will allow Clipboard/Pasteboard exchange to work)
-
-tmp=/tmp/start_x11vnc.$$
-
-cat > $tmp <<END
-
-tell application "Terminal"
-        activate
-        do script with command "$HOME/x11vnc -rfbauth .vnc/passwd -ssl SAVE"
-end tell
-
-END
-
-osascript $tmp
-rm -f $tmp
-
-   where you should customize the x11vnc command line to your needs and
-   the full path to the binary. Save it in a file e.g. "start_x11vnc" and
-   then after you SSH in just type "./start_x11vnc" (or have ssh run the
-   command for you.) Then once you are connected via VNC, iconify the
-   Terminal windows (you can't delete them since that will kill x11vnc.)
-
-   Update Aug/2010: A user reports the following useful information:
-This is not a problem on Mac OS X 10.6.x (Snow Leopard) when connecting
-via ssh to start x11vnc.  And, on Mac OS X 10.5.x (Leopard), the problem
-can be permanently eliminated by doing this:
-
-
-sudo /usr/libexec/PlistBuddy -c 'delete :LimitLoadToSessionType' \
-   -c 'add :LimitLoadToSessionType string Background' \
-   /System/Library/LaunchAgents/com.apple.pboard.plist
-# ignore any 'Delete: Entry, ":LimitLoadToSessionType", Does Not Exist' message
-
-and then restarting (yes, you must restart not just log off).  But
-ONLY do that for Mac OS X 10.5.x and NOT for 10.6.x (which doesn't
-need it anyway).
-
-   We recently got access to a MacOSX 10.6.4 (Snow Leopard) macbook and
-   have confirmed that the above is correct.
-
-
-   Q-120: Can x11vnc be used as a VNC reflector/repeater to improve
-   performance for the case of a large number of simultaneous VNC viewers
-   (e.g. classroom broadcasting or a large demo)?
-
-   Yes, as of Feb/2007 there is the "-reflect host:N" option to connect
-   to the VNC server "host:N" (either another x11vnc or any other VNC
-   server) and re-export it. VNC viewers then connect to the x11vnc(s)
-   running -reflect.
-
-   The -reflect option is the same as: "-rawfb vnc:host:N". See the
-   -rawfb description under "VNC HOST" for more details.
-
-   You can replace "host:N" with "listen" or "listen:port" for reverse
-   connections.
-
-   One can set up a number of such reflectors/repeaters to spread the
-   resource usage around, e.g.:
-       C -------<-------|
-       C -------<-------|
-       C -------<-------|---- R -----|
-       C -------<-------|            |
-       C -------<-------|            |
-                                     |
-       C -------<-------|            |
-       C -------<-------|            |
-       C -------<-------|---- R -----|
-       C -------<-------|            |
-       C -------<-------|            |
-                                     |====== S
-       C -------<-------|            |
-       C -------<-------|            |
-       C -------<-------|---- R -----|
-       C -------<-------|            |
-       C -------<-------|            |
-                                     |
-       C -------<-------|            |
-       C -------<-------|            |
-       C -------<-------|---- R -----|
-       C -------<-------|
-       C -------<-------|
-
-   Where "S" is the original VNC Server, "C" denote VNC viewer clients,
-   and "R" denotes an x11vnc running -reflect to "S".
-
-   Ideally, a client "C" will be fairly close network-wise to its "R". It
-   is fine to run the "R" on the same machine as one of its "C's". A nice
-   setup for a large, (e.g. 64-128) viewer classroom broadcast case would
-   be to run R's on areas isolated by network switches, e.g. one R per
-   switch.
-
-   In an extreme case (e.g. 1000 viewers) one might actually need a 2nd
-   layer of R's in the tree. If you try something like that let us know!
-
-   There are many resource savings in doing something like the above. The
-   first obvious one is network bandwidth savings. Another is less CPU
-   load on "S" since it handles many fewer simultaneous connections.
-   Also, if there are a few clients C on very slow links, their presence
-   does not slow down every other client, just the clients on their "R".
-   One way a slow client affects things is if there are some large
-   framebuffer writes (e.g. jpeg image region) then the repeater may
-   block waiting for that large write to finish before going onto the
-   next client (however, if the write is small enough, the kernel will
-   buffer it and the server can go on to service the next client.)
-
-   The x11vnc -reflect implementation uses the libvncclient library in
-   the LibVNCServer project to handle the connection to "S". It is not
-   currently very efficient since it simply does its normal framebuffer
-   polling scheme on the libvncclient framebuffer (which it then
-   re-exports via VNC to its clients C.) However, CopyRect and
-   CursorShape encodings are preserved in the reflection and that helps.
-   Dragging windows with the mouse can be a problem (especially if S is
-   not doing wireframing somehow, consider -nodragging if the problem is
-   severe) For a really fast reflector/repeater it would have to be
-   implemented from scratch with performance in mind. See these other
-   projects:
-    http://sourceforge.net/projects/vnc-reflector/,
-    http://www.tightvnc.com/projector/                (closed source?),
-
-
-   Automation via Reverse Connections:   Instead of having the R's
-   connect directly to S and then the C's connect directly to the R they
-   should use, some convenience can be achieved by using reverse
-   connections (the x11vnc ""-connect host1,host2,..." option.) Suppose
-   all the clients "C" are started up in Listen mode:
-    client1>  vncviewer -listen
-    client2>  vncviewer -listen
-    client3>  vncviewer -listen
-    ...
-    client64> vncviewer -listen
-
-   (e.g. client1> is the cmdline prompt on machine client1 ... etc) and
-   all the repeaters R are started like this:
-    repeater1> x11vnc -reflect listen -connect client1,client2,...client8
-    repeater2> x11vnc -reflect listen -connect client9,client10,...client16
-    ...
-    repeater8> x11vnc -reflect listen -connect client57,client58,...client64
-
-   and finally the main server is started to kick the whole thing into
-   motion:
-    vncserver> x11vnc -display :0 -connect repeater1,repeater2,...repeater8
-
-   (or instruct a non-x11vnc VNC server to reverse connect to the
-   repeaters.) For a classroom broadcasting setup one might have the
-   first two sets of commands start automatically at bootup or when
-   someone logs in, and then start everything up with the S server. One
-   may even be able to script the forward connection bootstrap case, let
-   us know what you did. A really nice thing would be some sort of
-   auto-discovery of your repeater, etc...
-
-   Q-121: Can x11vnc be used during a Linux, Solaris, etc. system
-   Installation so the Installation can be done remotely?
-
-   This can be done, but it doesn't always work because it depends on how
-   the OS does its install. We have to "sneak in" somehow. Note that some
-   OS's have a remote install (ssh etc.) built in and so you might want
-   to use that instead.
-
-   Usually the OS install will have to be a network-install in order to
-   have networking up during the install. Otherwise, you may have a
-   (slim) chance to configure the networking manually (ifconfig(8) and
-   route(8).)
-
-   To avoid library dependencies problems in the typical minimal (e.g.
-   busybox) installation OS it is a good idea to build a statically
-   linked x11vnc binary. A way that often works is to do a normal build
-   and then paste the final x11vnc link line into a shell script. Then
-   change the "gcc" to "gcc -static" and run the shell script. You may
-   need to disable features (e.g. "--without-xfixes") if there is not a
-   static library for the feature available. You may also need to add
-   extra link options (e.g. "-lXrender") to complete library dependencies
-   manually.
-
-   Let's call the binary x11vnc.static. Place it on a webserver
-   somewhere. It may be possible to retrieve it via scp(1) too.
-
-   During the install you need to get a shell to retreive x11vnc.static
-   and run it.
-
-   If the Solaris install is an older X-based one, there will be a menu
-   for you to get a terminal window. From that window you might be able
-   to retrieve x11vnc.static via wget, scp, or ftp. Remember to do "chmod
-   755 ./x11vnc.static" and then find the -auth file as in this FAQ.
-
-   If it is a Linux install that uses an X server (e.g. SuSE and probably
-   Fedora), then you can often get a shell by pressing Ctrl-Alt-F2 or
-   similar. Then get the x11vnc binary via something like this:
-   cd /tmp
-   wget http://192.168.0.22/x11vnc.static
-   chmod 755 ./x11vnc.static
-
-   Find the name of the auth file as in this FAQ. (maybe run "ps wwaux |
-   grep auth".) Then run it like this:
-   ./x11vnc.static -forever -nopw -display :0 -auth /tmp/wherever/the/authfile
-
-   then press Alt-F7 to go back to the X install. You should now be able
-   to connect via a vnc viewer and continue the install. Watch out for
-   the display being :1, etc.
-
-   If there is a firewall blocking incoming connections during the
-   install, use the "-connect hostname" option option for a reverse
-   connection to the hostname running the VNC viewer in listen mode.
-
-   Debian based installs are either console-text or console-framebuffer
-   based. These are install (or expert) and installgui (or expertgui)
-   boot lines, respectively. For the console-text based installs you
-   probably need to add a boot cmd line option like vga=0x314 (which is
-   800x600x16) to get the console-text to use the linux framebuffer
-   device properly.
-
-   For a Debian console-text based install after the network is
-   configured press Ctrl-Alt-F2 to get a shell. Retrieve the binary via
-   wget as above and chmod 755 it. Then run it something like this:
-   sleep 10; ./x11vnc.static -forever -nopw -rawfb console
-
-   then before the sleep is over press Alt-F1 to get back to the install
-   virtual console. You should be able to connect via a VNC viewer and
-   continue with the install.
-
-   For a recent (2009) Debian install we booted with "expert vga=0x301"
-   and "expert vga=0x311" to get console text based installs at 640x480x8
-   and 640x480x16, respectively (replace "expert" with "install" if you
-   like.) Otherwise it was giving a 16 color 640x480x4 (4 bit per pixel)
-   display which x11vnc could not handle.
-
-   For Debian console-framebuffer GUI based installs (installgui or
-   expertgui) we have not be able to enter keystrokes or mouse motions.
-   This may be resolved if the install had the Linux kernel module
-   uinput, but it doesn't; one can wget uinput.ko and then run insmod on
-   it, but the module must match the installation kernel. So, failing
-   that, you can only do the GUI view-only, which can be handy to watch a
-   long network install from your desk instead of in front of the machine
-   being installed. For these, after the network is configured press
-   Ctrl-Alt-F2 to get a shell. Retrieve the binary via wget as above and
-   chmod 755 it. Then run it something like this:
-   sleep 10; ./x11vnc.static -forever -nopw -rawfb console
-
-   then before the sleep is over press Alt-F5 to get back to the GUI
-   install console. You should be able to connect via a VNC viewer and
-   watch the install.
-   [Misc: Clipboard, File Transfer/Sharing, Printing, Sound, Beeps,
-   Thanks, etc.]
-
-   Q-122: Does the Clipboard/Selection get transferred between the
-   vncviewer and the X display?
-
-   As of Jan/2004 x11vnc supports the "CutText" part of the RFB (aka VNC)
-   protocol. When text is selected/copied in the X session that x11vnc is
-   polling it will be sent to connected VNC viewers. And when CutText is
-   received from a VNC viewer then x11vnc will set the X11 selections
-   PRIMARY, CLIPBOARD, and CUTBUFFER0 to it. x11vnc is able to hold the
-   PRIMARY and CLIPBOARD selections (Xvnc does not seem to do this.)
-
-   The X11 selections can be confusing, especially to those coming from
-   Windows or MacOSX where there is just a single 'Clipboard'. The X11
-   CLIPBOARD selection is a lot like that of Windows and MacOSX, e.g.
-   highlighted text is sent to the clipboard when the user activates
-   "Edit -> Copy" or presses "Control+C" (and pasting it via "Edit ->
-   Paste" or "Control+V".) The X11 PRIMARY selection has been described
-   as 'for power users' or 'an Easter Egg'. As soon as text is
-   highlighted it is set to the PRIMARY selection and so it is
-   immediately ready for pasting, usually via the Middle Mouse Button or
-   "Shift+Insert". See this jwz link for more information.
-
-   x11vnc's default behavior is to watch both CLIPBOARD and PRIMARY and
-   whenever one of them changes, it sends the new text to connected
-   viewers. Note that since the RFB protocol only has a single "CutText"
-   then both selections are "merged" to some degree (and this can lead to
-   confusing results.) One user was confused why x11vnc was "forgetting"
-   his CLIPBOARD selection and the reason was he also changed PRIMARY
-   some time after he copied text to the clipboard. Usually an app will
-   set PRIMARY as soon as any text is highlighted so it easy to see how
-   CLIPBOARD was forgotten. Use the -noprimary described below as a
-   workaround. Similarly, by default when x11vnc receives CutText it sets
-   both CLIPBOARD and PRIMARY to it (this is probably less confusing, but
-   could possibly lead to some failure modes as well.)
-
-   You may not like these defaults. Here are ways to change the behavior:
-     * If you don't want the Clipboard/Selection exchanged at all use the
-       -nosel option.
-     * If you want changes in PRIMARY to be ignored use the -noprimary
-       option.
-     * If you want changes in CLIPBOARD to be ignored use the
-       -noclipboard option.
-     * If you don't want x11vnc to set PRIMARY to the "CutText" received
-       from viewers use the -nosetprimary option.
-     * If you don't want x11vnc to set CLIPBOARD to the "CutText"
-       received from viewers use the -nosetclipboard option.
-
-   You can also fine-tune it a bit with the -seldir dir option and also
-   -input.
-
-   You may need to watch out for desktop utilities such as KDE's
-   "Klipper" that do odd things with the selection, clipboard, and
-   cutbuffers.
-
-
-   Q-123: Can I use x11vnc to record a Shock Wave Flash (or other format)
-   video of my desktop, e.g. to record a tutorial or demo?
-
-   Yes, it is possible with a number of tools that record VNC and
-   transform it to swf format or others. One such popular tool is
-   pyvnc2swf. There are a number of tutorials (broken link?) on how to do
-   this. Another option is to use the vnc2mpg that comes in the
-   LibVNCServer package.
-   An important thing to remember when doing this is that tuning
-   parameters should be applied to x11vnc to speed up its polling for
-   this sort of application, e.g. "-wait 10 -defer 10".
-
-   Q-124: Can I transfer files back and forth with x11vnc?
-
-   As of Oct/2005 and May/2006 x11vnc enables, respectively, the TightVNC
-   and UltraVNC file transfer implementations that were added to
-   libvncserver. This currently works with TightVNC and UltraVNC viewers
-   (and Windows viewers only support filetransfer it appears... but they
-   do work to some degree under Wine on Linux.)
-
-   The SSVNC Unix VNC viewer supports UltraVNC file transfer by use of a
-   Java helper program.
-
-   TightVNC file transfer is off by default, if you want to enable it use
-   the -tightfilexfer option.
-
-   UltraVNC file transfer is off by default, to enable it use something
-   like "-rfbversion 3.6 -permitfiletransfer"
-   options (UltraVNC incorrectly uses the RFB protocol version to
-   determine if its features are available, so x11vnc has to pretend to
-   be version 3.6.) As of Sep/2006 "-ultrafilexfer" is an alias for these
-   two options. Note that running as RFB version 3.6 may confuse other
-   VNC Viewers.
-
-   Sadly you cannot do both -tightfilexfer and -ultrafilexfer at the same
-   time because the latter requires setting the version to 3.6 and
-   tightvnc will not do filetransfer when it sees that version number.
-
-   Also, because of the way the LibVNCServer TightVNC file transfer is
-   implemented, you cannot do Tightvnc file transfer in -unixpw mode.
-   However, UltraVNC file transfer does work in -unixpw (but if a client
-   tries it do a filetransfer during the login process it will be
-   disconnected.)
-
-   IMPORTANT: please understand if -ultrafilexfer or -tightfilexfer is
-   specified and you run x11vnc as root for, say, inetd or display
-   manager (gdm, kdm, ...) access and you do not have it switch users via
-   the -users option, then VNC Viewers that connect are able to do
-   filetransfer reads and writes as *root*.
-
-   The UltraVNC and TightVNC settings can be toggled on and off inside
-   the gui or by -R remote control. However for TightVNC the changed
-   setting only applies for NEW clients, current clients retain their
-   TightVNC file transfer ability. For UltraVNC it works better, however
-   if an UltraVNC client has initiated a file transfer dialog it will
-   remain in effect until the dialog is closed. If you want to switch
-   between UltraVNC and TightVNC file transfer in the gui or by remote
-   control you will probably be foiled by the "-rfbversion 3.6" issue.
-
-
-   Q-125: Which UltraVNC extensions are supported?
-
-   Some of them are supported. To get UltraVNC Viewers to attempt to use
-   these extensions you will need to supply this option to x11vnc:
-   -rfbversion 3.6
-
-   Or use -ultrafilexfer which is an alias for the above option and
-   "-permitfiletransfer". UltraVNC evidently treats any other RFB version
-   number as non-UltraVNC.
-
-   Here are a list of the UltraVNC extensions supported by x11vnc:
-     * ServerInput: "Toggle Remote Input and Remote Blank Monitor"
-     * FileTransfer: "Open File Transfer..."
-     * SingleWindow: "Select Single Window..."
-     * TextChat: "Open Chat..."
-     * 1/n Server Scaling
-
-   The SSVNC Unix VNC viewer supports these UltraVNC extensions.
-
-   To disable SingleWindow and ServerInput use -noultraext (the others
-   are managed by LibVNCServer.) See this option too: -noserverdpms.
-
-   Also, the UltraVNC repeater proxy is supported for use with reverse
-   connections: "-connect repeater://host:port+ID:NNNN". Use it for both
-   plaintext and SSL connections. This mode can send any string before
-   switching to the VNC protocol, and so could be used with other
-   proxy/gateway tools. Also, a perl repeater implemention is here:
-   ultravnc_repeater.pl
-
-
-   Q-126: Can x11vnc emulate UltraVNC's Single Click helpdesk mode for
-   Unix? I.e. something very simple for a naive user to initiate a
-   reverse vnc connection from their Unix desktop to a helpdesk
-   operator's VNC Viewer.
-
-   Yes, UltraVNC's Single Click (SC) mode can be emulated fairly well on
-   Unix.
-
-   We use the term "helpdesk" below, but it could be any sort of remote
-   assistance you want to set up, e.g. something for Unix-using friends
-   or family to use. This includes Mac OS X.
-
-   Assume you create a helpdesk directory "hd" on your website:
-   http://www.mysite.com/hd (any website that you can upload files to
-   should work, although remember the user will be running the programs
-   you place there.)
-
-   In that "hd" subdirectory copy an x11vnc binary to be run on the Unix
-   user's machine (e.g. Linux, etc) and also create a file named "vnc"
-   containing the following:
-#!/bin/sh
-
-webhost="http://www.mysite.com/hd"  # Your helpdesk dir URL.
-
-vnchost="ip.someplace.net"          # Your host running 'vncviewer -listen'
-                                    # It could also be your IP number. If it is
-                                    # a router/firewall, you will need to
-                                    # configure it to redirect port 5500 to you
-r
-                                    # workstation running 'vncviewer -listen'
-
-dir=/tmp/vnc_helpdesk.$$            # Make a temporary working dir.
-mkdir $dir || exit 1
-cd $dir || exit 1
-
-trap "cd /tmp; rm -rf $dir" 0 2 15  # Cleans up on exit.
-
-wget $webhost/x11vnc                # Fetch x11vnc binary.  If multi-
-chmod 755 ./x11vnc                  # platform, use $webhost/`uname`/x11vnc
-                                    # or similar.
-
-./x11vnc -connect_or_exit $vnchost -rfbport 0 -nopw
-
-   with the hostnames / IP addresses customized to your case.
-
-   On the helpdesk VNC viewer machine (ip.someplace.net in this example)
-   you have the helpdesk operator running VNC viewer in listen mode:
-   vncviewer -listen
-
-   or if on Windows, etc. somehow have the VNC viewer be in "listen"
-   mode.
-
-   Then, when the naive user needs assistance you instruct him to open up
-   a terminal window on his Unix desktop and paste the following into the
-   shell:
-   wget -qO - http://www.mysite.com/hd/vnc | sh -
-
-   and then press Enter. You could have this instruction on a web page or
-   in an email you send him, etc. This requires that the wget is
-   installed on the user's Unix machine (he might only have curl or lynx,
-   see below for more info.)
-
-
-   So I guess this is about 3-4 clicks (start a terminal and paste) and
-   pressing "Enter" instead of "single click"...
-
-   See this page for some variations on this method, e.g. how to add a
-   password, SSL Certificates, etc.
-
-
-   If you don't have a website (there are many free ones) or don't want
-   to use one you will have to email him all of the ingredients (x11vnc
-   binary and a launcher script) and tell him how to run it. This could
-   be easy or challenging depending on the skill of the naive unix
-   user...
-
-   A bit of obscurity security could be put in with a -passwd, -rfbauth
-   options, etc. (note that x11vnc will require a password even for
-   reverse connections.) More info here.
-
-
-   Firewalls: If the helpdesk (you) with the vncviewer is behind a
-   NAT/Firewall/Router the router will have to be configured to redirect
-   a port (i.e. 5500 or maybe different one if you like) to the vncviewer
-   machine. If the vncviewer machine also has its own host-level
-   firewall, you will have to open up the port there as well.
-
-   NAT-2-NAT: There is currently no way to go "NAT-2-NAT", i.e. both User
-   and Helpdesk workstations behind NAT'ing Firewall/Routers without
-   configuring a router to do a port redirection (i.e. on your side, the
-   HelpDesk.) To avoid modifying either firewall/router, one would need
-   some public (IP address reachable on the internet) redirection/proxy
-   service. Perhaps such a thing exists. http://sc.uvnc.com provides this
-   service for their UltraVNC Single Click users.
-
-   Update: It may be possible to do "NAT-2-NAT" with a UDP tunnel such as
-   http://samy.pl/pwnat/. All that is required is that both NAT firewalls
-   allow in UDP packets from an IP address to which a UDP packet has
-   recently been sent to. If you try it out let us know how it went.
-
-
-   Very Naive Users:
-
-   If it is beyond the user how to open a terminal window and paste in a
-   command (you have my condolences...) you would have to somehow setup
-   his Web browser to download the "vnc" file (or a script containing the
-   above wget line) and prompt the user if he wants to run it. This may
-   be tricky to set up (which is probably a good thing to not have the
-   web browser readily run arbitrary programs downloaded from the
-   internet...)
-
-   One command-line free way, tested with KDE, is to name the file vnc.sh
-   and then instruct the user to right-click on the link and do "Save
-   Link As" to his Desktop. It will appear as an icon, probably one that
-   looks like a terminal or a command line prompt. He next should
-   right-click on the icon and select "Properties" and go to the
-   "Permissions" tab. Then in that dialog select the checkbox "Is
-   executable". He should then be able to click on the icon to launch it.
-   Another option is to right-click on the icon and select "Open With ->
-   Other ..." and for the name of the application type in "/bin/sh".
-   Unfortunately in both cases the command output is lost and so errors
-   cannot be debugged as easily. A similar thing appears to work in GNOME
-   if under "Properties -> Permissions" they click on "Execute" checkbox
-   for "Owner". Then when they click on the icon, they will get a dialog
-   where they can select "Run in Terminal". In general for such cases, if
-   it is feasible, it might be easier to ssh to his machine and set
-   things up yourself...
-
-
-   SSL Encrypted Helpdesk Connections:
-
-   As of Apr/2007 x11vnc supports reverse connections in SSL and so we
-   can do this. On the Helpdesk side (Viewer) you will need STUNNEL or
-   better use the Enhanced TightVNC Viewer (SSVNC) package we provide
-   that automates all of the SSL for you.
-
-   To do this create a file named "vncs" in the website "hd" directory
-   containing the following:
-#!/bin/sh
-
-webhost="http://www.mysite.com/hd"  # Your helpdesk dir URL.
-
-vnchost="ip.someplace.net"          # Your host running 'vncviewer -listen'
-                                    # It could also be your IP number. If it is
-                                    # a router/firewall, you will need to
-                                    # configure it to redirect port 5500 to you
-r
-                                    # workstation running 'vncviewer -listen'
-
-dir=/tmp/vnc_helpdesk.$$            # Make a temporary working dir.
-mkdir $dir || exit 1
-cd $dir || exit 1
-
-trap "cd /tmp; rm -rf $dir" 0 2 15  # Cleans up on exit.
-
-wget $webhost/x11vnc                # Fetch x11vnc binary.  If multi-
-chmod 755 ./x11vnc                  # platform, use $webhost/`uname`/x11vnc
-                                    # or similar.
-
-./x11vnc -connect_or_exit $vnchost -rfbport 0 -nopw -ssl    # Note -ssl option.
-
-   with the hostnames or IP addresses customized to your case.
-
-   The only change from the "vnc" above is the addition of the -ssl
-   option to x11vnc. This will create a temporary SSL cert: openssl(1)
-   will need to be installed on the user's end. A fixed SSL cert file
-   could be used to avoid this (and provide some authentication; more
-   info here.)
-
-   The naive user will be doing this:
-   wget -qO - http://www.mysite.com/hd/vncs | sh -
-
-   (or perhaps even use https:// if available.)
-
-   But before that, the helpdesk operator needs to have "vncviewer
-   -listen" running as before, however he needs an SSL tunnel at his end.
-   The easiest way to do this is use Enhanced TightVNC Viewer (SSVNC).
-   Start it, and select Options -> 'Reverse VNC Connection (-listen)'.
-   Then UN-select 'Verify All Certs' (this can be enabled later if you
-   want; you'll need the x11vnc SSL certificate), and click 'Listen'.
-
-   If you don't want to use SSVNC for the viewer, but rather set up
-   STUNNEL manually instead, make a file "stunnel.cfg" containing:
-foreground = yes
-pid =
-
-[vnc]
-accept = 5500
-connect = localhost:5501
-
-   and run:
-  stunnel ./stunnel.cfg
-
-   and then start the "vncviewer -listen 1" (i.e. 1 to correspond to the
-   5501 port.) Note that this assumes the stunnel install created a
-   Server SSL cert+key, usually /etc/stunnel/stunnel.pem (not all distros
-   will do this.) Also, that file is by default only readable by root, so
-   stunnel needs to be run as root. If your system does not have a key
-   installed or you do not want to run stunnel as root (or change the
-   permissions on the file), you can use x11vnc to create one for you for
-   example:
-  x11vnc -sslGenCert server self:mystunnel
-
-   answer the prompts with whatever you want; you can take the default
-   for all of them if you like. The openssl(1) package must be installed.
-   See this link and this one too for more info on SSL certs. This
-   creates $HOME/.vnc/certs/server-self:mystunnel.pem, then you would
-   change the "stunnel.cfg" to look something like:
-foreground = yes
-pid =
-cert = /home/myusername/.vnc/certs/server-self:mystunnel.pem
-
-[vnc]
-accept = 5500
-connect = localhost:5501
-
-   In any event, with stunnel having been setup, the naive user is
-   instructed to paste in and run:
-   wget -qO - http://www.mysite.com/hd/vncs | sh -
-
-   to pick up the vncs script this time.
-
-   Of course if a man-in-the-middle can alter what the user downloads
-   then all bets are off!.
-
-   More SSL variations and info about certificates can be found here.
-
-
-   OpenSSL libssl.so.0.9.7 problems:
-
-   If you build your own stunnel or x11vnc for deployment, you may want
-   to statically link libssl.a and libcrypto.a into it because Linux
-   distros are currently a bit of a mess regarding which version of
-   libssl is installed.
-
-   You will find the details here.
-
-
-   Q-127: Can I (temporarily) mount my local (viewer-side) Windows/Samba
-   File share on the machine where x11vnc is running?
-
-   You will have to use an external network redirection for this.
-   Filesystem mounting is not part of the VNC protocol.
-
-   We show a simple Samba example here.
-
-   First you will need a tunnel to redirect the SMB requests from the
-   remote machine to the one you sitting at. We use an ssh tunnel:
-  sitting-here> ssh -C -R 1139:localhost:139 far-away.east
-
-   Or one could combine this with the VNC tunnel at the same time, e.g.:
-  sitting-here> ssh -C -R 1139:localhost:139 -t -L 5900:localhost:5900 far-away
-.east 'x11vnc -localhost -display :0'
-
-   Port 139 is the Windows Service port. For Windows systems instead of
-   Samba, you may need to use the actual IP address of the Window machine
-   instead of "localhost" in the -R option (since the Windows service
-   does not listen on localhost by default.)
-
-   Note that we use 1139 instead of 139 on the remote side because 139
-   would require root permission to listen on (and you may have a samba
-   server running on it already.)
-
-   The ssh -C is to enable compression, which might speed up the data
-   transfers.
-
-   Depending on the remote system side configuration, it may or may not
-   be possible to mount the SMB share as a non-root user. Try it first as
-   a non-root user and if that fails you will have to become root.
-
-   We will assume the user name is "fred" and we will try to mount the
-   viewer-side Windows SMB share "//haystack/pub" in
-   /home/fred/smb-haystack-pub.
-  far-away> mkdir -p /home/fred/smb-haystack-pub
-  far-away> smbmount //haystack/pub /home/fred/smb-haystack-pub -o username=fre
-d,ip=127.0.0.1,port=1139
-
-   (The 2nd command may need to be run as root.) Then run "df" or "ls -l
-   /home/fred/smb-haystack-pub" to see if it is mounted properly. Consult
-   the smbmount(8) and related documentation (it may require some
-   fiddling to get write permissions correct, etc.) To unmount:
-  far-away> smbumount /home/fred/smb-haystack-pub
-
-   At some point we hope to fold some automation for SMB ssh redir setup
-   into the Enhanced TightVNC Viewer (SSVNC) package we provide (as of
-   Sep 2006 it is there for testing.)
-
-
-   Q-128: Can I redirect CUPS print jobs from the remote desktop where
-   x11vnc is running to a printer on my local (viewer-side) machine?
-
-   You will have to use an external network redirection for this.
-   Printing is not part of the VNC protocol.
-
-   We show a simple Unix to Unix CUPS example here. Non-CUPS port
-   redirections (e.g. LPD) should also be possible, but may be a bit more
-   tricky. If you are viewing on Windows SMB and don't have a local cups
-   server it may be trickier still (see below.)
-
-   First you will need a tunnel to redirect the print requests from the
-   remote machine to the one you sitting at. We use an ssh tunnel:
-  sitting-here> ssh -C -R 6631:localhost:631 far-away.east
-
-   Or one could combine this with the VNC tunnel at the same time, e.g.:
-  sitting-here> ssh -C -R 6631:localhost:631 -t -L 5900:localhost:5900 far-away
-.east 'x11vnc -localhost -display :0'
-
-   Port 631 is the default CUPS port. The above assumes you have a Cups
-   server running on your viewer machine (localhost:631), if not, use
-   something like my-cups-srv:631 (the viewer-side Cups server) in the -R
-   instead.
-
-   Note that we use 6631 instead of 631 on the remote side because 631
-   would require root permission to listen on (and you likely have a cups
-   server running on it already.)
-
-   Now the tricky part: to get applications to notice your cups
-   server/printer on localhost:6631.
-
-   If you have administrative privilege (i.e. root password) on the
-   x11vnc side where the desktop is running, it should be easy to add the
-   printer through some configuration utility (e.g. in KDE: Utilities ->
-   Printing -> Printing Manager, and then supply admin password, and then
-   Add Printer/Class, and then fill in the inquisitive wizard. Most
-   important is the "Remote IPP server" panel where you put in localhost
-   for Host and 6631 for Port.) The main setting you want to convey is
-   the host is localhost and the port is non-standard (e.g. 6631.) Some
-   configuration utilities will take an Internet Printing Protocol (IPP)
-   URI, e.g. http://localhost:6631/printers/,
-   ipp://localhost:6631/printers/printer-name,
-   ipp://localhost:6631/ipp/printer-name, etc. Check your CUPS
-   documentation and admin interfaces to find what the syntax is and what
-   the "printer name" is.
-
-   If you do not have root or print admin privileges, but are running a
-   recent (version 1.2 or greater) of the Cups client software, then an
-   easy way to temporarily switch Cups servers is to create the directory
-   and file: $HOME/.cups/client.conf on the remote side with a line like:
-  ServerName localhost:6631
-
-   When not using x11vnc for remote access you can comment the above line
-   out with a '#' (or rename the client.conf file), to have normal cups
-   operation.
-
-   Unfortunately, running applications may need to be restarted to notice
-   the new printers (libcups does not track changes in client.conf.)
-   Depending on circumstances, a running application may actually notice
-   the new printers without restarting (e.g. no print dialog has taken
-   place yet, or there are no CUPS printers configured on the remote
-   side.)
-
-   Cups client software that is older (1.1) does not support appending
-   the port number, and for newer ones there is a bug preventing it from
-   always working (fixed in 1.2.3.) Kludges like these at the command
-   line will work:
-  far-away> env CUPS_SERVER=localhost IPP_PORT=6631 lpstat -p -d
-  far-away> env CUPS_SERVER=localhost IPP_PORT=6631 lpr -P myprinter file.ps
-  far-away> env CUPS_SERVER=localhost IPP_PORT=6631 firefox
-
-   but are somewhat awkward since you have to retroactively set the env.
-   var IPP_PORT. Its value cannot be broadcast to already running apps
-   (like the $HOME/.cups/client.conf trick sometimes does.) A common
-   workaround for an already running app is to somehow get it to "Print
-   To File", e.g. file.ps and then use something like the lpr example
-   above. Also, the option "-h host:port" works with CUPS lp(1) and
-   lpr(1).
-
-   You can also print to Windows shares printers in principle. You may do
-   this with the smbspool(8) command, or configure the remote CUPS via
-   lpadmin(8), etc, to use a printer URI something like
-   smb://machine:port/printer (this may have some name resolution
-   problems WRT localhost.) Also, as with SMB mounting, the port redir
-   (-R) to the Windows machine must use the actual IP address instead of
-   "localhost".
-
-   At some point we hope to fold some automation for CUPS ssh redir setup
-   into the Enhanced TightVNC Viewer (SSVNC) package we provide (as of
-   Sep 2006 it is there for testing.)
-
-
-   Q-129: How can I hear the sound (audio) from the remote applications
-   on the desktop I am viewing via x11vnc?
-
-   You will have to use an external network audio mechanism for this.
-   Audio is not part of the VNC protocol.
-
-   We show a simple Unix to Unix esd example here (artsd should be
-   possible too, we have also verified the esd Windows port works for the
-   method described below.)
-
-   First you will need a tunnel to redirect the audio from the remote
-   machine to the one you sitting at. We use an ssh tunnel:
-  sitting-here> ssh -C -R 16001:localhost:16001 far-away.east
-
-   Or one could combine this with the VNC tunnel at the same time, e.g.:
-  sitting-here> ssh -C -R 16001:localhost:16001 -t -L 5900:localhost:5900 far-a
-way.east 'x11vnc -localhost -display :0'
-
-   Port 16001 is the default ESD uses. So when an application on the
-   remote desktop makes a sound it will connect to this tunnel and be
-   redirected to port 16001 on the local machine (sitting-here in this
-   example.) The -C option is an attempt to compress the audio a little
-   bit.
-
-   So we next need a local (sitting-here) esd daemon running that will
-   receive those requests and play them on the local sound device:
-  sitting-here> esd -promiscuous -port 16001 -tcp -bind 127.0.0.1
-
-   See the esd(1) man page for the meaning of the options (the above are
-   not very secure.) (This method also works with the EsounD windows port
-   esd.exe)
-
-   To test this sound tunnel, we use the esdplay program to play a simple
-   .wav file:
-  far-away> esdplay -s localhost:16001 im_so_happy.wav
-
-   If you hear the sound (Captain Kirk in this example), that means you
-   are in great shape.
-
-   To run individual audio applications you can use the esddsp(1)
-   command:
-  far-away> esddsp -s localhost:16001 xmms
-
-   Then you could try playing some sounds inside xmms. You could also set
-   the environment variable ESPEAKER=localhost:16001 to not need to
-   supply the -s option all the time. (for reasons not clear, sometimes
-   esddsp can figure it out on its own.) All the script esddsp does is to
-   set ESPEAKER and LD_PRELOAD for you so that when the application opens
-   the sound device (usually /dev/dsp) its interactions with the device
-   will be intercepted and sent to the esd daemon running on sitting-here
-   (that in turn writes them to the real, local /dev/dsp.)
-
-   Redirecting All sound:
-
-   It does not seem to be possible to switch all of the sound of the
-   remote machine from its sound device to the above esd+ssh tunnel
-   without some preparation. But it can be done reasonably well if you
-   prepare (i.e. restart) the desktop with this in mind.
-
-   Here is one way to redirect all sound. The idea is we run the entire
-   desktop with sound directed to localhost:16001. When we are sitting at
-   far-away.east we run "esd -promiscuous -port 16001 -tcp -bind
-   127.0.0.1" on far-away.east (to be able to hear the sound.) However,
-   when we are sitting at sitting-here.west we kill that esd process and
-   run that same esd command on sitting-here.west and start up the above
-   ssh tunnel. This is a little awkward, but with some scripts one would
-   probably kill and restart the esd processes automatically when x11vnc
-   is used.
-
-   So next we have to run the whole desktop pointing toward our esd. Here
-   is a simple way to test. Log in to the machine via the "FailSafe"
-   desktop. Then in the lone terminal type something like:
-  esddsp -s localhost:16001 gnome-session
-or:
-  esddsp -s localhost:16001 startkde
-
-   where the last part is whatever command starts your desktop (even
-   fvwm2.) This causes the environment variables ESPEAKER and LD_PRELOAD
-   to be set appropriately and every application (processes with the
-   desktop as an ancestor) will use them. If this scheme works well you
-   can make it less klunky by adding the command to your ~/.xsession,
-   etc. file that starts your default desktop. Or you may be able to
-   configure your desktop to use localhost:16001, or whatever is needed,
-   via a gui configuration panel. Some Notes:
-     * Not all audio applications are compatible with the esd and artsd
-       mechanisms, but many are.
-     * The audio is not compressed so you probably need a broadband or
-       faster connection. Listening to music may not be very pleasant...
-       (Although we found streaming music from across the US over cable
-       modem worked OK, but took 200 KB/sec, to use less bandwidth
-       consider something like "ssh far-away.east 'cat favorite.mp3' |
-       mpg123 -b 4000 -")
-     * Linux does not seem to have the concept of LD_PRELOAD_64 so if you
-       run on a mixed 64- and 32-bit ABI system (e.g. AMD x86_64) some of
-       the applications will fail to run because LD_PRELOAD will point to
-       libraries of the wrong wordsize.
-     * At some point we hope to fold some automation for esd or artsd ssh
-       redir setup into the Enhanced TightVNC Viewer (SSVNC) package we
-       provide (as of Sep/2006 it is there for testing.)
-
-
-   Q-130: Why don't I hear the "Beeps" in my X session (e.g. when typing
-   tput bel in an xterm)?
-
-   As of Dec/2003 "Beep" XBell events are tracked by default. The X
-   server must support the XKEYBOARD extension (this is not on by default
-   in Solaris, see Xserver(1) for how to turn it on via +kb), and so you
-   won't hear them if the extension is not present.
-
-   If you don't want to hear the beeps use the -nobell option. If you
-   want to hear the audio from the remote applications, consider trying a
-   redirector such as esd.
-
-
-   Q-131: Does x11vnc work with IPv6?
-
-   Update: as of Apr/2010 in the 0.9.10 x11vnc development tarball, there
-   is now built-in support for IPv6 (128 bit internet addresses.) See the
-   -6 and -connect options for details.
-
-   The remainder of this FAQ entry shows how to do with this with pre
-   0.9.10 x11vnc using IPv6 helper tools.
-     _________________________________________________________________
-
-   Using an external IPv6 helper:
-   A way to do this is via a separate helper program such as inetd (or
-   for encrypted connections: ssh or stunnel.) For example, you configure
-   x11vnc to be run from inetd or xinetd and instruct it to listen on an
-   IPv6 address. For xinetd the setting "flags = IPv6" will be needed.
-   For inetd.conf, an example is:
-  5900 stream tcp6 nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc_wrapper.sh
-
-   We also provide a transitional tool in "x11vnc/misc/inet6to4" that
-   acts as a relay for any IPv4 application to allow connections over
-   IPv6. For example:
-  inet6to4 5900 localhost:5900
-
-   where x11vnc is listening on IPv4 port 5900.
-
-   Also note that not all VNC Viewers are IPv6 enabled, so a redirector
-   may also be needed for them. The tool "inet6to4 -r ..." can do this as
-   well. SSVNC (see below) supports IPv6 without need for the helper.
-
-  # ./inet6to4 -help
-
-  inet6to4:  Act as an ipv6-to-ipv4 relay for tcp applications that
-             do not support ipv6.
-
-  Usage:     inet6to4
-             inet6to4 -r
-
-  Examples:  inet6to4 5900 localhost:5900
-             inet6to4 8080 web1:80
-             inet6to4 -r 5900 fe80::217:f2ff:fee6:6f5a%eth0:5900
-
-  The -r option reverses the direction of translation (e.g. for ipv4
-  clients that need to connect to ipv6 servers.)  Reversing is the default
-  if this script is named 'inet4to6' (e.g. by a symlink.)
-
-  Use Ctrl-C to stop this program.
-
-  You can also set env. vars INET6TO4_LOOP=1 or INET6TO4_LOOP=BG
-  to have an outer loop restarting this program (BG means do that
-  in the background), and INET6TO4_LOGFILE for a log file.
-  Also set INET6TO4_VERBOSE to verbosity level and INET6TO4_WAITTIME
-  and INET6TO4_PIDFILE (see below.)
-
-   The "INET6TO4_LOOP=BG" and "INET6TO4_LOGFILE=..." env. variables make
-   the tool run reliably as a daemon for very long periods. Read the top
-   part of the script for more information.
-     _________________________________________________________________
-
-   Encrypted Tunnels with IPv6 Support:
-   For SSH tunnelled encrypted VNC connections, one can of course use the
-   IPv6 support in ssh(1).
-
-   For SSL encrypted VNC connections, one possibility is to use the IPv6
-   support in stunnel(1). This includes the built-in support via the
-   -stunnel option. For example:
-  x11vnc -stunnel SAVE -env STUNNEL_LISTEN=:: -env STUNNEL_DEBUG=1 ...
-     _________________________________________________________________
-
-   SSH IPv6 Tricks:
-   It is interesting to note that ssh(1) can do basically the same thing
-   as inet6to4 above by:
-  ssh -g -L 5900:localhost:5901 localhost "printf 'Press Enter to Exit: '; read
- x"
-
-   (where we have x11vnc running via "-rfbport 5901" in this case.)
-
-   Note that one can also make a home-brew SOCKS5 ipv4-to-ipv6 gateway
-   proxy using ssh like this:
-  ssh -D '*:1080' localhost "printf 'Press Enter to Exit: '; read x"
-
-   then specify a proxy like socks://hostname:1080 where hostname is the
-   machine running the above ssh command (add -v to ssh for connection
-   logging info.)
-     _________________________________________________________________
-
-   IPv6 SSVNC Viewer:
-   Our SSVNC VNC Viewer is basically a wrapper for ssh(1) and stunnel(1),
-   and so it already has good IPv6 support because these two commands do.
-   On Unix, MacOSX, and Windows nearly all of the the remaining parts of
-   SSVNC (e.g. the built-in proxying and un-encrypted connections) have
-   been modified to support IPv6 in SSVNC 1.0.26.
-
-
-
-
-
-
-    Contributions:
-
-   Q-132: Thanks for your program or for your help! Can I make a
-   donation?
-
-   Please do (any amount is appreciated; very few have donated) and thank
-   you for your support! Click on the PayPal button below for more info.
-
-   [x-click-but04.gif]-Submit
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/chainingssh.html:
-
-
-     _________________________________________________________________
-
-   Chaining ssh's: Note that for use of a ssh gateway and -L redirection
-   to an internal host (e.g. "-L 5900:otherhost:5900") the VNC traffic
-   inside the firewall is not encrypted and you have to manually log into
-   otherhost to start x11vnc. Kyle Amon shows a method where you chain
-   two ssh's together that encrypts all network traffic and also
-   automatically starts up x11vnc on the internal workstation:
-#!/bin/sh
-#
-gateway="example.com"   # or "user@example.com"
-host="labyrinth"        # or "user@hostname"
-user="kyle"
-
-# Need to sleep long enough for all of the passwords and x11vnc to start up.
-# The </dev/null below makes the vncviewer prompt for passwd via popup window.
-#
-(sleep 10; vncviewer -encodings "copyrect tight zrle zlib hextile" \
-    localhost:0 </dev/null >/dev/null) &
-
-# Chain the vnc connection thru 2 ssh's, and connect x11vnc to user's display:
-#
-exec /usr/bin/ssh -t -L 5900:localhost:5900 $gateway \
-     /usr/bin/ssh -t -L 5900:localhost:5900 $host \
-     sudo /usr/bin/x11vnc -localhost -auth /home/$user/.Xauthority \
-         -rfbauth .vnc/passwd -display :0
-
-   Also note the use of sudo(1) to switch to root so that the different
-   user's .Xauthority file can be accessed. See the visudo(8) manpage for
-   details on how to set this up (remove the sudo if you do not want to
-   do this). One can also chain together ssh's for reverse connections
-   with vncviewers using the -listen option. For this case -R would
-   replace the -L (and 5500 the 5900, see the #2 example script above).
-   If the gateway machine's sshd is configured with GatewayPorts=no (the
-   default) then the double chaining of "ssh -R ..." will be required for
-   reverse connections to work.
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/miscbuild.html:
-
-
-     _________________________________________________________________
-
-   Misc. Build problems:   We collect here rare build problems some users
-   have reported and the corresponding workarounds. See also the FAQ's on
-   building.
-     _________________________________________________________________
-
-   ENV parameter: One user had a problem where the build script below was
-   failing because his work environment had the ENV variable set to a
-   script that was resetting his PATH so that gcc could no longer be
-   found. Make sure you do not have any ENV or BASH_ENV in your
-   environment doing things like that. Typing "unset ENV", etc. before
-   configuring and building should clear it.
-     _________________________________________________________________
-
-   Bash xpg: One user had his bash shell compiled with
-   --enable-xpg-echo-default that causes some strange behavior with
-   things like echo "\\1 ..." the configure script executes. In
-   particular instead of getting "\1" the non-printable character "^A" is
-   produced, and causes failures at compile time like:
-  ../rfb/rfbconfig.h:9:22: warning: extra tokens at end of #ifndef directive
-
-   The workaround is to configure like this:
-  env CONFIG_SHELL=/bin/sh /bin/sh ./configure
-
-   i.e. avoid using the bash with the misbehavior. A bug has been filed
-   against autoconf to guard against this.
-     _________________________________________________________________
-
-   AIX: one user had to add the "X11.adt" package to AIX to get build
-   header files like XShm.h, etc.
-     _________________________________________________________________
-
-   Ubuntu Feisty Fawn 7.04: In May/2007 one user said he needed to add
-   these packages to compile x11vnc on that Linux distro and version:
-  apt-get install build-essential make bin86 libjpeg62-dev libssl-dev libxtst-d
-ev
-
-   Note that Ubuntu is based on Debian, so perhaps this is the list
-   needed on Debian (testing?) as well. To build in Avahi (mDNS service
-   advertising) support it would appear that libavahi-client-dev is
-   needed as well.
-     _________________________________________________________________
-
-   Exceedingly slow compilation: x11vnc has a couple of files which
-   contain very large "case statements" (over 100 cases) that on some
-   platforms can take a very long time to compile (in extreme cases over
-   an hour). However on 32bit Linux with intel/amd processor and gcc
-   these files usually take less than 10 seconds to compile. For 64bit
-   systems using gcc the problem appears to be much worse.
-
-   The two files with the large number of cases, remote.c and x11vnc.c,
-   have no real need to be optimized (the code is used only very
-   infrequently). So it is fine to supply "-O0" (disables optimization)
-   to CFLAGS when compiling them. However, it is tricky with
-   autoconf/automake to do this (especially since both the compiler and
-   make versions have a big effect).
-
-   So if the compile times are getting too long for you for these two
-   files you will need to manually change some things. First, run
-   configure and when it has finished, edit the generated file
-   x11vnc/Makefile and put these lines at the very top:
-x11vnc-x11vnc.o :  CFLAGS += -O0
-x11vnc-remote.o :  CFLAGS += -O0
-
-   Those lines assume gnu make (gmake) is being used. If you are using
-   another make, say Solaris make, insert these instead:
-x11vnc-x11vnc.o := CFLAGS += -O0
-x11vnc-remote.o := CFLAGS += -O0
-
-   You could write a build shell script that modified the Makefile this
-   way before running make.
-
-   The "-O0" (note it is "capital Oh" followed by "zero") assumes the gcc
-   compiler. If you are using a different compiler you will need to find
-   the command line option to disable optimization, or otherwise have the
-   lines set CFLAGS to the empty string.
-     _________________________________________________________________
-
-   Broken Thread Local Storage on SuSE 9.2: Starting with x11vnc 0.9.8
-   the bundled libvncserver uses the __thread keyword to make some of the
-   encodings (i.e. tight) thread safe (multiple VNC clients can be using
-   tight at the same time in x11vnc -threads mode.) Evidently on the old
-   SuSE 9.2 system the compiler does not support the thread local storage
-   properly. Here is an example build failure:
-tight.c:1126: error: unrecognizable insn:
-(insn:HI 11 10 13 0 (nil) (set (reg/f:SI 59)
-        (const:SI (plus:SI (symbol_ref:SI ("%lpalette"))
-                (const_int 2048 [0x800])))) -1 (nil)
-    (expr_list:REG_EQUAL (const:SI (plus:SI (symbol_ref:SI ("%lpalette"))
-                (const_int 2048 [0x800])))
-        (nil)))
-tight.c:1126: internal compiler error: in extract_insn, at recog.c:2175
-Please submit a full bug report,
-with preprocessed source if appropriate.
-See URL:http://www.suse.de/feedback for instructions.
-
-   The workaround is to disable thread local storage at configure time
-   like this:
-env CPPFLAGS="-DTLS=''" ./configure
-
-   and then build it.
-     _________________________________________________________________
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/sunray.html:
-
-
-    Sun Ray Notes:
-
-   You can run x11vnc on your (connected or disconnected) SunRay session
-   (Please remember to use settings like -wait 200, -sb 15, and not
-   running a screensaver animation (blank instead) to avoid being a
-   resource hog! x11vnc does induce a lot of memory I/O from polling the
-   X server. It also helps to have a solid background color, e.g.
-   -solid).
-
-   News: Sun Ray Remote Control Toolkit: See the nice set of tools in the
-   Sun Ray Remote Control Toolkit that launch x11vnc automatically for
-   you for certain usage modes.
-
-   You have to know the name of the machine your SunRay session X server
-   is running on (so you can ssh into it and start x11vnc). You also need
-   to know the X11 DISPLAY number for the session: on a SunRay it could
-   be a large number, e.g. :137, since there are many people with X
-   sessions (Xsun processes) on the same machine. If you don't know it,
-   you can get it by running who(1) in a shell on the SunRay server and
-   looking for the dtlocal entry with your username (and if you don't
-   even know which server machine has your session, you could login to
-   all possible ones looking at the who output for your username...).
-
-   I put some code in my ~/.dtprofile script that stores $DISPLAY
-   (including the hostname) in a ~/.sunray_current file at session
-   startup (and deletes it when the X session ends) to make it easy to
-   get at the hostname and X11 display number info for my current X
-   sessions when I ssh in and am about to start x11vnc.
-
-   SunRay Gotcha #1:   Note that even though your SunRay X11 DISPLAY is
-   something like :137, x11vnc still tries for port 5900 as its listening
-   port if it can get it, in which case the VNC display (i.e. the
-   information you supply to the VNC viewer) is something like
-   sunray-server:0   (note the :0 corresponding to port 5900, it is not
-   :137). If it cannot get 5900, it tries for 5901, and so on. You can
-   also try to force the port (and thereby the VNC display) using the
-   -rfbport NNNN option.
-
-   Especially on a busy Sun Ray server it is often difficult to find free
-   ports for both VNC and the HTTP Java applet server to listen on. This
-   script, vnc_findports may be of use for doing this automatically. It
-   suggests x11vnc command line options based on netstat output that
-   lists the occupied ports. It is even more difficult to start
-   vncserver/Xvnc on a busy Sun Ray because then 3 ports (HTTP, VNC, and
-   X11), all separated by 100 are needed! This script, findvncports may
-   be helpful as well. Both scripts start at VNC display :10 and work
-   their way up.
-
-   SunRay Gotcha #2:   If you get an error like:
-        shmget(tile) failed.
-        shmget: No space left on device
-
-   when starting up x11vnc that most likely means all the shared memory
-   (shm) slots are filled up on your machine. The Solaris default is only
-   100, and that can get filled up in a week or so on a SunRay server
-   with lots of users. If the shm slot is orphaned (e.g. creator process
-   dies) the slot is not reclaimed. You can view the shm slots with the
-   "ipcs -mA" command. If there are about 100 then you've probably hit
-   this problem. They can be cleaned out (by the owner or by root) using
-   the ipcrm command. I wrote a script shm_clear that finds the orphans
-   and lists or removes them. Longer term, have your SunRay sysadmin add
-   something like this to /etc/system:
-        set shmsys:shminfo_shmmax = 0x2000000
-        set shmsys:shminfo_shmmni = 0x1000
-
-   SunRay Gotcha #3:   Some SunRay installations have implemented
-   suspending certain applications when a SunRay session is in a
-   disconnected state (e.g. Java Badge pulled out, utdetach, etc). This
-   is a good thing because it limits hoggy or runaway apps from wasting
-   the shared CPU resource. Think how much CPU and memory I/O is wasted
-   by a bunch of Firefox windows running worthless Flash animations while
-   your session is disconnected!
-
-   So some sites have implemented scripts to suspend (e.g. kill -STOP)
-   certain apps when your badge is removed from the SunRay terminal. When
-   you reattach, it kill -CONT them. This causes problems for viewing the
-   detached SunRay session via x11vnc: those suspended apps will not
-   respond (their windows will be blank or otherwise inactive).
-
-   What to do? Well, since you are going to be using the application you
-   might as well unfreeze it rather than starting up a 2nd instance. Here
-   is one way to do it using the kill -CONT mechanism:
-   kill -CONT `ps -ealf | grep ' T ' | grep $LOGNAME | awk '{print $4}'`
-
-   If you want to be a good citizen and re-freeze them before you exit
-   x11vnc this script could be of use:
-#!/bin/sh
-#
-# kill -STOP/-CONT script for x11vnc (or other) SunRay usage ("freezes"
-# certain apps from hogging resources when disconnected).
-#
-# Put here a pattern that matches the apps that are frozen:
-#
-appmatch="java_vm|jre|netscape-bin|firefox-bin|realplay|acroread|mozilla-bin"
-
-if [ "X$1" = "Xfreeze" ]; then
-        pkill -STOP -U $LOGNAME "$appmatch"
-elif [ "X$1" = "Xthaw" ]; then
-        pkill -CONT -U $LOGNAME "$appmatch"
-
-elif [ "$RFB_MODE" = "afteraccept" -a "$RFB_STATE" = "NORMAL" ]; then
-        # a valid x11vnc login.
-        if [ "$RFB_CLIENT_COUNT" = "1" ]; then
-                # only one client present.
-                pkill -CONT -U $LOGNAME "$appmatch"
-        fi
-elif [ "$RFB_MODE" = "gone" -a "$RFB_STATE" = "NORMAL" ]; then
-        # a valid x11vnc login.
-        if [ "$RFB_CLIENT_COUNT" = "0" ]; then
-                # last client present has just left.
-                pkill -STOP -U $LOGNAME "$appmatch"
-        fi
-fi
-exit 0
-
-   If you called the script "goodcitizen" you could type "goodcitizen
-   thaw" to unfreeze them, and then "goodcitizen freeze" to refreeze
-   them. One could also use these x11vnc options "-afteraccept
-   goodcitizen -gone goodcitizen" to do it automatically.
-
-   SunRay Gotcha #4:   Recent versions of the Sun Ray Server Software
-   SRSS (seems to be version 3.0 or 3.1) have a "misfeature" that when
-   the session is disconnected (i.e. badge/smartcard out) the screen
-   locker (xscreensaver) will freeze the X server just when the "Enter
-   Password" dialog box appears. So you cannot unlock the screen remotely
-   via x11vnc!
-
-   Update: please see Bob Doolittle's detailed description of the this
-   issue at the bottom of this section.
-
-   Here "freeze" means "stop other X clients from inserting keyboard and
-   mouse input and from viewing the current contents of the screen". Or
-   something like that; the upshot is x11vnc can't do its normal thing.
-
-   There are several workarounds for this.
-
-   1) The easiest one by far is to put these lines in your
-   $HOME/.dtprofile file:
-SUN_SUNRAY_UTXLOCK_PREF="/usr/openwin/bin/xlock -mode blank"
-export SUN_SUNRAY_UTXLOCK_PREF
-
-   One might argue that xlock isn't particularly "pretty". (Just IMHO,
-   but if something like this not being pretty actually gets in the way
-   of your work I think some introspection may be in order. :-)
-
-   2) The problem has been traced to the pam_sunray.so PAM module.
-   Evidently xscreensaver invokes this pam module and it communicates
-   with utsessiond who in turn instructs the Xsun server to not process
-   any synthetic mouse/keyboard input or to update the screen
-   framebuffer. It is not clear if this is by design (security?) or
-   something else.
-
-   In any event, the problem can be avoided, somewhat drastically, by
-   commenting out the corresponding line in /etc/pam.conf:
-#xscreensaver auth sufficient /opt/SUNWut/lib/pam_sunray.so syncondisplay
-
-   Leave the other xscreensaver pam authentication lines unchanged. The
-   dtsession-SunRay line may also need to be commented out to avoid the
-   problem for CDE sessions. N.B. it is possible the application of a
-   SSRS patch, etc, may re-enable that /etc/pam.conf line. It may be
-   difficult to convince a sysadmin to make this change.
-
-   3) A more forceful way is to kill the xscreensaver process from a
-   shell prompt whenever you connect via x11vnc and the screen is in a
-   locked state:
-pkill -U $LOGNAME '^xscreensaver$'
-
-   And then after you are in be sure to restart it by typing something
-   like:
-xscreensaver &
-
-   You may want to avoid restarting it until you are about to disconnect
-   your VNC viewer (since if it locks the screen while you are working
-   you'll be stuck again).
-
-   3') The above idea can be done a bit more cleanly by having x11vnc do
-   it. Suppose we called the following script xss_killer:
-#!/bin/sh
-#
-# xss_killer: kill xscreensaver after a valid x11vnc client logs in.
-#             Restart xscreensaver and lock it when the last client
-#             disconnects.
-
-PATH=/usr/openwin/bin:/usr/bin:$PATH
-export PATH
-
-if [ "$RFB_MODE" = "afteraccept" -a "$RFB_STATE" = "NORMAL" ]; then
-        # a valid x11vnc login.
-        if [ "$RFB_CLIENT_COUNT" = "1" ]; then
-                # only one client present.
-                pkill -U $LOGNAME '^xscreensaver$'
-                pkill -KILL -U $LOGNAME -f xscreensaver/hacks
-        fi
-elif [ "$RFB_MODE" = "gone" -a "$RFB_STATE" = "NORMAL" ]; then
-        # a valid x11vnc login.
-        if [ "$RFB_CLIENT_COUNT" = "0" ]; then
-                # last client present has just left.
-                xscreensaver -nosplash &
-                sleep 1
-                xscreensaver-command -lock &
-        fi
-fi
-
-   Then we would run x11vnc with these options: "-afteraccept xss_killer
-   -gone xss_killer". The -afteraccept option (introduced in version 0.8)
-   is used to run a command after a vncviewer has successfully logged in
-   (note that this is a VNC login, not a Unix login, so you may not want
-   to do this if you are really paranoid...)
-
-   Note if you use the above script and also plan to Ctrl-C (SIGINT)
-   x11vnc you have to run the xscreensaver in a new process group to
-   avoid killing it as well. One way to do this is via this kludge:
-perl -e 'setpgrp(0,0); exec "xscreensaver -nosplash &"'
-
-   in the above script.
-
-   4) There appears to be a bug in pam_sunray.so in that it doesn't seem
-   to honor the convention that, say, DISPLAY=unix:3 means to use Unix
-   sockets to connect to display 3 on the local machine (this is a bit
-   faster than TCP sockets). Rather, it thinks the display is a non-local
-   one to a machine named "unix" (that usually does not resolve to an IP
-   address).
-
-   Amusingly, this can be used to bypass the pam_sunray.so blocking of
-   Xsun that prevents one from unlocking the screen remotely via x11vnc.
-   One could put something like this in $HOME/.dtprofile to kill any
-   existing xscreensavers and then start up a fresh xscreensaver using
-   DISPLAY=unix:N
-# stop/kill any running xscreensavers (probably not running yet, but to be sure
-)
-xscreensaver-command -exit
-pkill -U $LOGNAME '^xscreensaver$'
-env DISPLAY=`echo $DISPLAY | sed -e 's/^.*:/unix:/'` xscreensaver &
-
-
-   Important: Note that all of the above workarounds side-step the
-   pam_sunray.so PAM module in one way or another. You'll need to see if
-   that is appropriate for your site's SunRay / smartcard usage. Also,
-   these hacks may break other things and so you may want to test various
-   scenarios carefully. E.g. check corner cases like XDMCP/dtremote,
-   NSCM, etc.
-
-
-   Update May 2008: Here is a useful description of this issue from Bob
-   Doolittle who is a developer for Sun Ray at Sun. I don't have the time
-   to digest and distill it and then adjust the above methods to provide
-   a clearer description, so I just include below the description he sent
-   me with the hope that it will help some users:
-
-     In SRSS 4.0 and earlier, the purpose of pam_sunray.so in the "auth"
-     PAM stack of screensavers is to enable NSCM (and, although this is
-     much less commonly used, "SC", which is configured when 3rd-party
-     software is installed to allow smartcards to be used as part of the
-     authentication process) to work. It should have no effect with
-     smartcards. Currently, however, it does block the PAM stack for all
-     sessions, which causes xscreensaver, when it locks a disconnected
-     session, to not process any mouse or keyboard events as you
-     describe (unless xscreensaver does an X server grab, however, other
-     applications should still be able to draw in the session although
-     xscreensaver may be playing tricks like putting a black window on
-     top of everything). In both of the NSCM and SC models,
-     authentication occurs in a separate session before SRSS will
-     reconnect to the user session, in which case pam_sunray.so causes
-     xscreensaver to just unlock the screen without prompting the user
-     to enter their password again. To do this, pam_sunray.so has to
-     block until the session becomes reconnected, so it can query SRSS
-     at that time to determine whether the user has already
-     authenticated or not. In SRSS 4.0 and earlier releases,
-     pam_sunray.so could have been optimized to not block smartcard
-     sessions, although since the session is disconnected this typically
-     isn't important (except in the x11vnc case, as you've observed).
-
-     In SRSS 4.1, however, for increased security the out-of-session
-     authentication model has been extended to *all* session types, so
-     pam_sunray.so will be required in all cases unless users are
-     willing to authenticate twice upon hotdesking (e.g. when their card
-     is inserted). In future, we may do away with pam_sunray.so, and in
-     fact with any traditional screen locker in the user session, since
-     SRSS itself will be providing better security than a screen locker
-     running entirely within the user's X session is capable of
-     providing.
-
-     Your trick of setting DISPLAY to unix:DPY will effectively disable
-     pam_sunray.so (I'm not sure I'd call that a bug - you're going out
-     of your way to do something that wouldn't occur in the normal
-     course of events, and really provides no useful value other than to
-     tickle this behavior in pam_sunray.so). This will mean that, in
-     SRSS 4.0 and earlier releases, users will be prompted for their
-     passwords twice when reconnecting to their sessions for NSCM and SC
-     session types. In 4.1, disabling pam_sunray.so in this way will
-     cause this double-authentication to occur for *all* sessions,
-     including simple smartcard sessions. Users may be willing to pay
-     that price in order to be able to use x11vnc in disconnected
-     sessions. I like this hack, personally. It's a little less
-     convenient than some of the other approaches you describe, but it's
-     lighter-weight and more secure than most of the other approaches,
-     and provides the value of being able to use x11vnc in locked
-     sessions.
-
-     Here are some other minor notes: - I wouldn't recommend storing
-     your display in your .dtprofile, unless you're willing to live with
-     a single session at a time. Personally, I often find myself using
-     several sessions, in several FoGs, for short periods of time so
-     this would certainly break. IMO it's pretty easy to use $DISPLAY to
-     do what you want on the fly, as needed, so I don't think the price
-     of breaking multiple-session functionality would be worth the
-     convenience, to me at least. Here's some ksh/bash syntax to extract
-     the hostname and display number on the fly which you may find
-     useful:
-HOSTNAME=${DISPLAY%:*}
-FULLDPY=${DISPLAY#*:}
-DPYNUM=${FULLDPY%.*}
-
-     A final note may give you some insight into other clever hacks in
-     this area: - Check out utaction. It's a very handy little utility
-     that can be run as a daemon in the user session which will invoke a
-     specified command upon session connects and/or disconnects.
-     Personally, I start one up in my .dtprofile as follows:
-utaction -c $HOME/.srconnectrc -d $HOME/.srdisconnectrc &
-
-     This then allows me to construct a .srconnectrc script containing
-     useful commands I'd like to have run every time I insert my
-     smartcard, and a .srdisconnectrc script of commands to be run every
-     time I remove my smartcard (or, connect/disconnect to my session
-     via NSCM or SC). This can be used for things like notifying a chat
-     client of away status, as well as some of the hacks you've
-     described on your page such as freeze/unfreeze, or perhaps to
-     terminate an xscreensaver and start up a new one with the unix:DPY
-     $DISPLAY specification as you describe (although it probably makes
-     most sense to do this at login time, as opposed to every connect or
-     disconnect event).
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/ssl.html:
-
-
-     _________________________________________________________________
-
-   Notes on x11vnc SSL Certificates and Key Management:
-
-   The simplest scheme ("x11vnc -ssl TMP") is where x11vnc generates a
-   temporary, self-signed certificate each time (automatically using
-   openssl(1)) and the VNC viewer client accepts the certificate without
-   question (e.g. user clicks "Yes" in a dialog box. Perhaps the dialog
-   allows them to view the certificate too). Also note stunnel's default
-   is to quietly accept all certificates.
-
-   The encryption this provides protects against all passive sniffing of
-   the VNC traffic and passwords on the network and so it is quite good,
-   but it does not prevent a Man-In-The-Middle active attack: e.g. an
-   attacker intercepts the VNC client stream and sends it his own Public
-   key for SSL negotiation (pretending to be the server). Then it makes a
-   connection to SSL x11vnc itself and forwards the data back and forth.
-   He can see all the traffic and modify it as well.
-
-   Most people don't seem to worry about Man-In-The-Middle attacks these
-   days; they are more concerned about passive sniffing of passwords,
-   etc. Perhaps someday that will change if attack tools are used more
-   widely to perform the attack. NOTE: There are hacker tools like
-   dsniff/webmitm and cain that implement SSL Man-In-The-Middle attacks.
-   They all rely on the client not bothering to check that the cert is
-   valid.
-
-   If you are not worried about Man-In-The-Middle attacks you do not have
-   to read the techniques described in the rest of this document.
-
-   To prevent Man-In-The-Middle attacks, certificates must somehow be
-   verified. This requires the VNC client side have some piece of
-   information that can be used to verify the SSL x11vnc server.
-   Alternatively, although rarely done, x11vnc can verify VNC Clients'
-   certificates, see the -sslverify option that is discussed below.
-
-   There are a number of ways to have the client authenticate the SSL
-   x11vnc server. The quickest way perhaps would be to copy (safely) the
-   certificate x11vnc prints out:
-26/03/2006 21:12:00 Creating a temporary, self-signed PEM certificate...
-...
------BEGIN CERTIFICATE-----
-MIIC4TCCAkqgAwIBAgIJAMnwCaOjvEKaMA0GCSqGSIb3DQEBBAUAMIGmMQswCQYD
-VQQGEwJBVTEOMAwGA1UEBxMFTGludXgxITAfBgNVBAsTGGFuZ2VsYS0xMTQzNDI1
-NTIwLjQxMTE2OTEPMA0GA1UEChMGeDExdm5jMS4wLAYDVQQDEyV4MTF2bmMtU0VM
-(more lines) ...
------END CERTIFICATE-----
-
-   to the client machine(s) and have the client's SSL machinery (e.g.
-   stunnel, Web Browser, or Java plugin) import the certificate. That way
-   when the connection to x11vnc is made the client can verify that is it
-   the desired server on the other side of the SSL connection.
-
-   So, for example suppose the user is using the SSL enabled Java VNC
-   Viewer and has incorporated the x11vnc certificate into his Web
-   browser on the viewing side. If he gets a dialog that the certificate
-   is not verified he knows something is wrong. It may be a
-   Man-In-The-Middle attack, but more likely x11vnc certificate has
-   changed or expired or his browser was reinstalled and/or lost the
-   certificate, etc, etc.
-
-   As another example, if the user was using stunnel with his VNC viewer
-   (this is mentioned in this FAQ), e.g. STUNNEL.EXE on Windows, then he
-   would have to set the "CAfile = path-to-the-cert" and "verify = 2"
-   options in the stunnel.conf file before starting up the tunnel. If a
-   x11vnc certificate cannot be verified, stunnel will drop the
-   connection (and print a failure message in its log file).
-
-   A third example, using the VNC viewer on Unix with stunnel the wrapper
-   script can be used this way: "ss_vncviewer -verify ./x11vnc.crt
-   far-away.east:0" where ./x11vnc.crt is the copied certificate x11vnc
-   printed out.
-
-   As fourth example, our SSVNC enhanced tightvnc viewer can also use
-   these certificate files for server authentication. You can load them
-   via the SSVNC 'Certs...' dialog and set 'ServerCert' to the
-   certificate file you safely copied there.
-
-   Note that in principle the copying of the certificate to the client
-   machine(s) itself could be altered by a Man-In-The-Middle attack! You
-   can't win; it is very difficult to be completely secure. It is
-   unlikely the attacker could predict how you were going to send it
-   unless you had, say, done it many times before the same way. SSH is a
-   very good way to send it (but of course it too depends on public keys
-   being sent unaltered between the two machines!).
-
-   If you are really paranoid, I'm sure you'll figure out a really good
-   way to transport the certificates. See the Certificate Authority
-   scheme below for a way to make this easier (you just have to do it
-   once).
-
-     _________________________________________________________________
-
-   Saving SSL certificates and keys:
-
-   Now, it would be very inconvenient to copy the new temporary
-   certificate every time x11vnc is run in SSL mode. So for convenience
-   there is the "SAVE" keyword to instruct x11vnc to save the certificate
-   it creates:
-  x11vnc -ssl SAVE -display :0 ...
-
-   This behavior is now the default, you must use "TMP" for a temporary
-   one. It will save the certificate and private key in these files:
-  ~/.vnc/certs/server.crt
-  ~/.vnc/certs/server.pem
-
-   The ".crt" file contains only the certificate and should be safely
-   copied to the VNC Viewer machine(s) that will be authenticating the
-   x11vnc server. The ".pem" file contains both the certificate and the
-   private key and should be kept secret. (If you don't like the default
-   location ~/.vnc/certs, e.g. it is on an NFS share and you are worried
-   about local network sniffing, use the -ssldir dir option to point to a
-   different directory.)
-
-   So the next time you run "x11vnc -ssl SAVE ..." it will read the
-   server.pem file directly instead of creating a new one.
-
-   You can manage multiple SSL x11vnc server keys in this simple way by
-   using:
-  x11vnc -ssl SAVE-key2 -display :0 ...
-
-   etc, where you put whatever name you choose for the key after "SAVE-".
-   E.g. "-ssl SAVE-fred".
-
-   Also, if you want to be prompted to possibly change the made up names,
-   etc. that x11vnc creates (e.g. "x11vnc-SELF-SIGNED-CERT-7762" for the
-   CommonName) for the certificates distinguished name (DN), then use
-   "x11vnc -ssl SAVE_PROMPT ...", "x11vnc -ssl SAVE_PROMPT-fred ..." etc.
-   when you create the key the first time.
-
-   Tip: when prompting, if you choose the CommonName entry to be the full
-   internet hostname of the machine the clients will be connecting to
-   then that will avoid an annoying dialog box in their Web browsers that
-   warn that the CommonName doesn't match the hostname.
-
-     _________________________________________________________________
-
-   Passphrases for server keys:
-
-   Well, since now with the "SAVE" keyword the certificate and key will
-   be longer lived, one can next worry about somebody stealing the
-   private key and pretending to be the x11vnc server! How to guard
-   against this?
-
-   The first is that the file is created with perms 600 (i.e. -rw-------)
-   to make it harder for an untrusted user to copy the file. A better way
-   is to also encrypt the private key with a passphrase. You are prompted
-   whether you want to do this or not when the key is first created under
-   "-ssl SAVE" mode ("Protect key with a passphrase? y/n"). It is
-   suggested that you use a passphrase. The inconvenience is every time
-   you run "x11vnc -ssl SAVE ..." you will need to supply the passphrase
-   to access the private key:
-  06/04/2006 11:39:11 using PEM /home/runge/.vnc/certs/server.pem  0.000s
-
-  A passphrase is needed to unlock an OpenSSL private key (PEM file).
-  Enter passphrase>
-
-   before x11vnc can continue.
-
-     _________________________________________________________________
-
-   Being your own Certificate Authority:
-
-   A very sophisticated way that scales well if the number of users is
-   large is to use a Certificate Authority (CA) whose public certificate
-   is available to all of the VNC clients and whose private key has been
-   used to digitally sign the x11vnc server certificate(s).
-
-   The idea is as follows:
-     * A special CA cert and key is generated.
-     * Its private key is always protected by a good passphrase since it
-       is only used for signing.
-     * The CA cert is (safely) distributed to all machines where VNC
-       clients will run.
-     * One or more x11vnc server certs and keys are generated.
-     * The x11vnc server cert is signed with the CA private key.
-     * x11vnc is run using the server key. (e.g. "-ssl SAVE")
-     * VNC clients (viewers) can now authenticate the x11vnc server
-       because they have the CA certificate.
-
-   The advantage is the CA cert only needs to be distributed once to the
-   various machines, that can be done even before x11vnc server certs are
-   generated.
-
-   As above, it is important the CA private key and the x11vnc server key
-   are kept secret, otherwise someone could steal them and pretend to be
-   the CA or the x11vnc server if they copied the key. It is recommended
-   that the x11vnc server keys are also protected via a passphrase (see
-   the previous section).
-
-   Optionally, VNC viewer certs and keys could also be generated to
-   enable the x11vnc server to authenticate each client. This is not
-   normally done (usually a simple viewer password scheme is used), but
-   this can be useful in some situations. These optional steps go like
-   this:
-     * One or more VNC client certs and keys are generated.
-     * These VNC client certs are signed with the CA private key.
-     * The VNC client certs+keys are safely distributed to the
-       corresponding client machines.
-     * x11vnc is told to verify clients by using the CA cert. (e.g.
-       "-sslverify CA")
-     * When VNC clients (viewers) connect, they must authenticate
-       themselves to x11vnc by using their client key.
-
-   Again, it is a good idea if the client private keys are protected with
-   a passphrase, otherwise if stolen they could be used to gain access to
-   the x11vnc server. Once distributed to the client machines, there is
-   no need to keep the client key on the CA machine that generated and
-   signed it. You can keep the client certs if you like because they are
-   public.
-
-     _________________________________________________________________
-
-   How to do the above CA steps with x11vnc:
-
-   Some utility commands are provided to ease the cert+key creation,
-   signing, and management: -sslGenCA, -sslGenCert, -sslDelCert,
-   -sslEncKey, -sslCertInfo. They basically run the openssl(1) command
-   for you to manage the certs/keys. It is required that openssl(1) is
-   installed on the machine and available in PATH. All commands can be
-   pointed to an alternate toplevel certificate directory via the -ssldir
-   option if you don't want to use the default ~/.vnc/certs.
-
-   1) To generate your Certificate Authority (CA) cert and key run this:
-  x11vnc -sslGenCA
-
-   Follow the prompts, you can modify any informational strings you care
-   to. You will also be required to encrypt the CA private key with a
-   passphrase. This generates these files:
-  ~/.vnc/certs/CA/cacert.pem             (the CA public certificate)
-  ~/.vnc/certs/CA/private/cakey.pem      (the encrypted CA private key)
-
-   If you want to use a different directory use -ssldir It must supplied
-   with all subsequent SSL utility options to point them to the correct
-   directory.
-
-   2) To generate a signed x11vnc server cert and key run this:
-  x11vnc -sslGenCert server
-
-   As with the CA generation, follow the prompts and you can modify any
-   informational strings that you care to. This will create the files:
-  ~/.vnc/certs/server.crt             (the server public certificate)
-  ~/.vnc/certs/server.pem             (the server private key + public cert)
-
-   It is recommended to protect the server private key with a passphrase
-   (you will be prompted whether you want to). You will need to provide
-   it whenever you start x11vnc using this key.
-
-   3) Start up x11vnc using this server key:
-  x11vnc -ssl SAVE -display :0 ...
-
-   (SAVE corresponds to server.pem, see -sslGenCert server somename info
-   on creating additional server keys, server-somename.crt ...)
-
-   4) Next, safely copy the CA certificate to the VNC viewer (client)
-   machine(s). Perhaps:
-  scp ~/.vnc/CA/cacert.pem clientmachine:.
-
-   5) Then the tricky part, make it so the SSL VNC Viewer uses this
-   certificate! There are a number of ways this might be done, it depends
-   on what your client and/or SSL tunnel is. Some examples:
-
-   For the SSL Java VNC viewer supplied with x11vnc in
-   classes/ssl/VncViewer.jar or classes/ssl/SignedVncViewer.jar:
-     * Import the cacert.pem cert into your Web Browser (e.g. Edit ->
-       Preferences -> Privacy & Security -> Manage Certificates ->
-       WebSites -> Import)
-     * Or Import the cacert.pem cert into your Java Plugin (e.g. run
-       ControlPanel, then Security -> Certificates -> Secure Site ->
-       Import)
-
-   When importing, one would give the browser/java-plugin the path to the
-   copied cacert.pem file in some dialog. Note that the Web browser or
-   Java plugin is used for the server authentication. If the user gets a
-   "Site not verified" message while connecting he should investigate
-   further.
-
-   For the use of stunnel (e.g. on Windows) one would add this to the
-   stunnel.conf:
-  # stunnel.conf:
-  client = yes
-  options = ALL
-  CAfile = /path/to/cacert.pem          # or maybe C:\path\to\cacert.pem
-  [myvncssl]
-  accept = 5901
-  connect = far-away.east:5900
-
-   (then point the VNC viewer to localhost:1).
-
-   Here is an example for the Unix stunnel wrapper script ss_vncviewer in
-   our SSVNC package:
-  ss_vncviewer -verify ./cacert.pem far-away.east:0
-
-   Our SSVNC enhanced tightvnc viewer GUI can also use the certificate
-   file for server authentication. You can load it via the SSVNC
-   'Certs...' dialog and set 'ServerCert' to the cacert.pem file you
-   safely copied there.
-
-     _________________________________________________________________
-
-   Tricks for server keys:
-
-   To create additional x11vnc server keys do something like this:
-  x11vnc -sslGenCert server myotherkey
-
-   and use it this way:
-  x11vnc -ssl SAVE-myotherkey ...
-
-   The files will be ~/.vnc/certs/server-myotherkey.{crt,pem}
-
-   You can also create a self-signed server key:
-  x11vnc -sslGenCert server self:third_key
-
-   and use it this way:
-  x11vnc -ssl SAVE-self:third_key ...
-
-   This key is not signed by your CA. This can be handy to have a key set
-   separate from your CA when you do not want to create a 2nd CA
-   cert+key.
-
-     _________________________________________________________________
-
-   Using external CA's:
-
-   You don't have to use your own CA cert+key, you can use a third
-   party's instead. Perhaps you have a company-wide CA or you can even
-   have your x11vnc certificate signed by a professional CA (e.g.
-   www.thawte.com or www.verisign.com or perhaps the free certificate
-   service www.startcom.org or www.cacert.org).
-
-   The advantage to doing this is that the VNC client machines will
-   already have the CA certificates installed and you don't have to
-   install it on each machine.
-
-   To generate an x11vnc server cert+key this way you should generate a
-   "request" for a certicate signing something like this (we use the name
-   "external" in this example, it could be anything you want):
-  x11vnc -sslGenCert server req:external
-
-   This will create the request file:
-  ~/.vnc/certs/server-req:external.req
-
-   Which you should send to the external CA. When you get the signed
-   certificate back from them, save it in the file:
-  ~/.vnc/certs/server-req:external.crt
-
-   and create the .pem this way:
-  mv  ~/.vnc/certs/server-req:external.key    ~/.vnc/certs/server-req:external.
-pem
-  chmod 600 ~/.vnc/certs/server-req:external.pem
-  cat ~/.vnc/certs/server-req:external.crt >> ~/.vnc/certs/server-req:external.
-pem
-
-   You also rename the two files (.crt and .pem) to have a shorter
-   basename if you like. E.g.:
-  mv  ~/.vnc/certs/server-req:external.pem  ~/.vnc/certs/server-ext.pem
-  mv  ~/.vnc/certs/server-req:external.crt  ~/.vnc/certs/server-ext.crt
-
-   and the use via "x11vnc -ssl SAVE-ext ...", etc.
-
-   On the viewer side make sure the external CA's certificate is
-   installed an available for the VNC viewer software you plan to use.
-
-     _________________________________________________________________
-
-   Using Client Keys for Authentication:
-
-   You can optionally create certs+keys for your VNC client machines as
-   well. After distributing them to the client machines you can have
-   x11vnc verify the clients using SSL. Here is how to do this:
-
-  x11vnc -sslGenCert client dilbert
-  x11vnc -sslGenCert client wally
-  x11vnc -sslGenCert client alice
-  ...
-
-   As usual, follow the prompts if you want to change any of the info
-   field values. As always, it is a good idea (although inconvenient) to
-   protect the private keys with a passphrase. These files are created:
-  ~/.vnc/certs/clients/dilbert.crt
-  ~/.vnc/certs/clients/dilbert.pem
-  ...
-
-   Note that these are kept in a clients subdirectory.
-
-   Next, safely copy the .pem files to each corresponding client machine
-   and incorporate them into the VNC viewer / SSL software (see the ideas
-   mentioned above for the CA and server keys). The only difference is
-   these certificates might be referred to as "My Certificates" or
-   "Client Certificates". They are used for client authentication (which
-   is relatively rare for SSL).
-
-   After copying them you can delete the clients/*.pem files for extra
-   safety because the private keys are not needed by the x11vnc server.
-   You don't really need the clients/*.crt files either (because they
-   have been signed by the CA). But they could come in handy for tracking
-   or troubleshooting, etc.
-
-   Now start up x11vnc and instruct it to verify connecting clients via
-   SSL and the CA cert:
-  x11vnc -ssl SAVE -sslverify CA
-
-   The "CA" special token instructs x11vnc to use its CA signed certs for
-   verification.
-
-   For arbitrary self-signed client certificates (no CA) it might be
-   something like this:
-  x11vnc -ssl SAVE -sslverify path/to/client.crt
-  x11vnc -ssl SAVE -sslverify path/to/client-hash-dir
-  x11vnc -ssl SAVE -sslverify path/to/certs.txt
-
-   Where client.crt would be an individual client certificate;
-   client-hash-dir a directory of file names based on md5 hashes of the
-   certs (see -sslverify); and certs.txt signifies a single file full of
-   client certificates.
-
-   Finally, connect with your VNC viewer using the key. Here is an
-   example for the Unix stunnel wrapper script ss_vncviewer: using client
-   authentication (and the standard server authentication with the CA
-   cert):
-  ss_vncviewer -mycert ./dilbert.pem -verify ./cacert.pem far-away.east:0
-
-   Our SSVNC enhanced tightvnc viewer can also use these openssl .pem
-   files (you can load them via Certs... -> MyCert dialog).
-
-   It is also possible to use -sslverify on a per-client key basis, and
-   also using self-signed client keys (x11vnc -sslGenCert client
-   self:dilbert)
-
-   Now a tricky part is to get Web browsers or Java Runtime to import and
-   use the openssl .pem cert+key files. See the next paragraph on how to
-   convert them to pkcs12 format. If you find a robust way to import them
-   and and get them to use the cert please let us know!
-
-   Here is how to convert our openssl crt/pem files to pkcs12 format
-   (contains both the client certificate and key) that can be read by Web
-   browsers and Java for use in client authentication:
-  openssl pkcs12 -export -in mycert.crt -inkey mycert.pem -out mycert.p12
-
-   it will ask for a passphrase to protect mycert.p12. Some software
-   (e.g. Java ControlPanel) may require a non-empty passphrase. Actually,
-   since our .pem contains both the certificate and private key, you
-   could just supply it for the -in and remove the -inkey option. It
-   appears that for certificates only importing, our .crt file is
-   sufficient and can be read by Mozilla/Firefox and Java...
-
-   If you have trouble getting your Java Runtime to import and use the
-   cert+key, there is a workaround for the SSL-enabled Java applet. On
-   the Web browser URL that retrieves the VNC applet, simply add a
-   "/?oneTimeKey=..." applet parameter (see ssl-portal for more details
-   on applet parameters; you don't need to do the full portal setup
-   though). The value of the oneTimeKey will be the very long string that
-   is output of the onetimekey program found in the classes/ssl x11vnc
-   directory. Or you can set oneTimeKey=PROMPT in which case the applet
-   will ask you to paste in the long string. These scheme is pretty ugly,
-   but it works. A nice application of it is to make one time keys for
-   users that have already logged into a secure HTTPS site via password.
-   A cgi program then makes a one time key for the logged in user to use:
-   it is passed back over HTTPS as the applet parameter in the URL and so
-   cannot be sniffed. x11vnc is run to use that key via -sslverify.
-
-   Update: as of Apr 2007 in the 0.9.1 x11vnc tarball there is a new
-   option setting "-users sslpeer=" that will do a switch user much like
-   -unixpw does, but this time using the emailAddress field of the
-   Certificate subject of the verified Client. This mode requires
-   -sslverify turned on to verify the clients via SSL. This mode can be
-   useful in situations using -create or -svc where a new X server needs
-   to be started up as the authenticated user (but unlike in -unixpw
-   mode, the unix username is not obviously known).
-
-     _________________________________________________________________
-
-   Revoking Certificates:
-
-   A large, scaled-up installation may benefit from being able to revoke
-   certificates (e.g. suppose a user's laptop with a vnc client or server
-   key is compromised.) You can use this option with x11vnc: -sslCRL. See
-   the info at that link for a guide on what openssl(1) commands you will
-   need to run to revoke a certificate.
-
-     _________________________________________________________________
-
-   Additional utlities:
-
-   You can get information about your keys via -sslCertInfo. These lists
-   all your keys:
-  x11vnc -sslCertInfo list
-  x11vnc -sslCertInfo ll
-
-   (the latter is long format).
-
-   These print long output, including the public certificate, for
-   individual keys:
-  x11vnc -sslCertInfo server
-  x11vnc -sslCertInfo dilbert
-  x11vnc -sslCertInfo all             (every key, very long)
-
-   If you want to add a protecting passphrase to a key originally created
-   without one:
-  x11vnc -sslEncKey SAVE
-  x11vnc -sslEncKey SAVE-fred
-
-   To delete a cert+key:
-  x11vnc -sslDelCert SAVE
-  x11vnc -sslDelCert SAVE-fred
-  x11vnc -sslDelCert wally
-
-   (but rm(1) will be just as effective).
-
-     _________________________________________________________________
-
-   Chained Certificates:
-
-   There is increasing interest in using chained CA's instead of a single
-   CA. The merits of using chained CA's are not described here besides to
-   say its use may make some things easier when a certificate needs to be
-   revoked.
-
-   x11vnc supports chained CA certificates. We describe a basic use case
-   here.
-
-   Background: Of course the most straight forward way to use SSL with
-   x11vnc is to use no CA at all (see above): a self-signed certificate
-   and key is used and its certificate needs to be safely copied to the
-   client side. This is basically the same as the SSH style of managing
-   keys. Next level up, one can use a single CA to sign server keys: then
-   only the CA's certificate needs to be safely copied to the client
-   side, this can happen even before any server certs are created (again,
-   see all of the discussion above.)
-
-   With a certificate chain there are two or more CA's involved. Perhaps
-   it looks like this:
-  root_CA ---> intermediate_CA ---> server_cert
-
-   Where the arrow basically means "signs".
-
-   In this usage mode the client (viewer-side) will have root_CA's
-   certificate available for verifying (and nothing else.) If the viewer
-   only received server_cert's certificate, it would not have enough info
-   to verify the server. The client needs to have intermediate_CA's cert
-   as well. The way to do this with x11vnc (i.e. an OpenSSL using app) is
-   to concatenate the server_cert's pem and the intermediate_CA's
-   certificate together.
-
-   For example, suppose the file intermediate_CA.crt had
-   intermediate_CA's certificate. And suppose the file server_cert.pem
-   had the server's certificate and private key pair as described above
-   on this page. We need to do this:
-  cat intermediate_CA.crt >> server_cert.pem
-
-   (Note: the order of the items inside the file matters; intermediate_CA
-   must be after the server key and cert) and then we run x11vnc like
-   this:
-  x11vnc -ssl ./server_cert.pem ...
-
-   Then, on the VNC viewer client side, the viewer authenticates the
-   x11vnc server by using root_CA's certificate. Suppose that is in a
-   file named root_CA.crt, then using the SSVNC wrapper script
-   ss_vncviewer (which is also included in the SSVNC package) as our
-   example, we have:
-  ss_vncviewer -verify ./root_CA.crt hostname:0
-
-   (where "hostname" is the machine where x11vnc is running.) One could
-   also use the SSVNC GUI setting Certs -> ServerCert to the root_CA.crt
-   file. Any other SSL enabled VNC viewer would use root_CA.crt in a
-   similar way.
-     _________________________________________________________________
-
-   Creating Chained Certificates:
-
-   Here is a fun example using VeriSign's "Trial Certificate" program.
-   Note that VeriSign has a Root CA and also an Intermediate CA and uses
-   the latter to sign customers certificates. So this provides an easy
-   way to test out the chained certificates mechanism with x11vnc.
-
-   First we created a test x11vnc server key:
-  openssl genrsa -out V1.key 1024
-
-   then we created a certificate signing request (CSR) for it:
-  openssl req -new -key V1.key -out V1.csr
-
-   (we followed the prompts and supplied information for the various
-   fields.)
-
-   Then we went to VeriSign's page http://www.verisign.com/ssl/index.html
-   and clicked on "FREE TRIAL" (the certificate is good for 14 days.) We
-   filled in the forms and got to the point where it asked for the CSR
-   and so we pasted in the contents of the above V1.csr file. Then, after
-   a few more steps, VeriSign signed and emailed us our certificate.
-
-   The VeriSign Trial certificates were found here:
-  http://www.verisign.com/support/verisign-intermediate-ca/Trial_Secure_Server_
-Root/index.html
-  http://www.verisign.com/support/verisign-intermediate-ca/trial-secure-server-
-intermediate/index.html
-
-   The former was pasted into a file V-Root.crt and the latter was pasted
-   into V-Intermediate.crt
-
-   We pasted our Trial certificate that VeriSign signed and emailed to us
-   into a file named V1.crt and then we typed:
-  cat V1.key V1.crt > V1.pem
-  cat V1.pem V-Intermediate.crt > V1-combined.pem
-  chmod 600 V1.pem V1-combined.pem
-
-   So now the file V1-combined.pem has our private key and (VeriSign
-   signed) certificate and VeriSign's Trial Intermediate certificate.
-
-   Next, we start x11vnc:
-  x11vnc -ssl ./V1-combined.pem ...
-
-   and finally, on the viewer side (SSVNC wrapper script example):
-  ss_vncviewer -verify ./V-Root.crt hostname:0
-
-   One will find that only that combination of certs and keys will work,
-   i.e. allow the SSL connection to be established. Every other
-   combination we tried failed (note that ss_vncviewer uses the external
-   stunnel command to handle the SSL so we are really testing stunnel's
-   SSL implementation on the viewer side); and so the system works as
-   expected.
-     _________________________________________________________________
-
-   VNC Client Authentication using Certificate Chains:
-
-   Now, going the other way around with the client authenticating himself
-   via this chain of SSL certificates, x11vnc is run this way:
-  x11vnc -ssl SAVE -sslverify ./V-Root.crt ...
-
-   (note since the server must always supply a cert, we use its normal
-   self-signed, etc., one via "-ssl SAVE" and use the VeriSign root cert
-   for client authentication via -sslverify. The viewer must now supply
-   the combined certificates, e.g.:
-  ss_vncviewer -mycert ./V1-combined.pem hostname:0
-     _________________________________________________________________
-
-   Using OpenSSL and x11vnc to create Certificate Chains:
-
-   Although the x11vnc CA mechanism (-sslGenCA and -sslGenCert; see
-   above) was designed to only handle a single root CA (to sign server
-   and/or client certs) it can be coerced into creating a certificate
-   chain by way of an extra openssl(1) command.
-
-   We will first create two CA's via -sslGenCA; then use one of these CA
-   to sign the other; create a new (non-CA) server cert; and append the
-   intermediate CA's cert to the server cert to have everything needed in
-   the one file.
-
-   Here are the commands we ran to do what the previous paragraph
-   outlines.
-
-   First we create the two CA's, called CA_root and CA_Intermediate here,
-   in separate directories via x11vnc:
-  x11vnc -ssldir ~/CA_Root -sslGenCA
-     (follow the prompts, we included "CA_Root", e.g. Common Name, to aid ident
-ifying it)
-
-  x11vnc -ssldir ~/CA_Intermediate -sslGenCA
-     (follow the prompts, we included "CA_Intermediate", e.g. Common Name, to a
-id identifying it)
-
-   Next backup CA_Intermediate's cert and then sign it with CA_Root:
-  mv ~/CA_Intermediate/CA/cacert.pem ~/CA_Intermediate/CA/cacert.pem.ORIG
-  cd ~/CA_Root
-  openssl ca -config ./CA/ssl.cnf -policy policy_anything -extensions v3_ca -no
-text -ss_cert ~/CA_Intermediate/CA/cacert.pem.ORIG -out ~/CA_Intermediate/CA/ca
-cert.pem
-
-   Note that it is required to cd to the ~/CA_Root directory and run the
-   openssl command from there.
-
-   You can print out info about the cert you just modified by:
-  openssl x509 -noout -text -in ~/CA_Intermediate/CA/cacert.pem
-
-   Now we create an x11vnc server cert named "test_chain" that is signed
-   by CA_Intermediate:
-  x11vnc -ssldir ~/CA_Intermediate -sslGenCert server test_chain
-     (follow the prompts)
-
-   You can print out information about this server cert just created via
-   this command:
-  x11vnc -ssldir ~/CA_Intermediate -sslCertInfo SAVE-test_chain
-
-   This will tell you the full path to the server certificate, which is
-   needed because we need to manually append the CA_Intermediate cert for
-   the chain to work:
-  cat ~/CA_Intermediate/CA/cacert.pem >> ~/CA_Intermediate/server-test_chain.pe
-m
-
-   Now we are finally ready to use it. We can run x11vnc using this
-   server cert+key by either this command:
-  x11vnc -ssldir ~/CA_Intermediate -ssl SAVE-test_chain ...
-
-   or this command:
-  x11vnc -ssl ~/CA_Intermediate/server-test_chain.pem ...
-
-   since they are equivalent (both load the same pem file.)
-
-   Finally we connect via VNC viewer that uses CA_Root to verify the
-   server. As before we use ss_vncviewer:
-  ss_vncviewer -verify ~/CA_Root/CA/cacert.pem hostname:0
-
-   Client Certificates (see above) work in a similar manner.
-
-   So although it is a little awkward with the extra steps (e.g.
-   appending the CA_Intermediate cert) it is possible. If you want to do
-   this entirely with openssl(1) you will have to learn the openssl
-   commands corresponding to -genCA and -genCert. You may be able to find
-   guides on the Internet to do this. Starting with x11vnc 0.9.10, you
-   can have it print out the wrapper scripts it uses via: -sslScripts
-   (you will still need to fill in a few pieces of information; ask if it
-   is not clear from the source code.)
-
-     _________________________________________________________________
-
-   More info:
-
-   See also this article for some some general info and examples using
-   stunnel and openssl on Windows with VNC. Also
-   http://www.stunnel.org/faq/certs.html is a very good source of
-   information on SSL certificate creation and management.
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/ssl-portal.html:
-
-
-     _________________________________________________________________
-
-   Using Apache as an SSL Gateway to multiple x11vnc servers inside a
-   firewall:
-
-   Background:
-
-   The typical way to allow access to x11vnc (or any other VNC server)
-   running on multiple workstations inside a firewall is via SSH. The
-   user somewhere out on the Internet logs in to the SSH gateway machine
-   and uses port forwarding (e.g. ssh -t -L 5900:myworkstation:5900
-   user@gateway) to set up the encrypted channel that VNC is then
-   tunneled through. Next he starts up the VNC viewer on the machine
-   where he is sitting directed to the local tunnel port (e.g.
-   localhost:0).
-
-   The SSH scheme is nice because it is a widely used and well tested
-   login technique for users connecting to machines inside their company
-   or home firewall. For VNC access it is a bit awkward, however, because
-   SSH needs to be installed on the Viewer machine and the user usually
-   has to rig up his own port redirection plumbing (however, see our
-   other tool).
-
-   Also, some users have restrictive work environments where SSH and
-   similar applications are prohibited (i.e. only outgoing connections to
-   standard WWW ports from a browser are allowed, perhaps mediated by a
-   proxy server). These users have successfully used the method described
-   here for remote access.
-
-   With the SSL support in x11vnc and the SSL enabled Java VNC viewer
-   applet, a convenient and secure alternative exists that uses the
-   Apache webserver as a gateway. The idea is that the company or home
-   internet connection is already running apache as a web server (either
-   SSL or non-SSL) and we add to it the ability to act as a gateway for
-   SSL VNC connections. The only thing needed on the Viewer side is a
-   Java enabled Web Browser: the user simply enters a URL that starts the
-   entire VNC connection process. No VNC or SSH specific software needs
-   to be installed on the viewer side machine.
-
-   The stunnel VNC viewer stunnel wrapper script provided (ss_vncviewer)
-   can also take advantage of the method described here with its -proxy
-   option.
-
-     _________________________________________________________________
-
-   Simpler Solutions: This apache SSL VNC portal solution may be too much
-   for you. It is mainly intended for automatically redirecting to
-   MULTIPLE workstations inside the firewall. If you only have one or two
-   inside machines that you want to access, the method described here is
-   overly complicated! See below for some simpler (and still non-SSH)
-   encrypted setups.
-
-   Also see the recent (Mar/2010) desktop.cgi x11vnc desktop web login
-   CGI script that achieves much of what the method describes here
-   (especially if its 'port redirection' feature is enabled.)
-     _________________________________________________________________
-
-
-
-   There are numerous ways to achieve this with Apache. We present one of
-   the simplest ones here.
-
-   Important: these sorts of schemes allow incoming connections from
-   anywhere on the Internet to fixed ports on machines inside the
-   firewall. Care must be taken to implement and test thoroughly. If one
-   is paranoid one can (and should) add extra layers of protection. (e.g.
-   extra passwords, packet filtering, SSL certificate verification, etc).
-
-   Also, it is easy to miss the point that unless precautions are taken
-   to verify SSL Certificates, then the VNC Viewer is vulnerable to
-   man-in-the-middle attacks (but not to the more common passive sniffing
-   attacks). Note that there are hacker tools like dsniff/webmitm and
-   cain that implement SSL Man-In-The-Middle attacks. They rely on the
-   client not bothering to check the cert.
-     _________________________________________________________________
-
-   The Holy Grail: a single https port (443)
-
-   Before we discuss the self-contained apache examples here, we want to
-   mention that many x11vnc users who read this page and implement the
-   apache SSL VNC portal ask for something that (so far) seems difficult
-   or impossible to do entirely inside apache:
-     * A single port, 443 (the default https:// port), is open to the
-       Internet
-     * It is HTTPS/SSL encrypted
-     * It handles both VNC traffic and Java VNC Applet downloads.
-     * And the server can also serve normal HTTPS webpages, CGI, etc.
-
-   It is the last item that makes it tricky (otherwise the method
-   described on this page will work). If you are interested in such a
-   solution and are willing to run a separate helper program
-   (connect_switch) look here. Also, see this apache patch.
-     _________________________________________________________________
-
-   Example:
-
-   The scheme described here sets up apache on the firewall/gateway as a
-   regular Web proxy into the intranet and allows connections to a single
-   fixed port on a limited set of machines.
-
-   The configuration described in this section does not use the mod_ssl
-   apache module (the optional configuration described in the section
-   "Downloading the Java applet to the browser via HTTPS" does take
-   advantage of mod_ssl)
-
-   In this example suppose the gateway machine running apache is named
-   "www.gateway.east" (e.g. it may also provide normal web service). We
-   also choose the Internet-facing port for this VNC service to be port
-   563. One could choose any port, including the default HTTP port 80.
-
-   Detail: We choose 563 because it is the rarely used SNEWS port that is
-   often allowed by Web proxies for the CONNECT method. The idea is the
-   user may be coming out of another firewall using a proxy (not the one
-   we describe here, that is, the case when two proxies are involved,
-   e.g. one at work and another Apache (described here) at home
-   redirecting into our firewall; the "double proxy" or "double firewall"
-   problem). Using port 563 simplifies things because CONNECT's to it are
-   usually allowed by default.
-
-   We also assume all of the x11vnc servers on the internal machines are
-   all listening on port 5915 ("-rfbport 5915") instead of the default
-   5900. This is to limit any unintended proxy redirections to a lesser
-   used port, and also to stay out of the way of normal VNC servers on
-   the same machines. One could obviously implement a scheme that handles
-   different ports, but we just discuss this simple setup here.
-
-   So we basically assume x11vnc has been started this way on all of the
-   workstations to be granted VNC access:
-  x11vnc -ssl SAVE -http -display :0 -forever -rfbauth ~/.vnc/passwd -rfbport 5
-915
-
-   i.e. we force SSL VNC connections, port 5915, serve the Java VNC
-   viewer applet, and require a VNC password (another option would be
-   -unixpw). The above command could also be run out of inetd(8). It can
-   also be used to autodetect the user's display and Xauthority data.
-
-
-   These sections are added to the httpd.conf apache configuration file
-   on www.gateway.east:
-
-# In the global section you need to enable these modules.
-# Note that the ORDER MATTERS! mod_rewrite must be before mod_proxy
-# (so that we can check the allowed host list via rewrite)
-#
-LoadModule rewrite_module modules/mod_rewrite.so
-LoadModule proxy_module modules/mod_proxy.so
-LoadModule proxy_connect_module modules/mod_proxy_connect.so
-LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
-LoadModule proxy_http_module modules/mod_proxy_http.so
-<IfDefine SSL>
-LoadModule ssl_module modules/mod_ssl.so
-</IfDefine>
-
-
-# Near the bottom of httpd.conf you put the port 563 virtual host:
-
-Listen 563
-
-<VirtualHost *:563>
-
-   # Allow proxy CONNECT requests *only* to port 5915.
-   # If the machines use different ports, e.g. 5916 list them here as well:
-   #
-   ProxyRequests On
-   AllowCONNECT 5915
-
-   RewriteEngine On
-
-   # Convenience rules to expand applet parameters.  These do not have a traili
-ng "/"
-   #
-   # /vnc   for http jar file downloading:
-   #
-   RewriteRule /vnc/([^/]+)$               /vnc/$1/index.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1 [R,NE,L]
-   RewriteRule /vnc/trust/([^/]+)$         /vnc/$1/index.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1&trustAllVncCerts=yes [R,NE,L]
-   RewriteRule /vnc/proxy/([^/]+)$         /vnc/$1/proxy.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1&forceProxy=yes [R,NE,L]
-   RewriteRule /vnc/trust/proxy/([^/]+)$   /vnc/$1/proxy.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1&forceProxy=yes&trustAllVncCerts=yes [R,NE,L]
-
-   # Read in the allowed host to vnc display mapping file.  It looks like:
-   #
-   #   host1     15
-   #   host2     15
-   #   ...
-   #
-   # the display "15" means 5815 for http applet download, 5915 for SSL vnc.
-   #
-   RewriteMap vnchosts txt:/dist/apache/conf/vnc.hosts
-
-   # Proxy: check for the CONNECT hostname and port being in the vnc.hosts list
-.
-   #
-   RewriteCond %{THE_REQUEST} ^CONNECT [NC]
-   RewriteCond %{REQUEST_URI} ^(.*):(.*)$
-   RewriteCond ${vnchosts:%1|NOTFOUND} NOTFOUND
-   RewriteRule ^.*$ /VNCFAIL [F,L]
-
-   RewriteCond %{THE_REQUEST} ^CONNECT [NC]
-   RewriteCond %{REQUEST_URI} ^(.*):(.*)$
-   RewriteCond 59${vnchosts:%1}=%2 !^(.*)=(\1)$
-   RewriteRule ^.*$ /VNCFAIL [F,L]
-
-
-   # Remap /vnc to the proxy http download (e.g. http://host:5815)
-   #
-   # First, fail if it starts with the string /vnc0:
-   #
-   RewriteRule ^/vnc0.*            /VNCFAIL [F,L]
-   #
-   # Next, map the prefix to /vnc0/host:protocol:port
-   #
-   RewriteRule ^/vnc/([^/]+)/(.*)  /vnc0/$1:http:58${vnchosts:$1|NOTFOUND}/$2
-[NE]
-   #
-   # Drop any not found:
-   #
-   RewriteRule ^/vnc0.*NOTFOUND.*  /VNCFAIL [F,L]
-
-   # Construct the proxy URL and retrieve it:
-   #
-   RewriteRule ^/vnc0/([^/]+):([^/]+):([^/]+)/(.*) $2://$1:$3/$4 [P,NE,L]
-
-</VirtualHost>
-
-   Then restart apache (perhaps: "apachectl stop; apachectl start").
-
-   Note that the listing of allowed internal workstations is done in an
-   external file (/dist/apache/conf/vnc.hosts in the example above), the
-   format is like this:
-# allowed vnc hosts file:
-hostname1  15
-hostname2  15
-...
-
-   You list the hostname and the VNC display (always 15 in our example).
-   Only to these hosts will the external VNC viewers be able to connect
-   to (via the HTTP CONNECT method).
-
-   The above setup requires mod_rewrite and mod_proxy be enabled in the
-   apache web server. In this example they are loaded as modules (and
-   note that mod_rewrite must be listed before mod_proxy);
-
-   The user at the Java enabled Web browser would simply enter this URL
-   into the browser:
-   http://www.gateway.east:563/vnc/host2
-
-   to connect to internal workstation host2, etc.
-
-   Important: do not put a trailing "/" on the URL, since that will
-   defeat the RewriteRules that look for the hostname at the very end.
-
-   There will be a number of SSL certificate, etc, dialogs he will have
-   to respond to in addition to any passwords he is required to provide
-   (this depends on how you set up user authentication for x11vnc).
-
-   If a second Web proxy is involved (i.e. the user's browser is inside
-   another firewall and policy requires using a Web proxy server) then
-   use this URL:
-   http://www.gateway.east:563/vnc/proxy/host2
-
-   This will involve downloading a signed java viewer applet jar file
-   that is able to interact with the internal proxy for the VNC
-   connection. See this FAQ for more info on how this works. Note:
-   sometimes with the Proxy case if you see 'Bad Gateway' error you will
-   have to wait 10 or so seconds and then hit reload. This seems to be
-   due to having to wait for a Connection Keepalive to terminate...
-
-   For completeness, the "trust" cases that skip a VNC certificate dialog
-   (discussed below) would be entered as:
-   http://www.gateway.east:563/vnc/trust/host2
-   http://www.gateway.east:563/vnc/trust/proxy/host2
-
-   You can of course choose shorter or more easy to remember URL formats.
-   Just change the Convenience RewriteRules in httpd.conf.
-
-     _________________________________________________________________
-
-   Port Variations:
-
-   Note that you can run this on the default HTTP port 80 instead of port
-   563. If you do not expect to have a browser connecting from inside a
-   proxying firewall (where sometimes only connections to ports 443 and
-   563 are allowed) this should be fine. Use "80" instead of "563" in the
-   httpd.conf config file (you may need to merge it with other default
-   port 80 things you have there).
-
-   Then the URL's will be a bit simpler:
-   http://www.gateway.east/vnc/host2
-   http://www.gateway.east/vnc/trust/host2
-
-   etc.
-
-   Besides 80 one could use any other random port number (since there are
-   so many port scans on 80, a little obscurity might be useful).
-
-   One option is to use port "443" (the default https:// port) instead of
-   "563". In this case Apache is not configured for mod_ssl; we just
-   happen to use port "443" in the way any random port would be used.
-   This could be handy if the Viewer side environment is restrictive in
-   that it only allows outgoing connections to ports 80 and 443 (and,
-   say, you didn't want to use port 80, or you wanted to use 80 for
-   something else). Another reason for using 443 would be some web proxy
-   environments only allow the CONNECT method to go to port 443 (and not
-   even the case 563 we use above).
-
-     _________________________________________________________________
-
-   Details:
-
-   Let's go through the httpd.conf additions in detail from the top.
-
-   The LoadModules directives load the necessary apache modules. Note
-   that mod_rewrite must be listed first. If you are compiling from
-   scratch something like this worked for us:
-  ./configure --enable-proxy=shared --enable-proxy-connect=shared --enable-ssl=
-shared --enable-rewrite=shared --prefix=/dist/apache
-
-   Then the VirtualHost *:563 virtual host section starts.
-
-   The "ProxyRequests On" and "AllowCONNECT 5915" enable the web server
-   to forward proxy requests to port 5915 (and only this port) INSIDE the
-   firewall. Think about the implications of this thoroughly and test it
-   carefully.
-
-   The RewriteRule's are for convenience only so that the URL entered
-   into the Web browser does not need the various extra parameters, e.g.:
-   http://www.gateway.east:563/vnc/host2/index.vnc?CONNECT=host2+5915&PORT=563,
-blah,blah...
-
-   (or otherwise make direct edits to index.vnc to set these parameters).
-   The forceProxy=yes parameter is passed to the applet to force the use
-   of a outgoing proxy socket connection. Use it only if the Web browser
-   is inside a separate Web proxying environment (i.e. large corporation)
-
-   The rewrites with parameter urlPrefix are described under Tricks for
-   Better Response. The "trust" ones (also described under Tricks) with
-   trustAllVncCerts tell the Java VNC applet to skip a dialog asking
-   about the VNC Certificate. They are a bit faster and more reliable
-   than the original method. In the best situation they lead to being
-   logged in 20 seconds or less (without them the time to login can be
-   much longer since a number of connections must timeout).
-
-   All of the x11vnc Java Viewer applet parameters are described in the
-   file classes/ssl/README
-
-   The external file /dist/apache/conf/vnc.hosts containing the allowed
-   VNC server hostnames is read in. Its 2nd column contains the VNC
-   display of the host (always 15 in our example; if you make it vary you
-   will need to adjust some lines in the httpd.conf accordingly, e.g.
-   AllowCONNECT). This list is used to constrain both the Jar file
-   download URL and the proxy CONNECT the VNC viewer makes to only the
-   intended VNC servers.
-
-   Limiting the proxy CONNECT is done with the two sets of RewriteCond
-   conditions.
-
-   Limiting the Jar file download URL is done in the remaining 4
-   RewriteRule's.
-
-   Note that these index.vnc and VncViewer.jar downloads to the browser
-   are not encrypted via SSL, and so in principle could be tampered with
-   by a really bad guy. The subsequent VNC connection, however, is
-   encrypted through a single SSL connection (it makes a CONNECT straight
-   to x11vnc). See below for how to have these initial downloads
-   encrypted as well (if the apache web server has SSL/mod_ssl, i.e.
-   https, enabled and configured).
-
-   Unfortunately the Java VNC viewer applet currently is not able to save
-   its own list of Certificates (e.g. the user says trust this VNC
-   certificate 'always'). This is because an applet it cannot open local
-   files, etc. Sadly, the applet cannot even remember certificates in the
-   same browser session because it is completely reinitialized for each
-   connection (see below).
-
-     _________________________________________________________________
-
-   Too Much?
-
-   If these apache rules are a little too much for you, there is a little
-   bit simpler scheme where you have to list each of the individual
-   machines in the httpd.conf and ssl.conf files. It may be a little more
-   typing to maintain, but perhaps being more straight forward (less
-   RewriteRule's) is desirable.
-
-     _________________________________________________________________
-
-   Problems?
-
-   To see example x11vnc output for a successful https://host:5900/
-   connection with the Java Applet see This Page.
-
-     _________________________________________________________________
-
-   Some Ideas for adding extra authentication, etc. for the paranoid:
-     * VNC passwords: -rfbauth, -passwdfile, or -usepw. Even adding a
-       simple company-wide VNC password helps block unwanted access.
-     * Unix passwords: -unixpw
-     * SSL Client certificates: -sslverify
-     * Apache AuthUserFile directive: .htaccess, etc.
-     * Filter connections based on IP address or hostname.
-     * Use Port-knocking on your firewall as described in: Enhanced
-       TightVNC Viewer (ssvnc).
-     * Add proxy password authentication (requires Viewer changes?)
-     * Run a separate instance of Apache that provides this VNC service
-       so it can be brought up and down independently of the normal web
-       server.
-     * How secure is the Client side? Public machines in internet cafes,
-       etc, are often hacked, with backdoors and VNC servers of their
-       own. Prefer using your own firewalled laptop to a public machine.
-
-
-     _________________________________________________________________
-
-   Using non-Java viewers with this scheme:
-
-   The ss_vncviewer stunnel wrapper script for VNC viewers has the -proxy
-   option that can take advantage of this method.
-   ss_vncviewer -proxy www.gateway.east:563   host1:15
-
-   For the case of the "double proxy" situation (see below) supply both
-   separated by a comma.
-   ss_vncviewer -proxy proxy1.foobar.com:8080,www.gateway.east:563   host1:15
-
-   For the Enhanced TightVNC Viewer (ssvnc) GUI (it uses ss_vncviewer on
-   Unix) put 'host1:15' into the 'VNC Server' entry box, and here are
-   possible Proxy/Gateway entries
-   Proxy/Gateway:   www.gateway.east:563
-   Proxy/Gateway:   proxy1.foobar.com:8080,www.gateway.east:563
-
-   then click on the 'Connect' button.
-
-     _________________________________________________________________
-
-   Downloading the Java applet to the browser via HTTPS:
-
-   To have the Java applet downloaded to the user's Web Browser via an
-   encrypted (and evidently safer) SSL connection the Apache webserver
-   should be configured for SSL via mod_ssl.
-
-   It is actually possible to use the x11vnc Key Management utility
-   "-sslGenCert" to generate your Apache/SSL .crt and .key files. (In
-   brief, run something like "x11vnc -sslGenCert server self:apache" then
-   copy the resulting self:apache.crt file to conf/ssl.crt/server.crt and
-   extract the private key part from self:apache.pem and paste it into
-   conf/ssl.key/server.key). Setting the env var REQ_ARGS='-days 1095'
-   before running x11vnc will bump up the expiration date (3 years in
-   this case).
-
-   Or you can use the standard methods described in the Apache mod_ssl
-   documentation to create your keys. Then restart Apache, usually
-   something like "apachectl stop" followed by "apachectl startssl"
-
-   In addition to the above sections in httpd.conf one should add the
-   following to ssl.conf:
-   SSLProxyEngine  On
-
-   RewriteEngine On
-
-   # Convenience rules to expand applet parameters.  These do not have a traili
-ng "/"
-   #
-   # /vnc   http jar file downloading:
-   #
-   RewriteRule /vnc/([^/]+)$                        /vnc/$1/index.vnc?CONNECT=$
-1+5915&PORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vnc_2F_$1 [R,NE,L]
-   RewriteRule /vnc/proxy/([^/]+)$                  /vnc/$1/proxy.vnc?CONNECT=$
-1+5915&PORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vnc_2F_$1&forceProxy=yes [R,N
-E,L]
-   #
-   # (we skipped the "trust" ones above, put them in if you like)
-   #
-   # /vncs  https jar file downloading:
-   #
-   RewriteRule /vncs/([^/]+)$                      /vncs/$1/index.vnc?CONNECT=$
-1+5915&PORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1 [R,NE,L]
-   RewriteRule /vncs/proxy/([^/]+)$                /vncs/$1/proxy.vnc?CONNECT=$
-1+5915&PORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&forceProxy=yes [R,
-NE,l]
-   RewriteRule /vncs/trust/([^/]+)$                /vncs/$1/index.vnc?CONNECT=$
-1+5915&PORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&trustAllVncCerts=y
-es [R,NE,L]
-   RewriteRule /vncs/trust/proxy/([^/]+)$          /vncs/$1/proxy.vnc?CONNECT=$
-1+5915&PORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&forceProxy=yes&tru
-stAllVncCerts=yes [R,NE,L]
-
-   # Convenience rules used for the connect_switch helper (requires Listen 127.
-0.0.1:443 above):
-   #
-   RewriteRule /vnc443/([^/]+)$                    /vncs/$1/index.vnc?CONNECT=$
-1+5915&PORT=443&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1 [R,NE,L]
-   RewriteRule /vnc443/proxy/([^/]+)$              /vncs/$1/proxy.vnc?CONNECT=$
-1+5915&PORT=443&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&forceProxy=yes [R,
-NE,L]
-   RewriteRule /vnc443/trust/([^/]+)$              /vncs/$1/index.vnc?CONNECT=$
-1+5915&PORT=443&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&trustAllVncCerts=y
-es [R,NE,L]
-   RewriteRule /vnc443/trust/proxy/([^/]+)$        /vncs/$1/proxy.vnc?CONNECT=$
-1+5915&PORT=443&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&forceProxy=yes&tru
-stAllVncCerts=yes [R,NE,L]
-
-   # Read in the allowed host to vnc display mapping file.  It looks like:
-   #
-   #   host1     15
-   #   host2     15
-   #   ...
-   #
-   # the display "15" means 5915 for SSL VNC and 5815 for http applet download.
-   #
-   RewriteMap vnchosts txt:/dist/apache/conf/vnc.hosts
-
-
-   # Remap /vnc and /vncs to the proxy http download (e.g. https://host:5915)
-   #
-   # First, fail if it starts with the string /vnc0:
-   #
-   RewriteRule ^/vnc0.*            /VNCFAIL [F,L]
-   #
-   # Next, map the prefix to /vnc0:host:protocol:port
-   #
-   RewriteRule ^/vnc/([^/]+)/(.*)  /vnc0/$1:http:58${vnchosts:$1|NOTFOUND}/$2
-[NE]
-   RewriteRule ^/vncs/([^/]+)/(.*) /vnc0/$1:https:59${vnchosts:$1|NOTFOUND}/$2
-[NE]
-   #
-   # Drop any not found:
-   #
-   RewriteRule ^/vnc0.*NOTFOUND.*  /VNCFAIL [F,L]
-
-   # Construct the proxy URL and retrieve it:
-   #
-   RewriteRule ^/vnc0/([^/]+):([^/]+):([^/]+)/(.*) $2://$1:$3/$4 [P,NE,L]
-
-   This is all in the "<VirtualHost _default_:443>" section of ssl.conf.
-
-   The user could then point the Web Browser to:
-   https://www.gateway.east/vnc/host2
-
-   or
-   https://www.gateway.east/vnc/proxy/host2
-
-   for the "double proxy" case. (Important: do not put a trailing "/" on
-   the URL, since that will defeat the RewriteRules.)
-
-   As with the httpd.conf case, the external file
-   (/dist/apache/conf/vnc.hosts in the above example) contains the
-   hostnames of the allowed VNC servers.
-
-   Note that inside the firewall the Java applet download traffic is not
-   encrypted (only over the Internet is SSL used) for these cases:
-   https://www.gateway.east/vnc/host2
-   https://www.gateway.east/vnc/proxy/host2
-
-   However for the special "vncs" rules above:
-   https://www.gateway.east/vncs/host2
-
-   the Java applet download is encrypted via SSL for both legs. Note that
-   the two legs are two separate SSL sessions. So the data is decrypted
-   inside an apache process and reencrypted by the apache process for the
-   2nd SSL session inside the same apache process (a very small gap one
-   might overlook).
-
-   The "vncs/trust" ones are like the "trust" ones described earlier
-   https://www.gateway.east/vncs/trust/mach2
-
-   and similarly for the httpsPort ones. See Tricks for Better Response.
-
-   In all of the above cases the VNC traffic from Viewer to x11vnc is
-   encrypted end-to-end in a single SSL session, even for the "double
-   proxy" case because the CONNECT method is used (there are actually two
-   CONNECT's for the "double proxy" case). This part (the VNC traffic) is
-   the most important part to have encrypted.
-
-   Note that the Certificate dialogs the user has in his web browser will
-   be for the Apache Certificate, while for the Java applet it will be
-   the x11vnc certificate.
-
-   Note also that you can have Apache serve up the Jar file VncViewer.jar
-   and/or index.vnc/proxy.vnc instead of each x11vnc if you want to.
-
-   The rules in ssl.conf are similar to the ones in httpd.conf and so are
-   not discussed in detail. The only really new thing is the /vncs
-   handling to download the applet jar via HTTPS on port 5915.
-
-   The special entries "/vnc443" are only used for the special helper
-   program (connect_switch) for the https port 443 only mode discussed
-   here.
-
-     _________________________________________________________________
-
-   INETD automation:
-
-   The "single-port" (i.e. 5915) HTTPS applet download and VNC connection
-   aspect shown here is convenient and also enables having x11vnc run out
-   of inetd. That way x11vnc is run on demand instead of being run all
-   the time (the user does not have to remember to start it). The first
-   connections to inetd download index.vnc and the Jar file (via https)
-   and the the last connection to inetd establishes the SSL VNC
-   connection. Since x11vnc is restarted for each connection, this will
-   be a bit slower than the normal process.
-
-   For example, the /etc/inetd.conf line could be:
-  5915 stream tcp nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc_ssl.sh
-
-   where the script x11vnc_ssl.sh looks something like this:
-#!/bin/sh
-
-/usr/local/bin/x11vnc -inetd -oa /var/log/x11vnc-15.log \
-        -ssl SAVE -http -unixpw -localhost \
-        -display :0 -auth /home/THE_USER/.Xauthority
-
-   where, as usual, the inetd launching needs to know which user is
-   typically using the display on that machine. One could imagine giving
-   different users different ports, 5915, 5916, etc. to distinguish (then
-   the script would need to be passed the username). mod_rewrite could be
-   used to automatically map username in the URL to his port number.
-
-   A better way is to use the "-display WAIT:cmd=FINDDISPLAY" feature to
-   autodetect the user and Xauthority data:
-#!/bin/sh
-
-/usr/local/bin/x11vnc -inetd -oa /var/log/x11vnc-15.log \
-        -ssl SAVE -http -unixpw -localhost -users unixpw= \
-        -find
-
-   (we have used the alias -find for "-display WAIT:cmd=FINDDISPLAY".)
-   This way the user must supply his Unix username and password and then
-   his display and Xauthority data on that machine will be located and
-   returned to x11vnc to allow it to attach. If he doesn't have a display
-   running on that machine or he fails to log in correctly, the
-   connection will be dropped.
-
-   The variant "-display WAIT:cmd=FINDCREATEDISPLAY" (aliased by
-   "-create") will actually create a (virtual or real) X server session
-   for the user if one doesn't already exist. See here for details.
-
-   To enable inetd operation for the non-HTTPS Java viewer download (port
-   5815 in the above httpd.conf example) you will need to run x11vnc in
-   HTTPONCE mode on port 5815: For example, the /etc/inetd.conf line
-   could be:
-  5815 stream tcp nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc \
-       -inetd -prog /usr/local/bin/x11vnc -oa /var/log/x11vnc-15.log \
-       -http_ssl -display WAIT:cmd=HTTPONCE
-
-   where the long inetd.conf line has been split. Note how the -http_ssl
-   tries to automatically find the .../classes/ssl subdirectory. This
-   requires the -prog option available in x11vnc 0.8.4 (a shell script
-   wrapper, e.g. /usr/local/bin/x11vnc_http.sh can be used to work around
-   this).
-
-   Also note the use of "-ssl SAVE" above. This way a saved server.pem is
-   used for each inetd invocation (rather generating a new one each time
-   as happens for "-ssl TMP"). Note that it cannot have a protecting
-   passphrase because inetd will not be able to supply it.
-
-   Another option is:
-  5815 stream tcp nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc \
-       -inetd -httpdir /usr/local/share/x11vnc/classes/ssl \
-       -oa /var/log/x11vnc-15.log -display WAIT:cmd=HTTPONCE
-
-   (this also requires a feature found in x11vnc 0.8.4).
-     _________________________________________________________________
-
-   Other Ideas:
-
-   - The above schemes work, but they are a bit complicated with all of
-   the rigging. There should be more elegant ways to configure Apache to
-   do these, but we have not found them (please let us know if you
-   discover something nice). However, once this scheme has been set up
-   and is working it is easy to maintain and add/delete workstations,
-   etc.
-
-   - In general Apache is not required, but it makes things convenient.
-   The firewall itself could do the port redirection via its firewall
-   rules. Evidently different Internet-facing ports would be required for
-   each workstation. This could be set up using iptables rules for
-   example. If there were just one or two machines this would be the
-   easiest method. For example:
-  iptables -t nat -A PREROUTING -p tcp -d 24.35.46.57 --dport 5901 -j DNAT --to
--destination 192.168.1.2:5915
-  iptables -t nat -A PREROUTING -p tcp -d 24.35.46.57 --dport 5902 -j DNAT --to
--destination 192.168.1.3:5915
-
-   Where 24.35.46.57 is the internet IP address of the gateway. In this
-   example 24.35.46.57:5901 is redirected to the internal machine
-   192.168.1.2:5915 and 24.35.46.57:5902 is redirected to another
-   internal machine 192.168.1.3:5915, both running x11vnc -ssl ... in SSL
-   mode. For this example, the user would point the web browser to, e.g.:
-  https://24.35.46.57:5901/?PORT=5901
-
-   or using the stunnel wrapper script:
-  ss_vncviewer 24.35.46.57:1
-
-   One can achieve similar things with dedicated firewall/routers (e.g.
-   Linksys) using the device's web or other interface to configure the
-   firewall.
-
-   If the user may be coming out of a firewall using a proxy it may be
-   better to redirect ports 443 and 563 (instead of 5901 and 5902) to the
-   internal machines so that the user's proxy will allow CONNECTing to
-   them.
-
-   - The redirection could also be done at the application level using a
-   TCP redirect program (e.g. ip_relay or fancier ones). Evidently more
-   careful internal hostname checking, etc., could be performed by the
-   special purpose application to add security. See connect_switch which
-   is somewhat related.
-
-   - One might imagine the ProxyPass could be done for the VNC traffic as
-   well (for the ssl.conf case) to avoid the CONNECT proxying completely
-   (which would be nice to avoid). Unfortunately we were not able to get
-   this to work. Since HTTP is a request-response protocol (as opposed to
-   a full bidirectional link required by VNC that CONNECT provides) this
-   makes it difficult to do. It may be possible, but we haven't found out
-   how yet.
-
-   All of the x11vnc Java Viewer applet parameters are described in the
-   file classes/ssl/README
-
-     _________________________________________________________________
-
-   Tricks for Better Response and reliability:
-
-   The "original scheme" using httpd.conf and ssl.conf rewrites without
-   urlPrefix and trustAllVncCerts above should work OK, but may lead to
-   slow and/or unreliable loading of the applet and final connection to
-   x11vnc. The following are what I do now to get better response and
-   reliability. YMMV.
-
-   The problem with the "original scheme" is that there is a point where
-   the VNC Viewer applet can try up to 3 times to retrieve the x11vnc
-   certificate, since it needs to get it to show it to you and ask you if
-   you accept it. This can add about 45 seconds to the whole process
-   (which takes 1 to 1.5 minutes with all the dialogs) since a couple of
-   those connections must time out. The "trust" items in the config add a
-   parameter trustAllVncCerts=yes similar to the forceProxy=yes
-   parameter. This can cut the total time to the VNC password prompt down
-   to 15 seconds which is pretty good. (Note by ignoring the certificate
-   this does not protect against man-in-the-middle attacks which are
-   rare, but maybe the won't be so rare in the future... see
-   dsniff/webmitm and cain)
-
-   First make sure the x11vnc SSL certificate+key is the same as
-   Apache's. (otherwise you may get one extra dialog and/or one extra
-   connection that has to time out).
-
-   The following RewriteRule's are the same now advocated in the
-   instructions above.
-
-   The httpsPort and urlPrefix= parameters give hints to the applet to
-   improve connecting: This is what goes in httpd.conf:
-   RewriteEngine On
-   RewriteRule /vnc/([^/]+)$               /vnc/$1/index.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1 [R,NE]
-   RewriteRule /vnc/trust/([^/]+)$         /vnc/$1/index.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1&trustAllVncCerts=yes [R,NE]
-   RewriteRule /vnc/proxy/([^/]+)$         /vnc/$1/proxy.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1&forceProxy=yes [R,NE]
-   RewriteRule /vnc/trust/proxy/([^/]+)$   /vnc/$1/proxy.vnc?CONNECT=$1+5915&PO
-RT=563&urlPrefix=_2F_vnc_2F_$1&forceProxy=yes&trustAllVncCerts=yes [R,NE]
-
-   The httpsPort and urlPrefix provide useful hints to the VNC Viewer
-   applet when it connects to x11vnc to glean information about Proxies,
-   certificates, etc.
-
-   This is what goes into ssl.conf:
-   RewriteEngine On
-   RewriteRule /vnc/([^/]+)$                /vnc/$1/index.vnc?CONNECT=$1+5915&P
-ORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vnc_2F_$1 [R,NE]
-   RewriteRule /vnc/proxy/([^/]+)$          /vnc/$1/proxy.vnc?CONNECT=$1+5915&P
-ORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vnc_2F_$1&forceProxy=yes [R,NE]
-   RewriteRule /vncs/([^/]+)$              /vncs/$1/index.vnc?CONNECT=$1+5915&P
-ORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1 [R,NE]
-   RewriteRule /vncs/proxy/([^/]+)$        /vncs/$1/proxy.vnc?CONNECT=$1+5915&P
-ORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&forceProxy=yes [R,NE]
-   RewriteRule /vncs/trust/([^/]+)$        /vncs/$1/index.vnc?CONNECT=$1+5915&P
-ORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&trustAllVncCerts=yes [R,NE
-]
-   RewriteRule /vncs/trust/proxy/([^/]+)$  /vncs/$1/proxy.vnc?CONNECT=$1+5915&P
-ORT=563&httpsPort=443&GET=1&urlPrefix=_2F_vncs_2F_$1&forceProxy=yes&trustAllVnc
-Certs=yes [R,NE]
-
-   The rest is the same.
-
-   The httpsPort and urlPrefix and GET provide useful hints to the VNC
-   Viewer applet when it connects to x11vnc to glean information about
-   Proxies, certificates, etc, and also for the ultimate VNC connection
-   (GET speeds this up by sending a special HTTP GET to cause x11vnc to
-   immediately switch to the VNC protocol).
-
-   To turn these into URLs, as was done above, take the string in the
-   RewriteRule, e.g. /vncs and turn it into
-   https://gateway/vncs/machinename Similarly for non-https:
-   http://gateway:563/vnc/machinename
-
-   If you use the 'trust' ones, you are performing NO checks, visual or
-   otherwise, on the VNC SSL certificate. It is trusted without question.
-   This speeds things up because it avoids a dialog about certificates,
-   but of course has some risk WRT Man in the Middle attacks. I don't
-   recommend them. It is better to use /vnc or /vncs and the first time
-   you connect carefully check the Certificate and then tell your Browser
-   and Java Virtual Machine to trust the certificate 'Always'. Then if
-   you later get an unexpected dialog, you know something is wrong.
-   Nearly always it is just a changed or expired certificate, but better
-   safe than sorry...
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/enhanced_tightvnc_viewer.html:
-
-
-     _________________________________________________________________
-
-Enhanced TightVNC Viewer   (SSVNC:   SSL/SSH VNC viewer)
-
-   (To Downloads)  (To Quick Start)
-
-   [ssvnc.gif] [ssvnc_windows.gif] [ssvnc_macosx.gif] . .
-
-
-   The Enhanced TightVNC Viewer, SSVNC, adds encryption security to VNC
-   connections.
-
-   The package provides a GUI for Windows, Mac OS X, and Unix that
-   automatically starts up an STUNNEL SSL tunnel for SSL or ssh/plink for
-   SSH connections to any VNC server, such as x11vnc, and then launches
-   the VNC Viewer to use the encrypted tunnel.
-
-   The x11vnc server has built-in SSL support, however SSVNC can make SSL
-   encrypted VNC connections to any VNC Server if they are running an SSL
-   tunnel, such as STUNNEL or socat, at their end. SSVNC's SSH tunnel
-   will work to any VNC Server host running sshd that you can log into.
-
-   The Enhanced TightVNC Viewer package started as a project to add some
-   patches to the long neglected Unix TightVNC Viewer. However, now the
-   front-end GUI, encryption, and wrapper scripts features possibly
-   outweigh the Unix TightVNC Viewer improvements (see the lists below to
-   compare).
-
-   The SSVNC Unix vncviewer can also be run without the SSVNC encryption
-   GUI as an enhanced replacement for the xvncviewer, xtightvncviewer,
-   etc., viewers.
-
-   In addition to normal SSL, SSVNC also supports the VeNCrypt SSL/TLS
-   and Vino/ANONTLS encryption extensions to VNC on Unix, Mac OS X, and
-   Windows. Via the provided SSVNC VeNCrypt bridge, VeNCrypt and ANONTLS
-   encryption also works with any third party VNC Viewer (e.g. RealVNC,
-   TightVNC, UltraVNC, etc...) you select via 'Change VNC Viewer'.
-
-   The short name for this project is "ssvnc" for SSL/SSH VNC Viewer.
-   This is the name of the command to start it.
-
-   There is a simplified SSH-Only mode (sshvnc). And an even more
-   simplified Terminal-Services mode (tsvnc) for use with x11vnc on the
-   remote side.
-
-   The tool has many additional features; see the descriptions below.
-
-   It is a self-contained bundle, you could carry it around on, say, a
-   USB memory stick / flash drive for secure VNC viewing from almost any
-   machine, Unix, Mac OS X, and Windows (and if you create a directory
-   named "Home" in the toplevel ssvnc directory on the drive your VNC
-   profiles and certs will be kept there as well). For Unix, there is
-   also a conventional source tarball to build and install in the normal
-   way and not use a pre-built bundle.
-
-     _________________________________________________________________
-
-    Announcements:
-
-   Important: If you created any SSL certificates with SSVNC (or anything
-   else) on a Debian or Ubuntu system from Sept. 2006 through May 2008,
-   then those keys are likely extremely weak and can be easily cracked.
-   The certificate files should be deleted and recreated on a non-Debian
-   system or an updated one. See
-   http://www.debian.org/security/2008/dsa-1571 for details. The same
-   applies to SSH keys.
-
-   Please read this information on using SSVNC on workstations with
-   Untrusted Local Users.
-
-     _________________________________________________________________
-
-    Feature List:
-
-   Wrapper scripts and a tcl/tk GUI were written to create these features
-   for Unix, Mac OS X, and Windows:
-     * SSL support for connections using the bundled stunnel program.
-     * Automatic SSH connections from the GUI (system ssh is used on Unix
-       and MacOS X; bundled plink is used on Windows)
-     * Ability to Save and Load VNC profiles for different hosts.
-     * You can also use your own VNC Viewer, e.g. UltraVNC or RealVNC,
-       with the SSVNC encryption GUI front-end if you prefer.
-     * Create or Import SSL Certificates and Private Keys.
-     * Reverse (viewer listening) VNC connections via SSL and SSH.
-     * VeNCrypt SSL/TLS VNC encryption support (used by VeNCrypt, QEMU,
-       ggi, libvirt/virt-manager/xen, vinagre/gvncviewer/gtk-vnc)
-     * ANONTLS SSL/TLS VNC encryption support (used by Vino)
-     * VeNCrypt and ANONTLS are also enabled for any 3rd party VNC Viewer
-       (e.g. RealVNC, TightVNC, UltraVNC ...) on Unix, MacOSX, and
-       Windows via the provided SSVNC VeNCrypt Viewer Bridge tool (use
-       'Change VNC Viewer' to select the one you want.)
-     * Support for Web Proxies, SOCKS Proxies, and the UltraVNC repeater
-       proxy (e.g. repeater://host:port+ID:1234). Multiple proxies may be
-       chained together (3 max).
-     * Support for SSH Gateway connections and non-standard SSH ports.
-     * Automatic Service tunnelling via SSH for CUPS and SMB Printing,
-       ESD/ARTSD Audio, and SMB (Windows/Samba) filesystem mounting.
-     * Sets up any additional SSH port redirections that you want.
-     * Zeroconf (aka Bonjour) is used on Unix and Mac OS X to find VNC
-       servers on your local network if the avahi-browse or dns-sd
-       program is available and in your PATH.
-     * Port Knocking for "closed port" SSH/SSL connections. In addition
-       to a simple fixed port sequence and one-time-pad implementation, a
-       hook is also provided to run any port knocking client before
-       connecting.
-     * Support for native MacOS X usage with bundled Chicken of the VNC
-       viewer (the Unix X11 viewer is also provided for MacOS X, and is
-       better IMHO. It is now the default on MacOS X.)
-     * Dynamic VNC Server Port determination and redirection (using ssh's
-       builtin SOCKS proxy, ssh -D) for servers like x11vnc that print
-       out PORT= at startup.
-     * Unix Username and Password entry for use with "x11vnc -unixpw"
-       type login dialogs.
-     * Simplified mode launched by command "sshvnc" that is SSH Only.
-     * Simplified mode launched by command "tsvnc" that provides a VNC
-       "Terminal Services" mode (uses x11vnc on the remote side).
-     * IPv6 support for all connection modes on Unix, MacOSX, and
-       Windows.
-
-   Patches to TightVNC 1.3.9 vnc_unixsrc tree were created for Unix
-   TightVNC Viewer improvements (these only apply to the Unix VNC viewer,
-   including MacOSX XQuartz):
-     * rfbNewFBSize VNC support (dynamic screen resizing)
-     * Client-side Scaling of the Desktop in the viewer.
-     * ZRLE VNC encoding support (RealVNC's encoding)
-     * Support for the ZYWRLE encoding, a wavelet based extension to ZRLE
-       to improve compression of motion video and photo regions.
-     * TurboVNC support (VirtualGL's modified TightVNC encoding; requires
-       TurboJPEG library)
-     * Pipelined Updates of the framebuffer as in TurboVNC (asks for the
-       next update before the current one has finished downloading; this
-       gives some speedup on high latency connections.)
-     * Cursor alphablending with x11vnc at 32bpp (-alpha option)
-     * Option "-unixpw ..." for use with "x11vnc -unixpw" type login
-       dialogs.
-     * Support for UltraVNC extensions: 1/n Server side scaling, Text
-       Chat, Single Window, Disable Server-side Input. Both UltraVNC and
-       x11vnc servers support these extensions.
-     * UltraVNC File Transfer via an auxiliary Java helper program (java
-       must be in $PATH). Note that the x11vnc server also supports
-       UltraVNC file transfer.
-     * Connection support for the UltraVNC repeater proxy (-repeater
-       option).
-     * Support for UltraVNC Single Click operation. (both unencrypted: SC
-       I, and SSL encrypted: SC III)
-     * Support for UltraVNC DSM Encryption Plugin symmetric encryption
-       mode. (ARC4, AESV2, MSRC4, and SecureVNC)
-     * Support for UltraVNC MS-Logon authentication (NOTE: the UltraVNC
-       MS-Logon key exchange implementation is very weak; an eavesdropper
-       on the network can recover your Windows password easily in a few
-       seconds; you need to use an additional encrypted tunnel with
-       MS-Logon.)
-     * Support for symmetric encryption (including blowfish and 3des
-       ciphers) to Non-UltraVNC Servers. Any server using the same
-       encryption method will work, e.g.:  x11vnc -enc blowfish:./my.key
-     * Instead of hostname:display one can also supply "exec=command
-       args..." to connect the viewer to the stdio of an external command
-       (e.g. stunnel or socat) rather than using a TCP/IP socket. Unix
-       domain sockets, e.g. /path/to/unix/socket, and a previously opened
-       file descriptor fd=0, work too.
-     * Local Port Protections for STUNNEL and SSH: avoid having for long
-       periods of time a listening port on the the local (VNC viewer)
-       side that redirects to the remote side.
-     * Reverse (viewer listening) VNC connections can show a Popup dialog
-       asking whether to accept the connection or not (-acceptpopup.) The
-       extra info provided by UltraVNC Single Click reverse connections
-       is also supported (-acceptpopupsc)
-     * Extremely low color modes: 64 and 8 colors in 8bpp
-       (-use64/-bgr222, -use8/-bgr111)
-     * Medium color mode: 16bpp mode on a 32bpp Viewer display
-       (-16bpp/-bgr565)
-     * For use with x11vnc's client-side caching -ncache method use the
-       cropping option -ycrop n. This will "hide" the large pixel buffer
-       cache below the actual display. Set to the actual height or use -1
-       for autodetection (also, tall screens, H > 2*W, are autodetected
-       by default).
-     * Escape Keys: specify a set of modifier keys so that when they are
-       all pressed down you can invoke Popup menu actions via keystrokes.
-       I.e., a set of 'Hot Keys'. One can also pan (move) the desktop
-       inside the viewport via Arrow keys or a mouse drag.
-     * Scrollbar width setting: -sbwidth n, the default is very thin, 2
-       pixels, for less distracting -ycrop usage.
-     * Selection text sending and receiving can be fine-tuned with the
-       -sendclipboard, -sendalways, and -recvtext options.
-     * TightVNC compression and quality levels are automatically set
-       based on observed network latency (n.b. not bandwidth.)
-     * Improvements to the Popup menu, all of these can now be changed
-       dynamically via the menu: ViewOnly, Toggle Bell, CursorShape
-       updates, X11 Cursor, Cursor Alphablending, Toggle Tight/ZRLE,
-       Toggle JPEG, FullColor/16bpp/8bpp (256/64/8 colors), Greyscale for
-       low color modes, Scaling the Viewer resolution, Escape Keys,
-       Pipeline Updates, and others, including UltraVNC extensions.
-     * Maintains its own BackingStore if the X server does not.
-     * The default for localhost:0 connections is not raw encoding since
-       same-machine connections are pretty rare. Default assumes you are
-       using a SSL or SSH tunnel. Use -rawlocal to revert.
-     * XGrabServer support for fullscreen mode, for old window managers
-       (-grab/-graball option).
-     * Fix for Popup menu positioning for old window managers (-popupfix
-       option).
-     * The VNC Viewer ssvncviewer supports IPv6 natively (no helpers
-       needed.)
-
-   The list of 3rd party software bundled in the archive files:
-     * TightVNC Viewer  (windows, unix, macosx)
-     * Chicken of the VNC Viewer  (macosx)
-     * Stunnel  (windows, unix, macosx)
-     * Putty/Plink/Pageant  (windows)
-     * OpenSSL  (windows)
-     * esound  (windows)
-
-   These are all self-contained in the bundle directory: they will not be
-   installed on your system. Just un-zip or un-tar the file you
-   downloaded and run the frontend ssvnc straight from its directory.
-   Alternatively, on Unix you can use the conventional source tarball.
-
-     _________________________________________________________________
-
-   Here is the Quick Start info from the README for how to setup and use
-   SSVNC:
-Quick Start:
------------
-
-Unix and Mac OS X:
-
-    Inside a Terminal do something like the following.
-
-    Unpack the archive:
-
-        % gzip -dc ssvnc-1.0.29.tar.gz | tar xvf -
-
-    Run the GUI:
-
-        % ./ssvnc/Unix/ssvnc               (for Unix)
-
-        % ./ssvnc/MacOSX/ssvnc             (for Mac OS X)
-
-    The smaller file "ssvnc_no_windows-1.0.29.tar.gz"
-    could have been used as well.
-
-    On MacOSX you could also click on the SSVNC app icon in the Finder.
-
-    On MacOSX if you don't like the Chicken of the VNC (e.g. no local
-    cursors, no screen size rescaling, and no password prompting), and you
-    have the XDarwin X server installed, you can set DISPLAY before starting
-    ssvnc (or type DISPLAY=... in Host:Disp and hit Return).  Then our
-    enhanced TightVNC viewer will be used instead of COTVNC.
-    Update: there is now a 'Use X11 vncviewer on MacOSX' under Options ...
-
-
-    If you want a SSH-only tool (without the distractions of SSL) run
-    the command:
-
-                sshvnc
-
-    instead of "ssvnc".  Or click "SSH-Only Mode" under Options.
-    Control-h will toggle between the two modes.
-
-
-    If you want a simple VNC Terminal Services only mode (requires x11vnc
-    on the remote server) run the command:
-
-                tsvnc
-
-    instead of "ssvnc".  Or click "Terminal Services" under Options.
-    Control-t will toggle between the two modes.
-
-    "tsvnc profile-name" and "tsvnc user@hostname" work too.
-
-
-Unix/MacOSX Install:
-
-    There is no standard install for the bundles, but you can make
-    symlinks like so:
-
-        cd /a/directory/in/PATH
-        ln -s /path/to/ssvnc/bin/{s,t}* .
-
-    Or put /path/to/ssvnc/bin, /path/to/ssvnc/Unix, or /path/to/ssvnc/MacOSX
-    in your PATH.
-
-    For the conventional source tarball it will compile and install, e.g.:
-
-       gzip -dc ssvnc-1.0.29.src.tar.gz | tar xvf -
-       cd ssvnc-1.0.29
-       make config
-       make all
-       make PREFIX=/my/install/dir install
-
-    then have /my/install/dir/bin in your PATH.
-
-
-
-Windows:
-
-    Unzip, using WinZip or a similar utility, the zip file:
-
-        ssvnc-1.0.29.zip
-
-    Run the GUI, e.g.:
-
-        Start -> Run -> Browse
-
-    and then navigate to
-
-        .../ssvnc/Windows/ssvnc.exe
-
-    select Open, and then OK to launch it.
-
-    The smaller file "ssvnc_windows_only-1.0.29.zip"
-    could have been used as well.
-
-    You can make a Windows shortcut to this program if you want to.
-
-    See the Windows/README.txt for more info.
-
-
-    If you want a SSH-only tool (without the distractions of SSL) run
-    the command:
-
-                sshvnc.bat
-
-    Or click "SSH-Only Mode" under Options.
-
-
-    If you want a simple VNC Terminal Services only mode (requires x11vnc
-    on the remote server) run the command:
-
-                tsvnc.bat
-
-    Or click "Terminal Services" under Options.  Control-t will toggle
-    between the two modes.  "tsvnc profile-name" and "tsvnc user@hostname"
-    work too.
-
-     _________________________________________________________________
-
-   You can read all of the SSVNC GUI's Online Help Text here.
-     _________________________________________________________________
-
-   The bundle unpacks a directory/folder named: ssvnc. It contains these
-   programs to launch the GUI:
-        Windows/ssvnc.exe        for Windows
-        MacOSX/ssvnc             for Mac OS X
-        Unix/ssvnc               for Unix
-
-   (the Mac OS X and Unix launchers are simply links to the bin
-   directory). See the README for more information.
-
-   The SSH-Only mode launcher program has name sshvnc. The Terminal
-   Services mode launcher program (assumes x11vnc 0.8.4 or later and Xvfb
-   installed on the server machine) has name tsvnc.
-
-   The Viewer SSL support is done via a wrapper script (bin/ssvnc_cmd
-   that calls bin/util/ss_vncviewer) that starts up the STUNNEL tunnel
-   first and then starts the TightVNC viewer pointed at that tunnel. The
-   bin/ssvnc program is a GUI front-end to that script. See this FAQ for
-   more details on SSL tunnelling. In SSH connection mode, the wrappers
-   start up SSH appropriately.
-
-
-   Memory Stick Usage: If you create a directory named "Home" in that
-   toplevel ssvnc directory then that will be used as the base for
-   storing VNC profiles and certificates. Also, for convenience, if you
-   first run the command with "." as an argument (e.g. "ssvnc .") it will
-   automatically create the "Home" directory for you. This is handy if
-   you want to place SSVNC on a USB flash drive that you carry around for
-   mobile use and you want the profiles you create to stay with the drive
-   (otherwise you'd have to browse to the drive directory each time you
-   load or save).
-
-   One user on Windows created a BAT file to launch SSVNC and needed to
-   do this to get the Home directory correct:
-cd \ssvnc\Windows
-start \ssvnc\Windows\ssvnc.exe
-
-   (an optional profile name can be supplied to the ssvnc.exe line)
-
-   WARNING: if you use ssvnc from an "Internet Cafe", i.e. some untrusted
-   computer, please be aware that someone may have set up that machine to
-   be capturing your keystrokes, etc.
-
-
-   SSH-Only version: The command "sshvnc" can be run instead of "ssvnc"
-   to get an SSH-only version of the tool:
-
-   [sshvnc.gif]
-
-   These also work: "sshvnc myprofile" and "sshvnc user@hostname". To
-   switch from the regular SSVNC mode, click "SSH-Only Mode" under
-   Options. This mode is less distracting if you never plan to use SSL,
-   manage certificates, etc.
-
-
-   Terminal Services Only: The command "tsvnc" can be run instead of
-   "ssvnc" to get a "Terminal Services" only version of the tool:
-
-   [tsvnc.gif]
-
-   These also work: "tsvnc myprofile" and "tsvnc user@hostname". To
-   switch from the regular SSVNC mode, click "Terminal Services" under
-   Options.
-
-   This mode requires x11vnc (0.9.3 or later) installed on the remote
-   machine to find, create, and manage the user sessions. SSH is used to
-   create the encrypted and authenticated tunnel. The Xvfb (virtual
-   framebuffer X server) program must also be installed on the remote
-   system. However tsvnc will also connect to a real X session (i.e. on
-   the physical hardware) if you are already logged into the X session;
-   this is a useful access mode and does not require Xvfb on the remote
-   system.
-
-   This mode should be very easy for beginner users to understand and
-   use. On the remote end you only need to have x11vnc and Xvfb available
-   in $PATH, and on the local end you just run something like:
-   tsvnc myname@myhost.com
-
-   (or start up the tsvnc GUI first and then enter myname@myhost.com and
-   press "Connect").
-
-   Normally the Terminal Services sessions created are virtual (RAM-only)
-   ones (e.g. Xvfb, Xdummy, or Xvnc), however a nice feature is if you
-   have a regular X session (i.e displaying on the physical hardware) on
-   the remote machine that you are ALREADY logged into, then the x11vnc
-   run from tsvnc will find it for you as well.
-
-   Also, there is setting "X Login" under Advanced Options that allows
-   you to attach to a real X server with no one logged in yet (i.e.
-   XDM/GDM/KDM Login Greeter screen) as long as you have sudo(1)
-   permission on the remote machine.
-
-   Nice features to soon to be added to the tsvnc mode are easy CUPS
-   printing (working fairly well) and Sound redirection (needs much work)
-   of the Terminal Services Desktop session. It is easier in tsvnc mode
-   because the entire desktop session can be started with the correct
-   environment. ssvnc tries to handle the general case of an already
-   started desktop and that is more difficult.
-
-
-   Proxies: Web proxies, SOCKS proxies, and the UltraVNC repeater proxy
-   are supported to allow the SSVNC connection to go through the proxy to
-   the otherwise unreachable VNC Server. SSH gateway machines can be used
-   in the same way. Read more about SSVNC proxy support here.
-
-
-   Dynamic VNC Server Port determination: If you are running SSVNC on
-   Unix and are using SSH to start the remote VNC server and the VNC
-   server prints out the line "PORT=NNNN" to indicate which dynamic port
-   it is using (x11vnc does this), then if you prefix the SSH command
-   with "PORT=" SSVNC will watch for the PORT=NNNN line and uses ssh's
-   built in SOCKS proxy (ssh -D ...) to connect to the dynamic VNC server
-   port through the SSH tunnel. For example:
-        VNC Host:Display     user@somehost.com
-        Remote SSH Command:  PORT= x11vnc -find
-
-   or "PORT= x11vnc -display :0 -localhost", etc. Or use "P= x11vnc ..."
-
-   There is also code to detect the display of the regular Unix
-   vncserver(1). It extracts the display (and hence port) from the lines
-   "New 'X' desktop is hostname:4" and also "VNC server is already
-   running as :4". So you can use something like:
-        PORT= vncserver; sleep 15
-or:     PORT= vncserver :4; sleep 15
-
-   the latter is preferred because when you reconnect with it will find
-   the already running one. The former one will keep creating new X
-   sessions if called repeatedly.
-
-   If you use PORT= on Windows, a large random port is selected instead
-   and the -rfbport option is passed to x11vnc (it does not work with
-   vncserver).
-
-
-
-   Patches for Unix Tightvnc viewer:
-
-   The rfbNewFBSize support allows the enhanced TightVNC Unix viewer to
-   resize when the server does (e.g. "x11vnc -R scale=3/4" remote control
-   command).
-
-   The cursor alphablending is described here.
-
-   The RealVNC ZRLE encoding is supported, in addition to some low colors
-   modes (16bpp and 8bpp at 256, 64, and even 8 colors, for use on very
-   slow connections). Greyscales are also enabled for the low color
-   modes.
-
-   The Popup menu (F8) is enhanced with the ability to change many things
-   on the fly. F9 is added as a shortcut to toggle FullScreen mode.
-
-   Client Side Caching: The x11vnc client-side caching is handled nicely
-   by this viewer. The very large pixel cache below the actual display in
-   this caching method is distracting. Our Unix VNC viewer will
-   automatically try to autodetect the actual display height if the
-   framebuffer is very tall (more than twice as high as it is wide). One
-   can also set the height to the known value via -ycrop n, or use -ycrop
-   -1 to force autodection. In fullscreen mode one is not possible to
-   scroll down to the pixel cache region. In non-fullscreen mode the
-   window manager frame is "shrink-wrapped" around the actual screen
-   display. You can still scroll down to the pixel cache region. The
-   scrollbars are set to be very thin (2 pixels) to be less distracting.
-   Use the -sbwidth n to make them wider.
-
-   Probably nobody is interested in the grabserver patch for old window
-   managers when the viewer is in fullscreen mode... This and some other
-   unfixed bugs have been fixed in our patches (fullscreen toggle works
-   with KDE, -x11cursor has been fixed, and the dot cursor has been made
-   smaller).
-
-   From the -help output:
-SSVNC Viewer (based on TightVNC viewer version 1.3.9)
-
-Usage: vncviewer [<OPTIONS>] [<HOST>][:<DISPLAY#>]
-       vncviewer [<OPTIONS>] [<HOST>][::<PORT#>]
-       vncviewer [<OPTIONS>] exec=[CMD ARGS...]
-       vncviewer [<OPTIONS>] fd=n
-       vncviewer [<OPTIONS>] /path/to/unix/socket
-       vncviewer [<OPTIONS>] -listen [<DISPLAY#>]
-       vncviewer -help
-
-<OPTIONS> are standard Xt options, or:
-        -via <GATEWAY>
-        -shared (set by default)
-        -noshared
-        -viewonly
-        -fullscreen
-        -noraiseonbeep
-        -passwd <PASSWD-FILENAME> (standard VNC authentication)
-        -user <USERNAME> (Unix login authentication)
-        -encodings <ENCODING-LIST> (e.g. "tight,copyrect")
-        -bgr233
-        -owncmap
-        -truecolour
-        -depth <DEPTH>
-        -compresslevel <COMPRESS-VALUE> (0..9: 0-fast, 9-best)
-        -quality <JPEG-QUALITY-VALUE> (0..9: 0-low, 9-high)
-        -nojpeg
-        -nocursorshape
-        -x11cursor
-        -autopass
-
-Option names may be abbreviated, e.g. -bgr instead of -bgr233.
-See the manual page for more information.
-
-
-Enhanced TightVNC viewer (SSVNC) options:
-
-   URL http://www.karlrunge.com/x11vnc/ssvnc.html
-
-   Note: ZRLE and ZYWRLE encodings are now supported.
-
-   Note: F9 is shortcut to Toggle FullScreen mode.
-
-   Note: In -listen mode set the env var. SSVNC_MULTIPLE_LISTEN=1
-         to allow more than one incoming VNC server at a time.
-         This is the same as -multilisten described below.  Set
-         SSVNC_MULTIPLE_LISTEN=MAX:n to allow no more than "n"
-         simultaneous reverse connections.
-
-   Note: If the host:port is specified as "exec=command args..."
-         then instead of making a TCP/IP socket connection to the
-         remote VNC server, "command args..." is executed and the
-         viewer is attached to its stdio.  This enables tunnelling
-         established via an external command, e.g. an stunnel(8)
-         that does not involve a listening socket.  This mode does
-         not work for -listen reverse connections.
-
-         If the host:port is specified as "fd=n" then it is assumed
-         n is an already opened file descriptor to the socket. (i.e
-         the parent did fork+exec)
-
-         If the host:port contains a '/' it is interpreted as a
-         unix-domain socket (AF_LOCAL insead of AF_INET)
-
-        -multilisten  As in -listen (reverse connection listening) except
-                    allow more than one incoming VNC server to be connected
-                    at a time.  The default for -listen of only one at a
-                    time tries to play it safe by not allowing anyone on
-                    the network to put (many) desktops on your screen over
-                    a long window of time. Use -multilisten for no limit.
-
-        -acceptpopup  In -listen (reverse connection listening) mode when
-                    a reverse VNC connection comes in show a popup asking
-                    whether to Accept or Reject the connection.  The IP
-                    address of the connecting host is shown.  Same as
-                    setting the env. var. SSVNC_ACCEPT_POPUP=1.
-
-        -acceptpopupsc  As in -acceptpopup except assume UltraVNC Single
-                    Click (SC) server.  Retrieve User and ComputerName
-                    info from UltraVNC Server and display in the Popup.
-
-        -use64      In -bgr233 mode, use 64 colors instead of 256.
-        -bgr222     Same as -use64.
-
-        -use8       In -bgr233 mode, use 8 colors instead of 256.
-        -bgr111     Same as -use8.
-
-        -16bpp      If the vnc viewer X display is depth 24 at 32bpp
-                    request a 16bpp format from the VNC server to cut
-                    network traffic by up to 2X, then tranlate the
-                    pixels to 32bpp locally.
-        -bgr565     Same as -16bpp.
-
-        -grey       Use a grey scale for the 16- and 8-bpp modes.
-
-        -alpha      Use alphablending transparency for local cursors
-                    requires: x11vnc server, both client and server
-                    must be 32bpp and same endianness.
-
-        -scale str  Scale the desktop locally.  The string "str" can
-                    a floating point ratio, e.g. "0.9", or a fraction,
-                    e.g. "3/4", or WxH, e.g. 1280x1024.  Use "fit"
-                    to fit in the current screen size.  Use "auto" to
-                    fit in the window size.  "str" can also be set by
-                    the env. var. SSVNC_SCALE.
-
-                    If you observe mouse trail painting errors, enable
-                    X11 Cursor mode (either via Popup or -x11cursor.)
-
-                    Note that scaling is done in software and so can be
-                    slow and requires more memory.  Some speedup Tips:
-
-                        ZRLE is faster than Tight in this mode.  When
-                        scaling is first detected, the encoding will
-                        be automatically switched to ZRLE.  Use the
-                        Popup menu if you want to go back to Tight.
-                        Set SSVNC_PRESERVE_ENCODING=1 to disable this.
-
-                        Use a solid background on the remote side.
-                        (e.g. manually or via x11vnc -solid ...)
-
-                        If the remote server is x11vnc, try client
-                        side caching: x11vnc -ncache 10 ...
-
-        -ycrop n    Only show the top n rows of the framebuffer.  For
-                    use with x11vnc -ncache client caching option
-                    to help "hide" the pixel cache region.
-                    Use a negative value (e.g. -1) for autodetection.
-                    Autodetection will always take place if the remote
-                    fb height is more than 2 times the width.
-
-        -sbwidth n  Scrollbar width for x11vnc -ncache mode (-ycrop),
-                    default is very narrow: 2 pixels, it is narrow to
-                    avoid distraction in -ycrop mode.
-
-        -nobell     Disable bell.
-
-        -rawlocal   Prefer raw encoding for localhost, default is
-                    no, i.e. assumes you have a SSH tunnel instead.
-
-        -notty      Try to avoid using the terminal for interactive
-                    responses: use windows for messages and prompting
-                    instead.  Messages will also be printed to terminal.
-
-        -sendclipboard  Send the X CLIPBOARD selection (i.e. Ctrl+C,
-                        Ctrl+V) instead of the X PRIMARY selection (mouse
-                        select and middle button paste.)
-
-        -sendalways     Whenever the mouse enters the VNC viewer main
-                        window, send the selection to the VNC server even if
-                        it has not changed.  This is like the Xt resource
-                        translation SelectionToVNC(always)
-
-        -recvtext str   When cut text is received from the VNC server,
-                        ssvncviewer will set both the X PRIMARY and the
-                        X CLIPBOARD local selections.  To control which
-                        is set, specify 'str' as 'primary', 'clipboard',
-                        or 'both' (the default.)
-
-        -graball    Grab the entire X server when in fullscreen mode,
-                    needed by some old window managers like fvwm2.
-
-        -popupfix   Warp the popup back to the pointer position,
-                    needed by some old window managers like fvwm2.
-        -sendclipboard  Send the X CLIPBOARD selection (i.e. Ctrl+C,
-                        Ctrl+V) instead of the X PRIMARY selection (mouse
-                        select and middle button paste.)
-
-        -sendalways     Whenever the mouse enters the VNC viewer main
-                        window, send the selection to the VNC server even if
-                        it has not changed.  This is like the Xt resource
-                        translation SelectionToVNC(always)
-
-        -recvtext str   When cut text is received from the VNC server,
-                        ssvncviewer will set both the X PRIMARY and the
-                        X CLIPBOARD local selections.  To control which
-                        is set, specify 'str' as 'primary', 'clipboard',
-                        or 'both' (the default.)
-
-        -graball    Grab the entire X server when in fullscreen mode,
-                    needed by some old window managers like fvwm2.
-
-        -popupfix   Warp the popup back to the pointer position,
-                    needed by some old window managers like fvwm2.
-
-        -grabkbd    Grab the X keyboard when in fullscreen mode,
-                    needed by some window managers. Same as -grabkeyboard.
-                    -grabkbd is the default, use -nograbkbd to disable.
-
-        -bs, -nobs  Whether or not to use X server Backingstore for the
-                    main viewer window.  The default is to not, mainly
-                    because most Linux, etc, systems X servers disable
-                    *all* Backingstore by default.  To re-enable it put
-
-                        Option "Backingstore"
-
-                    in the Device section of /etc/X11/xorg.conf.
-                    In -bs mode with no X server backingstore, whenever an
-                    area of the screen is re-exposed it must go out to the
-                    VNC server to retrieve the pixels. This is too slow.
-
-                    In -nobs mode, memory is allocated by the viewer to
-                    provide its own backing of the main viewer window. This
-                    actually makes some activities faster (changes in large
-                    regions) but can appear to "flash" too much.
-
-        -noshm      Disable use of MIT shared memory extension (not recommended
-)
-
-        -termchat   Do the UltraVNC chat in the terminal vncviewer is in
-                    instead of in an independent window.
-
-        -unixpw str Useful for logging into x11vnc in -unixpw mode. "str" is a
-                    string that allows many ways to enter the Unix Username
-                    and Unix Password.  These characters: username, newline,
-                    password, newline are sent to the VNC server after any VNC
-                    authentication has taken place.  Under x11vnc they are
-                    used for the -unixpw login.  Other VNC servers could do
-                    something similar.
-
-                    You can also indicate "str" via the environment
-                    variable SSVNC_UNIXPW.
-
-                    Note that the Escape key is actually sent first to tell
-                    x11vnc to not echo the Unix Username back to the VNC
-                    viewer. Set SSVNC_UNIXPW_NOESC=1 to override this.
-
-                    If str is ".", then you are prompted at the command line
-                    for the username and password in the normal way.  If str is
-                    "-" the stdin is read via getpass(3) for username@password.
-                    Otherwise if str is a file, it is opened and the first line
-                    read is taken as the Unix username and the 2nd as the
-                    password. If str prefixed by "rm:" the file is removed
-                    after reading. Otherwise, if str has a "@" character,
-                    it is taken as username@password. Otherwise, the program
-                    exits with an error. Got all that?
-
-     -repeater str  This is for use with UltraVNC repeater proxy described
-                    here: http://www.uvnc.com/addons/repeater.html.  The "str"
-                    is the ID string to be sent to the repeater.  E.g. ID:1234
-                    It can also be the hostname and port or display of the VNC
-                    server, e.g. 12.34.56.78:0 or snoopy.com:1.  Note that when
-                    using -repeater, the host:dpy on the cmdline is the repeate
-r
-                    server, NOT the VNC server.  The repeater will connect you.
-
-                    Example: vncviewer ... -repeater ID:3333 repeat.host:5900
-                    Example: vncviewer ... -repeater vhost:0 repeat.host:5900
-
-                    Use, e.g., '-repeater SCIII=ID:3210' if the repeater is a
-                    Single Click III (SSL) repeater (repeater_SSL.exe) and you
-                    are passing the SSL part of the connection through stunnel,
-                    socat, etc. This way the magic UltraVNC string 'testB'
-                    needed to work with the repeater is sent to it.
-
-     -rfbversion str Set the advertised RFB version.  E.g.: -rfbversion 3.6
-                    For some servers, e.g. UltraVNC this needs to be done.
-
-     -ultradsm      UltraVNC has symmetric private key encryption DSM plugins:
-                    http://www.uvnc.com/features/encryption.html. It is assumed
-                    you are using a unix program (e.g. our ultravnc_dsm_helper)
-                    to encrypt and decrypt the UltraVNC DSM stream. IN ADDITION
-                    TO THAT supply -ultradsm to tell THIS viewer to modify the
-                    RFB data sent so as to work with the UltraVNC Server. For
-                    some reason, each RFB msg type must be sent twice under DSM
-.
-
-     -mslogon user  Use Windows MS Logon to an UltraVNC server.  Supply the
-                    username or "1" to be prompted.  The default is to
-                    autodetect the UltraVNC MS Logon server and prompt for
-                    the username and password.
-
-                    IMPORTANT NOTE: The UltraVNC MS-Logon Diffie-Hellman
-                    exchange is very weak and can be brute forced to recover
-                    your username and password in a few seconds of CPU time.
-                    To be safe, be sure to use an additional encrypted tunnel
-                    (e.g. SSL or SSH) for the entire VNC session.
-
-     -chatonly      Try to be a client that only does UltraVNC text chat. This
-                    mode is used by x11vnc to present a chat window on the
-                    physical X11 console (i.e. chat with the person at the
-                    display).
-
-     -env VAR=VALUE To save writing a shell script to set environment variables
-,
-                    specify as many as you need on the command line.  For
-                    example, -env SSVNC_MULTIPLE_LISTEN=MAX:5 -env EDITOR=vi
-
-     -noipv6        Disable all IPv6 sockets.  Same as VNCVIEWER_NO_IPV6=1.
-
-     -noipv4        Disable all IPv4 sockets.  Same as VNCVIEWER_NO_IPV4=1.
-
-     -printres      Print out the Ssvnc X resources (appdefaults) and then exit
-                    You can save them to a file and customize them (e.g. the
-                    keybindings and Popup menu)  Then point to the file via
-                    XENVIRONMENT or XAPPLRESDIR.
-
-     -pipeline      Like TurboVNC, request the next framebuffer update as soon
-                    as possible instead of waiting until the end of the current
-                    framebuffer update coming in.  Helps 'pipeline' the updates
-.
-                    This is currently the default, use -nopipeline to disable.
-
-     -appshare      Enable features for use with x11vnc's -appshare mode where
-                    instead of sharing the full desktop only the application's
-                    windows are shared.  Viewer multilisten mode is used to
-                    create the multiple windows: -multilisten is implied.
-                    See 'x11vnc -appshare -help' more information on the mode.
-
-                    Features enabled in the viewer under -appshare are:
-                    Minimum extra text in the title, auto -ycrop is disabled,
-                    x11vnc -remote_prefix X11VNC_APPSHARE_CMD: message channel,
-                    x11vnc initial window position hints.  See also Escape Keys
-                    below for additional key and mouse bindings.
-
-     -escape str    This sets the 'Escape Keys' modifier sequence and enables
-                    escape keys mode.  When the modifier keys escape sequence
-                    is held down, the next keystroke is interpreted locally
-                    to perform a special action instead of being sent to the
-                    remote VNC server.
-
-                    Use '-escape default' for the default modifier sequence.
-                    (Unix: Alt_L,Super_L and MacOSX: Control_L,Meta_L)
-
-    Here are the 'Escape Keys: Help+Set' instructions from the Popup Menu:
-
-    Escape Keys:  Enter a comma separated list of modifier keys to be the
-    'escape sequence'.  When these keys are held down, the next keystroke is
-    interpreted locally to invoke a special action instead of being sent to
-    the remote VNC server.  In other words, a set of 'Hot Keys'.
-
-    To enable or disable this, click on 'Escape Keys: Toggle' in the Popup.
-
-    Here is the list of hot-key mappings to special actions:
-
-       r: refresh desktop  b: toggle bell   c: toggle full-color
-       f: file transfer    x: x11cursor     z: toggle Tight/ZRLE
-       l: full screen      g: graball       e: escape keys dialog
-       s: scale dialog     +: scale up (=)  -: scale down (_)
-       t: text chat                         a: alphablend cursor
-       V: toggle viewonly  Q: quit viewer   1 2 3 4 5 6: UltraVNC scale 1/n
-
-       Arrow keys:         pan the viewport about 10% for each keypress.
-       PageUp / PageDown:  pan the viewport by a screenful vertically.
-       Home   / End:       pan the viewport by a screenful horizontally.
-       KeyPad Arrow keys:  pan the viewport by 1 pixel for each keypress.
-       Dragging the Mouse with Button1 pressed also pans the viewport.
-       Clicking Mouse Button3 brings up the Popup Menu.
-
-    The above mappings are *always* active in ViewOnly mode, unless you set the
-    Escape Keys value to 'never'.
-
-    If the Escape Keys value below is set to 'default' then a default list of
-    of modifier keys is used.  For Unix it is: Alt_L,Super_L and for MacOSX it
-    is Control_L,Meta_L.  Note: the Super_L key usually has a Windows(TM) Flag
-    on it.  Also note the _L and _R mean the key is on the LEFT or RIGHT side
-    of the keyboard.
-
-    On Unix   the default is Alt and Windows keys on Left side of keyboard.
-    On MacOSX the default is Control and Command keys on Left side of keyboard.
-
-    Example: Press and hold the Alt and Windows keys on the LEFT side of the
-    keyboard and then press 'c' to toggle the full-color state.  Or press 't'
-    to toggle the ultravnc Text Chat window, etc.
-
-    To use something besides the default, supply a comma separated list (or a
-    single one) from: Shift_L Shift_R Control_L Control_R Alt_L Alt_R Meta_L
-    Meta_R Super_L Super_R Hyper_L Hyper_R or Mode_switch.
-
-
-   New Popup actions:
-
-        ViewOnly:                ~ -viewonly
-        Disable Bell:            ~ -nobell
-        Cursor Shape:            ~ -nocursorshape
-        X11 Cursor:              ~ -x11cursor
-        Cursor Alphablend:       ~ -alpha
-        Toggle Tight/Hextile:    ~ -encodings hextile...
-        Toggle Tight/ZRLE:       ~ -encodings zrle...
-        Toggle ZRLE/ZYWRLE:      ~ -encodings zywrle...
-        Quality Level            ~ -quality (both Tight and ZYWRLE)
-        Compress Level           ~ -compresslevel
-        Disable JPEG:            ~ -nojpeg  (Tight)
-        Pipeline Updates         ~ -pipeline
-
-        Full Color                 as many colors as local screen allows.
-        Grey scale (16 & 8-bpp)  ~ -grey, for low colors 16/8bpp modes only.
-        16 bit color (BGR565)    ~ -16bpp / -bgr565
-        8  bit color (BGR233)    ~ -bgr233
-        256 colors               ~ -bgr233 default # of colors.
-         64 colors               ~ -bgr222 / -use64
-          8 colors               ~ -bgr111 / -use8
-        Scale Viewer             ~ -scale
-        Escape Keys: Toggle      ~ -escape
-        Escape Keys: Help+Set    ~ -escape
-        Set Y Crop (y-max)       ~ -ycrop
-        Set Scrollbar Width      ~ -sbwidth
-        XGrabServer              ~ -graball
-
-        UltraVNC Extensions:
-
-          Set 1/n Server Scale     Ultravnc ext. Scale desktop by 1/n.
-          Text Chat                Ultravnc ext. Do Text Chat.
-          File Transfer            Ultravnc ext. File xfer via Java helper.
-          Single Window            Ultravnc ext. Grab and view a single window.
-                                   (select then click on the window you want).
-          Disable Remote Input     Ultravnc ext. Try to prevent input and
-                                   viewing of monitor at physical display.
-
-        Note: the Ultravnc extensions only apply to servers that support
-              them.  x11vnc/libvncserver supports some of them.
-
-        Send Clipboard not Primary  ~ -sendclipboard
-        Send Selection Every time   ~ -sendalways
-
-   Nearly all of these can be changed dynamically in the Popup menu
-   (press F8 for it):
-
-   [viewer_menu.gif] [unixviewer.jpg]
-
-     _________________________________________________________________
-
-   Windows:
-
-   For Windows, SSL Viewer support is provided by a GUI Windows/ssvnc.exe
-   that prompts for the VNC display and then starts up STUNNEL followed
-   by the Stock TightVNC Windows Viewer. Both are bundled in the package
-   for your convenience. The GUI has other useful features. When the
-   connection is finished, you will be asked if you want to terminate the
-   STUNNEL program. For SSH connections from Windows the GUI will use
-   PLINK instead of STUNNEL.
-
-   Unix and Mac OS X:
-
-   Run the GUI (ssvnc, see above) and let me know how it goes.
-     _________________________________________________________________
-
-   Hopefully this tool will make it convenient for people to help test
-   and use the built-in SSL support in x11vnc. Extra testing of this
-   feature is much appreciated!! Thanks.
-
-   Please Help Test the newly added features:
-     * Automatic Service tunnelling via SSH for CUPS and SMB Printing
-     * ESD/ARTSD Audio
-     * SMB (Windows/Samba) filesystem mounting
-
-   These allow you to print from the remote (VNC Server) machine to local
-   printers, listen to sounds (with some limitations) from the remote VNC
-   Server machine, and to mount your local Windows or Samba shares on the
-   remote VNC Server machine. Basically these new features try to
-   automate the tricks described here:
-    http://www.karlrunge.com/x11vnc/faq.html#faq-smb-shares
-    http://www.karlrunge.com/x11vnc/faq.html#faq-cups
-    http://www.karlrunge.com/x11vnc/faq.html#faq-sound
-     _________________________________________________________________
-
-   Downloading: Downloads for this project are hosted at Sourceforge.net.
-
-   Choose the archive file bundle that best suits you (e.g. no source
-   code, windows only, unix only, zip, tar etc).
-
-   A quick guide:
-
-      On some flavor of Unix, e.g. Linux or Solaris? Use
-   "ssvnc_unix_only" (or "ssvnc_no_windows" to recompile).
-      On Mac OS X? Use "ssvnc_no_windows".
-      On Windows? Use "ssvnc_windows_only".
-  ssvnc_windows_only-1.0.28.zip      Windows Binaries Only.  No source included
- (6.2MB)
-  ssvnc_no_windows-1.0.28.tar.gz     Unix and Mac OS X Only. No Windows binarie
-s.  Source included. (10.1MB)
-  ssvnc_unix_only-1.0.28.tar.gz      Unix Binaries Only.     No source included
-. (7.2MB)
-  ssvnc_unix_minimal-1.0.28.tar.gz   Unix Minimal.  You must supply your own vn
-cviewer and stunnel. (0.2MB)
-
-  ssvnc-1.0.28.tar.gz                All Unix, Mac OS X, and Windows binaries a
-nd source TGZ. (16.1MB)
-  ssvnc-1.0.28.zip                   All Unix, Mac OS X, and Windows binaries a
-nd source ZIP. (16.4MB)
-  ssvnc_all-1.0.28.zip               All Unix, Mac OS X, and Windows binaries a
-nd source AND full archives in the zip dir. (19.2MB)
-
-
-   Here is a conventional source tarball:
-  ssvnc-1.0.28.src.tar.gz            Conventional Source for SSVNC GUI and Unix
- VNCviewer  (0.5MB)
-
-   it will be of use to those who do not want the SSVNC
-   "one-size-fits-all" bundles. For example, package/distro maintainers
-   will find this more familiar and useful to them (i.e. they run: "make
-   config; make all; make install"). Note that it does not include the
-   stunnel source, and so has a dependency that the system stunnel is
-   installed.
-
-   Read the README.src file for more information on using the
-   conventional source tarball.
-
-
-   Note: even with the Unix bundles, e.g. "ssvnc_no_windows" or
-   "ssvnc_all", you may need to run the "./build.unix" script in the top
-   directory to recompile for your operating system.
-
-   Here are the corresponding 1.0.29 development bundles (Please help
-   test them):
-
-  ssvnc_windows_only-1.0.29.zip
-  ssvnc_no_windows-1.0.29.tar.gz
-  ssvnc_unix_only-1.0.29.tar.gz
-  ssvnc_unix_minimal-1.0.29.tar.gz
-
-  ssvnc-1.0.29.tar.gz
-  ssvnc-1.0.29.zip
-  ssvnc_all-1.0.29.zip
-
-  ssvnc-1.0.29.src.tar.gz            Conventional Source for SSVNC GUI and Unix
- VNCviewer  (0.5MB)
-
-
-   For any Unix system, a self-extracting and running file for the
-   "ssvnc_unix_minimal" package is here: ssvnc. Save it as filename
-   "ssvnc", type "chmod 755 ./ssvnc", and then launch the GUI via typing
-   "./ssvnc". Note that this "ssvnc_unix_minimal" mode requires you
-   install the "stunnel" and "vncviewer" programs externally (for
-   example, install your distros' versions, e.g. on debian: "apt-get
-   install stunnel4 xtightvncviewer".) It will work, but many of the
-   SSVNC features will be missing.
-
-   Previous releases:
-      Release 1.0.18 at Sourceforge.net
-      Release 1.0.19 at Sourceforge.net
-      Release 1.0.20 at Sourceforge.net
-      Release 1.0.21 at Sourceforge.net
-      Release 1.0.22 at Sourceforge.net
-      Release 1.0.23 at Sourceforge.net
-      Release 1.0.24 at Sourceforge.net
-      Release 1.0.25 at Sourceforge.net
-      Release 1.0.26 at Sourceforge.net
-      Release 1.0.27 at Sourceforge.net
-      Release 1.0.28 at Sourceforge.net
-
-
-   Please help test the UltraVNC File Transfer support in the native Unix
-   VNC viewer! Let us know how it went.
-
-   Current Unix binaries in the archives:
-    Linux.i686
-    Linux.x86_64
-    Linux.ppc64    X (removed)
-    Linux.alpha    X (removed)
-    SunOS.sun4u
-    SunOS.sun4m
-    SunOS.i86pc
-    Darwin.Power.Macintosh
-    Darwin.i386
-    HP-UX.9000     X (removed)
-    FreeBSD.i386   X (removed)
-    NetBSD.i386    X (removed)
-    OpenBSD.i386   X (removed)
-
-   (some of these are out of date, marked with 'X' above, because I no
-   longer have access to machines running those OS's. Use the
-   "build.unix" script to recompile on your system).
-
-   Note: some of the above binaries depend on libssl.so.0.9.7, whereas
-   some recent distros only provide libssl.so.0.9.8 by default (for
-   compatibility reasons they should install both by default but not all
-   do). So you may need to instruct your distro to install the 0.9.7
-   library (it is fine to have both runtimes installed simultaneously
-   since the libraries have different names). Update: I now try to
-   statically link libssl.a for all of the binaries in the archive.
-
-   You can also run the included build.unix script to try to
-   automatically build the binaries if your OS is not in the above list
-   or the included binary does not run properly on your system. Let me
-   know how that goes.
-     _________________________________________________________________
-
-   IMPORTANT: there may be restrictions for you to download, use, or
-   redistribute the above because of cryptographic software they contain
-   or for other reasons. Please check out your situation and information
-   at the following and related sites:
-        http://stunnel.mirt.net
-        http://www.stunnel.org
-        http://www.openssl.org
-        http://www.chiark.greenend.org.uk/~sgtatham/putty/
-        http://www.tightvnc.com
-        http://www.realvnc.com
-        http://sourceforge.net/projects/cotvnc/
-     _________________________________________________________________
-
-   README: Here is the toplevel README from the bundle.
-	
-=======================================================================
-http://www.karlrunge.com/x11vnc/x11vnc_opts.html:
-
-
-     _________________________________________________________________
-
-x11vnc: a VNC server for real X displays
-
-   Here are all of x11vnc command line options:
-% x11vnc -opts      (see below for -help long descriptions)
-
-x11vnc: allow VNC connections to real X11 displays. 0.9.13 lastmod: 2010-12-27
-
-x11vnc options:
-  -display disp            -auth file               -N                     
-  -autoport n              -rfbport str             -6                     
-  -no6                     -noipv6                  -noipv4                
-  -reopen                  -reflect host:N          -id windowid           
-  -sid windowid            -appshare                -clip WxH+X+Y          
-  -flashcmap               -shiftcmap n             -notruecolor           
-  -advertise_truecolor     -visual n                -overlay               
-  -overlay_nocursor        -8to24 [opts]            -24to32                
-  -scale fraction          -geometry WxH            -scale_cursor frac     
-  -viewonly                -shared                  -once                  
-  -forever                 -loop                    -timeout n             
-  -sleepin n               -inetd                   -tightfilexfer         
-  -ultrafilexfer           -http                    -http_ssl              
-  -avahi                   -mdns                    -zeroconf              
-  -connect string          -connect_or_exit str     -proxy string          
-  -vncconnect              -novncconnect            -allow host1[,host2..] 
-  -localhost               -unixsock str            -listen6 str           
-  -nolookup                -input string            -grabkbd               
-  -grabptr                 -ungrabboth              -grabalways            
-  -viewpasswd string       -passwdfile filename     -showrfbauth filename  
-  -unixpw [list]           -unixpw_nis [list]       -unixpw_cmd cmd        
-  -find                    -finddpy                 -listdpy               
-  -findauth [disp]         -create                  -xdummy                
-  -xvnc                    -xvnc_redirect           -xdummy_xvfb           
-  -create_xsrv str         -svc                     -svc_xdummy            
-  -svc_xvnc                -svc_xdummy_xvfb         -xdmsvc                
-  -sshxdmsvc               -unixpw_system_greeter   -redirect port         
-  -display WAIT:...        -vencrypt mode           -anontls mode          
-  -sslonly                 -dhparams file           -nossl                 
-  -ssl [pem]               -ssltimeout n            -sslnofail             
-  -ssldir dir              -sslverify path          -sslCRL path           
-  -sslGenCA [dir]          -sslGenCert type name    -sslEncKey pem         
-  -sslCertInfo pem         -sslDelCert pem          -sslScripts            
-  -stunnel [pem]           -stunnel3  [pem]         -enc cipher:keyfile    
-  -https [port]            -httpsredir [port]       -http_oneport          
-  -ssh user@host:disp      -usepw                   -storepasswd pass file 
-  -nopw                    -accept string           -afteraccept string    
-  -gone string             -users list              -noshm                 
-  -flipbyteorder           -onetile                 -solid [color]         
-  -blackout string         -xinerama                -noxinerama            
-  -xtrap                   -xrandr [mode]           -rotate string         
-  -padgeom WxH             -o logfile               -flag file             
-  -rmflag file             -rc filename             -norc                  
-  -env VAR=VALUE           -prog /path/to/x11vnc    -h, -help              
-  -?, -opts                -V, -version             -license               
-  -dbg                     -q, -quiet               -v, -verbose           
-  -bg                      -modtweak                -nomodtweak            
-  -xkb                     -noxkb                   -capslock              
-  -skip_lockkeys           -noskip_lockkeys         -skip_keycodes string  
-  -sloppy_keys             -skip_dups               -noskip_dups           
-  -add_keysyms             -noadd_keysyms           -clear_mods            
-  -clear_keys              -clear_all               -remap string          
-  -norepeat                -repeat                  -nofb                  
-  -nobell                  -nosel                   -noprimary             
-  -nosetprimary            -noclipboard             -nosetclipboard        
-  -seldir string           -cursor [mode]           -nocursor              
-  -cursor_drag             -arrow n                 -noxfixes              
-  -alphacut n              -alphafrac fraction      -alpharemove           
-  -noalphablend            -nocursorshape           -cursorpos             
-  -nocursorpos             -xwarppointer            -noxwarppointer        
-  -always_inject           -buttonmap string        -nodragging            
-  -ncache n                -ncache_cr               -ncache_no_moveraise   
-  -ncache_no_dtchange      -ncache_no_rootpixmap    -ncache_keep_anims     
-  -ncache_old_wm           -ncache_pad n            -debug_ncache          
-  -wireframe [str]         -nowireframe             -nowireframelocal      
-  -wirecopyrect mode       -nowirecopyrect          -debug_wireframe       
-  -scrollcopyrect mode     -noscrollcopyrect        -scr_area n            
-  -scr_skip list           -scr_inc list            -scr_keys list         
-  -scr_term list           -scr_keyrepeat lo-hi     -scr_parms string      
-  -fixscreen string        -debug_scroll            -noxrecord             
-  -grab_buster             -nograb_buster           -debug_grabs           
-  -debug_sel               -pointer_mode n          -input_skip n          
-  -allinput                -input_eagerly           -speeds rd,bw,lat      
-  -wmdt string             -debug_pointer           -debug_keyboard        
-  -defer time              -wait time               -extra_fbur n          
-  -wait_ui factor          -setdefer n              -nowait_bog            
-  -slow_fb time            -xrefresh time           -nap                   
-  -nonap                   -sb time                 -readtimeout n         
-  -ping n                  -nofbpm                  -fbpm                  
-  -nodpms                  -dpms                    -forcedpms             
-  -clientdpms              -noserverdpms            -noultraext            
-  -chatwindow              -noxdamage               -xd_area A             
-  -xd_mem f                -sigpipe string          -threads               
-  -nothreads               -fs f                    -gaps n                
-  -grow n                  -fuzz n                  -debug_tiles           
-  -snapfb                  -rawfb string            -freqtab file          
-  -pipeinput cmd           -macnodim                -macnosleep            
-  -macnosaver              -macnowait               -macwheel n            
-  -macnoswap               -macnoresize             -maciconanim n         
-  -macmenu                 -macuskbd                -macnoopengl           
-  -macnorawfb              -gui [gui-opts]          -remote command        
-  -query variable          -QD variable             -sync                  
-  -query_retries str       -remote_prefix str       -noremote              
-  -yesremote               -unsafe                  -safer                 
-  -privremote              -nocmds                  -allowedcmds list      
-  -deny_all              
-
-LibVNCServer options:
--rfbport port          TCP port for RFB protocol
--rfbwait time          max time in ms to wait for RFB client
--rfbauth passwd-file   use authentication on RFB protocol
-                       (use 'storepasswd' to create a password file)
--rfbversion 3.x        Set the version of the RFB we choose to advertise
--permitfiletransfer    permit file transfer support
--passwd plain-password use authentication 
-                       (use plain-password as password, USE AT YOUR RISK)
--deferupdate time      time in ms to defer updates (default 40)
--deferptrupdate time   time in ms to defer pointer updates (default none)
--desktop name          VNC desktop name (default "LibVNCServer")
--alwaysshared          always treat new clients as shared
--nevershared           never treat new clients as shared
--dontdisconnect        don't disconnect existing clients when a new non-shared
-                       connection comes in (refuse new connection instead)
--httpdir dir-path      enable http server using dir-path home
--httpport portnum      use portnum for http connection
--enablehttpproxy       enable http proxy support
--progressive height    enable progressive updating for slow links
--listen ipaddr         listen for connections only on network interface with
-                       addr ipaddr. '-listen localhost' and hostname work too.
-
-libvncserver-tight-extension options:
--disablefiletransfer   disable file transfer
--ftproot string        set ftp root
-
-
-
-
-% x11vnc -help
-
-x11vnc: allow VNC connections to real X11 displays. 0.9.13 lastmod: 2010-12-27
-
-(type "x11vnc -opts" to just list the options.)
-
-Typical usage is:
-
-   Run this command in a shell on the remote machine "far-host"
-   with X session you wish to view:
-
-       x11vnc -display :0
-
-   Then run this in another window on the machine you are sitting at:
-
-       vncviewer far-host:0
-
-Once x11vnc establishes connections with the X11 server and starts listening
-as a VNC server it will print out a string: PORT=XXXX where XXXX is typically
-5900 (the default VNC server port).  One would next run something like
-this on the local machine: "vncviewer hostname:N" where "hostname" is
-the name of the machine running x11vnc and N is XXXX - 5900, i.e. usually
-"vncviewer hostname:0".
-
-By default x11vnc will not allow the screen to be shared and it will exit
-as soon as the client disconnects.  See -shared and -forever below to override
-these protections.  See the FAQ for details how to tunnel the VNC connection
-through an encrypted channel such as ssh(1).  In brief:
-
-       ssh -t -L 5900:localhost:5900 far-host 'x11vnc -localhost -display :0'
-
-       vncviewer -encodings 'copyrect tight zrle hextile' localhost:0
-
-Also, use of a VNC password (-rfbauth or -passwdfile) is strongly recommended.
-
-For additional info see: http://www.karlrunge.com/x11vnc/
-                    and  http://www.karlrunge.com/x11vnc/faq.html
-
-
-Config file support: if the file $HOME/.x11vncrc exists then each line in
-it is treated as a single command line option.  Disable with -norc.  For
-each option name, the leading character "-" is not required.  E.g. a line
-that is either "forever" or "-forever" may be used and are equivalent.
-Likewise "wait 100" or "-wait 100" are acceptable and equivalent lines.
-The "#" character comments out to the end of the line in the usual way
-(backslash it for a literal).  Leading and trailing whitespace is trimmed off.
-Lines may be continued with a "\" as the last character of a line (it
-becomes a space character).
-
-Options:
-
--display disp          X11 server display to connect to, usually :0.  The X
-                       server process must be running on same machine and
-                       support MIT-SHM.  Equivalent to setting the DISPLAY
-                       environment variable to "disp".
-
-                       See the description below of the "-display WAIT:..."
-                       extensions, where alias "-find" will find the user's
-                       display automatically, and "-create" will create a
-                       Xvfb session if no session is found.
-
--auth file             Set the X authority file to be "file", equivalent to
-                       setting the XAUTHORITY environment variable to "file"
-                       before startup.  Same as -xauth file.  See Xsecurity(7),
-                       xauth(1) man pages for more info.
-
-                       Use '-auth guess' to have x11vnc use its -findauth
-                       mechanism (described below) to try to guess the
-                       XAUTHORITY filename and use it.
-
-                       XDM/GDM/KDM: if you are running x11vnc as root and want
-                       to find the XAUTHORITY before anyone has logged into an
-                       X session yet, use: x11vnc -env FD_XDM=1 -auth guess ...
-                       (This will also find the XAUTHORITY if a user is already
-                       logged into the X session.)  When running as root,
-                       FD_XDM=1 will be tried if the initial -auth guess fails.
-
--N                     If the X display is :N, try to set the VNC display to
-                       also be :N This just sets the -rfbport option to 5900+N
-                       The program will exit immediately if that port is not
-                       available. The -N option only works with normal -display
-                       usage, e.g. :0 or :8, -N is ignored in the -display
-                       WAIT:..., -create, -find, -svc, -redirect, etc modes.
-
--autoport n            Automatically probe for a free VNC port starting at n.
-                       The default is to start probing at 5900.  Use this to
-                       stay away from other VNC servers near 5900.
-
--rfbport str           The VNC port to listen on (a LibVNCServer option), e.g.
-                       5900, 5901, etc.  If specified as "-rfbport PROMPT"
-                       then the x11vnc -gui is used to prompt the user to
-                       enter the port number.
-
--6                     IPv6 listening support.  In addition to IPv4, the
-                       IPv6 address is listened on for incoming connections.
-                       The same port number as IPv4 is used.
-
-                       NOTE:  This x11vnc binary was compiled to have the
-                       "-6" IPv6 listening mode ENABLED by default (CPPFLAGS
-                       -DX11VNC_LISTEN6=1).  So to disable IPv6 listening mode
-                       you MUST supply the "-no6" option (see below.)
-
-                       The "-6" mode works for both normal connections and
-                       -ssl encrypted ones.  Nearly everything is supported
-                       for the IPv6 case, but there are a few exceptions.
-                       See -stunnel for its IPv6 support.
-
-                       Currently, for absolutely everything to work correctly
-                       the machine may need to have some IPv4 support, at the
-                       least for the loopback interface.  However, for nearly
-                       all usage modes no IPv4 support is required. See -nopiv4
-.
-
-                       If you have trouble compiling or running in IPv6 mode,
-                       set -DX11VNC_IPV6=0 in CPPFLAGS when configuring to
-                       disable IPv6 support.
-
--no6                   Disable IPv6 listening support (only useful if the
-                       "-6" mode is compiled in to be the default; see the
-                       X11VNC_LISTEN6 description above under "-6".)
-
--noipv6                Do not try to use IPv6 for any listening or connecting
-                       sockets.  This includes both the listening service
-                       port(s) and outgoing connections from -connect,
-                       -connect_or_exit, or -proxy.  Use this if you are having
-                       problems due to IPv6.
-
--noipv4                Do not try to use IPv4 for any listening or connecting
-                       sockets.  This is mainly for exploring the behavior of
-                       x11vnc on an IPv6-only system, but may have other uses.
-
--reopen                If the X server connection is disconnected, try to
-                       reopen the X display (up to one time.)  This is of use
-                       for display managers like GDM (KillInitClients option)
-                       that kill x11vnc just after the user logs into the
-                       X session.  Note: the reopened state may be unstable.
-                       Set X11VNC_REOPEN_DISPLAY=n to reopen n times and
-                       set X11VNC_REOPEN_SLEEP_MAX to the number of seconds,
-                       default 10, to keep trying to reopen the display (once
-                       per second.)
-
-                       Update: as of 0.9.9, x11vnc tries to automatically avoid
-                       being killed by the display manager by delaying creating
-                       windows or using XFIXES.  So you shouldn't need to use
-                       KillInitClients=false as long as you log in quickly
-                       enough (within 45 seconds of connecting.)  You can
-                       disable this by setting X11VNC_AVOID_WINDOWS=never.
-                       You can also set it to the number of seconds to delay.
-
--reflect host:N        Instead of connecting to and polling an X display,
-                       connect to the remote VNC server host:N and be a
-                       reflector/repeater for it.  This is useful for trying
-                       to manage the case of many simultaneous VNC viewers
-                       (e.g. classroom broadcasting) where, e.g. you put
-                       a repeater on each network switch, etc, to improve
-                       performance by distributing the load and network
-                       traffic.  Implies -shared (use -noshared as a later
-                       option to disable). See the discussion below under
-                       -rawfb vnc:host:N for more details.
-
--id windowid           Show the X window corresponding to "windowid" not
-                       the entire display.  New windows like popup menus,
-                       transient toplevels, etc, may not be seen or may be
-                       clipped.  Disabling SaveUnders or BackingStore in the
-                       X server may help show them.  x11vnc may crash if the
-                       window is initially partially obscured, changes size,
-                       is iconified, etc.  Some steps are taken to avoid this
-                       and the -xrandr mechanism is used to track resizes.  Use
-                       xwininfo(1) to get the window id, or use "-id pick"
-                       to have x11vnc run xwininfo(1) for you and extract
-                       the id.  The -id option is useful for exporting very
-                       simple applications (e.g. the current view on a webcam).
--sid windowid          As -id, but instead of using the window directly it
-                       shifts a root view to it: this shows SaveUnders menus,
-                       etc, although they will be clipped if they extend beyond
-                       the window.
-
--appshare              Simple application sharing based on the -id/-sid
-                       mechanism.  Every new toplevel window that the
-                       application creates induces a new viewer window via
-                       a reverse connection.  The -id/-sid and -connect
-                       options are required.  Run 'x11vnc -appshare -help'
-                       for more info.
-
--clip WxH+X+Y          Only show the sub-region of the full display that
-                       corresponds to the rectangle geometry with size WxH and
-                       offset +X+Y.  The VNC display has size WxH (i.e. smaller
-                       than the full display).  This also works for -id/-sid
-                       mode where the offset is relative to the upper left
-                       corner of the selected window.  An example use of this
-                       option would be to split a large (e.g. Xinerama) display
-                       into two parts to be accessed via separate viewers by
-                       running a separate x11vnc on each part.
-
-                       Use '-clip xinerama0' to clip to the first xinerama
-                       sub-screen (if xinerama is active).  xinerama1 for the
-                       2nd sub-screen, etc.  This way you don't need to figure
-                       out the WxH+X+Y of the desired xinerama sub-screen.
-                       screens are sorted in increasing distance from the
-                       (0,0) origin (I.e. not the Xserver's order).
-
--flashcmap             In 8bpp indexed color, let the installed colormap flash
-                       as the pointer moves from window to window (slow).
-                       Also try the -8to24 option to avoid flash altogether.
--shiftcmap n           Rare problem, but some 8bpp displays use less than 256
-                       colorcells (e.g. 16-color grayscale, perhaps the other
-                       bits are used for double buffering) *and* also need to
-                       shift the pixels values away from 0, .., ncells.  "n"
-                       indicates the shift to be applied to the pixel values.
-                       To see the pixel values set DEBUG_CMAP=1 to print out
-                       a colormap histogram.  Example: -shiftcmap 240
--notruecolor           For 8bpp displays, force indexed color (i.e. a colormap)
-                       even if it looks like 8bpp TrueColor (rare problem).
--advertise_truecolor   If the X11 display is indexed color, lie to clients
-                       when they first connect by telling them it is truecolor.
-                       To workaround RealVNC: inPF has colourMap but not 8bpp
-                       Use '-advertise_truecolor reset' to reset client fb too.
-
--visual n              This option probably does not do what you think.
-                       It simply *forces* the visual used for the framebuffer;
-                       this may be a bad thing... (e.g. messes up colors or
-                       cause a crash). It is useful for testing and for some
-                       workarounds.  n may be a decimal number, or 0x hex.
-                       Run xdpyinfo(1) for the values.  One may also use
-                       "TrueColor", etc. see <X11/X.h> for a list.  If the
-                       string ends in ":m" then for better or for worse
-                       the visual depth is forced to be m.  You may want to
-                       use -noshm when using this option (so XGetImage may
-                       automatically translate the pixel data).
-
--overlay               Handle multiple depth visuals on one screen, e.g. 8+24
-                       and 24+8 overlay visuals (the 32 bits per pixel are
-                       packed with 8 for PseudoColor and 24 for TrueColor).
-
-                       Currently -overlay only works on Solaris via
-                       XReadScreen(3X11) and IRIX using XReadDisplay(3).
-                       On Solaris there is a problem with image "bleeding"
-                       around transient popup menus (but not for the menu
-                       itself): a workaround is to disable SaveUnders
-                       by passing the "-su" argument to Xsun (in
-                       /etc/dt/config/Xservers).
-
-                       Use -overlay as a workaround for situations like these:
-                       Some legacy applications require the default visual to
-                       be 8bpp (8+24), or they will use 8bpp PseudoColor even
-                       when the default visual is depth 24 TrueColor (24+8).
-                       In these cases colors in some windows will be incorrect
-                       in x11vnc unless -overlay is used.  Another use of
-                       -overlay is to enable showing the exact mouse cursor
-                       shape (details below).
-
-                       Under -overlay, performance will be somewhat slower
-                       due to the extra image transformations required.
-                       For optimal performance do not use -overlay, but rather
-                       configure the X server so that the default visual is
-                       depth 24 TrueColor and try to have all apps use that
-                       visual (e.g. some apps have -use24 or -visual options).
--overlay_nocursor      Sets -overlay, but does not try to draw the exact mouse
-                       cursor shape using the overlay mechanism.
-
--8to24 [opts]          Try this option if -overlay is not supported on your
-                       OS, and you have a legacy 8bpp app that you want to
-                       view on a multi-depth display with default depth 24
-                       (and is 32 bpp) OR have a default depth 8 display with
-                       depth 24 overlay windows for some apps.  This option
-                       may not work on all X servers and hardware (tested
-                       on XFree86/Xorg mga driver and Xsun).  The "opts"
-                       string is not required and is described below.
-
-                       This mode enables a hack where x11vnc monitors windows
-                       within 3 levels from the root window.  If it finds
-                       any that are 8bpp it extracts the indexed color
-                       pixel values using XGetImage() and then applies a
-                       transformation using the colormap(s) to create TrueColor
-                       RGB values that it in turn inserts into bits 1-24 of
-                       the framebuffer.  This creates a depth 24 "view"
-                       of the display that is then exported via VNC.
-
-                       Conversely, for default depth 8 displays, the depth
-                       24 regions are read by XGetImage() and everything is
-                       transformed and inserted into a depth 24 TrueColor
-                       framebuffer.
-
-                       Note that even if there are *no* depth 24 visuals or
-                       windows (i.e. pure 8bpp), this mode is potentially
-                       an improvement over -flashcmap because it avoids the
-                       flashing and shows each window in the correct color.
-
-                       This method works OK, but may still have bugs and it
-                       does hog resources.  If there are multiple 8bpp windows
-                       using different colormaps, one may have to iconify all
-                       but one for the colors to be correct.
-
-                       There may be painting errors for clipping and switching
-                       between windows of depths 8 and 24.  Heuristics are
-                       applied to try to minimize the painting errors.  One can
-                       also press 3 Alt_L's in a row to refresh the screen
-                       if the error does not repair itself.  Also the option
-                       -fixscreen 8=3.0 or -fixscreen V=3.0 may be used to
-                       periodically refresh the screen at the cost of bandwidth
-                       (every 3 sec for this example).
-
-                       The [opts] string can contain the following settings.
-                       Multiple settings are separated by commas.
-
-                       For for some X servers with default depth 24 a
-                       speedup may be achieved via the option "nogetimage".
-                       This enables a scheme were XGetImage() is not used
-                       to retrieve the 8bpp data.  Instead, it assumes that
-                       the 8bpp data is in bits 25-32 of the 32bit X pixels.
-                       There is no requirement that the X server should put
-                       the data there for our poll requests, but some do and
-                       so the extra steps to retrieve it can be skipped.
-                       Tested with mga driver with XFree86/Xorg.  For the
-                       default depth 8 case this option is ignored.
-
-                       To adjust how often XGetImage() is used to poll the
-                       non-default visual regions for changes, use the option
-                       "poll=t" where "t" is a floating point time.
-                       (default: 0.05)
-
-                       Setting the option "level2" will limit the search
-                       for non-default visual windows to two levels from the
-                       root window.  Do this on slow machines where you know
-                       the window manager only imposes one extra window between
-                       the app window and the root window.
-
-                       Also for very slow machines use "cachewin=t"
-                       where t is a floating point amount of time to cache
-                       XGetWindowAttributes results.  E.g. cachewin=5.0.
-                       This may lead to the windows being unnoticed for this
-                       amount of time when deiconifying, painting errors, etc.
-
-                       While testing on a very old SS20 these options gave
-                       tolerable response: -8to24 poll=0.2,cachewin=5.0. For
-                       this machine -overlay is supported and gives better
-                       response.
-
-                       Debugging for this mode can be enabled by setting
-                       "dbg=1", "dbg=2", or "dbg=3".
-
--24to32                Very rare problem: if the framebuffer (X display
-                       or -rawfb) is 24bpp instead of the usual 32bpp, then
-                       dynamically transform the pixels to 32bpp.  This will be
-                       slower, but can be used to work around problems where
-                       VNC viewers cannot handle 24bpp (e.g. "main: setPF:
-                       not 8, 16 or 32 bpp?").  See the FAQ for more info.
-
-                       In the case of -rawfb mode, the pixels are directly
-                       modified by inserting a 0 byte to pad them out to 32bpp.
-                       For X displays, a kludge is done that is equivalent to
-                       "-noshm -visual TrueColor:32".  (If better performance
-                       is needed for the latter, feel free to ask).
-
--scale fraction        Scale the framebuffer by factor "fraction".  Values
-                       less than 1 shrink the fb, larger ones expand it. Note:
-                       the image may not be sharp and response may be slower.
-                       If "fraction" contains a decimal point "." it
-                       is taken as a floating point number, alternatively
-                       the notation "m/n" may be used to denote fractions
-                       exactly, e.g. -scale 2/3
-
-                       To scale asymmetrically in the horizontal and vertical
-                       directions, specify a WxH geometry to stretch to:
-                       e.g. '-scale 1024x768', or also '-scale 0.9x0.75'
-
-                       Scaling Options: can be added after "fraction" via
-                       ":", to supply multiple ":" options use commas.
-                       If you just want a quick, rough scaling without
-                       blending, append ":nb" to "fraction" (e.g. -scale
-                       1/3:nb).  No blending is the default for 8bpp indexed
-                       color, to force blending for this case use ":fb".
-
-                       To disable -scrollcopyrect and -wirecopyrect under
-                       -scale use ":nocr".  If you need to to enable them use
-                       ":cr" or specify them explicitly on the command line.
-                       If a slow link is detected, ":nocr" may be applied
-                       automatically.  Default: :cr
-
-                       More esoteric options: for compatibility with vncviewers
-                       the scaled width is adjusted to be a multiple of 4:
-                       to disable this use ":n4".  ":in" use interpolation
-                       scheme even when shrinking, ":pad" pad scaled width
-                       and height to be multiples of scaling denominator
-                       (e.g. 3 for 2/3).
-
--geometry WxH          Same as -scale WxH
-
--scale_cursor frac     By default if -scale is supplied the cursor shape is
-                       scaled by the same factor.  Depending on your usage,
-                       you may want to scale the cursor independently of the
-                       screen or not at all.  If you specify -scale_cursor
-                       the cursor will be scaled by that factor.  When using
-                       -scale mode to keep the cursor at its "natural" size
-                       use "-scale_cursor 1".  Most of the ":" scaling
-                       options apply here as well.
-
--viewonly              All VNC clients can only watch (default off).
--shared                VNC display is shared, i.e. more than one viewer can
-                       connect at the same time (default off).
--once                  Exit after the first successfully connected viewer
-                       disconnects, opposite of -forever. This is the Default.
--forever               Keep listening for more connections rather than exiting
-                       as soon as the first client(s) disconnect. Same as -many
-
-                       To get the standard non-shared VNC behavior where when
-                       a new VNC client connects the existing VNC client is
-                       dropped use:  -nevershared -forever   This method can
-                       also be used to guard against hung TCP connections that
-                       do not go away.
-
--loop                  Create an outer loop restarting the x11vnc process
-                       whenever it terminates.  -bg and -inetd are ignored
-                       in this mode (however see -loopbg below).
-
-                       Useful for continuing even if the X server terminates
-                       and restarts (at that moment the process will need
-                       permission to reconnect to the new X server of course).
-
-                       Use, e.g., -loop100 to sleep 100 millisecs between
-                       restarts, etc.  Default is 2000ms (i.e. 2 secs) Use,
-                       e.g. -loop300,5 to sleep 300 ms and only loop 5 times.
-
-                       If -loopbg (plus any numbers) is specified instead,
-                       the "-bg" option is implied and the mode approximates
-                       inetd(8) usage to some degree.  In this case when
-                       it goes into the background any listening sockets
-                       (i.e. ports 5900, 5800) are closed, so the next one
-                       in the loop can use them.  This mode will only be of
-                       use if a VNC client (the only client for that process)
-                       is already connected before the process goes into the
-                       background, for example, usage of -display WAIT:..,
-                       -svc, and -connect can make use of this "poor man's"
-                       inetd mode.  The default wait time is 500ms in this
-                       mode.  This usage could use useful:  -svc -bg -loopbg
-
--timeout n             Exit unless a client connects within the first n seconds
-                       after startup.
-
-                       If there have been no connection attempts after n
-                       seconds x11vnc exits immediately.  If a client is
-                       trying to connect but has not progressed to the normal
-                       operating state, x11vnc gives it a few more seconds
-                       to finish and exits if it does not make it to the
-                       normal state.
-
-                       For reverse connections via -connect or -connect_or_exit
-                       a timeout of n seconds will be set for all reverse
-                       connects.  If the connect timeout alarm goes off,
-                       x11vnc will exit immediately.
-
--sleepin n             At startup sleep n seconds before proceeding (e.g. to
-                       allow redirs and listening clients to start up)
-
-                       If a range is given: '-sleepin min-max', a random value
-                       between min and max is slept. E.g. '-sleepin 0-20' and
-                       '-sleepin 10-30'.  Floats are allowed too.
-
--inetd                 Launched by inetd(8): stdio instead of listening socket.
-                       Note: if you are not redirecting stderr to a log file
-                       (via shell 2> or -o option) you MUST also specify the -q
-                       option, otherwise the stderr goes to the viewer which
-                       will cause it to abort.  Specifying both -inetd and -q
-                       and no -o will automatically close the stderr.
-
--tightfilexfer         Enable the TightVNC file transfer extension. Note that
-                       that when the -viewonly option is supplied all file
-                       transfers are disabled.  Also clients that log in
-                       viewonly cannot transfer files.  However, if the remote
-                       control mechanism is used to change the global or
-                       per-client viewonly state the filetransfer permissions
-                       will NOT change.
-
-                       IMPORTANT: please understand if -tightfilexfer is
-                       specified and you run x11vnc as root for, say, inetd
-                       or display manager (gdm, kdm, ...) access and you do
-                       not have it switch users via the -users option, then
-                       VNC Viewers that connect are able to do filetransfer
-                       reads and writes as *root*.
-
-                       Also, tightfilexfer is disabled in -unixpw mode.
-
--ultrafilexfer         Note: to enable UltraVNC filetransfer and to get it to
-                       work you probably need to supply these LibVNCServer
-                       options: "-rfbversion 3.6 -permitfiletransfer"
-                       "-ultrafilexfer" is an alias for this combination.
-
-                       IMPORTANT: please understand if -ultrafilexfer is
-                       specified and you run x11vnc as root for, say, inetd
-                       or display manager (gdm, kdm, ...) access and you do
-                       not have it switch users via the -users option, then
-                       VNC Viewers that connect are able to do filetransfer
-                       reads and writes as *root*.
-
-                       Note that sadly you cannot do both -tightfilexfer and
-                       -ultrafilexfer at the same time because the latter
-                       requires setting the version to 3.6 and tightvnc will
-                       not do filetransfer when it sees that version number.
-
--http                  Instead of using -httpdir (see below) to specify
-                       where the Java vncviewer applet is, have x11vnc try
-                       to *guess* where the directory is by looking relative
-                       to the program location and in standard locations
-                       (/usr/local/share/x11vnc/classes, etc).  Under -ssl or
-                       -stunnel the ssl classes subdirectory is sought.
--http_ssl              As -http, but force lookup for ssl classes subdir.
-
-                       Note that for HTTPS, single-port Java applet delivery
-                       you can set X11VNC_HTTPS_DOWNLOAD_WAIT_TIME to the
-                       max number of seconds to wait for the applet download
-                       to finish.  The default is 15.
-
--avahi                 Use the Avahi/mDNS ZeroConf protocol to advertise
-                       this VNC server to the local network. (Related terms:
-                       Rendezvous, Bonjour).  Depending on your setup, you
-                       may need to start avahi-daemon and open udp port 5353
-                       in your firewall.
-
-                       You can set X11VNC_AVAHI_NAME, X11VNC_AVAHI_HOST,
-                       and/or X11VNC_AVAHI_PORT environment variables
-                       to override the default values.  For example:
-                       -env X11VNC_AVAHI_NAME=wally
-
-                       If the avahi API cannot be found at build time, a helper
-                       program like avahi-publish(1) or dns-sd(1) will be tried
-
--mdns                  Same as -avahi.
--zeroconf              Same as -avahi.
-
--connect string        For use with "vncviewer -listen" reverse connections.
-                       If "string" has the form "host" or "host:port"
-                       the connection is made once at startup.
-
-                       Use commas for a list of host's and host:port's.
-                       E.g. -connect host1,host2 or host1:0,host2:5678.
-                       Note that to reverse connect to multiple hosts at the
-                       same time you will likely need to also supply: -shared
-
-                       Note that unlike most vnc servers, x11vnc will require a
-                       password for reverse as well as for forward connections.
-                       (provided password auth has been enabled, -rfbauth, etc)
-                       If you do not want to require a password for reverse
-                       connections set X11VNC_REVERSE_CONNECTION_NO_AUTH=1 in
-                       your environment before starting x11vnc.
-
-                       If "string" contains "/" it is instead interpreted
-                       as a file to periodically check for new hosts.
-                       The first line is read and then the file is truncated.
-                       Be careful about the location of this file if x11vnc
-                       is running as root (e.g. via gdm(1), etc).
-
-
-                       Repeater mode: Some services provide an intermediate
-                       "vnc repeater": http://www.uvnc.com/addons/repeater.html
-                       (and also http://koti.mbnet.fi/jtko/ for linux port)
-                       that acts as a proxy/gateway.  Modes like these require
-                       an initial string to be sent for the reverse connection
-                       before the VNC protocol is started.  Here are the ways
-                       to do this:
-
-                         -connect pre=some_string+host:port
-                         -connect pre128=some_string+host:port
-                         -connect repeater=ID:1234+host:port
-                         -connect repeater=23.45.67.89::5501+host:port
-
-                       SSVNC notation is also supported:
-
-                         -connect repeater://host:port+ID:1234
-
-                       As with normal -connect usage, if the repeater port is
-                       not supplied 5500 is assumed.
-
-                       The basic idea is between the special tag, e.g. "pre="
-                       and "+" is the pre-string to be sent.  Note that in
-                       this case host:port is the repeater server, NOT the
-                       vnc viewer.  Somehow the pre-string tells the repeater
-                       server how to find the vnc viewer and connect you to it.
-
-                       In the case pre=some_string+host:port, "some_string"
-                       is simply sent. In the case preNNN=some_string+host:port
-                       "some_string" is sent in a null padded buffer of
-                       length NNN.  repeater= is the same as pre250=, this is
-                       the ultravnc repeater buffer size.
-
-                       Strings like "\n" and "\r", etc. are expanded to
-                       newline and carriage return.  "\c" is expanded to
-                       "," since the connect string is comma separated.
-
-                       See also the -proxy option below for additional ways
-                       to plumb reverse connections.
-
-                       Reverse SSL: using -connect in -ssl mode makes x11vnc
-                       act as an SSL client (initiates SSL connection) rather
-                       than an SSL server.  The idea is x11vnc might be
-                       connecting to stunnel on the viewer side with the
-                       viewer in listening mode.  If you do not want this
-                       behavior, use -env X11VNC_DISABLE_SSL_CLIENT_MODE=1.
-                       With this the viewer side can act as the SSL client
-                       as it normally does for forward connections.
-
-                       Reverse SSL Repeater mode:  This will work, but note
-                       that if the VNC Client does any sort of a 'Fetch Cert'
-                       action before connecting, then the Repeater will
-                       likely drop the connection and both sides will need
-                       to restart.  Consider the use of -connect_or_exit
-                       and -loop300,2 to have x11vnc reconnect once to the
-                       repeater after the fetch.  You will probably also want
-                       to supply -sslonly to avoid x11vnc thinking the delay
-                       in response means the connection is VeNCrypt.  The env
-                       var X11VNC_DISABLE_SSL_CLIENT_MODE=1 discussed above
-                       may also be useful (i.e. the viewer can do a forward
-                       connection as it normally does.)
-
-                       IPv6: as of x11vnc 0.9.10 the -connect option should
-                       connect to IPv6 hosts properly.  If there are problems
-                       you can disable IPv6 by setting -DX11VNC_IPV6=0
-                       in CPPFLAGS when configuring.  If there problems
-                       connecting to IPv6 hosts consider a relay like the
-                       included inet6to4 script or the -proxy option.
-
--connect_or_exit str   As with -connect, except if none of the reverse
-                       connections succeed, then x11vnc shuts down immediately
-
-                       An easier to type alias for this option is '-coe'
-
-                       By the way, if you do not want x11vnc to listen on
-                       ANY interface use -rfbport 0  which is handy for the
-                       -connect_or_exit mode.
-
--proxy string          Use proxy in string (e.g. host:port) as a proxy for
-                       making reverse connections (-connect or -connect_or_exit
-                       options).
-
-                       Web proxies are supported, but note by default most of
-                       them only support destination connections to ports 443
-                       or 563, so this might not be very useful (the viewer
-                       would need to listen on that port or the router would
-                       have to do a port redirection).
-
-                       A web proxy may be specified by either "host:port"
-                       or "http://host:port" (the port is required even if
-                       it is the common choices 80 or 8080)
-
-                       SOCKS4, SOCKS4a, and SOCKS5 are also supported.
-                       SOCKS proxies normally do not have restrictions on the
-                       destination port number.
-
-                       Use a format like this: socks://host:port or
-                       socks5://host:port.  Note that ssh -D does not support
-                       SOCKS4a, so use socks5://.  For socks:// SOCKS4 is used
-                       on a numerical IP and "localhost", otherwise SOCKS4a
-                       is used (and so the proxy tries to do the DNS lookup).
-
-                       An experimental mode is "-proxy http://host:port/..."
-                       Note the "/" after the port that distinguishes it from
-                       a normal web proxy.  The port must be supplied even if
-                       it is the default 80.  For this mode a GET is done to
-                       the supplied URL with the string host=H&port=P appended.
-                       H and P will be the -connect reverse connect host
-                       and port.  Use the string "__END__" to disable the
-                       appending.  The basic idea here is that maybe some cgi
-                       script provides the actual viewer hookup and tunnelling.
-                       How to actually achieve this within cgi, php, etc. is
-                       not clear...  A custom web server or apache module
-                       would be straight-forward.
-
-                       Another experimental mode is "-proxy ssh://user@host"
-                       in which case a SSH tunnel is used for the proxying.
-                       "user@" is not needed unless your unix username is
-                       different on "host".  For a non-standard SSH port
-                       use ssh://user@host:port.  If proxies are chained (see
-                       next paragraph) then the ssh one must be the first one.
-                       If ssh-agent is not active, then the ssh password needs
-                       to be entered in the terminal where x11vnc is running.
-                       Examples:
-
-                         -connect localhost:0 -proxy ssh://me@friends-pc:2222
-
-                         -connect snoopy:0 -proxy ssh://ssh.company.com
-
-                       Multiple proxies may be chained together in case one
-                       needs to ricochet off of a number of hosts to finally
-                       reach the VNC viewer.  Up to 3 may be chained, separate
-                       them by commas in the order they are to be connected to.
-                       E.g.:  http://host1:port1,socks5://host2:port2 or three
-                       like:  first,second,third
-
-                       IPv6: as of x11vnc 0.9.10 the -proxy option should
-                       connect to IPv6 hosts properly.  If there are problems
-                       you can disable IPv6 by setting -DX11VNC_IPV6=0
-                       in CPPFLAGS when configuring.  If there problems
-                       connecting to IPv6 hosts consider a relay like the
-                       included inet6to4 script.
-
--vncconnect            Monitor the VNC_CONNECT X property set by the standard
--novncconnect          VNC program vncconnect(1).  When the property is
-                       set to "host" or "host:port" establish a reverse
-                       connection.  Using xprop(1) instead of vncconnect may
-                       work (see the FAQ).  The -remote control mechanism uses
-                       X11VNC_REMOTE channel, and this option disables/enables
-                       it as well.  Default: -vncconnect
-
-                       To use different names for these X11 properties (e.g. to
-                       have separate communication channels for multiple
-                       x11vnc's on the same display) set the VNC_CONNECT or
-                       X11VNC_REMOTE env. vars. to the string you want, for
-                       example: -env X11VNC_REMOTE=X11VNC_REMOTE_12345
-                       Both sides of the channel must use the same unique name.
-                       The same can be done for the internal X11VNC_TICKER
-                       property (heartbeat and timestamp) if desired.
-
--allow host1[,host2..] Only allow client connections from hosts matching
-                       the comma separated list of hostnames or IP addresses.
-                       Can also be a numerical IP prefix, e.g. "192.168.100."
-                       to match a simple subnet, for more control build
-                       LibVNCServer with libwrap support (See the FAQ).  If the
-                       list contains a "/" it instead is a interpreted
-                       as a file containing addresses or prefixes that is
-                       re-read each time a new client connects.  Lines can be
-                       commented out with the "#" character in the usual way.
-
-                       -allow applies in -ssl mode, but not in -stunnel mode.
-
-                       IPv6: as of x11vnc 0.9.10 a host can be specified
-                       in IPv6 numerical format, e.g. 2001:4860:b009::93.
-
--localhost             Basically the same as "-allow 127.0.0.1".
-
-                       Note: if you want to restrict which network interface
-                       x11vnc listens on, see the -listen option below.
-                       E.g. "-listen localhost" or "-listen 192.168.3.21".
-                       As a special case, the option "-localhost" implies
-                       "-listen localhost".
-
-                       A rare case, but for non-localhost -listen usage, if
-                       you use the remote control mechanism (-R) to change
-                       the -listen interface you may need to manually adjust
-                       the -allow list (and vice versa) to avoid situations
-                       where no connections (or too many) are allowed.
-
-                       If you do not want x11vnc to listen on ANY interface
-                       (evidently you are using -connect or -connect_or_exit,
-                       or plan to use remote control: -R connect:host), use
-                       -rfbport 0
-
-                       IPv6: if IPv6 is supported, this option automatically
-                       implies the IPv6 loopback address '::1' as well.
-
--unixsock str          Listen on the unix socket (AF_UNIX) 'str'
-                       for connections.  This mode is for either local
-                       connections or a tunnel endpoint where one wants the
-                       file permission of the unix socket file to determine
-                       what can connect to it.  (This currently requires an
-                       edit to libvnserver/rfbserver.c: comment out lines 310
-                       and 311, 'close(sock)' and 'return NULL' in rfbserver.c
-                       after the setsockopt() call.) Note that to disable all
-                       tcp listening ports specify '-rfbport 0' and should be
-                       useful with this mode.  Example:
-                           mkdir ~/s; chmod 700 ~/s;
-                           x11vnc -unixsock ~/s/mysock -rfbport 0 ...
-                       The SSVNC unix vncviewer can connect to unix sockets.
-
--listen6 str           When in IPv6 listen mode "-6", listen only on the
-                       network interface with address "str".  It also works
-                       for link scope addresses (fe80::219:dbff:fee5:3f92%eth0)
-                       and IPv6 hostname strings (e.g. ipv6.google.com.)
-                       Use LibVNCServer -listen option for the IPv4 interface.
-
--nolookup              Do not use gethostbyname() or gethostbyaddr() to look up
-                       host names or IP numbers.  Use this if name resolution
-                       is incorrectly set up and leads to long pauses as name
-                       lookups time out, etc.
-
--input string          Fine tuning of allowed user input.  If "string" does
-                       not contain a comma "," the tuning applies only to
-                       normal clients.  Otherwise the part before "," is
-                       for normal clients and the part after for view-only
-                       clients.  "K" is for Keystroke input, "M" for
-                       Mouse-motion input, "B" for Button-click input, "C"
-                       is for Clipboard input, and "F" is for File transfer
-                       (ultravnc only).  Their presence in the string enables
-                       that type of input.  E.g. "-input M" means normal
-                       users can only move the mouse and  "-input KMBCF,M"
-                       lets normal users do anything and enables view-only
-                       users to move the mouse.  This option is ignored when
-                       a global -viewonly is in effect (all input is discarded
-                       in that case).
-
--grabkbd               When VNC viewers are connected, attempt to the grab
-                       the keyboard so a (non-malicious) user sitting at the
-                       physical display is not able to enter keystrokes.
-                       This method uses XGrabKeyboard(3X11) and so it is
-                       not secure and does not rule out the person at the
-                       physical display injecting keystrokes by flooding the
-                       server with them, grabbing the keyboard himself, etc.
-                       Some degree of cooperation from the person at the
-                       display is assumed.  This is intended for remote
-                       help-desk or educational usage modes.
-
-                       Note: on some recent (12/2010) X servers and/or
-                       desktops, -grabkbd no longer works: it prevents the
-                       window manager from resizing windows and similar things.
-                       Try -ungrabboth below (might not work.)
-
--grabptr               As -grabkbd, but for the mouse pointer using
-                       XGrabPointer(3X11).  Unfortunately due to the way the X
-                       server works, the mouse can still be moved around by the
-                       user at the physical display, but he will not be able to
-                       change window focus with it.  Also some window managers
-                       that call XGrabServer(3X11) for resizes, etc, will
-                       act on the local user's input.  Again, some degree of
-                       cooperation from the person at the display is assumed.
-
--ungrabboth            Whenever there is any input (either keyboard or
-                       pointer), ungrab *both* the keyboard and the pointer
-                       while injecting the synthetic input.  This is to allow
-                       window managers, etc. a chance to grab.
-
--grabalways            Apply both -grabkbd and -grabptr even when no VNC
-                       viewers are connected.  If you only want one of them,
-                       use the -R remote control to turn the other back on,
-                       e.g. -R nograbptr.
-
--viewpasswd string     Supply a 2nd password for view-only logins.  The -passwd
-                       (full-access) password must also be supplied.
-
--passwdfile filename   Specify the LibVNCServer password via the first line
-                       of the file "filename" (instead of via -passwd on
-                       the command line where others might see it via ps(1)).
-
-                       See the descriptions below for how to supply multiple
-                       passwords, view-only passwords, to specify external
-                       programs for the authentication, and other features.
-
-                       If the filename is prefixed with "rm:" it will be
-                       removed after being read.  Perhaps this is useful in
-                       limiting the readability of the file.  In general, the
-                       password file should not be readable by untrusted users
-                       (BTW: neither should the VNC -rfbauth file: it is NOT
-                       encrypted, only obscured with a fixed key).
-
-                       If the filename is prefixed with "read:" it will
-                       periodically be checked for changes and reread.  It is
-                       guaranteed to be reread just when a new client connects
-                       so that the latest passwords will be used.
-
-                       If "filename" is prefixed with "cmd:" then the
-                       string after the ":" is run as an external command:
-                       the output of the command will be interpreted as if it
-                       were read from a password file (see below).  If the
-                       command does not exit with 0, then x11vnc terminates
-                       immediately.  To specify more than 1000 passwords this
-                       way set X11VNC_MAX_PASSWDS before starting x11vnc.
-                       The environment variables are set as in -accept.
-
-                       Note that due to the VNC protocol only the first 8
-                       characters of a password are used (DES key).
-
-                       If "filename" is prefixed with "custom:" then a
-                       custom password checker is supplied as an external
-                       command following the ":". The command will be run
-                       when a client authenticates.  If the command exits with
-                       0 the client is accepted, otherwise it is rejected.
-                       The environment variables are set as in -accept.
-
-                       The standard input to the custom command will be a
-                       decimal digit "len" followed by a newline. "len"
-                       specifies the challenge size and is usually 16 (the
-                       VNC spec).  Then follows len bytes which is the random
-                       challenge string that was sent to the client. This is
-                       then followed by len more bytes holding the client's
-                       response (i.e. the challenge string encrypted via DES
-                       with the user password in the standard situation).
-
-                       The "custom:" scheme can be useful to implement
-                       dynamic passwords or to implement methods where longer
-                       passwords and/or different encryption algorithms
-                       are used.  The latter will require customizing the VNC
-                       client as well.  One could create an MD5SUM based scheme
-                       for example.
-
-                       File format for -passwdfile:
-
-                       If multiple non-blank lines exist in the file they are
-                       all taken as valid passwords.  Blank lines are ignored.
-                       Password lines may be "commented out" (ignored) if
-                       they begin with the character "#" or the line contains
-                       the string "__SKIP__".  Lines may be annotated by use
-                       of the "__COMM__" string: from it to the end of the
-                       line is ignored.  An empty password may be specified
-                       via the "__EMPTY__" string on a line by itself (note
-                       your viewer might not accept empty passwords).
-
-                       If the string "__BEGIN_VIEWONLY__" appears on a
-                       line by itself, the remaining passwords are used for
-                       viewonly access.  For compatibility, as a special case
-                       if the file contains only two password lines the 2nd
-                       one is automatically taken as the viewonly password.
-                       Otherwise the "__BEGIN_VIEWONLY__" token must be
-                       used to have viewonly passwords.  (tip: make the 3rd
-                       and last line be "__BEGIN_VIEWONLY__" to have 2
-                       full-access passwords)
-
--showrfbauth filename  Print to the screen the obscured VNC password kept in
-                       the rfbauth file "filename" and then exit.
-
--unixpw [list]         Use Unix username and password authentication.  x11vnc
-                       will use the su(1) program to verify the user's
-                       password.  [list] is an optional comma separated list
-                       of allowed Unix usernames.  If the [list] string begins
-                       with the character "!" then the entire list is taken
-                       as an exclude list.  See below for per-user options
-                       that can be applied.
-
-                       A familiar "login:" and "Password:" dialog is
-                       presented to the user on a black screen inside the
-                       vncviewer.  The connection is dropped if the user fails
-                       to supply the correct password in 3 tries or does not
-                       send one before a 45 second timeout.  Existing clients
-                       are view-only during this period.
-
-                       If the first character received is "Escape" then the
-                       unix username will not be displayed after "login:"
-                       as it is typed.  This could be of use for VNC viewers
-                       that automatically type the username and password.
-
-                       Since the detailed behavior of su(1) can vary from
-                       OS to OS and for local configurations, test the mode
-                       before deployment to make sure it is working properly.
-                       x11vnc will attempt to be conservative and reject a
-                       login if anything abnormal occurs.
-
-                       One case to note: FreeBSD and the other BSD's by
-                       default it is impossible for the user running x11vnc to
-                       validate his *own* password via su(1) (commenting out
-                       the pam_self.so entry in /etc/pam.d/su eliminates this
-                       behavior).  So the x11vnc login will always *FAIL* for
-                       this case (even when the correct password is supplied).
-
-                       A possible workaround for this on *BSD would be to
-                       start x11vnc as root with the "-users +nobody" option
-                       to immediately switch to user nobody where the su'ing
-                       will proceed normally.
-
-                       Another source of potential problems are PAM modules
-                       that prompt for extra info, e.g. password aging modules.
-                       These logins will fail as well even when the correct
-                       password is supplied.
-
-                       **IMPORTANT**: to prevent the Unix password being sent
-                       in *clear text* over the network, one of two schemes
-                       will be enforced: 1) the -ssl builtin SSL mode, or 2)
-                       require both -localhost and -stunnel be enabled.
-
-                       Method 1) ensures the traffic is encrypted between
-                       viewer and server.  A PEM file will be required, see the
-                       discussion under -ssl below (under some circumstances
-                       a temporary one can be automatically generated).
-
-                       Method 2) requires the viewer connection to appear
-                       to come from the same machine x11vnc is running on
-                       (e.g. from a ssh -L port redirection).  And that the
-                       -stunnel SSL mode be used for encryption over the
-                       network. (see the description of -stunnel below).
-
-                       Note: as a convenience, if you ssh(1) in and start
-                       x11vnc it will check if the environment variable
-                       SSH_CONNECTION is set and appears reasonable.  If it
-                       does, then the -ssl or -stunnel requirement will be
-                       dropped since it is assumed you are using ssh for the
-                       encrypted tunnelling.  -localhost is still enforced.
-                       Use -ssl or -stunnel to force SSL usage even if
-                       SSH_CONNECTION is set.
-
-                       To override the above restrictions you can set
-                       environment variables before starting x11vnc:
-
-                       Set UNIXPW_DISABLE_SSL=1 to disable requiring either
-                       -ssl or -stunnel (as under SSH_CONNECTION.)  Evidently
-                       you will be using a different method to encrypt the
-                       data between the vncviewer and x11vnc: perhaps ssh(1)
-                       or an IPSEC VPN. -localhost is still enforced (however,
-                       see the next paragraph.)
-
-                       Set UNIXPW_DISABLE_LOCALHOST=1 to disable the -localhost
-                       requirement in -unixpw modes.  One should never do this
-                       (i.e. allow the Unix passwords to be sniffed on the
-                       network.)  This also disables the localhost requirement
-                       for reverse connections (see below.)
-
-                       Note that use of -localhost with ssh(1) (and no -unixpw)
-                       is roughly the same as requiring a Unix user login
-                       (since a Unix password or the user's public key
-                       authentication is used by sshd on the machine where
-                       x11vnc runs and only local connections from that machine
-                       are accepted).
-
-                       Regarding reverse connections (e.g. -R connect:host
-                       and -connect host), when the -localhost constraint is
-                       in effect then reverse connections can only be used
-                       to connect to the same machine x11vnc is running on
-                       (default port 5500).  Please use a ssh or stunnel port
-                       redirection to the viewer machine to tunnel the reverse
-                       connection over an encrypted channel.
-
-                       In -inetd mode the Method 1) will be enforced (not
-                       Method 2).  With -ssl in effect reverse connections
-                       are disabled.  If you override this via env. var, be
-                       sure to also use encryption from the viewer to inetd.
-                       Tip: you can also have your own stunnel spawn x11vnc
-                       in -inetd mode (thereby bypassing inetd).  See the FAQ
-                       for details.
-
-                       The user names in the comma separated [list] may have
-                       per-user options after a ":", e.g. "fred:opts"
-                       where "opts" is a "+" separated list of
-                       "viewonly", "fullaccess", "input=XXXX", or
-                       "deny", e.g. "karl,wally:viewonly,boss:input=M".
-                       For "input=" it is the K,M,B,C described under -input.
-
-                       If an item in the list is "*" that means those
-                       options apply to all users.  It ALSO implies all users
-                       are allowed to log in after supplying a valid password.
-                       Use "deny" to explicitly deny some users if you use
-                       "*" to set a global option.  If [list] begins with the
-                       "!" character then "*" is ignored for checking if
-                       the user is allowed, but the option values associated
-                       with it do apply as normal.
-
-                       There are also some utilities for checking passwords
-                       if [list] starts with the "%" character.  See the
-                       quick_pw() function for more details.  Description:
-                       "%-" or "%stdin" means read one line from stdin.
-                       "%env" means it is in $UNIXPW env var.  A leading
-                       "%/" or "%." means read the first line from the
-                       filename that follows after the % character. % by
-                       itself means prompt for the username and password.
-                       Otherwise: %user:pass   E.g. -unixpw %fred:swordfish
-                       For the other cases user:pass is read from the indicated
-                       source.  If the password is correct 'Y user' is printed
-                       and the program exit code is 0.  If the password is
-                       incorrect it prints 'N user' and the exit code is 1.
-                       If there is some other error the exit code is 2.
-                       This feature enables x11vnc to be a general unix user
-                       password checking tool; it could be used from scripts
-                       or other programs.  These % password checks also apply
-                       to the -unixpw_nis and -unixpw_cmd options.
-
-                       For the % password check, if the env. var. UNIXPW_CMD
-                       is set to a command then it is run as the user (assuming
-                       the password is correct.)  The output of the command is
-                       not printed, the program or script must manage that by
-                       some other means.  The exit code of x11vnc will depend
-                       on the exit code of the command that is run.
-
-                       Use -nounixpw to disable unixpw mode if it was enabled
-                       earlier in the cmd line (e.g. -svc mode)
-
--unixpw_nis [list]     As -unixpw above, however do not use su(1) but rather
-                       use the traditional getpwnam(3) + crypt(3) method to
-                       verify passwords. All of the above -unixpw options and
-                       constraints apply.
-
-                       This mode requires that the encrypted passwords be
-                       readable.  Encrypted passwords stored in /etc/shadow
-                       will be inaccessible unless x11vnc is run as root.
-
-                       This is called "NIS" mode simply because in most
-                       NIS setups user encrypted passwords are accessible
-                       (e.g. "ypcat passwd") by an ordinary user and so that
-                       user can authenticate ANY user.
-
-                       NIS is not required for this mode to work (only that
-                       getpwnam(3) return the encrypted password is required),
-                       but it is unlikely it will work (as an ordinary user)
-                       for most modern environments unless NIS is available.
-                       On the other hand, when x11vnc is run as root it will
-                       be able to to access /etc/shadow even if NIS is not
-                       available (note running as root is often done when
-                       running x11vnc from inetd and xdm/gdm/kdm).
-
-                       Looked at another way, if you do not want to use the
-                       su(1) method provided by -unixpw (i.e. su_verify()), you
-                       can run x11vnc as root and use -unixpw_nis.  Any users
-                       with passwords in /etc/shadow can then be authenticated.
-
-                       In -unixpw_nis mode, under no circumstances is x11vnc's
-                       user password verifying function based on su called
-                       (i.e. the function su_verify() that runs /bin/su
-                       in a pseudoterminal to verify passwords.)  However,
-                       if -unixpw_nis is used in conjunction with the -find
-                       and -create -display WAIT:... modes then, if x11vnc is
-                       running as root, /bin/su may be called externally to
-                       run the find or create commands.
-
--unixpw_cmd cmd        As -unixpw above, however do not use su(1) but rather
-                       run the externally supplied command "cmd".  The first
-                       line of its stdin will be the username and the second
-                       line the received password.  If the command exits
-                       with status 0 (success) the VNC user will be accepted.
-                       It will be rejected for any other return status.
-
-                       Dynamic passwords and non-unix passwords, e.g. LDAP,
-                       can be implemented this way by providing your own custom
-                       helper program.  Note that the remote viewer is given 3
-                       tries to enter the correct password, and so the program
-                       may be called in a row that many (or more) times.
-
-                       If a list of allowed users is needed to limit who can
-                       log in, use -unixpw [list] in addition to this option.
-
-                       In FINDDISPLAY and FINDCREATEDISPLAY modes the "cmd"
-                       will also be run with the RFB_UNIXPW_CMD_RUN env. var.
-                       non-empty and set to the corresponding display
-                       find/create command.  The first two lines of input are
-                       the username and passwd as in the normal case described
-                       above.  To support FINDDISPLAY and FINDCREATEDISPLAY,
-                       "cmd" should run the requested command as the user
-                       (and most likely refusing to run it if the password is
-                       not correct.)  Here is an example script (note it has
-                       a hardwired bogus password "abc"!)
-
-                         #!/bin/sh
-                         # Example x11vnc -unixpw_cmd script.
-                         # Read the first two lines of stdin (user and passwd)
-                         read user
-                         read pass
-
-                         debug=0
-                         if [ $debug = 1 ]; then
-                                echo "user: $user" 1>&2
-                                echo "pass: $pass" 1>&2
-                                env | egrep -i 'rfb|vnc' 1>&2
-                         fi
-
-                         # Check if the password is valid.
-                         # (A real example would use ldap lookup, etc!)
-                         if [ "X$pass" != "Xabc" ]; then
-                                exit 1  # incorrect password
-                         fi
-
-                         if [ "X$RFB_UNIXPW_CMD_RUN" = "X" ]; then
-                                exit 0  # correct password
-                         else
-                                # Run the requested command (finddisplay)
-                                if [ $debug = 1 ]; then
-                                        echo "run: $RFB_UNIXPW_CMD_RUN" 1>&2
-                                fi
-                                exec /bin/su - "$user" -c "$RFB_UNIXPW_CMD_RUN"
-                         fi
-
-                       In -unixpw_cmd mode, under no circumstances is x11vnc's
-                       user password verifying function based on su called
-                       (i.e. the function su_verify() that runs /bin/su in a
-                       pseudoterminal to verify passwords.)  It is up to the
-                       supplied unixpw_cmd to do user switching if desired
-                       and if it has the permissions to do so.
-
--find                  Find the user's display using FINDDISPLAY. This
-                       is an alias for "-display WAIT:cmd=FINDDISPLAY".
-
-                       Note: if a -display occurs later on the command line
-                       it will override the -find setting.
-
-                       For this and the next few options see -display WAIT:...
-                       below for all of the details.
-
--finddpy               Run the FINDDISPLAY program, print out the found
-                       display (if any) and exit.  Output is like: DISPLAY=:0.0
-                       DISPLAY=:0.0,XPID=12345 or DISPLAY=:0.0,VT=7.  XPID is
-                       the process ID of the found X server.  VT is the Linux
-                       virtual terminal of the X server.
--listdpy               Have the FINDDISPLAY program list all of your displays
-                       (i.e. all the X displays on the local machine that you
-                       have access rights to).  x11vnc then exits.
-
--findauth [disp]       Apply the -find/-finddpy heuristics to try to guess
-                       the XAUTHORITY file for DISPLAY 'disp'.  If 'disp'
-                       is not supplied, then the value in the -display on
-                       the cmdline is used; failing that $DISPLAY is used;
-                       and failing that ":0" is used.  x11vnc then exits.
-
-                       If nothing is printed out, that means no XAUTHORITY was
-                       found for 'disp'; i.e. failure.  If "XAUTHORITY="
-                       is printed out, that means use the default (i.e. do
-                       not set XAUTHORITY).  If "XAUTHORITY=/path/to/file"
-                       is printed out, then use that file.
-
-                       XDM/GDM/KDM: if you are running x11vnc as root and want
-                       to find the XAUTHORITY before anyone has logged into an
-                       X session yet, use: x11vnc -env FD_XDM=1 -findauth ...
-                       (This will also find the XAUTHORITY if a user is already
-                       logged into the X session.)  When running as root,
-                       FD_XDM=1 will be tried if the initial -findauth fails.
-
--create                First try to find the user's display using FINDDISPLAY,
-                       if that doesn't succeed create an X session via the
-                       FINDCREATEDISPLAY method.  This is an alias for
-                       "-display WAIT:cmd=FINDCREATEDISPLAY-Xvfb".
-
-                       Note: if a -display occurs later on the command line
-                       it will override the -create setting.
-
-                       SSH NOTE: for both -find and -create you can (should!)
-                       add the "-localhost" option to force SSH tunnel access.
-
--xdummy                As in -create, except Xdummy instead of Xvfb.
--xvnc                  As in -create, except Xvnc instead of Xvfb.
--xvnc_redirect         As in -create, except Xvnc.redirect instead of Xvfb.
--xdummy_xvfb           Sets WAIT:cmd=FINDCREATEDISPLAY-Xdummy,Xvfb
-
--create_xsrv str       Sets WAIT:cmd=FINDCREATEDISPLAY-<str>  Can be on cmdline
-                       after anything that sets WAIT:.. and other things
-                       (e.g. -svc, -xdmsvc) to adjust the X server list.
-                       Example: -svc ... -create_xsrv Xdummy,X
-
--svc                   Terminal services mode based on SSL access.  Alias for
-                       -display WAIT:cmd=FINDCREATEDISPLAY-Xvfb -unixpw -users
-                       unixpw= -ssl SAVE   Also "-service".
-
-                       Note: if a -display, -unixpw, -users, or -ssl occurs
-                       later on the command line it will override the -svc
-                       setting.
-
--svc_xdummy            As -svc except Xdummy instead of Xvfb.
--svc_xvnc              As -svc except Xvnc instead of Xvfb.
--svc_xdummy_xvfb       As -svc with Xdummy,Xvfb.
-
--xdmsvc                Display manager Terminal services mode based on SSL.
-                       Alias for -display WAIT:cmd=FINDCREATEDISPLAY-Xvfb.xdmcp
-                       -unixpw -users unixpw= -ssl SAVE  Also "-xdm_service".
-
-                       Note: if a -display, -unixpw, -users, or -ssl occurs
-                       later on the command line it will override the -xdmsvc
-                       setting.
-
-                       To create a session a user will have to first log in
-                       to the -unixpw dialog and then log in again to the
-                       XDM/GDM/KDM prompt.  Subsequent re-connections will
-                       only require the -unixpw password.  See the discussion
-                       under -display WAIT:... for more details about XDM,
-                       etc configuration.
-
-                       Remember to enable XDMCP in the xdm-config, gdm.conf,
-                       or kdmrc configuration file.  See -display WAIT: for
-                       more info.
-
--sshxdmsvc             Display manager Terminal services mode based on SSH.
-                       Alias for -display WAIT:cmd=FINDCREATEDISPLAY-Xvfb.xdmcp
-                       -localhost.
-
-                       The -localhost option constrains connections to come
-                       in via a SSH tunnel (which will require a login).
-                       To create a session a user will also have to log into
-                       the XDM GDM KDM prompt. Subsequent re-connections will
-                       only only require the SSH login.  See the discussion
-                       under -display WAIT:... for more details about XDM,
-                       etc configuration.
-
-                       Remember to enable XDMCP in the xdm-config, gdm.conf,
-                       or kdmrc configuration file.  See -display WAIT: for
-                       more info.
-
--unixpw_system_greeter Present a "Press 'Escape' for System Greeter" option
-                       to the connecting VNC client in combined -unixpw
-                       and xdmcp FINDCREATEDISPLAY modes (e.g. -xdmsvc).
-
-                       Normally in a -unixpw mode the VNC client must
-                       supply a valid username and password to gain access.
-                       However, if -unixpw_system_greeter is supplied AND
-                       the FINDCREATEDISPLAY command matches 'xdmcp', then
-                       the user has the option to press Escape and then get a
-                       XDM/GDM/KDM login/greeter panel instead. They will then
-                       supply a username and password directly to the greeter.
-
-                       Otherwise, in xdmcp FINDCREATEDISPLAY mode the user
-                       must supply his username and password TWICE.  First to
-                       the initial unixpw login dialog, and second to the
-                       subsequent XDM/GDM/KDM greeter.  Note that if the user
-                       re-connects and supplies his username and password in
-                       the unixpw dialog the xdmcp greeter is skipped and
-                       he is connected directly to his existing X session.
-                       So the -unixpw_system_greeter option avoids the extra
-                       password at X session creation time.
-
-                       Example:  x11vnc -xdmsvc -unixpw_system_greeter
-                       See -unixpw and -display WAIT:... for more info.
-
-                       The special options after a colon at the end of the
-                       username (e.g. user:solid) described under -display
-                       WAIT: are also applied in this mode if they are typed
-                       in before the user hits Escape.  The username is ignored
-                       but the colon options are not.
-
-                       The default message is 2 lines in a small font, set
-                       the env. var. X11VNC_SYSTEM_GREETER1=true for a 1 line
-                       message in a larger font.
-
-                       If the user pressed Escape the FINDCREATEDISPLAY command
-                       will be run with the env. var. X11VNC_XDM_ONLY=1.
-
-                       Remember to enable XDMCP in the xdm-config, gdm.conf,
-                       or kdmrc configuration file.  See -display WAIT: for
-                       more info.
-
--redirect port         As in FINDCREATEDISPLAY-Xvnc.redirect mode except
-                       redirect immediately (i.e. without X session finding
-                       or creation) to a VNC server listening on port. You
-                       can also supply host:port to redirect to a different
-                       machine.
-
-                       If 0 <= port < 200 it is taken as a VNC display (5900 is
-                       added to get the actual port), if port < 0 then -port
-                       is used.
-
-                       Probably the only reason to use the -redirect option
-                       is in conjunction with SSL support, e.g. -ssl SAVE.
-                       This provides an easy way to add SSL encryption to a VNC
-                       server that does not support SSL (e.g. Xvnc or vnc.so)
-                       In fact, the protocol does not even need to be VNC,
-                       and so "-rfbport port1 -ssl SAVE -redirect host:port2"
-                       can act as a replacement for stunnel(1).
-
-                       This mode only allows one redirected connection.
-                       The -forever option does not apply.  Use -inetd or
-                       -loop for persistent service.
-
--display_WAIT :...      A special usage mode for the normal -display option.
-                       Useful with -unixpw, but can be used independently
-                       of it.  If the display string begins with WAIT: then
-                       x11vnc waits until a VNC client connects before opening
-                       the X display (or -rawfb device).
-
-                       This could be useful for delaying opening the display
-                       for certain usage modes (say if x11vnc is started at
-                       boot time and no X server is running or users logged
-                       in yet).
-
-                       If the string is, e.g. WAIT:0.0 or WAIT:1, i.e. "WAIT"
-                       in front of a normal X display, then that indicated
-                       display is used.
-
-                       One can also insert a geometry between colons, e.g.
-                       WAIT:1280x1024:... to set the size of the display the
-                       VNC client first attaches to since some VNC viewers
-                       will not automatically adjust to a new framebuffer size.
-
-                       A more interesting case is like this:
-
-                            WAIT:cmd=/usr/local/bin/find_display
-
-                       in which case the command after "cmd=" is run to
-                       dynamically work out the DISPLAY and optionally the
-                       XAUTHORITY data.  The first line of the command output
-                       must be of the form DISPLAY=<xdisplay>.  On Linux
-                       if the virtual terminal is known append ",VT=n" to
-                       this string and the chvt(1) program will also be run.
-                       Any remaining output is taken as XAUTHORITY data.
-                       It can be either of the form XAUTHORITY=<file> or raw
-                       xauthority data for the display. For example;
-
-                            xauth extract - $DISPLAY"
-
-                       NOTE: As specified in the previous paragraph, you can
-                       supply your own WAIT:cmd=... program or script, BUT
-                       there are two very useful *BUILT-IN* ones: FINDDISPLAY
-                       (alias -find above) and FINDCREATEDISPLAY (alias -create
-                       above.)  Most people use these instead of creating
-                       their own script.  Read the following (especially the
-                       BUILT-IN modes sections) to see how to configure these
-                       two useful builtin -display WAIT: modes.
-
-                       In the case of -unixpw (and -unixpw_nis only if x11vnc
-                       is running as root), then the cmd= command is run
-                       as the user who just authenticated via the login and
-                       password prompt.
-
-                       In the case of -unixpw_cmd, the commands will also be
-                       run as the logged-in user, as long as the user-supplied
-                       helper program supports RFB_UNIXPW_CMD_RUN (see the
-                       -unixpw_cmd option.)
-
-                       Also in the case of -unixpw, the user logging in can
-                       place a colon at the end of her username and supply
-                       a few options: scale=, scale_cursor= (or sc=), solid
-                       (or so), id=, clear_mods (or cm), clear_keys (or
-                       ck), clear_all (or ca), repeat, speeds= (or sp=),
-                       readtimeout= (or rd=), viewonly (or vo), nodisplay=
-                       (or nd=), rotate= (or ro=), or noncache (or nc),
-                       all separated by commas if there is more than one.
-                       After the user logs in successfully, these options will
-                       be applied to the VNC screen.  For example,
-
-                          login: fred:scale=3/4,sc=1,repeat
-                          Password: ...
-
-                          login: runge:sp=modem,rd=120,solid
-
-                       for convenience m/n implies scale= e.g. fred:3/4  If you
-                       type and enter your password incorrectly, to retrieve
-                       your long "login:" line press the Up arrow once
-                       (before typing anything else).
-
-                       Most of these colon options only apply to the builtin
-                       FINDDISPLAY and FINDCREATEDISPLAY modes, but note
-                       that they are passed to the extrenal command in the
-                       environment as well and so could be used.
-
-                       In the login panel, press F1 to get a list of the
-                       available options that you can add after the username.
-
-                       Another option is "geom=WxH" or "geom=WxHxD" (or
-                       ge=). This only has an effect in FINDCREATEDISPLAY
-                       mode when a virtual X server such as Xvfb is going
-                       to be created.  It sets the width and height of
-                       the new display, and optionally the color depth as
-                       well.
-
-                       You can also supply "gnome", "kde", "twm",
-                       "fvwm", "mwm", "dtwm", "wmaker", "xfce",
-                       "lxde", "enlightenment", "Xsession", or
-                       "failsafe" (same as "xterm") to have the created
-                       display use that mode for the user session.
-
-                       Specify "tag=..." to set the unique FD_TAG desktop
-                       session tag described below.  Note: this option will
-                       be ignored if the FD_TAG env. var. is already set or
-                       if the viewer-side supplied value is not completely
-                       composed of alphanumeric or '_' or '-' characters.
-
-                       User preferences file: Instead of having the user type
-                       in geom=WxH,... etc. every time he logs in to find
-                       or create his X session, if you set FD_USERPREFS to
-                       a string that does not contain the "/" character,
-                       then the user's home directory is prepended to that
-                       string and if the file exists its first line is read
-                       and appended to any options he supplied at the login:
-                       prompt.  For example -env FD_USERPREFS=.x11vnc_create
-                       and the user put "geom=1600x1200" in his
-                       ~/.x11vnc_create file.
-
-                       To disable the option setting set the environment
-                       variable X11VNC_NO_UNIXPW_OPTS=1 before starting x11vnc.
-                       To set any other options, the user can use the gui
-                       (x11vnc -gui connect) or the remote control method
-                       (x11vnc -R opt:val) during his VNC session.
-
-                       So we see the combination of -display WAIT:cmd=... and
-                       -unixpw allows automatic pairing of an unix
-                       authenticated VNC user with his desktop.  This could
-                       be very useful on SunRays and also any system where
-                       multiple users share a given machine.  The user does
-                       not need to remember special ports or passwords set up
-                       for his desktop and VNC.
-
-                       A nice way to use WAIT:cmd=... is out of inetd(8)
-                       (it automatically forks a new x11vnc for each user).
-                       You can have the x11vnc inetd spawned process run as,
-                       say, root or nobody.  When run as root (for either inetd
-                       or display manager), you can also supply the option
-                       "-users unixpw=" to have the x11vnc process switch to
-                       the user as well.  Note: there will be a 2nd SSL helper
-                       process that will not switch, but it is only encoding
-                       and decoding the encrypted stream at that point.
-
-                       BUILT-IN modes:
-
-                       -- Automatic Finding of User X Sessions --
-
-                       As a special case, WAIT:cmd=FINDDISPLAY will run a
-                       script that works on most Unixes to determine a user's
-                       DISPLAY variable and xauthority data (see who(1)).
-
-                       NOTE: The option "-find" is an alias for this mode.
-
-                       To have this default script printed to stdout (e.g. for
-                       customization) run with WAIT:cmd=FINDDISPLAY-print To
-                       have the script run to print what display it would find
-                       use "-finddpy" or WAIT:cmd=FINDDISPLAY-run
-
-                       The standard script runs xdpyinfo(1) run on potential
-                       displays.  If your X server(s) have a login greeter
-                       that exclusively grabs the Xserver, then xdpyinfo
-                       blocks forever and this mode will not work.  See
-                       www.karlrunge.com/x11vnc/faq.html#faq-display-manager
-                       for how to disable this for dtgreet on Solaris and
-                       possibly for other greeters.
-
-                       In -find/cmd=FINDDISPLAY mode, if you set FD_XDM=1,
-                       e.g. 'x11vnc -env FD_XDM=1 -find ...' and x11vnc is
-                       running as root (e.g. inetd) then it will try to find
-                       the XAUTHORITY file of a running XDM/GDM/KDM login
-                       greeter (i.e. no user has logged into an X session yet.)
-
-                       As another special case, WAIT:cmd=HTTPONCE will allow
-                       x11vnc to service one http request and then exit.
-                       This is usually done in -inetd mode to run on, say,
-                       port 5800 and allow the Java vncviewer to be downloaded
-                       by client web browsers.  For example:
-
-                        5815 stream tcp nowait root /usr/sbin/tcpd /.../x11vnc
-\
-                          -inetd -q -http_ssl -prog /.../x11vnc \
-                          -display WAIT:cmd=HTTPONCE
-
-                       Where /.../x11vnc is the full path to x11vnc.
-                       It is used in the Apache SSL-portal example (see FAQ).
-
-                       In this mode you can set X11VNC_SKIP_DISPLAY to a
-                       comma separated list of displays (e.g. ":0,:1") to
-                       ignore in the finding process.  The ":" is optional.
-                       Ranges n-m e.g. 0-20 can also be supplied. This string
-                       can also be set by the connecting user via "nd="
-                       using "+" instead of ","  If "nd=all" or you set
-                       X11VNC_SKIP_DISPLAY=all then all display finding fails
-                       as if you set X11VNC_FINDDISPLAY_ALWAYS_FAILS=1 (below.)
-
-                       On some systems lsof(1) can be very slow.  Set the
-                       env. var. FIND_DISPLAY_NO_LSOF=1 to skip using lsof to
-                       try to find the Linux VT the X server is running on.
-                       set FIND_DISPLAY_NO_VT_FIND=1 to avoid looking at all.
-
-                       -- Automatic Creation of User X Sessions --
-
-                       An interesting option is WAIT:cmd=FINDCREATEDISPLAY
-                       that is like FINDDISPLAY in that is uses the same method
-                       to find an existing display.  However, if it does not
-                       find one it will try to *start* up an X server session
-                       for the user.  This is the only time x11vnc tries to
-                       actually start up an X server.
-
-                       NOTE: The option "-create" is an alias for this mode.
-
-                       It will start looking for an open display number at :20
-                       Override via X11VNC_CREATE_STARTING_DISPLAY_NUMBER=n
-                       By default 80 X displays are allowed (i.e. going to :99)
-                       Override via X11VNC_CREATE_MAX_DISPLAYS=n
-
-                       For its heuristics, the create display script sets
-                       LC_ALL=C so that command output is uniform.  By default
-                       it will try to restore LC_ALL right before starting the
-                       user session.  However, if you don't mind it keeping
-                       LC_ALL=C set the env. var.: X11VNC_CREATE_LC_ALL_C_OK=1
-
-                       By default FINDCREATEDISPLAY will try Xvfb and then
-                       Xdummy:
-
-                       The Xdummy wrapper is part of the x11vnc source code
-                       (x11vnc/misc/Xdummy)  It should be available in PATH
-                       and have run "Xdummy -install" once to create the
-                       shared library.  Xdummy only works on Linux.  As of
-                       12/2009 it no longer needs to be run as root, and the
-                       default is to not run as root.  In some circumstances
-                       permissions may require running it as root, in these
-                       cases specify FD_XDUMMY_RUN_AS_ROOT=1, this is the same
-                       as supplying -root to the Xdummy cmdline.
-
-                       Xvfb is available on most platforms and does not
-                       require root.
-
-                       An advantage of Xdummy over Xvfb is that Xdummy supports
-                       RANDR dynamic screen resizing.
-
-                       When x11vnc exits (i.e. user disconnects) the X
-                       server session stays running in the background.
-                       The FINDDISPLAY will find it directly next time.
-                       The user must exit the X session in the usual way for
-                       it to terminate (or kill the X server process if all
-                       else fails).
-
-                       To troubleshoot the FINDCREATEDISPLAY mechanism,
-                       set the following env. var. to an output log file,
-                       e.g -env CREATE_DISPLAY_OUTPUT=/tmp/mydebug.txt
-
-                       So this is a somewhat odd mode for x11vnc in that it
-                       will start up and poll virtual X servers!  This can
-                       be used from, say, inetd(8) to provide a means of
-                       definitely getting a desktop (either real or virtual)
-                       on the machine.  E.g. a desktop service:
-
-                         5900 stream tcp nowait root /usr/sbin/tcpd /.../x11vnc
-                          -inetd -q -http -ssl SAVE -unixpw -users unixpw=\
-                          -passwd secret -prog /.../x11vnc \
-                          -display WAIT:cmd=FINDCREATEDISPLAY
-
-                       Where /.../x11vnc is the full path to x11vnc.
-
-                       See the -svc/-service option alias above.
-
-                       If for some reason you do not want x11vnc to ever
-                       try to find an existing display set the env. var
-                       X11VNC_FINDDISPLAY_ALWAYS_FAILS=1 (also -env ...)
-                       This is the same as setting X11VNC_SKIP_DISPLAY=all or
-                       supplying "nd=all" after "username:"
-
-                       Use WAIT:cmd=FINDCREATEDISPLAY-print to print out the
-                       script that is used for this.
-
-                       You can specify the preferred X server order via e.g.,
-                       WAIT:cmd=FINDCREATEDISPLAY-Xdummy,Xvfb,X  and/or leave
-                       out ones you do not want.  The the case "X" means try
-                       to start up a real, hardware X server using xinit(1)
-                       or startx(1).  If there is already an X server running
-                       the X case may only work on Linux (see startx(1)).
-
-                       "Xvnc" will start up a VNC X server (real-
-                       or tight-vnc, e.g. use if Xvfb is not available).
-                       "Xsrv" will start up the server program in the
-                       variable "FD_XSRV" if it is non-empty. You can make
-                       this be a wrapper script if you like (it must handle :N,
-                       -geometry, and -depth and other X server options).
-
-                       You can set the environment variable FD_GEOM (or
-                       X11VNC_CREATE_GEOM) to WxH or WxHxD to set the width
-                       and height and optionally the color depth of the
-                       created display.  You can also set FD_SESS to be the
-                       session (short name of the windowmanager: kde, gnome,
-                       twm, failsafe, etc.). FD_OPTS contains extra options
-                       to pass to the X server. You can also set FD_PROG to
-                       be the full path to the session/windowmanager program.
-
-                       More FD tricks:  FD_CUPS=port or FD_CUPS=host:port
-                       will set the cups printing environment.  Similarly for
-                       FD_ESD=port or FD_ESD=host:port for esddsp sound
-                       redirection.  Set FD_EXTRA to a command to be run a
-                       few seconds after the X server starts up.  Set FD_TAG
-                       to be a unique name for the session, it is set as an
-                       X property, that makes FINDDISPLAY only find sessions
-                       with that tag value.
-
-                       Set FD_XDMCP_IF to the network interface that the
-                       display manager is running on; default is 'localhost'
-                       but you may need to set it to '::1' on some IPv6 only
-                       systems or misconfigured display managers.
-
-                       If you want the FINDCREATEDISPLAY session to contact an
-                       XDMCP login manager (xdm/gdm/kdm) on the same machine,
-                       then use "Xvfb.xdmcp" instead of "Xvfb", etc.
-                       The user will have to supply his username and password
-                       one more time (but he gets to select his desktop type
-                       so that can be useful).  For this to work, you will
-                       need to enable localhost XDMCP (udp port 177) for the
-                       display manager.  This seems to be:
-
-                        for gdm in gdm.conf:   Enable=true in section [xdmcp]
-                        for kdm in kdmrc:      Enable=true in section [Xdmcp]
-                        for xdm in xdm-config: DisplayManager.requestPort: 177
-
-                       See the shorthand options above "-svc", "-xdmsvc"
-                       and "-sshxdmsvc" that specify the above options for
-                       some useful cases.
-
-                       If you set the env. var WAITBG=1 x11vnc will go into
-                       the background once listening in wait mode.
-
-                       Another special mode is FINDCREATEDISPLAY-Xvnc.redirect,
-                       (or FINDDISPLAY-Xvnc.redirect).  In this case it will
-                       start up Xvnc as above if needed, but instead of
-                       polling it in its normal way, it simply does a socket
-                       redirection of the connected VNC viewer to the Xvnc.
-
-                       So in Xvnc.redirect x11vnc does no VNC but merely
-                       transfers the data back and forth.  This should be
-                       faster then x11vnc's polling method, but not as fast
-                       as connecting directly to the Xvnc with the VNC Viewer.
-                       The idea here is to take advantage of x11vnc's display
-                       finding/creating scheme, SSL, and perhaps a few others.
-                       Most of x11vnc's options do not apply in this mode.
-
-                       Xvnc.redirect should also work for the vnc.so X server
-                       module for the h/w display however it will work only
-                       for finding the display and the user must already be
-                       logged into the X console.
-
--vencrypt mode         The VeNCrypt extension to the VNC protocol allows
-                       encrypted SSL/TLS connections.  If the -ssl mode is
-                       enabled, then VeNCrypt is enabled as well BY DEFAULT
-                       (they both use a SSL/TLS tunnel, only the protocol
-                       handshake is a little different.)
-
-                       To control when and how VeNCrypt is used, specify the
-                       mode string.  If mode is "never", then VeNCrypt is
-                       not used.  If mode is "support" (the default) then
-                       VeNCrypt is supported.  If mode is "only", then the
-                       similar and older ANONTLS protocol is not simultaneously
-                       supported.  x11vnc's normal SSL mode (vncs://) will be
-                       supported under -ssl unless you set mode to "force".
-
-                       If mode is prefixed with "nodh:", then Diffie Hellman
-                       anonymous key exchange is disabled.  If mode is prefixed
-                       with "nox509:", then X509 key exchange is disabled.
-
-                       To disable all Anonymous Diffie-Hellman access
-                       (susceptible to Man-In-The-Middle attack) you will need
-                       to supply "-vencrypt nodh:support -anontls never"
-                       or "-vencrypt nodh:only"
-
-                       If mode is prefixed with "newdh:", then new Diffie
-                       Hellman parameters are generated for each connection
-                       (this can be time consuming: 1-60 secs; see -dhparams
-                       below for a faster way) rather than using the
-                       fixed values in the program.  Using fixed, publicly
-                       known values is not known to be a security problem.
-                       This setting applies to ANONTLS as well.
-
-                       Long example: -vencrypt newdh:nox509:support
-
-                       Also, if mode is prefixed with "plain:", then
-                       if -unixpw mode is active the VeNCrypt "*Plain"
-                       username+passwd method is enabled for Unix logins.
-                       Otherwise in -unixpw mode the normal login panel is
-                       provided.
-
-                       You *MUST* supply the -ssl option for VeNCrypt to
-                       be active.  The -vencrypt option only fine-tunes its
-                       operation.
-
--anontls mode          The ANONTLS extension to the VNC protocol allows
-                       encrypted SSL/TLS connections.  If the -ssl mode is
-                       enabled, then ANONTLS is enabled as well BY DEFAULT
-                       (they both use a SSL/TLS tunnel, only the protocol
-                       handshake is a little different.)
-
-                       ANONTLS is an older SSL/TLS mode introduced by vino.
-
-                       It is referred to as 'TLS' for its registered VNC
-                       security-type name, but we use the more descriptive
-                       'ANONTLS' here because it provides only Anonymous
-                       Diffie-Hellman encrypted connections, and hence no
-                       possibility for certificate authentication.
-
-                       To control when and how ANONTLS is used, specify the
-                       mode string.  If mode is "never", then ANONTLS is not
-                       used.  If mode is "support" (the default) then ANONTLS
-                       is supported.  If mode is "only", then the similar
-                       VeNCrypt protocol is not simultaneously supported.
-                       x11vnc's normal SSL mode (vncs://) will be supported
-                       under -ssl unless you set mode to "force".
-
-                       If mode is prefixed with "newdh:", then new Diffie
-                       Hellman parameters are generated for each connection
-                       (this can be time consuming: 1-60 secs; see -dhparams
-                       below for a faster way) rather than using the
-                       fixed values in the program.  Using fixed, publicly
-                       known values is not known to be a security problem.
-                       This setting applies to VeNCrypt as well.  See the
-                       description of "plain:" under -vencrypt.
-
-                       Long example: -anontls newdh:plain:support
-
-                       You *MUST* supply the -ssl option for ANONTLS to
-                       be active.  The -anontls option only fine-tunes its
-                       operation.
-
--sslonly               Same as: "-vencrypt never -anontls never"  i.e. it
-                       disables the VeNCrypt and ANONTLS encryption methods
-                       and only allows standard SSL tunneling.  You must also
-                       supply the -ssl ... option (see below.)
-
-
--dhparams file         For some operations a set of Diffie Hellman parameters
-                       (prime and generator) is needed.  If so, use the
-                       parameters in "file". In particular, the VeNCrypt and
-                       ANONTLS anonymous DH mode need them.  By default a
-                       fixed set is used. If you do not want to do that you
-                       can specify "newdh:" to the -vencrypt and -anontls
-                       options to generate a new set each session.  If that
-                       is too slow for you, use -dhparams file to a set you
-                       created manually via "openssl dhparam -out file 1024"
-
--nossl                 Disable the -ssl option (see below). Since -ssl is off
-                       by default -nossl would only be used on the commandline
-                       to unset any *earlier* -ssl option (or -svc...)
-
--ssl [pem]             Use the openssl library (www.openssl.org) to provide a
-                       built-in encrypted SSL/TLS tunnel between VNC viewers
-                       and x11vnc.  This requires libssl support to be
-                       compiled into x11vnc at build time.  If x11vnc is not
-                       built with libssl support it will exit immediately when
-                       -ssl is prescribed.  See the -stunnel option below for
-                       an alternative.
-
-                       The VNC Viewer-side needs to support SSL/TLS as well.
-                       See this URL and also the discussion below for
-                       ideas on how to enable SSL support for the viewer:
-                       http://www.karlrunge.com/x11vnc/faq.html#faq-ssl-tun
-                       nel-viewers .  x11vnc provides an SSL enabled Java
-                       viewer applet in the classes/ssl directory (-http or
-                       -httpdir options.)  The SSVNC viewer package supports
-                       SSL tunnels too.
-
-                       If the VNC Viewer supports VeNCrypt or ANONTLS (vino's
-                       encryption mode) they are also supported by the -ssl
-                       mode (see the -vencrypt and -anontls options for more
-                       info; use -sslonly to disable both of them.)
-
-                       Use "-ssl /path/to/mycert.pem" to specify an SSL
-                       certificate file in PEM format to use to identify and
-                       provide a key for this server.  See openssl(1) for more
-                       info about PEMs and the -sslGenCert and "-ssl SAVE"
-                       options below for how to create them.
-
-                       The connecting VNC viewer SSL tunnel can (at its option)
-                       authenticate this server if it has the public key part
-                       of the certificate (or a common certificate authority,
-                       CA, is a more sophisticated way to verify this server's
-                       cert, see -sslGenCA below).  This authentication is
-                       done to prevent Man-In-The-Middle attacks.  Otherwise,
-                       if the VNC viewer simply accepts this server's key
-                       WITHOUT verification, the traffic is protected from
-                       passive sniffing on the network, but *NOT* from
-                       Man-In-The-Middle attacks. There are hacker tools
-                       like dsniff/webmitm and cain that implement SSL
-                       Man-In-The-Middle attacks.
-
-                       If [pem] is empty or the string "SAVE" then the
-                       openssl(1) command must be available to generate the
-                       certificate the first time.  A self-signed certificate
-                       is generated (see -sslGenCA and -sslGenCert for use
-                       of a Certificate Authority.)  It will be saved to the
-                       file ~/.vnc/certs/server.pem.  On subsequent calls if
-                       that file already exists it will be used directly.
-
-                       Use "SAVE_NOPROMPT" to avoid being prompted to
-                       protect the generated key with a passphrase.  However in
-                       -inetd and -bg modes there will be no prompting for a
-                       passphrase in either case.
-
-                       If [pem] is "SAVE_PROMPT" the server.pem certificate
-                       will be created based on your answers to its prompts for
-                       all info such as OrganizationalName, CommonName, etc.
-
-                       Use "SAVE-<string>" and "SAVE_PROMPT-<string>"
-                       to refer to the file ~/.vnc/certs/server-<string>.pem
-                       instead (it will be generated if it does not already
-                       exist).  E.g. "SAVE-charlie" will store to the file
-                       ~/.vnc/certs/server-charlie.pem
-
-                       Examples: x11vnc -ssl SAVE -display :0 ...
-                                 x11vnc -ssl SAVE-someother -display :0 ...
-
-                       If [pem] is "TMP" and the openssl(1) utility
-                       command exists in PATH, then a temporary, self-signed
-                       certificate will be generated for this session.  If
-                       openssl(1) cannot be used to generate a temporary
-                       certificate x11vnc exits immediately.  The temporary
-                       cert will be discarded when x11vnc exits.
-
-                       If successful in using openssl(1) to generate a
-                       temporary certificate in "SAVE" or "TMP" creation
-                       modes, the public part of it will be displayed to stderr
-                       (e.g. one could copy it to the client-side to provide
-                       authentication of the server to VNC viewers.)
-
-                       NOTE: In "TMP" mode, unless you safely copy the
-                       public part of the temporary Cert to the viewer for
-                       authenticate *every time* (unlikely...), then only
-                       passive sniffing attacks are prevented and you are
-                       still open to Man-In-The-Middle attacks.  This is
-                       why the default "SAVE" mode is preferred (and more
-                       sophisticated CA mode too).  Only with saved keys AND
-                       the VNC viewer authenticating them (via the public
-                       certificate), are Man-In-The-Middle attacks prevented.
-
-                       If [pem] is "ANON" then the Diffie-Hellman anonymous
-                       key exchange method is used.  In this mode there
-                       are *no* SSL certificates and so it is not possible
-                       to authenticate either the VNC server or VNC client.
-                       Thus only passive network sniffing attacks are avoided:
-                       the "ANON" method is susceptible to Man-In-The-Middle
-                       attacks.  "ANON" is not recommended; instead use
-                       a SSL PEM you created or the default "SAVE" method.
-
-                       See -ssldir below to use a directory besides the
-                       default ~/.vnc/certs
-
-                       If your x11vnc binary was not compiled with OpenSSL
-                       library support, use of the -ssl option will induce an
-                       immediate failure and exit.  For such binaries, consider
-                       using the -stunnel option for SSL encrypted connections.
-
-                       Misc Info: In temporary cert creation mode "TMP", set
-                       the env. var. X11VNC_SHOW_TMP_PEM=1 to have x11vnc print
-                       out the entire certificate, including the PRIVATE KEY
-                       part, to stderr.  There are better ways to get/save this
-                       info.  See "SAVE" above and "-sslGenCert" below.
-
--ssltimeout n          Set SSL read timeout to n seconds.  In some situations
-                       (i.e. an iconified viewer in Windows) the viewer stops
-                       talking and the connection is dropped after the default
-                       timeout (25s for about the first minute, 43200s later).
-                       Set to zero to poll forever.  Set to a negative value
-                       to use the builtin setting.
-
-                       Note that this value does NOT apply to the *initial* ssl
-                       init connection.  The default timeout for that is 20sec.
-                       Use -env SSL_INIT_TIMEOUT=n to modify it.
-
--sslnofail             Exit at the first SSL connection failure. Useful when
-                       scripting SSL connections (e.g. x11vnc is started via
-                       ssh) and you do not want x11vnc waiting around for more
-                       connections, tying up ports, etc.
-
--ssldir dir            Use "dir" as an alternate ssl certificate and key
-                       management toplevel directory.  The default is
-                       ~/.vnc/certs
-
-                       This directory is used to store server and other
-                       certificates and keys and also other materials.  E.g. in
-                       the simplest case, "-ssl SAVE" will store the x11vnc
-                       server cert in dir/server.pem
-
-                       Use of alternate directories via -ssldir allows you to
-                       manage multiple VNC Certificate Authority (CA) keys.
-                       Another use is if ~/.vnc/cert is on an NFS share you
-                       might want your certificates and keys to be on a local
-                       filesystem to prevent network snooping (for example
-                       -ssldir /var/lib/x11vnc-certs).
-
-                       -ssldir affects nearly all of the other -ssl* options,
-                       e.g. -ssl SAVE, -sslGenCert, etc..
-
--sslverify path        For either of the -ssl or -stunnel modes, use "path"
-                       to provide certificates to authenticate incoming VNC
-                       *Client* connections (normally only the server is
-                       authenticated in SSL.)  This can be used as a method
-                       to replace standard password authentication of clients.
-
-                       If "path" is a directory it contains the client (or CA)
-                       certificates in separate files.  If path is a file,
-                       it contains one or more certificates. See special tokens
-                       below.  These correspond to the "CApath = dir" and
-                       "CAfile = file" stunnel options.  See the stunnel(8)
-                       manpage for details.
-
-                       Examples:
-                              x11vnc -ssl -sslverify ~/my.crt
-                              x11vnc -ssl -sslverify ~/my_pem_dir/
-
-                       Note that if path is a directory, it must contain
-                       the certs in separate files named like <HASH>.0, where
-                       the value of <HASH> is found by running the command
-                       "openssl x509 -hash -noout -in file.crt". Evidently
-                       one uses <HASH>.1 if there is a collision...
-
-                       The the key-management utility "-sslCertInfo HASHON"
-                       and "-sslCertInfo HASHOFF" will create/delete these
-                       hashes for you automatically (via symlink) in the HASH
-                       subdirs it manages.  Then you can point -sslverify to
-                       the HASH subdir.
-
-                       Special tokens: in -ssl mode, if "path" is not a file or
-                       a directory, it is taken as a comma separated list of
-                       tokens that are interpreted as follows:
-
-                       If a token is "CA" that means load the CA/cacert.pem
-                       file from the ssl directory.  If a token is "clients"
-                       then all the files clients/*.crt in the ssl directory
-                       are loaded.  Otherwise the file clients/token.crt
-                       is attempted to be loaded.  As a kludge, use a token
-                       like ../server-foo to load a server cert if you find
-                       that necessary.
-
-                       Use -ssldir to use a directory different from the
-                       ~/.vnc/certs default.
-
-                       Note that if the "CA" cert is loaded you do not need
-                       to load any of the certs that have been signed by it.
-                       You will need to load any additional self-signed certs
-                       however.
-
-                       Examples:
-                              x11vnc -ssl -sslverify CA
-                              x11vnc -ssl -sslverify self:fred,self:jim
-                              x11vnc -ssl -sslverify CA,clients
-
-                       Usually "-sslverify CA" is the most effective.
-                       See the -sslGenCA and -sslGenCert options below for
-                       how to set up and manage the CA framework.
-
-
-
-                       NOTE: the following utilities, -sslGenCA, -sslGenCert,
-                       -sslEncKey, -sslCertInfo, and -sslCRL are provided for
-                       completeness, but for casual usage they are overkill.
-
-                       They provide VNC Certificate Authority (CA) key creation
-                       and server / client key generation and signing.  So they
-                       provide a basic Public Key management framework for
-                       VNC-ing with x11vnc. (note that they require openssl(1)
-                       be installed on the system)
-
-                       However, the simplest usage mode, "-ssl TMP" (where
-                       x11vnc automatically generates its own, self-signed,
-                       temporary key and the VNC viewers always accept it,
-                       e.g. accepting via a dialog box) is probably safe enough
-                       for most scenarios.  CA management is not needed.
-
-                       To protect against Man-In-The-Middle attacks the "TMP"
-                       mode can be improved by using "-ssl SAVE" (same as
-                       "-ssl", i.e. the default) to have x11vnc create a
-                       longer term self-signed certificate, and then (safely)
-                       copy the corresponding public key cert to the desired
-                       client machines (care must be taken the private key part
-                       is not stolen; you will be prompted for a passphrase).
-
-                       So keep in mind no CA key creation or management
-                       (-sslGenCA and -sslGenCert) is needed for either of
-                       the above two common usage modes.
-
-                       One might want to use -sslGenCA and -sslGenCert
-                       if you had a large number of VNC client and server
-                       workstations.  That way the administrator could generate
-                       a single CA key with -sslGenCA and distribute its
-                       certificate part to all of the workstations.
-
-                       Next, he could create signed VNC server keys
-                       (-sslGenCert server ...) for each workstation or user
-                       that then x11vnc would use to authenticate itself to
-                       any VNC client that has the CA cert.
-
-                       Optionally, the admin could also make it so the
-                       VNC clients themselves are authenticated to x11vnc
-                       (-sslGenCert client ...)  For this -sslverify would be
-                       pointed to the CA cert (and/or self-signed certs).
-
-                       x11vnc will be able to use all of these cert and
-                       key files.  On the VNC client side, they will need to
-                       be "imported" somehow.  Web browsers have "Manage
-                       Certificates" actions as does the Java applet plugin
-                       Control Panel.  stunnel can also use these files (see
-                       the ss_vncviewer example script in the FAQ and SSVNC.)
-
--sslCRL path           Set the Certificate Revocation Lists (CRL) to "path".
-                       This setting applies for both -ssl and -stunnel modes.
-
-                       If path is a file, the file contains one or more CRLs
-                       in PEM format.  If path is a directory, it contains
-                       hash named files of CRLs in the usual OpenSSL manner.
-                       See the OpenSSL and stunnel(8) documentation for
-                       more info.
-
-                       This option only applies if -sslverify has been
-                       supplied: it checks for revocation along the
-                       certificate chain used to verify the VNC client.
-                       The -sslCRL setting will be ignored when -sslverify is
-                       not specified.
-
-                       Note that if a CRL's expiration date has passed, all
-                       SSL connections will fail regardless of if they are
-                       related to the subject of the CRL or not.
-
-                       Only rarely will one's x11vnc -ssl infrastructure be so
-                       large that this option would be useful (since normally
-                       maintaining the contents of the -sslverify file or
-                       directory should be enough.)  However, when using
-                       x11vnc with a Certificate Authority (see -sslGenCA)
-                       to authenticate Clients via SSL/TLS, the -sslCRL option
-                       can be useful to revoke users' certs whose private SSL
-                       keys were lost or stolen (e.g. laptop.)  This way a new
-                       CA cert+key does not need to be created and new signed
-                       client keys generated and distributed to all users.
-
-                       To create a CRL file with revoked certificates the
-                       commands 'openssl ca -revoke ...' and 'openssl ca
-                       -gencrl ...' are useful.  (Run them in ~/.vnc/certs)
-
--sslGenCA [dir]        Generate your own Certificate Authority private key,
-                       certificate, and other files in directory [dir].
-                       x11vnc then exits.
-
-                       If [dir] is not supplied, a -ssldir setting is used,
-                       or otherwise ~/.vnc/certs is used.
-
-                       This command also creates directories where server and
-                       client certs and keys will be stored.  The openssl(1)
-                       program must be installed on the system and available
-                       in PATH.
-
-                       After the CA files and directories are created the
-                       x11vnc command exits; the VNC server is not run.
-
-                       You will be prompted for information to put into the CA
-                       certificate.  The info does not have to be accurate just
-                       as long as clients accept the cert for VNC connections.
-                       You will also need to supply a passphrase of at least
-                       4 characters for the CA private key.
-
-                       Once you have generated the CA you can distribute
-                       its certificate part, [dir]/CA/cacert.pem, to other
-                       workstations where VNC viewers will be run.  One will
-                       need to "import" this certificate in the applications,
-                       e.g. Web browser, Java applet plugin, stunnel, etc.
-                       Next, you can create and sign keys using the CA with
-                       the -sslGenCert option below.
-
-                       Examples:
-                                x11vnc -sslGenCA
-                                x11vnc -sslGenCA  ~/myCAdir
-                                x11vnc -ssldir ~/myCAdir -sslGenCA
-
-                       (the last two lines are equivalent)
-
--sslGenCert type name  Generate a VNC server or client certificate and private
-                       key pair signed by the CA created previously with
-                       -sslGenCA.  The openssl(1) program must be installed
-                       on the system and available in PATH.
-
-                       After the Certificate is generated x11vnc exits; the
-                       VNC server is not run.
-
-                       The type of key to be generated is the string "type".
-                       It is either "server" (i.e. for use by x11vnc) or
-                       "client" (for a VNC viewer).  Note that typically
-                       only "server" is used: the VNC clients authenticate
-                       themselves by a non-public-key method (e.g. VNC or
-                       unix password).  "type" is required.
-
-                       An arbitrary default name you want to associate with
-                       the key is supplied by the "name" string.  You can
-                       change it at the various prompts when creating the key.
-                       "name" is optional.
-
-                       If name is left blank for clients keys then "nobody"
-                       is used.  If left blank for server keys, then the
-                       primary server key: "server.pem" is created (this
-                       is the saved one referenced by "-ssl SAVE" when the
-                       server is started)
-
-                       If "name" begins with the string "self:" then
-                       a self-signed certificate is created instead of one
-                       signed by your CA key.
-
-                       If "name" begins with the string "req:" then only a
-                       key (.key) and a certificate signing *request* (.req)
-                       are generated.  You can then send the .req file to
-                       an external CA (even a professional one, e.g. Thawte)
-                       and then combine the .key and the received cert into
-                       the .pem file with the same basename.
-
-                       The distinction between "server" and "client" is
-                       simply the choice of output filenames and sub-directory.
-                       This makes it so the -ssl SAVE-name option can easily
-                       pick up the x11vnc PEM file this option generates.
-                       And similarly makes it easy for the -sslverify option
-                       to pick up your client certs.
-
-                       There is nothing special about the filename or directory
-                       location of either the "server" and "client" certs.
-                       You can rename the files or move them to wherever
-                       you like.
-
-                       Precede this option with -ssldir [dir] to use a
-                       directory other than the default ~/.vnc/certs You will
-                       need to run -sslGenCA on that directory first before
-                       doing any -sslGenCert key creation.
-
-                       Note you cannot recreate a cert with exactly the same
-                       distiguished name (DN) as an existing one.  To do so,
-                       you will need to edit the [dir]/CA/index.txt file to
-                       delete the line.
-
-                       Similar to -sslGenCA, you will be prompted to fill
-                       in some information that will be recorded in the
-                       certificate when it is created.
-
-                       Tip: if you know the fully-qualified hostname other
-                       people will be connecting to, you can use that as the
-                       CommonName "CN" to avoid some applications (e.g. web
-                       browsers and java plugin) complaining that it does not
-                       match the hostname.
-
-                       You will also need to supply the CA private key
-                       passphrase to unlock the private key created from
-                       -sslGenCA.  This private key is used to sign the server
-                       or client certificate.
-
-                       The "server" certs can be used by x11vnc directly by
-                       pointing to them via the -ssl [pem] option.  The default
-                       file will be ~/.vnc/certs/server.pem.  This one would
-                       be used by simply typing -ssl SAVE.  The pem file
-                       contains both the certificate and the private key.
-                       server.crt file contains the cert only.
-
-                       The "client" cert + private key file will need
-                       to be copied and imported into the VNC viewer
-                       side applications (Web browser, Java plugin,
-                       stunnel, etc.)  Once that is done you can delete the
-                       "client" private key file on this machine since
-                       it is only needed on the VNC viewer side.  The,
-                       e.g. ~/.vnc/certs/clients/<name>.pem contains both
-                       the cert and private key.  The <name>.crt contains the
-                       certificate only.
-
-                       NOTE: It is very important to know one should
-                       generate new keys with a passphrase.  Otherwise if an
-                       untrusted user steals the key file he could use it to
-                       masquerade as the x11vnc server (or VNC viewer client).
-                       You will be prompted whether to encrypt the key with
-                       a passphrase or not.  It is recommended that you do.
-                       One inconvenience to a passphrase is that it must
-                       be typed in EVERY time x11vnc or the client app is
-                       started up.
-
-                       Examples:
-
-                               x11vnc -sslGenCert server
-                               x11vnc -ssl SAVE -display :0 ...
-
-                       and then on viewer using ss_vncviewer stunnel wrapper
-                       (see the FAQ):
-                               ss_vncviewer -verify ./cacert.crt hostname:0
-
-                       (this assumes the cacert.crt cert from -sslGenCA
-                       was safely copied to the VNC viewer machine where
-                       ss_vncviewer is run)
-
-                       Example using a name:
-
-                               x11vnc -sslGenCert server charlie
-                               x11vnc -ssl SAVE-charlie -display :0 ...
-
-                       Example for a client certificate (rarely used):
-
-                               x11vnc -sslGenCert client roger
-                               scp ~/.vnc/certs/clients/roger.pem somehost:.
-                               rm  ~/.vnc/certs/clients/roger.pem
-
-                       x11vnc is then started with the option -sslverify
-                       ~/.vnc/certs/clients/roger.crt (or simply -sslverify
-                       roger), and on the viewer user on somehost could do
-                       for example:
-
-                               ss_vncviewer -mycert ./roger.pem hostname:0
-
-                       If you set the env. var REQ_ARGS='...' it will be
-                       passed to openssl req(1).  A common use would be
-                       REQ_ARGS='-days 1095' to bump up the expiration date
-                       (3 years in this case).
-
--sslEncKey pem         Utility to encrypt an existing PEM file with a
-                       passphrase you supply when prompted.  For that key to be
-                       used (e.g. by x11vnc) the passphrase must be supplied
-                       each time.
-
-                       The "SAVE" notation described under -ssl applies as
-                       well. (precede this option with -ssldir [dir] to refer
-                       a directory besides the default ~/.vnc/certs)
-
-                       The openssl(1) program must be installed on the system
-                       and available in PATH.  After the Key file is encrypted
-                       the x11vnc command exits; the VNC server is not run.
-
-                       Examples:
-                               x11vnc -sslEncKey /path/to/foo.pem
-                               x11vnc -sslEncKey SAVE
-                               x11vnc -sslEncKey SAVE-charlie
-
--sslCertInfo pem       Prints out information about an existing PEM file.
-                       In addition the public certificate is also printed.
-                       The openssl(1) program must be in PATH. Basically the
-                       command "openssl x509 -text" is run on the pem.
-
-                       After the info is printed the x11vnc command exits;
-                       the VNC server is not run.
-
-                       The "SAVE" notation described under -ssl applies
-                       as well.
-
-                       Using  "LIST" will give a list of all certs being
-                       managed (in the ~/.vnc/certs dir, use -ssldir to refer
-                       to another dir).  "ALL" will print out the info for
-                       every managed key (this can be very long).  Giving a
-                       client or server cert shortname will also try a lookup
-                       (e.g. -sslCertInfo charlie).  Use "LISTL" or "LL"
-                       for a long (ls -l style) listing.
-
-                       Using "HASHON" will create subdirs [dir]/HASH and
-                       [dir]/HASH with OpenSSL hash filenames (e.g. 0d5fbbf1.0)
-                       symlinks pointing up to the corresponding *.crt file.
-                       ([dir] is ~/.vnc/certs or one given by -ssldir.)
-                       This is a useful way for other OpenSSL applications
-                       (e.g. stunnel) to access all of the certs without
-                       having to concatenate them.  x11vnc will not use them
-                       unless you specifically reference them.  "HASHOFF"
-                       removes these HASH subdirs.
-
-                       The LIST, LISTL, LL, ALL, HASHON, HASHOFF words can
-                       also be lowercase, e.g. "list".
-
--sslDelCert pem        Prompts you to delete all .crt .pem .key .req files
-                       associated with [pem].  x11vnc then exits. "SAVE"
-                       and lookups as in -sslCertInfo apply as well.
-
--sslScripts            Prints out both the 'genCA' and 'genCert' x11vnc
-                       openssl wrapper scripts for you to examine, modify, etc.
-                       The scripts are printed to stdout and then the x11vnc
-                       program exits.
-
-
--stunnel [pem]         Use the stunnel(8) (stunnel.mirt.net) to provide an
-                       encrypted SSL tunnel between viewers and x11vnc.
-
-                       This external tunnel method was implemented prior to the
-                       integrated -ssl encryption described above.  It still
-                       works well and avoids the requirement of linking with
-                       the OpenSSL libraries.  This mode requires stunnel
-                       to be installed on the system and available via PATH
-                       (n.b. stunnel is often installed in sbin directories).
-                       Version 4.x of stunnel is assumed (but see -stunnel3
-                       below.)
-
-                       [pem] is optional, use "-stunnel /path/to/stunnel.pem"
-                       to specify a PEM certificate file to pass to stunnel.
-                       See the -ssl option for more info on certificate files.
-
-                       Whether or not your stunnel has its own certificate
-                       depends on your stunnel configuration; stunnel often
-                       generates one at install time.  See your stunnel
-                       documentation for details.  In any event, if you want to
-                       use this certificate you must supply the full path to it
-                       as [pem].  Note: the file may only be readable by root.
-
-                       [pem] may also be the special strings "TMP", "SAVE",
-                       and "SAVE..." as described in the -ssl option.
-                       If [pem] is not supplied, "SAVE" is assumed.
-
-                       Note that the VeNCrypt, ANONTLS, and "ANON" modes
-                       are not supported in -stunnel mode.
-
-                       stunnel is started up as a child process of x11vnc and
-                       any SSL connections stunnel receives are decrypted and
-                       sent to x11vnc over a local socket.  The strings
-                       "The SSL VNC desktop is ..." and "SSLPORT=..."
-                       are printed out at startup to indicate this.
-
-                       The -localhost option is enforced by default to avoid
-                       people routing around the SSL channel.  Use -env
-                       STUNNEL_DISABLE_LOCALHOST=1 to disable this security
-                       requirement.
-
-                       Set -env STUNNEL_DEBUG=1 for more debugging printout.
-
-                       Set -env STUNNEL_PROG=xxx to the full path of stunnel
-                       program you want to be used (e.g. /usr/bin/stunnel4).
-
-                       Set -env STUNNEL_LISTEN=xxx to the address of the
-                       network interface to listen on (the default is to listen
-                       on all interfaces), e.g. STUNNEL_LISTEN=192.168.1.100.
-
-                       A simple way to add IPv6 support is STUNNEL_LISTEN=::
-
-                       Your VNC viewer will also need to be able to connect
-                       via SSL.  Unfortunately not too many do this.  See the
-                       information about SSL viewers under the -ssl option.
-                       The x11vnc project's SSVNC is an option.
-
-                       Also, in the x11vnc distribution, patched TightVNC
-                       and UltraVNC Java applet jar files are provided in
-                       the classes/ssl directory that do SSL connections.
-                       Enable serving them with the -http, -http_ssl, or
-                       -httpdir (see the option descriptions for more info.)
-
-                       Note that for the Java viewer applet usage the
-                       "?PORT=xxxx" in the various URLs printed at startup
-                       will need to be supplied to the web browser to connect
-                       properly.
-
-                       Currently the automatic "single port" HTTPS mode of
-                       -ssl is not fully supported in -stunnel mode.  However,
-                       it can be emulated via:
-
-                         % x11vnc -stunnel -http_ssl -http_oneport ...
-
-                       In general, it is also not too difficult to set up
-                       an stunnel or other SSL tunnel on the viewer side.
-                       A simple example on Unix using stunnel 3.x is:
-
-                         % stunnel -c -d localhost:5901 -r remotehost:5900
-                         % vncviewer localhost:1
-
-                       For Windows, stunnel has been ported to it and there
-                       are probably other such tools available.  See the FAQ
-                       and SSVNC for more examples.
-
--stunnel3  [pem]       Use version 3.x stunnel command line syntax instead of
-                       version 4.x.  The -http/-httpdir Java applet serving
-                       is currently not available in this mode.
-
--enc cipher:keyfile    Use symmetric encryption with cipher "cipher"
-                       and secret key data in "keyfile".  If keyfile is
-                       pw=<string> then "string" is used as the key data.
-
-                       NOTE: It is recommended that you use SSL via the -ssl
-                       option instead of this option because SSL is well
-                       understood and takes great care to establish unique
-                       session keys and is more compatible with other software.
-                       Use this option if you do not want to deal with SSL
-                       certificates for authentication and do not want to
-                       use SSH but want some encryption for your VNC session.
-                       Or if you must interface with a symmetric key tunnel
-                       that you do not have control over.
-
-                       Note that this mode will NOT work with the UltraVNC DSM
-                       plugins because they alter the RFB protocol in addition
-                       to tunnelling with the symmetric cipher (an unfortunate
-                       choice of implementation...)
-
-                       cipher can be one of:  arc4, aesv2, aes-cfb, blowfish,
-                       aes256, or 3des.  See the OpenSSL documentation for
-                       more info.  The keysize is 128 bits (except for aes256).
-                       Here is one way to make a keyfile with that many bits:
-
-                            dd if=/dev/random of=./my.key bs=16 count=1
-
-                       you will need to securely share this key with the other
-                       side of the VNC connection (See SSVNC for examples).
-
-                       Example:  -enc blowfish:./my.key
-                       Example:  -enc blowfish:pw=swordfish
-
-                       By default 16 bytes of random salt followed by 16 bytes
-                       of random initialization vector are sent at the very
-                       beginning of the stream.  The other side must read these
-                       and initialize their cipher with them.  These values
-                       make the session key unique (without them the security
-                       is minimal).  Similarly, the other side must send us
-                       its random salt and IV with those same lengths.
-
-                       The salt and key data are combined to create a session
-                       key using an md5 hash as described in EVP_BytesToKey(3).
-
-                       The exact call is: EVP_BytesToKey(Cipher, EVP_md5(),
-                       salt, keydata, len, 1, keystr, NULL);  where salt is
-                       the random data as described above, and keydata is the
-                       shared secret key data.  keystr is the resulting session
-                       key.  The cipher is then seeded with keystr and uses
-                       the random initialization vector as its first block.
-
-                       To modify the amount of random salt and initialization
-                       vector use cipher@n,m where n is the salt length and
-                       m the initialization vector length.  E.g.
-
-                                 -enc aes-cfb@8,16:./my.key
-
-                       It is not a good idea to set either one to zero,
-                       although you may be forced to if the other side of the
-                       tunnel is not under your control.
-
-                       To skip the salt and EVP_BytesToKey MD5 entirely (no
-                       hashing is done: the keydata is directly inserted into
-                       the cipher) specify "-1" for the salt, e.g.
-
-                                 -enc blowfish@-1,16:./my.key
-
-                       The message digest can also be changed to something
-                       besides the default MD5.  Use cipher@md+n,m where "md"
-                       can be one of sha, sha1, md5, or ripe.  For example:
-
-                                 -enc arc4@sha+8,16:./my.key
-
-                       The SSVNC vnc viewer project supplies a symmetric
-                       encryption tool named "ultravnc_dsm_helper" that can
-                       be used on the viewer side.  For example:
-
-                       ssvncviewer exec='ultravnc_dsm_helper arc4 my.key 0 h:p'
-
-                       where h:p is the hostname and port of the x11vnc server.
-                       ultravnc_dsm_helper may also be used standalone to
-                       provide a symmetric encryption tunnel for any viewer
-                       or server (VNC or otherwise.) The cipher (1st arg)
-                       is basically the same syntax as we use above.
-
-                       Also see the 'Non-Ultra DSM' SSVNC option for the
-                       'UltraVNC DSM Encryption Plugin' advanced option.
-
-                       For both ways of using the viewer, you can specify the
-                       salt,ivec sizes (in GUI or, e.g. arc4@8,16).
-
--https [port]          Use a special, separate HTTPS port (-ssl and
-                       -stunnel modes only) for HTTPS Java viewer applet
-                       downloading. I.e. not 5900 and not 5800 (the defaults.)
-
-                       BACKGROUND: In -ssl mode, it turns out you can use the
-                       single VNC port (e.g. 5900) for both VNC and HTTPS
-                       connections. (HTTPS is used to retrieve a SSL-aware
-                       VncViewer.jar applet that is provided with x11vnc).
-                       Since both use SSL the implementation was extended to
-                       detect if HTTP traffic (i.e. GET) is taking place and
-                       handle it accordingly.  The URL would be, e.g.:
-
-                       https://mymachine.org:5900/
-
-                       This is convenient for firewalls, etc, because only one
-                       port needs to be allowed in.  However, this heuristic
-                       adds a few seconds delay to each connection and can be
-                       unreliable (especially if the user takes much time to
-                       ponder the Certificate dialogs in his browser, Java VM,
-                       or VNC Viewer applet.  That's right 3 separate "Are
-                       you sure you want to connect?" dialogs!)
-
-                       END OF BACKGROUND.
-
-                       USAGE: So use the -https option to provide a separate,
-                       more reliable HTTPS port that x11vnc will listen on.  If
-                       [port] is not provided (or is 0), one is autoselected.
-                       The URL to use is printed out at startup.
-
-                       The SSL Java applet directory is specified via the
-                       -httpdir option.  If not supplied, -https will try
-                       to guess the directory as though the -http option
-                       was supplied.
-
--httpsredir [port]     In -ssl mode with the Java applet retrieved via HTTPS,
-                       when the HTML file containing applet parameters
-                       ('index.vnc' or 'proxy.vnc') is sent do NOT set the
-                       applet PORT parameter to the actual VNC port but set it
-                       to "port" instead.  If "port" is not supplied, then
-                       the port number is guessed from the Host: HTTP header.
-
-                       This is useful when an incoming TCP connection
-                       redirection is performed by a router/gateway/firewall
-                       from one port to an internal machine where x11vnc is
-                       listening on a different port. The Java applet needs to
-                       connect to the firewall/router port, not the VNC port
-                       on the internal workstation. For example, one could
-                       redir from mygateway.com:443 to workstation:5900.
-
-                       This spares the user from having to type in
-                       https://mygateway.com/?PORT=443 into their web
-                       browser. Note that port 443 is the default https port;
-                       other ports must be explicitly indicated, for example:
-                       https://mygateway.com:8000/?PORT=8000.  To avoid having
-                       to include the PORT= in the browser URL, simply supply
-                       "-httpsredir" to x11vnc.
-
-                       This option does not work in -stunnel mode.
-
-                       More tricks: set the env var X11VNC_EXTRA_HTTPS_PARAMS
-                       to be extra URL parameters to use.  This way you do
-                       not need to specify extra PARAMS in the index.vnc file.
-                       E.g. x11vnc -env X11VNC_EXTRA_HTTPS_PARAMS='?GET=1' ...
-
-                       If you do not want to expose the non-SSL HTTP port to
-                       the network (i.e. you just want the single VNC/HTTPS
-                       port, e.g. 5900, open for connections) then specify the
-                       option -env X11VNC_HTTP_LISTEN_LOCALHOST=1  This way
-                       the connection to the LibVNCServer httpd server will
-                       only be available on localhost (note that in -ssl mode,
-                       HTTPS requests are redirected from SSL to the non-SSL
-                       LibVNCServer HTTP server.)
-
--http_oneport          For UN-encrypted connections mode (i.e. no -ssl,
-                       -stunnel, or -enc options), allow the Java VNC Viewer
-                       applet to be downloaded thru the VNC port via HTTP.
-
-                       That is to say, you can use a single port for Java
-                       applet viewer connections by using a URL in your web
-                       browser like this, for example:
-
-                       http://hostname:5900
-
-                       The regular, two-port mode, URL http://hostname:5800
-                       will continue to work as well.
-
-                       As mentioned above, this mode will NOT work with
-                       the -ssl, -stunnel, or -enc encryption options.
-                       Note that is it equivalent to '-enc none' (i.e. it
-                       uses the same detection mechanism as for HTTPS, but
-                       with no encryption.)
-
-                       HTTPS single-port is on by default in -ssl encrypted
-                       mode (and -enc too), so you only need -http_oneport
-                       when doing non-SSL encrypted connections.
-
-                       This mode could also be useful for SSH tunnels since
-                       it means only one port needs to be redirected.
-
-                       The -httpsredir option may also be useful for this
-                       mode when using an SSH tunnel as well as for router
-                       port redirections.
-
-                       Note that the -env X11VNC_HTTP_LISTEN_LOCALHOST=1
-                       option described above under -httpsredir applies for
-                       the LibVNCServer httpd server in all cases (ssl or not.)
-
--ssh user@host:disp    Create a remote listening port on machine "host"
-                       via a SSH tunnel using the -R rport:localhost:lport
-                       method. lport will be the local x11vnc listening port,
-                       so a connection to rport (5900+disp) on "host"
-                       will reach x11vnc.  E.g. fred@snoopy.com:0
-
-                       This could be useful if a firewall/router prevents
-                       incoming connections to the x11vnc machine, but
-                       the ssh machine "host" can be reached by the VNC
-                       viewer. "user@" is not needed unless the remote unix
-                       username differs from the current one.
-
-                       By default the remote sshd is usually configured to
-                       listen only on localhost for rport, so the viewer may
-                       need to ssh -L redir to "host" as well (See SSVNC to
-                       automate this).  The sshd setting GatewayPorts enables
-                       listening on all interfaces for rport; viewers can
-                       reach it more easily.
-
-                       "disp" is the VNC display for the remote SSH side,
-                       e.g. 0 corresponds to port 5900, etc.  If disp is
-                       greater than 200 the value is used as the port.  Use a
-                       negative value to force a low port, e.g. host:-80 will
-                       use port 80.
-
-                       If ssh-agent is not active, then the ssh password needs
-                       to be entered in the terminal where x11vnc is running.
-
-                       By default the remote ssh will issue a 'sleep 300' to
-                       wait for the incoming connection for 5 mins.  To modify
-                       this use user@host:disp+secs.
-
-                       If the remote SSH server is on a non-standard port
-                       (i.e. not 22) use user@host:port:disp+secs.
-
-                       Note that the ssh process MAY NOT be killed when
-                       x11vnc exits.  It tries by looking at ps(1) output.
-
--usepw                 If no other password method was supplied on the command
-                       line, first look for ~/.vnc/passwd and if found use it
-                       with -rfbauth; next, look for ~/.vnc/passwdfile and
-                       use it with -passwdfile; otherwise, prompt the user
-                       for a password to create ~/.vnc/passwd and use it with
-                       the -rfbauth option.  If none of these succeed x11vnc
-                       exits immediately.
-
--storepasswd pass file Store password "pass" as the VNC password in the
-                       file "file".  Once the password is stored the
-                       program exits.  Use the password via "-rfbauth file"
-
-                       If called with no arguments, "x11vnc -storepasswd",
-                       the user is prompted for a password and it is stored
-                       in the file ~/.vnc/passwd.  Called with one argument,
-                       that will be the file to store the prompted password in.
-
--nopw                  Disable the big warning message when you use x11vnc
-                       without some sort of password.
-
--accept string         Run a command (possibly to prompt the user at the
-                       X11 display) to decide whether an incoming client
-                       should be allowed to connect or not.  "string" is
-                       an external command run via system(3) or some special
-                       cases described below.  Be sure to quote "string"
-                       if it contains spaces, shell characters, etc.  If the
-                       external command returns 0 the client is accepted,
-                       otherwise the client is rejected.  See below for an
-                       extension to accept a client view-only.
-
-                       If x11vnc is running as root (say from inetd(8) or from
-                       display managers xdm(1), gdm(1), etc), think about the
-                       security implications carefully before supplying this
-                       option (likewise for the -gone option).
-
-                       Environment: The RFB_CLIENT_IP environment variable will
-                       be set to the incoming client IP number and the port
-                       in RFB_CLIENT_PORT (or -1 if unavailable).  Similarly,
-                       RFB_SERVER_IP and RFB_SERVER_PORT (the x11vnc side
-                       of the connection), are set to allow identification
-                       of the tcp virtual circuit.  The x11vnc process
-                       id will be in RFB_X11VNC_PID, a client id number in
-                       RFB_CLIENT_ID, and the number of other connected clients
-                       in RFB_CLIENT_COUNT.  RFB_MODE will be "accept".
-                       RFB_STATE will be PROTOCOL_VERSION, SECURITY_TYPE,
-                       AUTHENTICATION, INITIALISATION, NORMAL, or UNKNOWN
-                       indicating up to which state the client has achieved.
-                       RFB_LOGIN_VIEWONLY will be 0, 1, or -1 (unknown).
-                       RFB_USERNAME, RFB_LOGIN_TIME, and RFB_CURRENT_TIME may
-                       also be set.
-
-                       If "string" is "popup" then a builtin popup window
-                       is used.  The popup will time out after 120 seconds,
-                       use "popup:N" to modify the timeout to N seconds
-                       (use 0 for no timeout).
-
-                       In the case of "popup" and when the -unixpw option
-                       is specified, then a *second* window will be popped
-                       up after the user successfully logs in via his UNIX
-                       password.  This time the user will be identified as
-                       UNIX:username@hostname, the "UNIX:" prefix indicates
-                       which user the viewer logged as via -unixpw.  The first
-                       popup is only for whether to allow him to even *try*
-                       to login via unix password.
-
-                       If "string" is "xmessage" then an xmessage(1)
-                       invocation is used for the command.  xmessage must be
-                       installed on the machine for this to work.
-
-                       Both "popup" and "xmessage" will present an option
-                       for accepting the client "View-Only" (the client
-                       can only watch).  This option will not be presented if
-                       -viewonly has been specified, in which case the entire
-                       display is view only.
-
-                       If the user supplied command is prefixed with something
-                       like "yes:0,no:*,view:3 mycommand ..." then this
-                       associates the numerical command return code with
-                       the actions: accept, reject, and accept-view-only,
-                       respectively.  Use "*" instead of a number to indicate
-                       the default action (in case the command returns an
-                       unexpected value).  E.g. "no:*" is a good choice.
-
-                       Note that x11vnc blocks while the external command
-                       or popup is running (other clients may see no updates
-                       during this period).  So a person sitting a the physical
-                       display is needed to respond to an popup prompt. (use
-                       a 2nd x11vnc if you lock yourself out).
-
-                       More -accept tricks: use "popupmouse" to only allow
-                       mouse clicks in the builtin popup to be recognized.
-                       Similarly use "popupkey" to only recognize
-                       keystroke responses.  These are to help avoid the
-                       user accidentally accepting a client by typing or
-                       clicking. All 3 of the popup keywords can be followed
-                       by +N+M to supply a position for the popup window.
-                       The default is to center the popup window.
--afteraccept string    As -accept, except to run a user supplied command after
-                       a client has been accepted and authenticated. RFB_MODE
-                       will be set to "afteraccept" and the other RFB_*
-                       variables are as in -accept.  Unlike -accept, the
-                       command return code is not interpreted by x11vnc.
-                       Example: -afteraccept 'killall xlock &'
--gone string           As -accept, except to run a user supplied command when
-                       a client goes away (disconnects).  RFB_MODE will be
-                       set to "gone" and the other RFB_* variables are as
-                       in -accept.  The "popup" actions apply as well.
-                       Unlike -accept, the command return code is not
-                       interpreted by x11vnc.  Example: -gone 'xlock &'
-
--users list            If x11vnc is started as root (say from inetd(8) or from
-                       display managers xdm(1), gdm(1), etc), then as soon
-                       as possible after connections to the X display are
-                       established try to switch to one of the users in the
-                       comma separated "list".  If x11vnc is not running as
-                       root this option is ignored.
-
-                       Why use this option?  In general it is not needed since
-                       x11vnc is already connected to the X display and can
-                       perform its primary functions.  The option was added
-                       to make some of the *external* utility commands x11vnc
-                       occasionally runs work properly.  In particular under
-                       GNOME and KDE to implement the "-solid color" feature
-                       external commands (gconftool-2 and dcop) unfortunately
-                       must be run as the user owning the desktop session.
-                       Since this option switches userid it also affects the
-                       userid used to run the processes for the -accept and
-                       -gone options.  It also affects the ability to read
-                       files for options such as -connect, -allow, and -remap
-                       and also the ultra and tight filetransfer feature if
-                       enabled.  Note that the -connect file is also sometimes
-                       written to.
-
-                       So be careful with this option since in some situations
-                       its use can decrease security.
-
-                       In general the switch to a user will only take place
-                       if the display can still be successfully opened as that
-                       user (this is primarily to try to guess the actual owner
-                       of the session). Example: "-users fred,wilma,betty".
-                       Note that a malicious local user "barney" by
-                       quickly using "xhost +" when logging in may possibly
-                       get the x11vnc process to switch to user "fred".
-                       What happens next?
-
-                       Under display managers it may be a long time before
-                       the switch succeeds (i.e. a user logs in).  To instead
-                       make it switch immediately regardless if the display
-                       can be reopened prefix the username with the "+"
-                       character. E.g. "-users +bob" or "-users +nobody".
-
-                       The latter (i.e. switching immediately to user
-                       "nobody") is the only obvious use of the -users option
-                       that increases security.
-
-                       Use the following notation to associate a group with
-                       a user: user1.group1,user2.group2,...  Note that
-                       initgroups(2) will still be called first to try to
-                       switch to ALL of a user's groups (primary and additional
-                       groups).  Only if that fails or it is not available
-                       then the single group specified as above (or the user's
-                       primary group if not specified) is switched to with
-                       setgid(2).  Use -env X11VNC_SINGLE_GROUP=1 to prevent
-                       trying initgroups(2) and only switch to the single
-                       group.  This sort of setting is only really needed to
-                       make the ultra or tight filetransfer permissions work
-                       properly. This format applies to any comma separated lis
-t
-                       of users, even the special "=" modes described below.
-
-                       In -unixpw mode, if "-users unixpw=" is supplied
-                       then after a user authenticates himself via the
-                       -unixpw mechanism, x11vnc will try to switch to that
-                       user as though "-users +username" had been supplied.
-                       If you want to limit which users this will be done for,
-                       provide them as a comma separated list after "unixpw="
-                       Groups can also be specified as described above.
-
-                       Similarly, in -ssl mode, if "-users sslpeer=" is
-                       supplied then after an SSL client authenticates with his
-                       cert (the -sslverify option is required for this) x11vnc
-                       will extract a UNIX username from the "emailAddress"
-                       field (username@hostname.com) of the "Subject" of the
-                       x509 SSL cert and then try to switch to that user as
-                       though "-users +username" had been supplied.  If you
-                       want to limit which users this will be done for, provide
-                       them as a comma separated list after "sslpeer=".
-                       Set the env. var X11VNC_SSLPEER_CN to use the Common
-                       Name (normally a hostname) instead of the Email field.
-
-                       NOTE: for sslpeer= mode the x11vnc administrator must
-                       take care that any client certs he adds to -sslverify
-                       have the intended UNIX username in the "emailAddress"
-                       field of the cert.  Otherwise a user may be able to
-                       log in as another.  This command can be of use in
-                       checking: "openssl x509 -text -in file.crt", see the
-                       "Subject:" line.  Also, along with the normal RFB_*
-                       env. vars. (see -accept) passed to external cmd=
-                       commands, RFB_SSL_CLIENT_CERT will be set to the
-                       client's x509 certificate string.
-
-                       The sslpeer= mode can aid finding X sessions via the
-                       FINDDISPLAY and FINDCREATEDISPLAY mechanisms.
-
-                       To immediately switch to a user *before* connections
-                       to the X display are made or any files opened use the
-                       "=" character: "-users =bob".  That user needs to
-                       be able to open the X display and any files of course.
-
-                       The special user "guess=" means to examine the utmpx
-                       database (see who(1)) looking for a user attached to
-                       the display number (from DISPLAY or -display option)
-                       and try him/her.  To limit the list of guesses, use:
-                       "-users guess=bob,betty".
-
-                       Even more sinister is the special user "lurk="
-                       that means to try to guess the DISPLAY from the utmpx
-                       login database as well.  So it "lurks" waiting for
-                       anyone to log into an X session and then connects to it.
-                       Specify a list of users after the = to limit which users
-                       will be tried.  To enable a different searching mode, if
-                       the first user in the list is something like ":0" or
-                       ":0-2" that indicates a range of DISPLAY numbers that
-                       will be tried (regardless of whether they are in the
-                       utmpx database) for all users that are logged in.  Also
-                       see the "-display WAIT:..." functionality.  Examples:
-                       "-users lurk=" and also "-users lurk=:0-1,bob,mary"
-
-                       Be especially careful using the "guess=" and "lurk="
-                       modes.  They are not recommended for use on machines
-                       with untrustworthy local users.
-
--noshm                 Do not use the MIT-SHM extension for the polling.
-                       Remote displays can be polled this way: be careful this
-                       can use large amounts of network bandwidth.  This is
-                       also of use if the local machine has a limited number
-                       of shm segments and -onetile is not sufficient.
--flipbyteorder         Sometimes needed if remotely polled host has different
-                       endianness.  Ignored unless -noshm is set.
--onetile               Do not use the new copy_tiles() framebuffer mechanism,
-                       just use 1 shm tile for polling.  Limits shm segments
-                       used to 3.
-
-                       To disable any automatic shm reduction set the
-                       env. var. X11VNC_NO_LIMIT_SHM.
-
--solid [color]         To improve performance, when VNC clients are connected
-                       try to change the desktop background to a solid color.
-                       The [color] is optional: the default color is "cyan4".
-                       For a different one specify the X color (rgb.txt name,
-                       e.g. "darkblue" or numerical "#RRGGBB").
-
-                       Currently this option only works on GNOME, KDE, CDE,
-                       XFCE, and classic X (i.e. with the background image
-                       on the root window).  The "gconftool-2", "dcop"
-                       and "xfconf-query" external commands are run for
-                       GNOME, KDE, and XFCE respectively.  This also works
-                       on native MacOSX.  (There is no color selection for
-                       MacOSX or XFCE.)  Other desktops won't work, (send
-                       us the corresponding commands if you find them).
-                       If x11vnc is running as root (inetd(8) or gdm(1)),
-                       the -users option may be needed for GNOME, KDE, XFCE.
-                       If x11vnc guesses your desktop incorrectly, you can
-                       force it by prefixing color with "gnome:", "kde:",
-                       "cde:", "xfce:", or "root:".
-
-                       Update: -solid no longer works on KDE4.
-
-                       This mode works in a limited way on the Mac OS X Console
-                       with one color ('kelp') using the screensaver writing
-                       to the background.  Look in "~/Library/Screen Savers"
-                       for VncSolidColor.png to change the color.
-
--blackout string       Black out rectangles on the screen. "string" is a
-                       comma separated list of WxH+X+Y type geometries for
-                       each rectangle.  If one of the items on the list is the
-                       string "noptr" the mouse pointer will not be allowed
-                       to go into a blacked out region.
--xinerama              If your screen is composed of multiple monitors
--noxinerama            glued together via XINERAMA, and that screen is
-                       not a rectangle this option will try to guess the
-                       areas to black out (if your system has libXinerama).
-                       default: -xinerama
-
-                       In general, we have noticed on XINERAMA displays you may
-                       need to use the "-xwarppointer" option if the mouse
-                       pointer misbehaves and it is enabled by default. Use
-                       "-noxwarppointer" if you do not want this.
-
--xtrap                 Use the DEC-XTRAP extension for keystroke and mouse
-                       input insertion.  For use on legacy systems, e.g. X11R5,
-                       running an incomplete or missing XTEST extension.
-                       By default DEC-XTRAP will be used if XTEST server grab
-                       control is missing, use -xtrap to do the keystroke and
-                       mouse insertion via DEC-XTRAP as well.
-
--xrandr [mode]         If the display supports the XRANDR (X Resize, Rotate
-                       and Reflection) extension, and you expect XRANDR events
-                       to occur to the display while x11vnc is running, this
-                       options indicates x11vnc should try to respond to
-                       them (as opposed to simply crashing by assuming the
-                       old screen size).  See the xrandr(1) manpage and run
-                       'xrandr -q' for more info.  [mode] is optional and
-                       described below.
-
-                       Since watching for XRANDR events and trapping errors
-                       increases polling overhead, only use this option if
-                       XRANDR changes are expected.  For example on a rotatable
-                       screen PDA or laptop, or using a XRANDR-aware Desktop
-                       where you resize often.  It is best to be viewing with a
-                       vncviewer that supports the NewFBSize encoding, since it
-                       knows how to react to screen size changes.  Otherwise,
-                       LibVNCServer tries to do so something reasonable for
-                       viewers that cannot do this (portions of the screen
-                       may be clipped, unused, etc).
-
-                       Note: the default now is to check for XRANDR events, but
-                       do not trap every X call that may fail due to resize.
-                       If a resize event is received, the full -xrandr mode
-                       is enabled.  To disable even checking for events supply:
-                       -noxrandr.
-
-                       "mode" defaults to "resize", which means create a
-                       new, resized, framebuffer and hope all viewers can cope
-                       with the change.  "newfbsize" means first disconnect
-                       all viewers that do not support the NewFBSize VNC
-                       encoding, and then resize the framebuffer.  "exit"
-                       means disconnect all viewer clients, and then terminate
-                       x11vnc.
-
--rotate string         Rotate and/or flip the framebuffer view exported by VNC.
-                       This transformation is independent of XRANDR and is
-                       done in software in main memory and so may be slower.
-                       This mode could be useful on a handheld with portrait or
-                       landscape modes that do not correspond to the scanline
-                       order of the actual framebuffer.  "string" can be:
-
-                             x     flip along x-axis
-                             y     flip along y-axis
-                            xy     flip along x- and y-axes
-                           +90     rotate 90 degrees clockwise
-                           -90     rotate 90 degrees counter-clockwise
-                          +90x     rotate 90 degrees CW, then flip along x
-                          +90y     rotate 90 degrees CW, then flip along y
-
-                       these give all possible rotations and reflections.
-
-                       Aliases: same as xy:  yx, +180, -180, 180
-                                same as -90: +270, 270
-                                same as +90: 90, (ditto for 90x, 90y)
-
-                       Like -scale, this transformation is applied at the very
-                       end of any chain of framebuffer transformations and so
-                       any options with geometries, e.g. -blackout, -clip, etc.
-                       are relative to the original X (or -rawfb) framebuffer,
-                       not the final one sent to VNC viewers.
-
-                       If you do not want the cursor shape to be rotated
-                       prefix "string" with "nc:", e.g. "nc:+90",
-                       "nc:xy", etc.
-
--padgeom WxH           Whenever a new vncviewer connects, the framebuffer is
-                       replaced with a fake, solid black one of geometry WxH.
-                       Shortly afterwards the framebuffer is replaced with the
-                       real one.  This is intended for use with vncviewers
-                       that do not support NewFBSize and one wants to make
-                       sure the initial viewer geometry will be big enough
-                       to handle all subsequent resizes (e.g. under -xrandr,
-                       -remote id:windowid, rescaling, etc.)
-
-                       In -unixpw mode this sets the size of the login screen.
-                       Use "once:WxH" it ignore padgeom after the login
-                       screen is set up.
-
--o logfile             Write stderr messages to file "logfile" instead of to
-                       the terminal.  Same as "-logfile file".  To append
-                       to the file use "-oa file" or "-logappend file".
-                       If "logfile" contains the string "%VNCDISPLAY"
-                       it is expanded to the vnc display (the name may need
-                       to be guessed at.)  "%HOME" works too.
-
--flag file             Write the "PORT=NNNN" (e.g. PORT=5900) string to
-                       "file" in addition to stdout.  This option could be
-                       useful by wrapper script to detect when x11vnc is ready.
-
--rmflag file           Remove "file" at exit to signal when x11vnc is done.
-                       The file is created at startup if it does not already
-                       exist or if "file" is prefixed with "create:".
-                       If the file is created, the x11vnc PID is placed in
-                       the file.  Otherwise the files contents is not changed.
-                       Use prefix "nocreate:" to prevent creation.
-
--rc filename           Use "filename" instead of $HOME/.x11vncrc for rc file.
--norc                  Do not process any .x11vncrc file for options.
-
--env VAR=VALUE         Set the environment variable 'VAR' to value 'VALUE'
-                       at x11vnc startup.  This is a convenience utility to
-                       avoid shell script wrappers, etc. to set the env. var.
-                       You may specify as many of these as needed on the
-                       command line.
--prog /path/to/x11vnc  Set the full path to the x11vnc program for cases when
-                       it cannot be determined from argv[0] (e.g. tcpd/inetd)
-
--h, -help              Print this help text.
--?, -opts              Only list the x11vnc options.
--V, -version           Print program version and last modification date.
--license               Print out license information.  Same as -copying and
-                       -warranty.
-
--dbg                   Instead of exiting after cleaning up, run a simple
-                       "debug crash shell" when fatal errors are trapped.
-
--q, -quiet             Be quiet by printing less informational output to
-                       stderr. (use -noquiet to undo an earlier -quiet.)
-
-                       The -quiet option does not eliminate all informational
-                       output, it only reduces it.  It is ignored in most
-                       auxiliary usage modes, e.g. -storepasswd.  To eliminate
-                       all output use: 2>/dev/null 1>&2, etc.
-
--v, -verbose           Print out more information to stderr.
-
--bg                    Go into the background after screen setup.  Messages to
-                       stderr are lost unless -o logfile is used.  Something
-                       like this could be useful in a script:
-                        port=`ssh -t $host "x11vnc -display :0 -bg" | grep PORT
-`
-                        port=`echo "$port" | sed -e 's/PORT=//'`
-                        port=`expr $port - 5900`
-                        vncviewer $host:$port
-
--modtweak              Option -modtweak automatically tries to adjust the AltGr
--nomodtweak            and Shift modifiers for differing language keyboards
-                       between client and host.  Otherwise, only a single key
-                       press/release of a Keycode is simulated (i.e. ignoring
-                       the state of the modifiers: this usually works for
-                       identical keyboards).  Also useful in resolving cases
-                       where a Keysym is bound to multiple keys (e.g. "<" + ">"
-                       and "," + "<" keys).  Default: -modtweak
-
-                       If you are having trouble with with keys and -xkb or
-                       -noxkb, and similar things don't help, try -nomodtweak.
-
-                       On some HP-UX systems it is been noted that they have
-                       an odd keymapping where a single keycode will have a
-                       keysym, e.g. "#", up to three times.  You can check
-                       via "xmodmap -pk" or the -dk option.  The failure
-                       is when you try to type "#" it yields "3".  If you
-                       see this problem try setting the environment variable
-                       MODTWEAK_LOWEST=1 to see if it helps.
-
--xkb                   When in modtweak mode, use the XKEYBOARD extension (if
--noxkb                 the X display supports it) to do the modifier tweaking.
-                       This is powerful and should be tried if there are still
-                       keymapping problems when using -modtweak by itself.
-                       The default is to check whether some common keysyms,
-                       e.g. !, @, [, are only accessible via -xkb mode and if
-                       so then automatically enable the mode.  To disable this
-                       automatic detection use -noxkb.
-
-                       When -xkb mode is active you can set these env. vars.
-                       They apply only when there is ambiguity as to which
-                       key to choose (i.e the mapping is not one-to-one).
-                       NOKEYHINTS=1: for up ascii keystrokes do not use score
-                       hints saved when the key was pressed down. NOANYDOWN=1:
-                       for up keystrokes do not resort to searching through
-                       keys that are currently pressed down.  KEYSDOWN=N:
-                       remember the last N keys press down for tie-breaking
-                       when an up keystroke comes in.
-
--capslock              When in -modtweak (the default) or -xkb mode,
-                       if a keysym in the range A-Z comes in check the X
-                       server to see if the Caps_Lock is set.  If it is do
-                       not artificially press Shift to generate the keysym.
-                       This will enable the CapsLock key to behave correctly
-                       in some circumstances: namely *both* the VNC viewer
-                       machine and the x11vnc X server are in the CapsLock
-                       on state.  If one side has CapsLock on and the other
-                       off and the keyboard is not behaving as you think it
-                       should you should correct the CapsLock states (hint:
-                       pressing CapsLock inside and outside of the viewer can
-                       help toggle them both to the correct state).  However,
-                       for best results do not use this option, but rather
-                       *only* enable CapsLock on the VNC viewer side (i.e. by
-                       pressing CapsLock outside of the viewer window, also
-                       -skip_lockkeys below).  Also try -nomodtweak for a
-                       possible workaround.
-
--skip_lockkeys         Have x11vnc ignore all Caps_Lock, Shift_Lock, Num_Lock,
--noskip_lockkeys       Scroll_Lock keysyms received from viewers.  The idea is
-                       you press Caps_Lock on the VNC Viewer side but that does
-                       not change the lock state in the x11vnc-side X server.
-                       Nevertheless your capitalized letters come in over
-                       the wire and are applied correctly to the x11vnc-side
-                       X server.  Note this mode probably won't do what you
-                       want in -nomodtweak mode.  Also, a kludge for KP_n
-                       digits is always done in this mode: they are mapped to
-                       regular digit keysyms.  See also -capslock above.
-                       The default is -noskip_lockkeys.
-
--skip_keycodes string  Ignore the comma separated list of decimal keycodes.
-                       Perhaps these are keycodes not on your keyboard but
-                       your X server thinks exist.  Currently only applies
-                       to -xkb mode.  Use this option to help x11vnc in the
-                       reverse problem it tries to solve: Keysym -> Keycode(s)
-                       when ambiguities exist (more than one Keycode per
-                       Keysym).  Run 'xmodmap -pk' to see your keymapping.
-                       Example: "-skip_keycodes 94,114"
--sloppy_keys           Experimental option that tries to correct some
-                       "sloppy" key behavior.  E.g. if at the viewer you
-                       press Shift+Key but then release the Shift before
-                       Key that could give rise to extra unwanted characters
-                       (usually only between keyboards of different languages).
-                       Only use this option if you observe problems with
-                       some keystrokes.
--skip_dups             Some VNC viewers send impossible repeated key events,
--noskip_dups           e.g. key-down, key-down, key-up, key-up all for the same
-                       key, or 20 downs in a row for the same modifier key!
-                       Setting -skip_dups means to skip these duplicates and
-                       just process the first event. Note: some VNC viewers
-                       assume they can send down's without the corresponding
-                       up's and so you should not set this option for
-                       these viewers (symptom: some keys do not autorepeat)
-                       Default: -noskip_dups
--add_keysyms           If a Keysym is received from a VNC viewer and that
--noadd_keysyms         Keysym does not exist in the X server, then add the
-                       Keysym to the X server's keyboard mapping on an unused
-                       key.  Added Keysyms will be removed periodically and
-                       also when x11vnc exits.  Default: -add_keysyms
--clear_mods            At startup and exit clear the modifier keys by sending
-                       KeyRelease for each one. The Lock modifiers are skipped.
-                       Used to clear the state if the display was accidentally
-                       left with any pressed down.
--clear_keys            As -clear_mods, except try to release ANY pressed key.
-                       Note that this option and -clear_mods can interfere
-                       with a person typing at the physical keyboard.
--clear_all             As -clear_keys, except try to release any CapsLock,
-                       NumLock, etc. locks as well.
-
--remap string          Read Keysym remappings from file named "string".
-                       Format is one pair of Keysyms per line (can be name
-                       or hex value) separated by a space.  If no file named
-                       "string" exists, it is instead interpreted as this
-                       form: key1-key2,key3-key4,...  See <X11/keysymdef.h>
-                       header file for a list of Keysym names, or use xev(1).
-
-                       To map a key to a button click, use the fake Keysyms
-                       "Button1", ..., etc. E.g: "-remap Super_R-Button2"
-                       (useful for pasting on a laptop)
-
-                       I use these if the machine I am viewing from does not
-                       have a scrollwheel or I don't like using the one it has:
-
-                              -remap Super_R-Button4,Menu-Button5
-                              -remap KP_Add-Button4,KP_Enter-Button5
-
-                       the former would be used on a PC, the latter on a
-                       MacBook.  This way those little used keys can be used
-                       to generate bigger hops than the Up and Down arrows
-                       provide.  One can scroll through text or web pages more
-                       quickly this way (especially if x11vnc scroll detection
-                       is active.)
-
-                       Use Button44, Button12, etc. for multiple clicks.
-
-                       To disable a keysym (i.e. make it so it will not be
-                       injected), remap it to "NoSymbol" or "None".
-
-                       Dead keys: "dead" (or silent, mute) keys are keys that
-                       do not produce a character but must be followed by a 2nd
-                       keystroke.  This is often used for accenting characters,
-                       e.g. to put "`" on top of "a" by pressing the dead
-                       key and then "a".  Note that this interpretation
-                       is not part of core X11, it is up to the toolkit or
-                       application to decide how to react to the sequence.
-                       The X11 names for these keysyms are "dead_grave",
-                       "dead_acute", etc.  However some VNC viewers send the
-                       keysyms "grave", "acute" instead thereby disabling
-                       the accenting.  To work around this -remap can be used.
-                       For example "-remap grave-dead_grave,acute-dead_acute"
-                       As a convenience, "-remap DEAD" applies these remaps:
-
-                               g     grave-dead_grave
-                               a     acute-dead_acute
-                               c     asciicircum-dead_circumflex
-                               t     asciitilde-dead_tilde
-                               m     macron-dead_macron
-                               b     breve-dead_breve
-                               D     abovedot-dead_abovedot
-                               d     diaeresis-dead_diaeresis
-                               o     degree-dead_abovering
-                               A     doubleacute-dead_doubleacute
-                               r     caron-dead_caron
-                               e     cedilla-dead_cedilla
-
-                       If you just want a subset use the first letter
-                       label, e.g. "-remap DEAD=ga" to get the first two.
-                       Additional remaps may also be supplied via commas,
-                       e.g.  "-remap DEAD=ga,Super_R-Button2".  Finally,
-                       "DEAD=missing" means to apply all of the above as
-                       long as the left hand member is not already in the
-                       X11 keymap.
-
--norepeat              Option -norepeat disables X server key auto repeat when
--repeat                VNC clients are connected and VNC keyboard input is
-                       not idle for more than 5 minutes.  This works around a
-                       repeating keystrokes bug (triggered by long processing
-                       delays between key down and key up client events:
-                       either from large screen changes or high latency).
-                       Default: -norepeat
-
-                       You can set the env. var. X11VNC_IDLE_TIMEOUT to the
-                       number of idle seconds you want (5min = 300secs).
-
-                       Note: your VNC viewer side will likely do autorepeating,
-                       so this is no loss unless someone is simultaneously at
-                       the real X display.
-
-                       Use "-norepeat N" to set how many times norepeat will
-                       be reset if something else (e.g. X session manager)
-                       undoes it.  The default is 2.  Use a negative value
-                       for unlimited resets.
-
--nofb                  Ignore video framebuffer: only process keyboard and
-                       pointer.  Intended for use with Win2VNC and x2vnc
-                       dual-monitor setups.
--nobell                Do not watch for XBell events. (no beeps will be heard)
-                       Note: XBell monitoring requires the XKEYBOARD extension.
--nosel                 Do not manage exchange of X selection/cutbuffer between
-                       VNC viewers and the X server at all.
--noprimary             Do not poll the PRIMARY selection for changes to send
-                       back to clients.  (PRIMARY is still set on received
-                       changes, however).
--nosetprimary          Do not set the PRIMARY selection for changes received
-                       from VNC clients.
--noclipboard           Do not poll the CLIPBOARD selection for changes to send
-                       back to clients.  (CLIPBOARD is still set on received
-                       changes, however).
--nosetclipboard        Do not set the CLIPBOARD selection for changes
-                       received from VNC clients.
--seldir string         If direction string is "send", only send the selection
-                       to viewers, and if it is "recv" only receive it from
-                       viewers.  To work around apps setting the selection
-                       too frequently and messing up the other end.  You can
-                       actually supply a comma separated list of directions,
-                       including "debug" to turn on debugging output.
-
--cursor [mode]         Sets how the pointer cursor shape (little icon at the
--nocursor              mouse pointer) should be handled.  The "mode" string
-                       is optional and is described below.  The default
-                       is to show some sort of cursor shape(s).  How this
-                       is done depends on the VNC viewer and the X server.
-                       Use -nocursor to disable cursor shapes completely.
-
-                       Some VNC viewers support the TightVNC CursorPosUpdates
-                       and CursorShapeUpdates extensions (cuts down on
-                       network traffic by not having to send the cursor image
-                       every time the pointer is moved), in which case these
-                       extensions are used (see -nocursorshape and -nocursorpos
-                       below to disable).  For other viewers the cursor shape
-                       is written directly to the framebuffer every time the
-                       pointer is moved or changed and gets sent along with
-                       the other framebuffer updates.  In this case, there
-                       will be some lag between the vnc viewer pointer and
-                       the remote cursor position.
-
-                       If the X display supports retrieving the cursor shape
-                       information from the X server, then the default is
-                       to use that mode.  On Solaris this can be done with
-                       the SUN_OVL extension using -overlay (see also the
-                       -overlay_nocursor option).  A similar overlay scheme
-                       is used on IRIX.  Xorg (e.g. Linux) and recent Solaris
-                       Xsun servers support the XFIXES extension to retrieve
-                       the exact cursor shape from the X server.  If XFIXES
-                       is present it is preferred over Overlay and is used by
-                       default (see -noxfixes below).  This can be disabled
-                       with -nocursor, and also some values of the "mode"
-                       option below.
-
-                       Note that under XFIXES cursors with transparency (alpha
-                       channel) will usually not be exactly represented and one
-                       may find Overlay preferable.  See also the -alphacut
-                       and -alphafrac options below as fudge factors to try
-                       to improve the situation for cursors with transparency
-                       for a given theme.
-
-                       The "mode" string can be used to fine-tune the
-                       displaying of cursor shapes.  It can be used the
-                       following ways:
-
-                       "-cursor arrow" - just show the standard arrow
-                       nothing more or nothing less.
-
-                       "-cursor none" - same as "-nocursor"
-
-                       "-cursor X" - when the cursor appears to be on the
-                       root window, draw the familiar X shape.  Some desktops
-                       such as GNOME cover up the root window completely,
-                       and so this will not work, try "X1", etc, to try to
-                       shift the tree depth.  On high latency links or slow
-                       machines there will be a time lag between expected and
-                       the actual cursor shape.
-
-                       "-cursor some" - like "X" but use additional
-                       heuristics to try to guess if the window should have
-                       a windowmanager-like resizer cursor or a text input
-                       I-beam cursor.  This is a complete hack, but may be
-                       useful in some situations because it provides a little
-                       more feedback about the cursor shape.
-
-                       "-cursor most" - try to show as many cursors as
-                       possible.  Often this will only be the same as "some"
-                       unless the display has overlay visuals or XFIXES
-                       extensions available.  On Solaris and IRIX if XFIXES
-                       is not available, -overlay mode will be attempted.
-
--cursor_drag           Show cursor shape changes even when the mouse is being
-                       dragged with a mouse button down.  This is useful if you
-                       want to be able to see Drag-and-Drop cursor icons, etc.
-
--arrow n               Choose an alternate "arrow" cursor from a set of
-                       some common ones.  n can be 1 to 6.  Default is: 1
-                       Ignored when in XFIXES cursor-grabbing mode.
-
--noxfixes              Do not use the XFIXES extension to draw the exact cursor
-                       shape even if it is available.
-
-                       Note: To work around a crash in Xorg 1.5 and later
-                       some people needed to use -noxfixes.  The Xorg crash
-                       occurred right after a Display Manager (e.g. GDM) login.
-                       Starting with x11vnc 0.9.9 it tries to automatically
-                       avoid using XFIXES until it is sure a window manager
-                       is running.  See the -reopen option for more info and
-                       how to use X11VNC_AVOID_WINDOWS=never to disable it.
-
--alphacut n            When using the XFIXES extension for the cursor shape,
-                       cursors with transparency will not usually be displayed
-                       exactly (but opaque ones will).  This option sets n as
-                       a cutoff for cursors that have transparency ("alpha
-                       channel" with values ranging from 0 to 255) Any cursor
-                       pixel with alpha value less than n becomes completely
-                       transparent.  Otherwise the pixel is completely opaque.
-                       Default 240
-
--alphafrac fraction    With the threshold in -alphacut some cursors will become
-                       almost completely transparent because their alpha values
-                       are not high enough.  For those cursors adjust the
-                       alpha threshold until fraction of the non-zero alpha
-                       channel pixels become opaque.  Default 0.33
--alpharemove           By default, XFIXES cursors pixels with transparency have
-                       the alpha factor multiplied into the RGB color values
-                       (i.e. that corresponding to blending the cursor with a
-                       black background).  Specify this option to remove the
-                       alpha factor. (useful for light colored semi-transparent
-                       cursors).
--noalphablend          In XFIXES mode do not send cursor alpha channel data
-                       to LibVNCServer.  The default is to send it.  The
-                       alphablend effect will only be visible in -nocursorshape
-                       mode or for clients with cursorshapeupdates turned
-                       off. (However there is a hack for 32bpp with depth 24,
-                       it uses the extra 8 bits to store cursor transparency
-                       for use with a hacked vncviewer that applies the
-                       transparency locally.  See the FAQ for more info).
-
--nocursorshape         Do not use the TightVNC CursorShapeUpdates extension
-                       even if clients support it.  See -cursor above.
--cursorpos             Option -cursorpos enables sending the X cursor position
--nocursorpos           back to all vnc clients that support the TightVNC
-                       CursorPosUpdates extension.  Other clients will be able
-                       to see the pointer motions. Default: -cursorpos
--xwarppointer          Move the pointer with XWarpPointer(3X) instead of
--noxwarppointer        the XTEST extension.  Use this as a workaround
-                       if the pointer motion behaves incorrectly, e.g.
-                       on touchscreens or other non-standard setups.
-
-                       It is also sometimes needed on XINERAMA displays and is
-                       enabled by default if XINERAMA is found to be active.
-                       To prevent this, use -noxwarppointer.
-
--always_inject         Even if there is no displacement (dx = dy = 0) for a
-                       VNC mouse event force the pointer to the indicated x,y
-                       position anyway.  Recent (2009) gui toolkits (gnome)
-                       have problems with x11vnc's original mouse input
-                       injection method.  So x11vnc's mouse input injection
-                       method has been modified.  To regain the OLD behavior
-                       use this option: -always_inject.  Then x11vnc will
-                       always force positioning the mouse to the x,y position
-                       even if that position has not changed since the previous
-                       VNC input event.
-
-                       The first place this problem was noticed was in gnome
-                       terminal: if you pressed and released mouse button 3, a
-                       menu was posted and then its first element 'New Terminal
-                       Window' was activated.  This was because x11vnc injected
-                       the mouse position twice: once on ButtonPress and again
-                       on ButtonRelease.  The toolkit interpreted the 2nd one
-                       as mouse motion even though the mouse hadn't moved.
-                       So now by default x11vnc tries to avoid injecting the
-                       2nd one.
-
-                       Note that with the new default x11vnc will be oblivious
-                       to applications moving the pointer (warping) or the
-                       user at the physical display moving it.  So it might,
-                       e.g., inject ButtonRelease at the wrong position.
-                       If this (or similar scenarios) causes problems in your
-                       environment, specify -always_inject for the old method.
-
--buttonmap string      String to remap mouse buttons.  Format: IJK-LMN, this
-                       maps buttons I -> L, etc., e.g.  -buttonmap 13-31
-
-                       Button presses can also be mapped to keystrokes: replace
-                       a button digit on the right of the dash with :<sym>:
-                       or :<sym1>+<sym2>: etc. for multiple keys. For example,
-                       if the viewing machine has a mouse-wheel (buttons 4 5)
-                       but the x11vnc side does not, these will do scrolls:
-                              -buttonmap 12345-123:Prior::Next:
-                              -buttonmap 12345-123:Up+Up+Up::Down+Down+Down:
-
-                       See <X11/keysymdef.h> header file for a list of Keysyms,
-                       or use the xev(1) program.  Note: mapping of button
-                       clicks to Keysyms may not work if -modtweak or -xkb is
-                       needed for the Keysym.
-
-                       If you include a modifier like "Shift_L" the
-                       modifier's up/down state is toggled, e.g. to send
-                       "The" use :Shift_L+t+Shift_L+h+e: (the 1st one is
-                       shift down and the 2nd one is shift up). (note: the
-                       initial state of the modifier is ignored and not reset)
-                       To include button events use "Button1", ... etc.
-
-                       -buttonmap currently does not work on MacOSX console
-                       or in -rawfb mode.
-
-                       Workaround: use -buttonmap IJ...-LM...=n to limit the
-                       number of mouse buttons to n, e.g. 123-123=3.  This will
-                       prevent x11vnc from crashing if the X server reports
-                       there are 5 buttons (4/5 scroll wheel), but there are
-                       only really 3.
-
--nodragging            Do not update the display during mouse dragging events
-                       (mouse button held down).  Greatly improves response on
-                       slow setups, but you lose all visual feedback for drags,
-                       text selection, and some menu traversals.  It overrides
-                       any -pointer_mode setting.
-
--ncache n              Client-side caching scheme.  Framebuffer memory "n"
-                       (an integer) times that of the full display is allocated
-                       below the actual framebuffer to cache screen contents
-                       for rapid retrieval.  So a W x H frambuffer is expanded
-                       to a W x (n+1)*H one.  Use 0 to disable.
-
-                       The "n" is actually optional, the default is 10.
-
-                       For this and the other -ncache* options below you can
-                       abbreviate "-ncache" with "-nc".  Also, "-nonc"
-                       is the same as "-ncache 0"
-
-                       This is an experimental option, currently implemented in
-                       an awkward way in that in the VNC Viewer you can see the
-                       pixel cache contents if you scroll down, etc.  So you
-                       will have to set things up so you can't see that region.
-                       If this method is successful, the changes required for
-                       clients to do this less awkwardly will be investigated.
-
-                       The SSVNC viewer does a good job at automatically hiding
-                       the pixel cache region.  Or use SSVNC's -ycrop option
-                       to explicitly hide the region.
-
-                       Note that this mode consumes a huge amount of memory,
-                       both on the x11vnc server side and on the VNC Viewer
-                       side.  If n=2 then the amount of RAM used is roughly
-                       tripled for both x11vnc and the VNC Viewer.  As a rule
-                       of thumb, note that 1280x1024 at depth 24 is about 5MB
-                       of pixel data.
-
-                       For reasonable response when cycling through 4 to 6
-                       large (e.g. web browser) windows a value n of 6 to 12
-                       is recommended. (that's right: ~10X more memory...)
-
-                       Because of the way window backingstore and saveunders
-                       are implemented, n must be even.  It will be incremented
-                       by 1 if it is not.
-
-                       This mode also works for native MacOS X, but may not
-                       be as effective as the X version.  This is due to a
-                       number of things, one is the drop-shadow compositing
-                       that leaves extra areas that need to be repaired (see
-                       -ncache_pad).  Another is the window iconification
-                       animations need to be avoided (see -macicontime).
-                       It appears the that the 'Scale' animation mode gives
-                       better results than the 'Genie' one.  Also, window event
-                       detection not as accurate as the X version.
-
--ncache_cr             In -ncache mode, try to do copyrect opaque window
-                       moves/drags instead of wireframes (this can induce
-                       painting errors).  The wireframe will still be used when
-                       moving a window whose save-unders has not yet been set
-                       or has been invalidated.
-
-                       Some VNC Viewers provide better response than others
-                       with this option.  On Unix, realvnc viewer gives
-                       smoother drags than tightvnc viewer.  Response may also
-                       be choppy if the server side machine is too slow.
-
-                       Sometimes on very slow modem connections, this actually
-                       gives an improvement because no pixel data at all
-                       (not even the box animation) is sent during the drag.
-
--ncache_no_moveraise   In -ncache mode, do not assume that moving a window
-                       will cause the window manager to raise it to the top
-                       of the stack.  The default is to assume it does, and
-                       so at the beginning of any wireframe, etc, window moves
-                       the window will be pushed to top in the VNC viewer.
-
--ncache_no_dtchange    In -ncache mode, do not try to guess when the desktop
-                       (viewport) changes to another one (i.e. another
-                       workarea).  The default is to try to guess and when
-                       detected try to make the transistion more smoothly.
-
--ncache_no_rootpixmap  In -ncache mode, do not try to snapshot the desktop
-                       background to use in guessing or reconstructing window
-                       save-unders.
-
--ncache_keep_anims     In -ncache mode, do not try to disable window
-                       manager animations and other effects (that usually
-                       degrade ncache performance or cause painting errors).
-                       The default is to try to disable them on KDE (but not
-                       GNOME) when VNC clients are connected.
-
-                       For other window managers or desktops that provide
-                       animations, effects, compositing, translucency,
-                       etc. that interfere with the -ncache method you will
-                       have to disable them manually.
-
--ncache_old_wm         In -ncache mode, enable some heuristics for old style
-                       window managers such as fvwm and twm.
-
--ncache_pad n          In -ncache mode, pad each window with n pixels for the
-                       caching rectangles.  This can be used to try to improve
-                       the situation with dropshadows or other compositing
-                       (e.g. MacOS X window manager), although it could make
-                       things worse.  The default is 0 on Unix and 24 on
-                       MacOS X.
--debug_ncache          Turn on debugging and profiling output under -ncache.
-
--wireframe [str]       Try to detect window moves or resizes when a mouse
--nowireframe           button is held down and show a wireframe instead of
-                       the full opaque window.  This is based completely on
-                       heuristics and may not always work: it depends on your
-                       window manager and even how you move things around.
-                       See -pointer_mode below for discussion of the "bogging
-                       down" problem this tries to avoid.
-                       Default: -wireframe
-
-                       Shorter aliases:  -wf [str]  and -nowf
-
-                       The value "str" is optional and, of course, is
-                       packed with many tunable parameters for this scheme:
-
-                       Format: shade,linewidth,percent,T+B+L+R,mod,t1+t2+t3+t4
-                       Default: 0xff,2,0,32+8+8+8,all,0.15+0.30+5.0+0.125
-
-                       If you leave nothing between commas: ",," the default
-                       value is used.  If you don't specify enough commas,
-                       the trailing parameters are set to their defaults.
-
-                       "shade" indicate the "color" for the wireframe,
-                       usually a greyscale: 0-255, however for 16 and 32bpp you
-                       can specify an rgb.txt X color (e.g. "dodgerblue") or
-                       a value > 255 is treated as RGB (e.g. red is 0xff0000).
-                       "linewidth" sets the width of the wireframe in pixels.
-                       "percent" indicates to not apply the wireframe scheme
-                       to windows with area less than this percent of the
-                       full screen.
-
-                       "T+B+L+R" indicates four integers for how close in
-                       pixels the pointer has to be from the Top, Bottom, Left,
-                       or Right edges of the window to consider wireframing.
-                       This is a speedup to quickly exclude a window from being
-                       wireframed: set them all to zero to not try the speedup
-                       (scrolling and selecting text will likely be slower).
-
-                       "mod" specifies if a button down event in the
-                       interior of the window with a modifier key (Alt, Shift,
-                       etc.) down should indicate a wireframe opportunity.
-                       It can be "0" or "none" to skip it, "1" or "all"
-                       to apply it to any modifier, or "Shift", "Alt",
-                       "Control", "Meta", "Super", or "Hyper" to only
-                       apply for that type of modifier key.
-
-                       "t1+t2+t3+t4" specify four floating point times in
-                       seconds: t1 is how long to wait for the pointer to move,
-                       t2 is how long to wait for the window to start moving
-                       or being resized (for some window managers this can be
-                       rather long), t3 is how long to keep a wireframe moving
-                       before repainting the window. t4 is the minimum time
-                       between sending wireframe "animations".  If a slow
-                       link is detected, these values may be automatically
-                       changed to something better for a slow link.
-
--nowireframelocal      By default, mouse motion and button presses of a
-                       user sitting at the LOCAL display are monitored for
-                       wireframing opportunities (so that the changes will be
-                       sent efficiently to the VNC clients).  Use this option
-                       to disable this behavior.
-
--wirecopyrect mode     Since the -wireframe mechanism evidently tracks moving
--nowirecopyrect        windows accurately, a speedup can be obtained by
-                       telling the VNC viewers to locally copy the translated
-                       window region.  This is the VNC CopyRect encoding:
-                       the framebuffer update doesn't need to send the actual
-                       new image data.
-
-                       Shorter aliases:  -wcr [mode]  and -nowcr
-
-                       "mode" can be "never" (same as -nowirecopyrect)
-                       to never try the copyrect, "top" means only do it if
-                       the window was not covered by any other windows, and
-                       "always" means to translate the orginally unobscured
-                       region (this may look odd as the remaining pieces come
-                       in, but helps on a slow link).  Default: "always"
-
-                       Note: there can be painting errors or slow response
-                       when using -scale so you may want to disable CopyRect
-                       in this case "-wirecopyrect never" on the command
-                       line or by remote-control.  Or you can also use the
-                       "-scale xxx:nocr" scale option.
-
--debug_wireframe       Turn on debugging info printout for the wireframe
-                       heuristics.  "-dwf" is an alias.  Specify multiple
-                       times for more output.
-
--scrollcopyrect mode   Like -wirecopyrect, but use heuristics to try to guess
--noscrollcopyrect      if a window has scrolled its contents (either vertically
-                       or horizontally).  This requires the RECORD X extension
-                       to "snoop" on X applications (currently for certain
-                       XCopyArea and XConfigureWindow X protocol requests).
-                       Examples: Hitting <Return> in a terminal window when the
-                       cursor was at the bottom, the text scrolls up one line.
-                       Hitting <Down> arrow in a web browser window, the web
-                       page scrolls up a small amount.  Or scrolling with a
-                       scrollbar or mouse wheel.
-
-                       Shorter aliases:  -scr [mode]  and -noscr
-
-                       This scheme will not always detect scrolls, but when
-                       it does there is a nice speedup from using the VNC
-                       CopyRect encoding (see -wirecopyrect).  The speedup
-                       is both in reduced network traffic and reduced X
-                       framebuffer polling/copying.  On the other hand, it may
-                       induce undesired transients (e.g. a terminal cursor
-                       being scrolled up when it should not be) or other
-                       painting errors (window tearing, bunching-up, etc).
-                       These are automatically repaired in a short period
-                       of time.  If this is unacceptable disable the feature
-                       with -noscrollcopyrect.
-
-                       Screen clearing kludges:  for testing at least, there
-                       are some "magic key sequences" (must be done in less
-                       than 1 second) to aid repairing painting errors that
-                       may be seen when using this mode:
-
-                       3 Alt_L's   in a row: resend whole screen,
-                       4 Alt_L's   in a row: reread and resend whole screen,
-                       3 Super_L's in a row: mark whole screen for polling,
-                       4 Super_L's in a row: reset RECORD context,
-                       5 Super_L's in a row: try to push a black screen
-
-                       note: Alt_L is the Left "Alt" key (a single key)
-                       Super_L is the Left "Super" key (Windows flag).
-                       Both of these are modifier keys, and so should not
-                       generate characters when pressed by themselves.  Also,
-                       your VNC viewer may have its own refresh hot-key
-                       or button.
-
-                       "mode" can be "never" (same as -noscrollcopyrect)
-                       to never try the copyrect, "keys" means to try it
-                       in response to keystrokes only, "mouse" means to
-                       try it in response to mouse events only, "always"
-                       means to do both. Default: "always"
-
-                       Note: there can be painting errors or slow response
-                       when using -scale so you may want to disable CopyRect
-                       in this case "-scrollcopyrect never" on the command
-                       line or by remote-control.  Or you can also use the
-                       "-scale xxx:nocr" scale option.
-
--scr_area n            Set the minimum area in pixels for a rectangle
-                       to be considered for the -scrollcopyrect detection
-                       scheme.  This is to avoid wasting the effort on small
-                       rectangles that would be quickly updated the normal way.
-                       E.g. suppose an app updated the position of its skinny
-                       scrollbar first and then shifted the large panel
-                       it controlled.  We want to be sure to skip the small
-                       scrollbar and get the large panel. Default: 60000
-
--scr_skip list         Skip scroll detection for applications matching
-                       the comma separated list of strings in "list".
-                       Some applications implement their scrolling in
-                       strange ways where the XCopyArea, etc, also applies
-                       to invisible portions of the window: if we CopyRect
-                       those areas it looks awful during the scroll and
-                       there may be painting errors left after the scroll.
-                       Soffice.bin is the worst known offender.
-
-                       Use "##" to denote the start of the application class
-                       (e.g. "##XTerm") and "++" to denote the start
-                       of the application instance name (e.g. "++xterm").
-                       The string your list is matched against is of the form
-                       "^^WM_NAME##Class++Instance<same-for-any-subwindows>"
-                       The "xlsclients -la" command will provide this info.
-
-                       If a pattern is prefixed with "KEY:" it only applies
-                       to Keystroke generated scrolls (e.g. Up arrow).  If it
-                       is prefixed with "MOUSE:" it only applies to Mouse
-                       induced scrolls (e.g. dragging on a scrollbar).
-                       Default: ##Soffice.bin,##StarOffice,##OpenOffice
-
--scr_inc list          Opposite of -scr_skip: this list is consulted first
-                       and if there is a match the window will be monitored
-                       via RECORD for scrolls irrespective of -scr_skip.
-                       Use -scr_skip '*' to skip anything that does not match
-                       your -scr_inc.  Use -scr_inc '*' to include everything.
-
--scr_keys list         For keystroke scroll detection, only apply the RECORD
-                       heuristics to the comma separated list of keysyms in
-                       "list".  You may find the RECORD overhead for every
-                       one of your keystrokes disrupts typing too much, but you
-                       don't want to turn it off completely with "-scr mouse"
-                       and -scr_parms does not work or is too confusing.
-
-                       The listed keysyms can be numeric or the keysym
-                       names in the <X11/keysymdef.h> header file or from the
-                       xev(1) program.  Example: "-scr_keys Up,Down,Return".
-                       One probably wants to have application specific lists
-                       (e.g. for terminals, etc) but that is too icky to think
-                       about for now...
-
-                       If "list" begins with the "-" character the list
-                       is taken as an exclude list: all keysyms except those
-                       list will be considered.  The special string "builtin"
-                       expands to an internal list of keysyms that are likely
-                       to cause scrolls.  BTW, by default modifier keys,
-                       Shift_L, Control_R, etc, are skipped since they almost
-                       never induce scrolling by themselves.
-
--scr_term list         Yet another cosmetic kludge.  Apply shell/terminal
-                       heuristics to applications matching comma separated
-                       list (same as for -scr_skip/-scr_inc).  For example an
-                       annoying transient under scroll detection is if you
-                       hit Enter in a terminal shell with full text window,
-                       the solid text cursor block will be scrolled up.
-                       So for a short time there are two (or more) block
-                       cursors on the screen.  There are similar scenarios,
-                       (e.g. an output line is duplicated).
-
-                       These transients are induced by the approximation of
-                       scroll detection (e.g. it detects the scroll, but not
-                       the fact that the block cursor was cleared just before
-                       the scroll).  In nearly all cases these transient errors
-                       are repaired when the true X framebuffer is consulted
-                       by the normal polling.  But they are distracting, so
-                       what this option provides is extra "padding" near the
-                       bottom of the terminal window: a few extra lines near
-                       the bottom will not be scrolled, but rather updated
-                       from the actual X framebuffer.  This usually reduces
-                       the annoying artifacts.  Use "none" to disable.
-                       Default: "term"
-
--scr_keyrepeat lo-hi   If a key is held down (or otherwise repeats rapidly) and
-                       this induces a rapid sequence of scrolls (e.g. holding
-                       down an Arrow key) the "scrollcopyrect" detection
-                       and overhead may not be able to keep up.  A time per
-                       single scroll estimate is performed and if that estimate
-                       predicts a sustainable scrollrate of keys per second
-                       between "lo" and "hi" then repeated keys will be
-                       DISCARDED to maintain the scrollrate. For example your
-                       key autorepeat may be 25 keys/sec, but for a large
-                       window or slow link only 8 scrolls per second can be
-                       sustained, then roughly 2 out of every 3 repeated keys
-                       will be discarded during this period. Default: "4-20"
-
--scr_parms string      Set various parameters for the scrollcopyrect mode.
-                       The format is similar to that for -wireframe and packed
-                       with lots of parameters:
-
-                       Format: T+B+L+R,t1+t2+t3,s1+s2+s3+s4+s5
-                       Default: 0+64+32+32,0.02+0.10+0.9,0.03+0.06+0.5+0.1+5.0
-
-                       If you leave nothing between commas: ",," the default
-                       value is used.  If you don't specify enough commas,
-                       the trailing parameters are set to their defaults.
-
-                       "T+B+L+R" indicates four integers for how close in
-                       pixels the pointer has to be from the Top, Bottom, Left,
-                       or Right edges of the window to consider scrollcopyrect.
-                       If -wireframe overlaps it takes precedence.  This is a
-                       speedup to quickly exclude a window from being watched
-                       for scrollcopyrect: set them all to zero to not try
-                       the speedup (things like selecting text will likely
-                       be slower).
-
-                       "t1+t2+t3" specify three floating point times in
-                       seconds that apply to scrollcopyrect detection with
-                       *Keystroke* input: t1 is how long to wait after a key
-                       is pressed for the first scroll, t2 is how long to keep
-                       looking after a Keystroke scroll for more scrolls.
-                       t3 is how frequently to try to update surrounding
-                       scrollbars outside of the scrolling area (0.0 to
-                       disable)
-
-                       "s1+s2+s3+s4+s5" specify five floating point times
-                       in seconds that apply to scrollcopyrect detection with
-                       *Mouse* input: s1 is how long to wait after a mouse
-                       button is pressed for the first scroll, s2 is how long
-                       to keep waiting for additional scrolls after the first
-                       Mouse scroll was detected.  s3 is how frequently to
-                       try to update surrounding scrollbars outside of the
-                       scrolling area (0.0 to disable).  s4 is how long to
-                       buffer pointer motion (to try to get fewer, bigger
-                       mouse scrolls). s5 is the maximum time to spend just
-                       updating the scroll window without updating the rest
-                       of the screen.
-
--fixscreen string      Periodically "repair" the screen based on settings
-                       in "string".  Hopefully you won't need this option,
-                       it is intended for cases when the -scrollcopyrect or
-                       -wirecopyrect features leave too many painting errors,
-                       but it can be used for any scenario.  This option
-                       periodically performs costly operations and so
-                       interactive response may be reduced when it is on.
-                       You can use 3 Alt_L's (the Left "Alt" key) taps in
-                       a row (as described under -scrollcopyrect) instead to
-                       manually request a screen repaint when it is needed.
-
-                       "string" is a comma separated list of one or more of
-                       the following: "V=t", "C=t", "X=t", and "8=t".
-                       In these "t" stands for a time in seconds (it is
-                       a floating point even though one should usually use
-                       values > 2 to avoid wasting resources).  V sets how
-                       frequently the entire screen should be sent to viewers
-                       (it is like the 3 Alt_L's).  C sets how long to wait
-                       after a CopyRect to repaint the full screen.  X sets
-                       how frequently to reread the full X11 framebuffer from
-                       the X server and push it out to connected viewers.
-                       Use of X should be rare, please report a bug if you
-                       find you need it. 8= applies only for -8to24 mode: it
-                       sets how often the non-default visual regions of the
-                       screen (e.g. 8bpp windows) are refreshed.  Examples:
-                       -fixscreen V=10 -fixscreen C=10
-
--debug_scroll          Turn on debugging info printout for the scroll
-                       heuristics.  "-ds" is an alias.  Specify it multiple
-                       times for more output.
-
--noxrecord             Disable any use of the RECORD extension.  This is
-                       currently used by the -scrollcopyrect scheme and to
-                       monitor X server grabs.
-
--grab_buster           Some of the use of the RECORD extension can leave a
--nograb_buster         tiny window for XGrabServer deadlock.  This is only if
-                       the whole-server grabbing application expects mouse or
-                       keyboard input before releasing the grab.  It is usually
-                       a window manager that does this.  x11vnc takes care to
-                       avoid the problem, but if caught x11vnc will freeze.
-                       Without -grab_buster, the only solution is to go the
-                       physical display and give it some input to satisfy the
-                       grabbing app.  Or manually kill and restart the window
-                       manager if that is feasible.  With -grab_buster, x11vnc
-                       will fork a helper thread and if x11vnc appears to be
-                       stuck in a grab after a period of time (20-30 sec) then
-                       it will inject some user input: button clicks, Escape,
-                       mouse motion, etc to try to break the grab.  If you
-                       experience a lot of grab deadlock, please report a bug.
-
--debug_grabs           Turn on debugging info printout with respect to
-                       XGrabServer() deadlock for -scrollcopyrect mode.
-
--debug_sel             Turn on debugging info printout with respect to
-                       PRIMARY, CLIPBOARD, and CUTBUFFER0 selections.
-
--pointer_mode n        Various pointer motion update schemes. "-pm" is
-                       an alias.  The problem is pointer motion can cause
-                       rapid changes on the screen: consider the rapid
-                       changes when you drag a large window around opaquely.
-                       Neither x11vnc's screen polling and vnc compression
-                       routines nor the bandwidth to the vncviewers can keep
-                       up these rapid screen changes: everything will bog down
-                       when dragging or scrolling.  So a scheme has to be used
-                       to "eat" much of that pointer input before re-polling
-                       the screen and sending out framebuffer updates. The
-                       mode number "n" can be 0 to 4 and selects one of
-                       the schemes desribed below.
-
-                       Note that the -wireframe and -scrollcopyrect modes
-                       complement -pointer_mode by detecting (and improving)
-                       certain periods of "rapid screen change".
-
-                       n=0: does the same as -nodragging. (all screen polling
-                       is suspended if a mouse button is pressed.)
-
-                       n=1: was the original scheme used to about Jan 2004:
-                       it basically just skips -input_skip keyboard or pointer
-                       events before repolling the screen.
-
-                       n=2 is an improved scheme: by watching the current rate
-                       of input events it tries to detect if it should try to
-                       "eat" additional pointer events before continuing.
-
-                       n=3 is basically a dynamic -nodragging mode: it detects
-                       when the mouse motion has paused and then refreshes
-                       the display.
-
-                       n=4 attempts to measures network rates and latency,
-                       the video card read rate, and how many tiles have been
-                       changed on the screen.  From this, it aggressively tries
-                       to push screen "frames" when it decides it has enough
-                       resources to do so.  NOT FINISHED.
-
-                       The default n is 2. Note that modes 2, 3, 4 will skip
-                       -input_skip keyboard events (but it will not count
-                       pointer events).  Also note that these modes are not
-                       available in -threads mode which has its own pointer
-                       event handling mechanism.
-
-                       To try out the different pointer modes to see which
-                       one gives the best response for your usage, it is
-                       convenient to use the remote control function, for
-                       example "x11vnc -R pm:4" or the tcl/tk gui (Tuning ->
-                       pointer_mode -> n).
-
--input_skip n          For the pointer handling when non-threaded: try to
-                       read n user input events before scanning display. n < 0
-                       means to act as though there is always user input.
-                       Default: 10
-
--allinput              Have x11vnc read and process all available client input
-                       before proceeding.
-
--input_eagerly         Similar to -allinput but use the handleEventsEagerly
-                       mechanism built into LibVNCServer.
-
--speeds rd,bw,lat      x11vnc tries to estimate some speed parameters that
-                       are used to optimize scheduling (e.g. -pointer_mode
-                       4, -wireframe, -scrollcopyrect) and other things.
-                       Use the -speeds option to set these manually.
-                       The triple "rd,bw,lat" corresponds to video h/w
-                       read rate in MB/sec, network bandwidth to clients in
-                       KB/sec, and network latency to clients in milliseconds,
-                       respectively.  If a value is left blank, e.g. "-speeds
-                       ,100,15", then the internal scheme is used to estimate
-                       the empty value(s).
-
-                       Typical PC video cards have read rates of 5-10 MB/sec.
-                       If the framebuffer is in main memory instead of video
-                       h/w (e.g. SunRay, shadowfb, dummy driver, Xvfb), the
-                       read rate may be much faster.  "x11perf -getimage500"
-                       can be used to get a lower bound (remember to factor
-                       in the bytes per pixel).  It is up to you to estimate
-                       the network bandwith and latency to clients.  For the
-                       latency the ping(1) command can be used.
-
-                       For convenience there are some aliases provided,
-                       e.g. "-speeds modem".  The aliases are: "modem" for
-                       6,4,200; "dsl" for 6,100,50; and "lan" for 6,5000,1
-
--wmdt string           For some features, e.g. -wireframe and -scrollcopyrect,
-                       x11vnc has to work around issues for certain window
-                       managers or desktops (currently kde and xfce).
-                       By default it tries to guess which one, but it can
-                       guess incorrectly.  Use this option to indicate which
-                       wm/dt.  "string" can be "gnome", "kde", "cde",
-                       "xfce", or "root" (classic X wm).  Anything else
-                       is interpreted as "root".
-
--debug_pointer         Print debugging output for every pointer event.
--debug_keyboard        Print debugging output for every keyboard event.
-                       Same as -dp and -dk, respectively.  Use multiple
-                       times for more output.
-
--defer time            Time in ms to delay sending updates to connected clients
-                       (deferUpdateTime)  Default: 20
-
--wait time             Time in ms to pause between screen polls.  Used to cut
-                       down on load.  Default: 20
-
--extra_fbur n          Perform extra FrameBufferUpdateRequests checks to
-                       try to be in better sync with the client's requests.
-                       What this does is perform extra polls of the client
-                       socket at critical times (before '-defer' and '-wait'
-                       calls.)  The default is n=1.  Set to a larger number to
-                       insert more checks or set to n=0 to disable.  A downside
-                       of these extra calls is that more mouse input may be
-                       processed than desired.
-
--wait_ui factor        Factor by which to cut the -wait time if there
-                       has been recent user input (pointer or keyboard).
-                       Improves response, but increases the load whenever you
-                       are moving the mouse or typing.  Default: 2.00
--setdefer n            When the -wait_ui mechanism cuts down the wait time ms,
-                       set the defer time to the same ms value. n=1 to enable,
-                       0 to disable, and -1 to set defer to 0 (no delay).
-                       Similarly, 2 and -2 indicate 'urgent_update' mode should
-                       be used to push the updates even sooner.  Default: 1
--nowait_bog            Do not detect if the screen polling is "bogging down"
-                       and sleep more.  Some activities with no user input can
-                       slow things down a lot: consider a large terminal window
-                       with a long build running in it continuously streaming
-                       text output.  By default x11vnc will try to detect this
-                       (3 screen polls in a row each longer than 0.25 sec with
-                       no user input), and sleep up to 1.5 secs to let things
-                       "catch up".  Use this option to disable that detection.
--slow_fb time          Floating point time in seconds to delay all screen
-                       polling.  For special purpose usage where a low frame
-                       rate is acceptable and desirable, but you want the
-                       user input processed at the normal rate so you cannot
-                       use -wait.
--xrefresh time         Floating point time in seconds to indicate how often to
-                       do the equivalent of xrefresh(1) to force all windows
-                       (in the viewable area if -id, -sid, or -clip is used)
-                       to repaint themselves.  Use this only if applications
-                       misbehave by not repainting themselves properly.
-                       See also -noxdamage.
--nap                   Monitor activity and if it is low take longer naps
--nonap                 between screen polls to really cut down load when idle.
-                       Default: take naps
--sb time               Time in seconds after NO activity (e.g. screen blank)
-                       to really throttle down the screen polls (i.e. sleep
-                       for about 1.5 secs). Use 0 to disable.  Default: 60
-                       Set the env. var. X11VNC_SB_FACTOR to scale it.
-
--readtimeout n         Set LibVNCServer rfbMaxClientWait to n seconds. On
-                       slow links that take a long time to paint the first
-                       screen LibVNCServer may hit the timeout and drop the
-                       connection.  Default: 20 seconds.
--ping n                Send a 1x1 framebuffer update to all clients every n
-                       seconds (e.g. to try to keep a network connection alive)
-
--nofbpm                If the system supports the FBPM (Frame Buffer Power
--fbpm                  Management) extension (i.e. some Sun systems), then
-                       prevent the video h/w from going into a reduced power
-                       state when VNC clients are connected.
-
-                       FBPM capable video h/w save energy when the workstation
-                       is idle by going into low power states (similar to DPMS
-                       for monitors).  This interferes with x11vnc's polling
-                       of the framebuffer data.
-
-                       "-nofbpm" means prevent FBPM low power states whenever
-                       VNC clients are connected, while "-fbpm" means to not
-                       monitor the FBPM state at all.  See the xset(1) manpage
-                       for details.  -nofbpm is basically the same as running
-                       "xset fbpm force on" periodically.  Default: -fbpm
-
--nodpms                If the system supports the DPMS (Display Power Managemen
-t
--dpms                  Signaling) extension, then prevent the monitor from
-                       going into a reduced power state when VNC clients
-                       are connected.
-
-                       DPMS reduced power monitor states are a good thing
-                       and you normally want the power down to take place
-                       (usually x11vnc has no problem exporting the display in
-                       this state).  You probably only want to use "-nodpms"
-                       to work around problems with Screen Savers kicking
-                       on in DPMS low power states.  There is known problem
-                       with kdesktop_lock on KDE where the screen saver keeps
-                       kicking in every time user input stops for a second
-                       or two.  Specifying "-nodpms" works around it.
-
-                       "-nodpms" means prevent DPMS low power states whenever
-                       VNC clients are connected, while "-dpms" means to not
-                       monitor the DPMS state at all.  See the xset(1) manpage
-                       for details.  -nodpms is basically the same as running
-                       "xset dpms force on" periodically.  Default: -dpms
-
--forcedpms             If the system supports the DPMS (Display Power
-                       Management Signaling) extension, then try to keep the
-                       monitor in a powered off state.  This is to prevent
-                       nosey people at the physical display from viewing what
-                       is on the screen.  Be sure to lock the screen before
-                       disconnecting.
-
-                       This method is far from bullet proof, e.g. suppose
-                       someone attaches a non-DPMS monitor, or loads the
-                       machine so that there is a gap of time before x11vnc
-                       restores the powered off state?  On many machines if
-                       he floods it with keyboard and mouse input he can see
-                       flashes of what is on the screen before the DPMS off
-                       state is reestablished.  For this to work securely
-                       there would need to be support in the X server to do
-                       this exactly rather than approximately with DPMS.
-
--clientdpms            As -forcedpms but only when VNC clients are connected.
-
--noserverdpms          The UltraVNC ServerInput extension is supported.
-                       This allows the VNC viewer to click a button that will
-                       cause the server (x11vnc) to try to disable keyboard
-                       and mouse input at the physical display and put the
-                       monitor in dpms powered off state.  Use this option to
-                       skip powering off the monitor.
-
--noultraext            Disable the following UltraVNC extensions: SingleWindow
-                       and ServerInput.  The others managed by LibVNCServer
-                       (textchat, 1/n scaling, rfbEncodingUltra) are not.
-
--chatwindow            Place a local UltraVNC chat window on the X11 display
-                       that x11vnc is polling.  That way the person on the VNC
-                       viewer-side can chat with the person at the physical
-                       X11 console. (e.g. helpdesk w/o telephone)
-
-                       For this to work the SSVNC package (version 1.0.21 or
-                       later) MUST BE installed on the system where x11vnc runs
-                       and the 'ssvnc' command must be available in $PATH.
-                       The ssvncviewer is used as a chat window helper.
-                       See http://www.karlrunge.com/x11vnc/ssvnc.html
-
-                       This option implies '-rfbversion 3.6' so as to trick
-                       UltraVNC viewers, otherwise they assume chat is not
-                       available.  To specify a different rfbversion, place
-                       it after the -chatwindow option on the cmdline.
-
-                       See also the remote control 'chaton' and 'chatoff'
-                       actions.  These can also be set from the tkx11vnc GUI.
-
--noxdamage             Do not use the X DAMAGE extension to detect framebuffer
-                       changes even if it is available.  Use -xdamage if your
-                       default is to have it off.
-
-                       x11vnc's use of the DAMAGE extension: 1) significantly
-                       reduces the load when the screen is not changing much,
-                       and 2) detects changed areas (small ones by default)
-                       more quickly.
-
-                       Currently the DAMAGE extension is overly conservative
-                       and often reports large areas (e.g. a whole terminal
-                       or browser window) as damaged even though the actual
-                       changed region is much smaller (sometimes just a few
-                       pixels).  So heuristics were introduced to skip large
-                       areas and use the damage rectangles only as "hints"
-                       for the traditional scanline polling.  The following
-                       tuning parameters are introduced to adjust this
-                       behavior:
-
--xd_area A             Set the largest DAMAGE rectangle area "A" (in
-                       pixels: width * height) to trust as truly damaged:
-                       the rectangle will be copied from the framebuffer
-                       (slow) no matter what.  Set to zero to trust *all*
-                       rectangles. Default: 20000
--xd_mem f              Set how long DAMAGE rectangles should be "remembered",
-                       "f" is a floating point number and is in units of the
-                       scanline repeat cycle time (32 iterations).  The default
-                       (1.0) should give no painting problems. Increase it if
-                       there are problems or decrease it to live on the edge
-                       (perhaps useful on a slow machine).
-
--sigpipe string        Broken pipe (SIGPIPE) handling.  "string" can be
-                       "ignore" or "exit".  For "ignore" LibVNCServer
-                       will handle the abrupt loss of a client and continue,
-                       for "exit" x11vnc will cleanup and exit at the 1st
-                       broken connection.
-
-                       This option is not really needed since LibVNCServer
-                       is doing the correct thing now for quite some time.
-                       However, for convenience you can use it to ignore other
-                       signals, e.g. "-sigpipe ignore:HUP,INT,TERM" in case
-                       that would be useful for some sort of application.
-                       You can also put "exit:.." in the list to have x11vnc
-                       cleanup on the listed signals. "-sig" is an alias
-                       for this option if you don't like the 'pipe'. Example:
-                       -sig ignore:INT,TERM,exit:USR1
-
--threads               Whether or not to use the threaded LibVNCServer
--nothreads             algorithm [rfbRunEventLoop] if libpthread is available.
-                       In this mode new threads (one for input and one
-                       for output) are created to handle each new client.
-                       Default: -nothreads.
-
-                       Thread stability is much improved in version 0.9.8.
-
-                       Multiple clients in threaded mode should be stable
-                       for the ZRLE encoding on all platforms.  The Tight and
-                       Zlib encodings are currently only stable on Linux for
-                       multiple clients.  Compile with -DTLS=__thread if your
-                       OS and compiler and linker support it.
-
-                       For resizes (randr, etc.) set this env. var. to the numb
-er
-                       of milliseconds to sleep: X11VNC_THREADS_NEW_FB_SLEEP
-                       at various places in the do_new_fb() action.  This is to
-                       let various activities settle.  Default is about 500ms.
-
-                       Multiple clients in threaded mode could yield better
-                       performance for 'class-room' broadcasting usage; also in
-                       -appshare broadcast mode.  See also the -reflect option.
-
--fs f                  If the fraction of changed tiles in a poll is greater
-                       than f, the whole screen is updated.  Default: 0.75
--gaps n                Heuristic to fill in gaps in rows or cols of n or
-                       less tiles.  Used to improve text paging.  Default: 4
--grow n                Heuristic to grow islands of changed tiles n or wider
-                       by checking the tile near the boundary.  Default: 3
--fuzz n                Tolerance in pixels to mark a tiles edges as changed.
-                       Default: 2
--debug_tiles           Print debugging output for tiles, fb updates, etc.
-
--snapfb                Instead of polling the X display framebuffer (fb)
-                       for changes, periodically copy all of X display fb
-                       into main memory and examine that copy for changes.
-                       (This setting also applies for non-X -rawfb modes).
-                       Under some circumstances this will improve interactive
-                       response, or at least make things look smoother, but in
-                       others (most!) it will make the response worse.  If the
-                       video h/w fb is such that reading small tiles is very
-                       slow this mode could help.  To keep the "framerate"
-                       up the screen size x bpp cannot be too large.  Note that
-                       this mode is very wasteful of memory I/O resources
-                       (it makes full screen copies even if nothing changes).
-                       It may be of use in video capture-like applications,
-                       webcams, or where window tearing is a problem.
-
--rawfb string          Instead of polling X, poll the memory object specified
-                       in "string".
-
-                       For file polling, to memory map mmap(2) a file use:
-                       "map:/path/to/a/file@WxHxB", with framebuffer Width,
-                       Height, and Bits per pixel.  "mmap:..." is the
-                       same.
-
-                       If there is trouble with mmap, use "file:/..."
-                       for slower lseek(2) based reading.
-
-                       Use "snap:..." to imply -snapfb mode and the "file:"
-                       access (this is for unseekable devices that only provide
-                       the fb all at once, e.g. a video camera provides the
-                       whole frame).
-
-                       For shared memory segments string is of the form:
-                       "shm:N@WxHxB" which specifies a shmid N and with
-                       WxHxB as above.  See shmat(1) and ipcs(1)
-
-                       If you do not supply a type "map" is assumed if
-                       the file exists (see the next paragraphs for some
-                       exceptions to this.)
-
-                       If string is "setup:cmd", then the command "cmd"
-                       is run and the first line from it is read and used
-                       as "string".  This allows initializing the device,
-                       determining WxHxB, etc. These are often done as root
-                       so take care.
-
-                       If the string begins with "video", see the VIDEO4LINUX
-                       discussion below where the device may be queried for
-                       (and possibly set) the framebuffer parameters.
-
-                       If the string begins with "console", "/dev/fb",
-                       "fb", or "vt", see the LINUX CONSOLE discussion
-                       below where the framebuffer device is opened and
-                       keystrokes (and possibly mouse events) are inserted
-                       into the console.
-
-                       If the string begins with "vnc", see the VNC HOST
-                       discussion below where the framebuffer is taken as that
-                       of another remote VNC server.
-
-                       Optional suffixes are ":R/G/B" and "+O" to specify
-                       red, green, and blue masks (in hex) and an offset into
-                       the memory object.  If the masks are not provided x11vnc
-                       guesses them based on the bpp (if the colors look wrong,
-                       you need to provide the masks.)
-
-                       Another optional suffix is the Bytes Per Line which in
-                       some cases is not WxB/8.  Specify it as WxHxB-BPL
-                       e.g. 800x600x16-2048.  This could be a normal width
-                       1024 at 16bpp fb, but only width 800 shows up.
-
-                       So the full format is: mode:file@WxHxB:R/G/B+O-BPL
-
-                       Examples:
-                           -rawfb shm:210337933@800x600x32:ff/ff00/ff0000
-                           -rawfb map:/dev/fb0@1024x768x32
-                           -rawfb map:/tmp/Xvfb_screen0@640x480x8+3232
-                           -rawfb file:/tmp/my.pnm@250x200x24+37
-                           -rawfb file:/dev/urandom@128x128x8
-                           -rawfb snap:/dev/video0@320x240x24 -24to32
-                           -rawfb video0
-                           -rawfb video -pipeinput VID
-                           -rawfb console
-                           -rawfb vt2
-                           -rawfb vnc:somehost:0
-
-                       (see ipcs(1) and fbset(1) for the first two examples)
-
-                       In general all user input is discarded by default (see
-                       the -pipeinput option for how to use a helper program
-                       to insert).  Most of the X11 (screen, keyboard, mouse)
-                       options do not make sense and many will cause this
-                       mode to crash, so please think twice before setting or
-                       changing them in a running x11vnc.
-
-                       If you DO NOT want x11vnc to close the X DISPLAY in
-                       rawfb mode, prepend a "+" e.g. +file:/dev/fb0...
-                       Keeping the display open enables the default
-                       remote-control channel, which could be useful.
-                       Alternatively, if you specify -noviewonly, then the
-                       mouse and keyboard input are STILL sent to the X
-                       display, this usage should be very rare, i.e. doing
-                       something strange with /dev/fb0.
-
-                       If the device is not "seekable" (e.g. webcam) try
-                       reading it all at once in full snaps via the "snap:"
-                       mode (note: this is a resource hog).  If you are using
-                       file: or map: AND the device needs to be reopened for
-                       *every* snapfb snapshot, set the environment variable:
-                       SNAPFB_RAWFB_RESET=1 as well.
-
-                       If you want x11vnc to dynamically transform a 24bpp
-                       rawfb to 32bpp (note that this will be slower) also
-                       supply the -24to32 option.  This would be useful for,
-                       say, a video camera that delivers the pixel data as
-                       24bpp packed RGB.  This is the default under "video"
-                       mode if the bpp is 24.
-
-                       Normally the bits per pixel, B, is 8, 16, or 32 (or
-                       rarely 24), however there is also some support for
-                       B < 8 (e.g. old graphics displays 4 bpp or 1 bpp).
-                       In this case you certainly must supply the masks as
-                       well: WxHxB:R/G/B.  The pixels will be padded out to
-                       8 bpp using depth 8 truecolor.  The scheme currently
-                       does not work with snap fb (ask if interested.) B=1
-                       monochrome example: file:/dev/urandom@128x128x1:1/1/1
-                       Some other like this are 128x128x2:3/3/3 128x128x4:7/7/7
-
-                       For B < 8 framebuffers you can also set the env. var
-                       RAWFB_CGA=1 to try a CGA mapping for B=4 (e.g. linux
-                       vga16fb driver.)  Note with low bpp and/or resolution
-                       VGA and VGA16 modes on the Linux console one's attempt
-                       to export them via x11vnc can often be thwarted due to
-                       special color palettes, pixel packings, and even video
-                       painting buffering.  OTOH, often experimenting with the
-                       RGB masks can yield something recognizable.
-
-                       VIDEO4LINUX: on Linux some attempt is made to handle
-                       video devices (webcams or TV tuners) automatically.
-                       The idea is the WxHxB will be extracted from the
-                       device itself.  So if you do not supply "@WxHxB...
-                       parameters x11vnc will try to determine them.  It first
-                       tries the v4l API if that support has been compiled in.
-                       Otherwise it will run the v4l-info(1) external program
-                       if it is available.
-
-                       The simplest examples are "-rawfb video" and "-rawfb
-                       video1" which imply the device file /dev/video and
-                       /dev/video1, respectively.  You can also supply the
-                       /dev if you like, e.g. "-rawfb /dev/video0"
-
-                       Since the video capture device framebuffer usually
-                       changes continuously (e.g. brightness fluctuations),
-                       you may want to use the -wait, -slow_fb, or -defer
-                       options to lower the "framerate" to cut down on
-                       network VNC traffic.
-
-                       A more sophisticated video device scheme allows
-                       initializing the device's settings using:
-
-                           -rawfb video:<settings>
-
-                       The prefix could also be, as above, e.g. "video1:" to
-                       specify the device file.  The v4l API must be available
-                       for this to work.  Otherwise, you will need to try
-                       to initialize the device with an external program,
-                       e.g. xawtv, spcaview, and hope they persist when x11vnc
-                       re-opens the device.
-
-                       <settings> is a comma separated list of key=value pairs.
-                       The device's brightness, color, contrast, and hue can
-                       be set to percentages, e.g. br=80,co=50,cn=44,hu=60.
-
-                       The device filename can be set too if needed (if it
-                       does not start with "video"), e.g. fn=/dev/qcam.
-
-                       The width, height and bpp of the framebuffer can be
-                       set via, e.g., w=160,h=120,bpp=16.
-
-                       Related to the bpp above, the pixel format can be set
-                       via the fmt=XXX, where XXX can be one of: GREY, HI240,
-                       RGB555, RGB565, RGB24, and RGB32 (with bpp 8, 8, 16, 16,
-                       24, and 32 respectively).  See http://www.linuxtv.org
-                       for more info (V4L api).
-
-                       For TV/rf tuner cards one can set the tuning mode
-                       via tun=XXX where XXX can be one of PAL, NTSC, SECAM,
-                       or AUTO.
-
-                       One can switch the input channel by the inp=XXX setting,
-                       where XXX is the name of the input channel (Television,
-                       Composite1, S-Video, etc).  Use the name that is in the
-                       information about the device that is printed at startup.
-
-                       For input channels with tuners (e.g. Television) one
-                       can change which station is selected by the sta=XXX
-                       setting.  XXX is the station number.  Currently only
-                       the ntsc-cable-us (US cable) channels are built into
-                       x11vnc.  See the -freqtab option below to supply one
-                       from xawtv. If XXX is greater than 500, then it is
-                       interpreted as a raw frequency in KHz.
-
-                       Example:
-
-                       -rawfb video:br=80,w=320,h=240,fmt=RGB32,tun=NTSC,sta=47
-
-                       one might need to add inp=Television too for the input
-                       channel to be TV if the card doesn't come up by default
-                       in that one.
-
-                       Note that not all video capture devices will support
-                       all of the above settings.
-
-                       See the -pipeinput VID option below for a way to control
-                       the settings through the VNC Viewer via keystrokes.
-                       As a shortcut, if the string begins "Video.." instead
-                       of "video.." then -pipeinput VID is implied.
-
-                       As above, if you specify a "@WxHxB..." after the
-                       <settings> string they are used verbatim: the device
-                       is not queried for the current values.  Otherwise the
-                       device will be queried.
-
-                       LINUX CONSOLE:  The following describes some ways to
-                       view and possibly interact with the Linux text/graphics
-                       console (i.e. not X11 XFree86/Xorg)
-
-                       Note: If the LibVNCServer LinuxVNC program is on your
-                       system you may want to use that instead of the following
-                       method because it will be faster and more accurate
-                       for the Linux text console and includes mouse support.
-                       There is, however, the basic LinuxVNC functionality in
-                       x11vnc if you replace "console" with "vt" in the
-                       examples below.
-
-                       If the rawfb string begins with "console" the
-                       framebuffer device /dev/fb0 is opened and /dev/tty0 is
-                       opened too.  The latter is used to inject keystrokes
-                       (not all are supported, but the basic ones are).
-                       You will need to be root to inject keystrokes, but
-                       not necessarily to open /dev/fb0.  /dev/tty0 refers to
-                       the active VT, to indicate one explicitly, use, e.g.,
-                       "console2" for /dev/tty2, etc. by indicating the
-                       specific VT number.
-
-                       For the Linux framebuffer device, /dev/fb0, (fb1,
-                       etc) to be enabled the appropriate kernel drivers must
-                       be loaded.  E.g. vesafb or vga16fb and also by setting
-                       the boot parameter vga=0x301 (or 0x314, 0x317, etc.)
-                       (The vga=... method is the preferred way; set your
-                       machines up that way.)  Otherwise there will be a
-                       'No such device' error.  You can also load a Linux
-                       framebuffer driver specific to your make of video card
-                       for more functionality.  Once the machine is booted one
-                       can often 'modprobe' the fb driver as root to obtain
-                       a framebuffer device.
-
-                       If you cannot get /dev/fb0 working on Linux, try
-                       using the LinuxVNC emulation mode by "-rawfb vtN"
-                       where N = 1, ... 6 is the Linux Virtual Terminal (aka
-                       virtual console) you wish to view, e.g. "-rawfb vt2".
-                       Unlike /dev/fb mode, it need not be the active Virtual
-                       Terminal.  Note that this mode can only show text and
-                       not graphics.  x11vnc polls the text in /dev/vcsaN
-
-                       Set the env. var. RAWFB_VCSA_BW=1 to disable colors in
-                       the "vtN" mode (i.e. black and white only.)  If you
-                       do not prefer the default 16bpp set RAWFB_VCSA_BPP to
-                       8 or 32.  If you need to tweak the rawfb parameters by
-                       using the 'console_guess' string printed at startup,
-                       be sure to indicate the snap: method.
-
-                       uinput: If the Linux version appears to be 2.6
-                       or later and the "uinput" module appears to be
-                       present (modprobe uinput), then the uinput method
-                       will be used instead of /dev/ttyN.  uinput allows
-                       insertion of BOTH keystrokes and mouse input and so it
-                       preferred when accessing graphical (e.g. QT-embedded)
-                       linux console apps.  It also provides more accurate
-                       keystroke insertion.  See -pipeinput UINPUT below for
-                       more information on this mode; you will have to use
-                       -pipeinput if you want to tweak any UINPUT parameters.
-                       You may also want to also use the -nodragging and
-                       -cursor none options.  Use "console0", etc  or
-                       -pipeinput CONSOLE to force the /dev/ttyN method.
-
-                       Note you can change the Linux VT remotely using the
-                       chvt(1) command to make the one you want be the active
-                       one (e.g. 'chvt 3').  Sometimes switching out and back
-                       corrects the framebuffer's graphics state.  For the
-                       "-rawfb vtN" mode there is no need to switch the VT's.
-
-                       To skip input injecting entirely use "consolex"
-                       or "vtx".
-
-                       The string "/dev/fb0" (1, etc.) can be used instead
-                       of "console".  This can be used to specify a different
-                       framebuffer device, e.g. /dev/fb1.  As a shortcut the
-                       "/dev/" can be dropped.  If the name is something
-                       nonstandard, use "console:/dev/foofb"
-
-                       If you do not want x11vnc to guess the framebuffer's
-                       WxHxB and masks automatically (sometimes the kernel
-                       gives incorrect information), specify them with a @WxHxB
-                       (and optional :R/G/B masks) at the end of the string.
-
-                       Examples:
-                           -rawfb console
-                           -rawfb /dev/fb0           (same)
-                           -rawfb console3           (force /dev/tty3)
-                           -rawfb consolex           (no keystrokes or mouse)
-                           -rawfb console:/dev/nonstd
-                           -rawfb console -pipeinput UINPUT:accel=4.0
-                           -rawfb vt3                (/dev/tty3 w/o /dev/fb0)
-
-                       VNC HOST: if the -rawfb string is of the form
-                       "vnc:host:N" then the VNC display "N" on the remote
-                       VNC server "host" is connected to (i.e. x11vnc acts as
-                       a VNC client itself) and that framebuffer is exported.
-
-                       This mode is really only of use if you are trying
-                       to improve performance in the case of many (e.g. >
-                       10) simultaneous VNC viewers, and you try a divide
-                       and conquer scheme to reduce bandwidth and improve
-                       responsiveness.  (However, another user found this mode
-                       useful to export a demo display through a slow link:
-                       then multiple demo viewers connected to the reflecting
-                       x11vnc on the fast side of the link, and so avoided
-                       all of the demo viewers going through the slow link.)
-
-                       For example, if there will be 64 simultaneous VNC
-                       viewers this can lead to a lot of redundant VNC traffic
-                       to and from the server host:N, extra CPU usage,
-                       and all viewers response can be reduced by having
-                       to wait for writes to the slowest client to finish.
-                       However, if you set up 8 reflectors/repeaters started
-                       with option -rawfb vnc:host:N, then there are only
-                       8 connections to host:N.  Each repeater then handles
-                       8 vnc viewer connections thereby spreading the load
-                       around.  In classroom broadcast usage, try to put the
-                       repeaters on different switches.  This mode is the same
-                       as -reflect host:N.  Replace "host:N" by "listen"
-                       or "listen:port" for a reverse connection.
-
-                       Overall performance will not be as good as a single
-                       direct connection because, among other things,
-                       there is an additional level of framebuffer polling
-                       and pointer motion can still induce many changes per
-                       second that must be propagated.  Tip: if the remote VNC
-                       is x11vnc doing wireframing, or an X display that does
-                       wireframing that gives much better response than opaque
-                       window dragging.  Consider the -nodragging option if
-                       the problem is severe.
-
-                       The env. var. X11VNC_REFLECT_PASSWORD can be set to
-                       the password needed to log into the vnc host server, or
-                       to "file:path_to_file" to indicate a file containing
-                       the password as its first line.
-
-                       To set the pixel format that x11vnc requests as a VNC
-                       CLIENT set the env. vars: X11VNC_REFLECT_bitsPerSample
-                       X11VNC_REFLECT_samplesPerPixel, and
-                       X11VNC_REFLECT_bytesPerPixel; the defaults are 8, 3, 4.
-                       2, 3, 1 would give a low color mode.  See the function
-                       rfbGetClient() in libvncclient for more info.
-
-                       The VNC HOST mode implies -shared.  Use -noshared as
-                       a subsequent cmdline option to disable sharing.
-
--freqtab file          For use with "-rawfb video" for TV tuner devices to
-                       specify station frequencies.  Instead of using the built
-                       in ntsc-cable-us mapping of station number to frequency,
-                       use the data in file.  For stations that are not
-                       numeric, e.g. SE20, they are placed above the highest
-                       numbered station in the order they are found.  Example:
-                       "-freqtab /usr/X11R6/share/xawtv/europe-west.list"
-                       You can make your own freqtab by copying the xawtv
-                       format.
-
--pipeinput cmd         This option lets you supply an external command in
-                       "cmd" that x11vnc will pipe all of the user input
-                       events to in a simple format.  In -pipeinput mode by
-                       default x11vnc will not process any of the user input
-                       events.  If you prefix "cmd" with "tee:" it will
-                       both send them to the pipe command and process them.
-                       For a description of the format run "-pipeinput
-                       tee:/bin/cat".  Another prefix is "reopen" which
-                       means to reopen pipe if it exits.  Separate multiple
-                       prefixes with commas.
-
-                       In combination with -rawfb one might be able to
-                       do amusing things (e.g. control non-X devices).
-                       To facilitate this, if -rawfb is in effect then the
-                       value is stored in X11VNC_RAWFB_STR for the pipe command
-                       to use if it wants. Do 'env | grep X11VNC' for more.
-
-                       Built-in pipeinput modes (no external program required):
-
-                       If cmd is "VID" and you are using the -rawfb for a
-                       video capture device, then an internal list of keyboard
-                       mappings is used to set parameters of the video.
-                       The mappings are:
-
-                         "B" and "b" adjust the brightness up and down.
-                         "H" and "h" adjust the hue.
-                         "C" and "c" adjust the colour.
-                         "N" and "n" adjust the contrast.
-                         "S" and "s" adjust the size of the capture screen.
-                         "I" and "i" cycle through input channels.
-                         Up and Down arrows adjust the station (if a tuner)
-                         F1, F2, ..., F6 will switch the video capture pixel
-                         format to HI240, RGB565, RGB24, RGB32, RGB555, and
-                         GREY respectively.  See -rawfb video for details.
-
-                       If cmd is "CONSOLE" or "CONSOLEn" where n
-                       is a Linux console number, then the linux console
-                       keystroke insertion to /dev/ttyN (see -rawfb console)
-                       is performed.
-
-                       If cmd begins with "UINPUT" then the Linux uinput
-                       module is used to insert both keystroke and mouse events
-                       to the Linux console (see -rawfb above).  This usually
-                       is the /dev/input/uinput device file (you may need to
-                       create it with "mknod /dev/input/uinput c 10 223"
-                       and insert the module with "modprobe uinput".
-
-                       The UINPUT mode currently only does US keyboards (a
-                       scan code option may be added), and not all keysyms
-                       are supported.  But it is probably more accurate than
-                       the "CONSOLE" method.
-
-                       You may want to use the options -cursor none and
-                       -nodragging in this mode.
-
-                       Additional tuning options may be supplied via:
-                       UINPUT:opt1,opt2,... (a comma separated list). If an
-                       option begins with "/" it is taken as the uinput
-                       device file.
-
-                       Which uinput is injected can be controlled by an option
-                       string made of the characters "K", "M", and "B"
-                       (see the -input option), e.g. "KM" allows keystroke
-                       and motion but not button clicks.
-
-                       A UINPUT option of the form: accel=f, or accel=fx+fy
-                       sets the mouse motion "acceleration".  This is used
-                       to correct raw mouse relative motion into how much the
-                       application cursor moves (x11vnc has no control over,
-                       or knowledge of how the windowing application interprets
-                       the raw mouse motions).  Typically the acceleration
-                       for an X display is 2 (see xset "m" option).  "f"
-                       is a floating point number, e.g. 3.0.  Use "fx+fy"
-                       if you need to supply different corrections for x and y.
-
-                       Note: the default acceleration is 2.0 since it seems
-                       both X and qt-embedded often (but not always) use
-                       this value.
-
-                       Even with a correct accel setting the mouse position
-                       will get out of sync (probably due to a mouse
-                       "threshold" setting where the acceleration doe not
-                       apply, set xset(1)).  The option reset=N sets the
-                       number of ms (default 150) after which the cursor is
-                       attempted to be reset (by forcing the mouse to (0,
-                       0) via small increments and then back out to (x, y)
-                       in 1 jump), This correction seems to be needed but can
-                       cause jerkiness or unexpected behavior with menus, etc.
-                       Use reset=0 to disable.
-
-                       If you set the env. var X11VNC_UINPUT_THRESHOLDS then
-                       the thresh=n mode will be enabled.  It is currently
-                       not working well.  If |dx| <= thresh and |dy| < thresh
-                       no acceleration is applied.  Use "thresh=+n" |dx| +
-                       |dy| < thresh to be used instead (X11?)
-
-                       Example:
-                           -pipeinput UINPUT:accel=4.0 -cursor none
-
-                       If the uinput device has an absolute pointer (as opposed
-                       to a normal mouse that is a relative pointer) you can
-                       specify the option "abs".  Note that a touchpad
-                       on a laptop is an absolute device to some degree.
-                       This (usually) avoids all the problems with mouse
-                       acceleration.  If x11vnc has trouble deducing the
-                       size of the device, use "abs=WxH".  Furthermore,
-                       if the device is a touchscreen (assumed to have an
-                       absolute pointer) use "touch" or "touch=WxH".
-                       For touchscreens, when a mouse button is pressed,
-                       a pressure increase is injected, and when the button
-                       is released a pressure of zero is injected.
-
-                       If touch has been set, use "touch_always=1" to
-                       indicate whenever the mouse moves with no button
-                       pressed, a touch event of zero pressure should be
-                       sent anyway.  Also use "btn_touch=1" to indicate a
-                       BTN_TOUCH keystroke press or release should be sent
-                       instead of a pressure change.  Set "dragskip=n" to
-                       skip n dragged mouse touches (with pressure applied)
-                       before injecting one.  To indicate the pressure that
-                       should be sent when there is a button click for a
-                       touchscreen device, specify pressure=n, e.g. n=5. The
-                       default is n=1.
-
-                       If a touch screen is being used ("touch" above)
-                       and it is having its input processed by tslib, you can
-                       specify the tslib calibration file via tslib_cal=<file>.
-                       For example, tslib_cal=/etc/pointercal.  To get accurate
-                       or even usable positioning this is required when tslib
-                       is in use.
-
-                       The Linux uinput mechanism can be bypassed and one can
-                       write input events DIRECTLY to the devices instead.
-                       To do this, specify one or more of the following
-                       for the input classes: direct_rel=<device>
-                       direct_abs=<device> direct_btn=<device> or
-                       direct_key=<device>.  The <device> file is usually
-                       something like /dev/input/event1 but you can specify
-                       any device file or pipe.  You must specify each one
-                       of the above classes even if they correspond to the
-                       same device file (rel/abs and btn are often the same.)
-                       Look at the file /proc/bus/input/devices to get an idea
-                       what is available and the device filenames.  Note:
-                       The /dev/input/mouse* devices do not seem to work,
-                       use the corresponding /dev/input/event* file instead.
-                       Any input class not directly specified as above will be
-                       handled via the uinput mechanism.  To disable creating a
-                       uinput device (and thereby discarding unhandled input),
-                       specify "nouinput".
-
-                       Examples:
-
-                         -pipeinput UINPUT:direct_abs=/dev/input/event1
-
-                       this was used on a qtmoko Neo freerunner (armel):
-
-                         -pipeinput UINPUT:touch,tslib_cal=/etc/pointercal,
-                          direct_abs=/dev/input/event1,nouinput,dragskip=4
-
-                       (where the long line has been split into two.)
-
-                       You can set the env. var X11VNC_UINPUT_DEBUG=1 or higher
-                       to get debugging output for UINPUT mode.
-
--macnodim              For the native MacOSX server, disable dimming.
--macnosleep            For the native MacOSX server, disable display sleep.
--macnosaver            For the native MacOSX server, disable screensaver.
--macnowait             For the native MacOSX server, do not wait for the
-                       user to switch back to his display.
--macwheel n            For the native MacOSX server, set the mouse wheel
-                       speed to n (default 5).
--macnoswap             For the native MacOSX server, do not swap mouse
-                       buttons 2 and 3.
--macnoresize           For the native MacOSX server, do not resize or reset
-                       the framebuffer even if it is detected that the screen
-                       resolution or depth has changed.
--maciconanim n         For the native MacOSX server, set n to the number
-                       of milliseconds that the window iconify/deiconify
-                       animation takes.  In -ncache mode this value will be
-                       used to skip the animation if possible. (default 400)
--macmenu               For the native MacOSX server, in -ncache client-side
-                       caching mode, try to cache pull down menus (not perfect
-                       because they have animated fades, etc.)
--macuskbd              For the native MacOSX server, use the original
-                       keystroke insertion code based on a US keyboard.
--macnoopengl           For the native MacOSX server, do not use OpenGL for
-                       screen capture, but rather use the original, deprecated
-                       raw memory access method: addr = CGDisplayBaseAddress().
--macnorawfb            For the native MacOSX server, disable the raw memory
-                       address screen capture method.
-
-                       MACOSX NOTE: There are some deprecated MacOSX interfaces
-                       to inject keyboard and mouse events and the raw memory
-                       access method is deprecated as well (however, OpenGL
-                       will be preferred if available because it is faster.)
-                       One can force not using any deprecated interfaces at
-                       compile time by setting -DX11VNC_MACOSX_NO_DEPRECATED=1
-                       in CPPFLAGS.  Or to turn them off one by one:
-                       -DX11VNC_MACOSX_NO_DEPRECATED_LOCALEVENTS=1,
-                       -DX11VNC_MACOSX_NO_DEPRECATED_POSTEVENTS=1 or
-                       -DX11VNC_MACOSX_NO_DEPRECATED_FRAMEBUFFER=1
-                       At run time, for testing and workarounds, one can
-                       disable them by using:
-                       -env X11VNC_MACOSX_NO_DEPRECATED=1
-                       -env X11VNC_MACOSX_NO_DEPRECATED_LOCALEVENTS=1
-                       -env X11VNC_MACOSX_NO_DEPRECATED_POSTEVENTS=1 or
-                       -env X11VNC_MACOSX_NO_DEPRECATED_FRAMEBUFFER=1
-                       Note: When doing either of these for the mouse input
-                       not everything works currently, e.g. double clicks and
-                       wireframing.  Also, screen resolution and pixel depth
-                       changes will not be automatically detected unless the
-                       deprecated framebuffer interfaces are allowed.
-
-                       Conversely, if you are compiling on an
-                       older machine that does not have some of
-                       the newer interfaces, you may need to specify
-                       -DX11VNC_MACOSX_NO_CGEVENTCREATESCROLLWHEELEVENT
-                       -DX11VNC_MACOSX_NO_CGEVENTCREATEMOUSEEVENT or
-                       -DX11VNC_MACOSX_NO_CGEVENTCREATEKEYBOARDEVENT.  Use
-                       -DX11VNC_MACOSX_USE_GETMAINDEVICE to regain the very
-                       old QuickDraw GetMainDevice() interface (rare...)
-
--gui [gui-opts]        Start up a simple tcl/tk gui based on the remote
-                       control options -remote/-query described below.
-                       Requires the "wish" program to be installed on the
-                       machine.  "gui-opts" is not required: the default
-                       is to start up both the full gui and x11vnc with the
-                       gui showing up on the X display in the environment
-                       variable DISPLAY.
-
-                       "gui-opts" can be a comma separated list of items.
-                       Currently there are these types of items: 1) a gui
-                       mode, a 2) gui "simplicity", 3) the X display the
-                       gui should display on, 4) a "tray" or "icon" mode,
-                       and 5) a gui geometry.
-
-                       1) The gui mode can be "start", "conn", or "wait"
-                       "start" is the default mode above and is not required.
-                       "conn" means do not automatically start up x11vnc,
-                       but instead just try to connect to an existing x11vnc
-                       process.  "wait" means just start the gui and nothing
-                       else (you will later instruct the gui to start x11vnc
-                       or connect to an existing one.)
-
-                       2) The gui simplicity is off by default (a power-user
-                       gui with all options is presented) To start with
-                       something less daunting supply the string "simple"
-                       ("ez" is an alias for this).  Once the gui is
-                       started you can toggle between the two with "Misc ->
-                       simple_gui".
-
-                       3) Note the possible confusion regarding the potentially
-                       two different X displays: x11vnc polls one, but you
-                       may want the gui to appear on another.  For example, if
-                       you ssh in and x11vnc is not running yet you may want
-                       the gui to come back to you via your ssh redirected X
-                       display (e.g. localhost:10).
-
-                       If you do not specify a gui X display in "gui-opts"
-                       then the DISPLAY environment variable and -display
-                       option are tried (in that order).  Regarding the x11vnc
-                       X display the gui will try to communication with, it
-                       first tries -display and then DISPLAY.  For example,
-                       "x11vnc -display :0 -gui otherhost:0", will remote
-                       control an x11vnc polling :0 and display the gui on
-                       otherhost:0 The "tray/icon" mode below reverses this
-                       preference, preferring to display on the x11vnc display.
-
-                       4) When "tray" or "icon" is specified, the gui
-                       presents itself as a small icon with behavior typical
-                       of a "system tray" or "dock applet".  The color
-                       of the icon indicates status (connected clients) and
-                       there is also a balloon status.  Clicking on the icon
-                       gives a menu from which properties, etc, can be set and
-                       the full gui is available under "Advanced".  To be
-                       fully functional, the gui mode should be "start"
-                       (the default).
-
-                       Note that tray or icon mode will imply the -forever
-                       x11vnc option (if the x11vnc server is started along
-                       with the gui) unless -connect or -connect_or_exit has
-                       been specified.  So x11vnc (and the tray/icon gui)
-                       will wait for more connections after the first client
-                       disconnects.  If you want only one viewer connection
-                       include the -once option.
-
-                       For "icon" the gui just a small standalone window.
-                       For "tray" it will attempt to embed itself in the
-                       "system tray" if possible. If "=setpass" is appended the
-n
-                       at startup the X11 user will be prompted to set the
-                       VNC session password.  If =<hexnumber> is appended
-                       that icon will attempt to embed itself in the window
-                       given by hexnumber.  Use =noadvanced to disable the
-                       full gui. (To supply more than one, use "+" sign).
-                       E.g. -gui tray=setpass and -gui icon=0x3600028
-
-                       Other modes: "full", the default and need not be
-                       specified.  "-gui none", do not show a gui, useful
-                       to override a ~/.x11vncrc setting, etc.
-
-                       5) When "geom=+X+Y" is specified, that geometry
-                       is passed to the gui toplevel.  This is the icon in
-                       icon/tray mode, or the full gui otherwise.  You can
-                       also specify width and height, i.e. WxH+X+Y, but it
-                       is not recommended.  In "tray" mode the geometry is
-                       ignored unless the system tray manager does not seem
-                       to be running.  One could imagine using something like
-                       "-gui tray,geom=+4000+4000" with a display manager
-                       to keep the gui invisible until someone logs in...
-
-                       More icon tricks, "icon=minimal" gives an icon just
-                       with the VNC display number.  You can also set the font
-                       with "iconfont=...".  The following could be useful:
-                       "-gui icon=minimal,iconfont=5x8,geom=24x10+0-0"
-
-                       General examples of the -gui option: "x11vnc -gui",
-                       "x11vnc -gui ez" "x11vnc -gui localhost:10",
-                       "x11vnc -gui conn,host:0", "x11vnc -gui tray,ez"
-                       "x11vnc -gui tray=setpass"
-
-                       If you do not intend to start x11vnc from the gui
-                       (i.e. just remote control an existing one), then the
-                       gui process can run on a different machine from the
-                       x11vnc server as long as X permissions, etc. permit
-                       communication between the two.
-
-                       FONTS: On some systems the tk fonts can be too small,
-                       jagged, or otherwise unreadable.  There are 4 env vars
-                       you can set to be the tk font you prefer:
-
-                       X11VNC_FONT_BOLD   main font for menus and buttons.
-                       X11VNC_FONT_FIXED  font for fixed width text.
-
-                       X11VNC_FONT_BOLD_SMALL  tray icon font.
-                       X11VNC_FONT_REG_SMALL   tray icon menu font.
-
-                       The last two only apply for the tray icon mode.
-
-                       Here are some examples:
-
-                       -env X11VNC_FONT_BOLD='Helvetica -16 bold'
-                       -env X11VNC_FONT_FIXED='Courier -14'
-                       -env X11VNC_FONT_REG_SMALL='Helvetica -12'
-
-                       You can put the lines like the above (without the
-                       quotes) in your ~/.x11vncrc file to avoid having to
-                       specify them on the x11vnc command line.
-
--remote command        Remotely control some aspects of an already running
-                       x11vnc server.  "-R" and "-r" are aliases for
-                       "-remote".  After the remote control command is
-                       sent to the running server the 'x11vnc -remote ...'
-                       x11vnc command exits.  You can often use the -query
-                       command (see below) to see if the x11vnc server
-                       processed your -remote command.
-
-                       The default communication channel is that of X
-                       properties (specifically X11VNC_REMOTE), and so this
-                       command must be run with correct settings for DISPLAY
-                       and possibly XAUTHORITY to connect to the X server
-                       and set the property.  Alternatively, use the -display
-                       and -auth options to set them to the correct values.
-                       The running server cannot use the -novncconnect option
-                       because that disables the communication channel.
-                       See below for alternate channels.
-
-                       For example: 'x11vnc -remote stop' (which is the same as
-                       'x11vnc -R stop') will close down the x11vnc server.
-                       'x11vnc -R shared' will enable shared connections, and
-                       'x11vnc -R scale:3/4' will rescale the desktop.
-
-                       To use a different name for the X11 property (e.g. to
-                       have separate communication channels for multiple
-                       x11vnc's on the same display) set the X11VNC_REMOTE
-                       environment variable to the string you want, for
-                       example: -env X11VNC_REMOTE=X11VNC_REMOTE_12345
-                       Both sides of the channel must use the same unique name.
-
-                       To run a bunch of commands in a sequence use something
-                       like: x11vnc -R 'script:firstcmd;secondcmd;...'
-
-                       Use x11vnc -R script:file=/path/to/file to read commands
-                       from a file (can be multi-line and use the comment '#'
-                       character in the normal way.  The ';' separator must
-                       still be used to separate each command.)
-
-                       To not try to contact another x11vnc process and instead
-                       just run the command (or query) directly, prefix the
-                       command with the string "DIRECT:"
-
-                       The following -remote/-R commands are supported:
-
-                       stop            terminate the server, same as "quit"
-                                       "exit" or "shutdown".
-                       ping            see if the x11vnc server responds.
-                                       return is: ans=ping:<display>
-                       ping:mystring   as above, but use your own unique string
-.
-                                       return is: ans=ping:mystring:<xdisplay>
-                       blacken         try to push a black fb update to all
-                                       clients (due to timings a client
-                                       could miss it). Same as "zero", also
-                                       "zero:x1,y1,x2,y2" for a rectangle.
-                       refresh         send the entire fb to all clients.
-                       reset           recreate the fb, polling memory, etc.
-                       id:windowid     set -id window to "windowid". empty
-                                       or "root" to go back to root window
-                       sid:windowid    set -sid window to "windowid"
-                       id_cmd:cmd      cmds: raise, lower, map, unmap, iconify,
-                                       move:dXdY, resize:dWdH, geom:WxH+X+Y. dX
-                                       dY, dW, and dH must have a leading "+"
-                                       or "-" e.g.: move:-30+10 resize:+20+35
-                                       also: wm_delete, wm_name:string and
-                                       icon_name:string. Also id_cmd:win=N:cmd
-                       waitmapped      wait until subwin is mapped.
-                       nowaitmapped    do not wait until subwin is mapped.
-                       clip:WxH+X+Y    set -clip mode to "WxH+X+Y"
-                       flashcmap       enable  -flashcmap mode.
-                       noflashcmap     disable -flashcmap mode.
-                       shiftcmap:n     set -shiftcmap to n.
-                       notruecolor     enable  -notruecolor mode.
-                       truecolor       disable -notruecolor mode.
-                       overlay         enable  -overlay mode (if applicable).
-                       nooverlay       disable -overlay mode.
-                       overlay_cursor  in -overlay mode, enable cursor drawing.
-                       overlay_nocursor disable cursor drawing. same as
-                                        nooverlay_cursor.
-                       8to24           enable  -8to24 mode (if applicable).
-                       no8to24         disable -8to24 mode.
-                       8to24_opts:str  set the -8to24 opts to "str".
-                       24to32          enable  -24to32 mode (if applicable).
-                       no24to32        disable -24to32 mode.
-                       visual:vis      set -visual to "vis"
-                       scale:frac      set -scale to "frac"
-                       scale_cursor:f  set -scale_cursor to "f"
-                       viewonly        enable  -viewonly mode.
-                       noviewonly      disable -viewonly mode.
-                       shared          enable  -shared mode.
-                       noshared        disable -shared mode.
-                       forever         enable  -forever mode.
-                       noforever       disable -forever mode.
-                       timeout:n       reset -timeout to n, if there are
-                                       currently no clients, exit unless one
-                                       connects in the next n secs.
-                       tightfilexfer   enable  filetransfer for NEW clients.
-                       notightfilexfer disable filetransfer for NEW clients.
-                       ultrafilexfer   enable  filetransfer for clients.
-                       noultrafilexfer disable filetransfer for clients.
-                       rfbversion:n.m  set -rfbversion for new clients.
-                       http            enable  http client connections.
-                       nohttp          disable http client connections.
-                       deny            deny any new connections, same as "lock"
-                       nodeny          allow new connections, same as "unlock"
-                       avahi           enable  avahi service advertising.
-                       noavahi         disable avahi service advertising.
-                       mdns            enable  avahi service advertising.
-                       nomdns          disable avahi service advertising.
-                       zeroconf        enable  avahi service advertising.
-                       nozeroconf      disable avahi service advertising.
-                       connect:host    do reverse connection to host, "host"
-                                       may be a comma separated list of hosts
-                                       or host:ports.  See -connect.  Passwords
-                                       required as with fwd connections.
-                                       See X11VNC_REVERSE_CONNECTION_NO_AUTH=1
-                       disconnect:host disconnect any clients from "host"
-                                       same as "close:host".  Use host
-                                       "all" to close all current clients.
-                                       If you know the client internal hex ID,
-                                       e.g. 0x3 (returned by "-query clients"
-                                       and RFB_CLIENT_ID) you can use that too.
-                       proxy:host:port set reverse connection proxy (empty to
-                                       disable).
-                       allowonce:host  For the next connection only, allow
-                                       connection from "host". In -ssl mode
-                                       two connections are allowed (i.e. Fetch
-                                       Cert) unless X11VNC_NO_SSL_ALLOW_TWICE=1
-                       allow:hostlist  set -allow list to (comma separated)
-                                       "hostlist". See -allow and -localhost.
-                                       Do not use with -allow /path/to/file
-                                       Use "+host" to add a single host, and
-                                       use "-host" to delete a single host
-                       localhost       enable  -localhost mode
-                       nolocalhost     disable -localhost mode
-                       listen:str      set -listen to str, empty to disable.
-                       noipv6          enable  -noipv6 mode.
-                       ipv6            disable -noipv6 mode.
-                       noipv4          enable  -noipv4 mode.
-                       ipv4            disable -noipv4 mode.
-                       6               enable  -6 IPv6 listening mode.
-                       no6             disable -6 IPv6 listening mode.
-                       lookup          disable -nolookup mode.
-                       nolookup        enable  -nolookup mode.
-                       lookup          disable -nolookup mode.
-                       input:str       set -input to "str", empty to disable.
-                       grabkbd         enable  -grabkbd mode.
-                       nograbkbd       disable -grabkbd mode.
-                       grabptr         enable  -grabptr mode.
-                       nograbptr       disable -grabptr mode.
-                       grabalways      enable  -grabalways mode.
-                       nograbalways    disable -grabalways mode.
-                       grablocal:n     set -grablocal to n.
-                       client_input:str set the K, M, B -input on a per-client
-                                       basis.  select which client as for
-                                       disconnect, e.g. client_input:host:MB
-                                       or client_input:0x2:K
-                       accept:cmd      set -accept "cmd" (empty to disable).
-                       afteraccept:cmd set -afteraccept (empty to disable).
-                       gone:cmd        set -gone "cmd" (empty to disable).
-                       noshm           enable  -noshm mode.
-                       shm             disable -noshm mode (i.e. use shm).
-                       flipbyteorder   enable -flipbyteorder mode, you may need
-                                       to set noshm for this to do something.
-                       noflipbyteorder disable -flipbyteorder mode.
-                       onetile         enable  -onetile mode. (you may need to
-                                       set shm for this to do something)
-                       noonetile       disable -onetile mode.
-                       solid           enable  -solid mode
-                       nosolid         disable -solid mode.
-                       solid_color:color set -solid color (and apply it).
-                       blackout:str    set -blackout "str" (empty to disable).
-                                       See -blackout for the form of "str"
-                                       (basically: WxH+X+Y,...)
-                                       Use "+WxH+X+Y" to append a single
-                                       rectangle use "-WxH+X+Y" to delete one
-                       xinerama        enable  -xinerama mode. (if applicable)
-                       noxinerama      disable -xinerama mode.
-                       xtrap           enable  -xtrap input mode(if applicable)
-                       noxtrap         disable -xtrap input mode.
-                       xrandr          enable  -xrandr mode. (if applicable)
-                       noxrandr        disable -xrandr mode.
-                       xrandr_mode:mode set the -xrandr mode to "mode".
-                       rotate:mode     set the -rotate mode to "mode".
-                       padgeom:WxH     set -padgeom to WxH (empty to disable)
-                                       If WxH is "force" or "do" the padded
-                                       geometry fb is immediately applied.
-                       quiet           enable  -quiet mode.
-                       noquiet         disable -quiet mode.
-                       modtweak        enable  -modtweak mode.
-                       nomodtweak      enable  -nomodtweak mode.
-                       xkb             enable  -xkb modtweak mode.
-                       noxkb           disable -xkb modtweak mode.
-                       capslock        enable  -capslock mode.
-                       nocapslock      disable -capslock mode.
-                       skip_lockkeys   enable  -skip_lockkeys mode.
-                       noskip_lockkeys disable -skip_lockkeys mode.
-                       skip_keycodes:str enable -xkb -skip_keycodes "str".
-                       sloppy_keys     enable  -sloppy_keys mode.
-                       nosloppy_keys   disable -sloppy_keys mode.
-                       skip_dups       enable  -skip_dups mode.
-                       noskip_dups     disable -skip_dups mode.
-                       add_keysyms     enable -add_keysyms mode.
-                       noadd_keysyms   stop adding keysyms. those added will
-                                       still be removed at exit.
-                       clear_mods      enable  -clear_mods mode and clear them.
-                       noclear_mods    disable -clear_mods mode.
-                       clear_keys      enable  -clear_keys mode and clear them.
-                       noclear_keys    disable -clear_keys mode.
-                       clear_locks     do the clear_locks action.
-                       clear_all       do the clear_all action.
-                       keystate        have x11vnc print current keystate.
-                       remap:str       set -remap "str" (empty to disable).
-                                       See -remap for the form of "str"
-                                       (basically: key1-key2,key3-key4,...)
-                                       Use "+key1-key2" to append a single
-                                       keymapping, use "-key1-key2" to delete.
-                       norepeat        enable  -norepeat mode.
-                       repeat          disable -norepeat mode.
-                       nofb            enable  -nofb mode.
-                       fb              disable -nofb mode.
-                       bell            enable  bell (if supported).
-                       nobell          disable bell.
-                       sendbell        ring the bell now.
-                       nosel           enable  -nosel mode.
-                       sel             disable -nosel mode.
-                       noprimary       enable  -noprimary mode.
-                       primary         disable -noprimary mode.
-                       nosetprimary    enable  -nosetprimary mode.
-                       setprimary      disable -nosetprimary mode.
-                       noclipboard     enable  -noclipboard mode.
-                       clipboard       disable -noclipboard mode.
-                       nosetclipboard  enable  -nosetclipboard mode.
-                       setclipboard    disable -nosetclipboard mode.
-                       seldir:str      set -seldir to "str"
-                       resend_cutbuffer resend the most recent CUTBUFFER0 copy
-                       resend_clipboard resend the most recent CLIPBOARD copy
-                       resend_primary   resend the most recent PRIMARY copy
-                       cursor:mode     enable  -cursor "mode".
-                       show_cursor     enable  showing a cursor.
-                       noshow_cursor   disable showing a cursor. (same as
-                                       "nocursor")
-                       cursor_drag     enable  cursor changes during drag.
-                       nocursor_drag   disable cursor changes during drag.
-                       arrow:n         set -arrow to alternate n.
-                       xfixes          enable  xfixes cursor shape mode.
-                       noxfixes        disable xfixes cursor shape mode.
-                       alphacut:n      set -alphacut to n.
-                       alphafrac:f     set -alphafrac to f.
-                       alpharemove     enable  -alpharemove mode.
-                       noalpharemove   disable -alpharemove mode.
-                       alphablend      disable -noalphablend mode.
-                       noalphablend    enable  -noalphablend mode.
-                       cursorshape     disable -nocursorshape mode.
-                       nocursorshape   enable  -nocursorshape mode.
-                       cursorpos       disable -nocursorpos mode.
-                       nocursorpos     enable  -nocursorpos mode.
-                       xwarp           enable  -xwarppointer mode.
-                       noxwarp         disable -xwarppointer mode.
-                       always_inject   enable  -always_inject mode.
-                       noalways_inject disable -always_inject mode.
-                       buttonmap:str   set -buttonmap "str", empty to disable
-                       dragging        disable -nodragging mode.
-                       nodragging      enable  -nodragging mode.
-                       ncache          reenable -ncache mode.
-                       noncache        disable  -ncache mode.
-                       ncache_size:n   set -ncache size to n.
-                       ncache_cr       enable  -ncache_cr mode.
-                       noncache_cr     disable -ncache_cr mode.
-                       ncache_no_moveraise     enable  no_moveraise mode.
-                       noncache_no_moveraise   disable no_moveraise mode.
-                       ncache_no_dtchange      enable  ncache_no_dtchange mode.
-                       noncache_no_dtchange    disable ncache_no_dtchange mode.
-                       ncache_old_wm           enable  ncache_old_wm mode.
-                       noncache_old_wm         disable ncache_old_wm mode.
-                       ncache_no_rootpixmap    enable  ncache_no_rootpixmap.
-                       noncache_no_rootpixmap  disable ncache_no_rootpixmap.
-                       ncache_reset_rootpixmap recheck the root pixmap, ncrp
-                       ncache_keep_anims       enable  ncache_keep_anims.
-                       noncache_keep_anims     disable ncache_keep_anims.
-                       ncache_pad:n    set -ncache_pad to n.
-                       wireframe       enable  -wireframe mode. same as "wf"
-                       nowireframe     disable -wireframe mode. same as "nowf"
-                       wireframe:str   enable  -wireframe mode string.
-                       wireframe_mode:str enable  -wireframe mode string.
-                       wireframelocal  enable  wireframelocal. same as "wfl"
-                       nowireframe     disable wireframelocal. same as "nowfl"
-                       wirecopyrect:str set -wirecopyrect string. same as "wcr:
-"
-                       scrollcopyrect:str set -scrollcopyrect string. same "scr
-"
-                       noscrollcopyrect disable -scrollcopyrect mode. "noscr"
-                       scr_area:n      set -scr_area to n
-                       scr_skip:list   set -scr_skip to "list"
-                       scr_inc:list    set -scr_inc to "list"
-                       scr_keys:list   set -scr_keys to "list"
-                       scr_term:list   set -scr_term to "list"
-                       scr_keyrepeat:str set -scr_keyrepeat to "str"
-                       scr_parms:str   set -scr_parms parameters.
-                       fixscreen:str   set -fixscreen to "str".
-                       noxrecord       disable all use of RECORD extension.
-                       xrecord         enable  use of RECORD extension.
-                       reset_record    reset RECORD extension (if avail.)
-                       pointer_mode:n  set -pointer_mode to n. same as "pm"
-                       input_skip:n    set -input_skip to n.
-                       allinput        enable  use of -allinput mode.
-                       noallinput      disable use of -allinput mode.
-                       input_eagerly   enable  use of -input_eagerly mode.
-                       noinput_eagerly disable use of -input_eagerly mode.
-                       ssltimeout:n    set -ssltimeout to n.
-                       speeds:str      set -speeds to str.
-                       wmdt:str        set -wmdt to str.
-                       debug_pointer   enable  -debug_pointer, same as "dp"
-                       nodebug_pointer disable -debug_pointer, same as "nodp"
-                       debug_keyboard   enable  -debug_keyboard, same as "dk"
-                       nodebug_keyboard disable -debug_keyboard, same as "nodk"
-                       keycode:n       inject keystroke 'keycode' (xmodmap -pk)
-                       keycode:n,down  inject 'keycode' (down=0,1)
-                       keysym:str      inject keystroke 'keysym' (number/name)
-                       keysym:str,down inject 'keysym' (down=0,1)
-                       ptr:x,y,mask    inject pointer event x, y, button-mask
-                       fakebuttonevent:button,down direct XTestFakeButtonEvent.
-                       sleep:t         sleep floating point time t.
-                       get_xprop:p     get X property named 'p'.
-                       set_xprop:p:val set X property named 'p' to 'val'.
-                                       p -> id=NNN:p for hex/dec window id.
-                       wininfo:id      get info about X window id.  use 'root'
-                                       for root window, use +id for children.
-                       grab_state      get state of pointer and keyboard grab.
-                       pointer_pos     print XQueryPointer x,y cursor position.
-                       pointer_x       print XQueryPointer x cursor position.
-                       pointer_y       print XQueryPointer y cursor position.
-                       pointer_same    print XQueryPointer ptr on same screen.
-                       pointer_root    print XQueryPointer curr ptr rootwin.
-                       pointer_mask    print XQueryPointer button and mods mask
-                       mouse_x         print x11vnc's idea of cursor position.
-                       mouse_y         print x11vnc's idea of cursor position.
-                       noop            do nothing.
-                       defer:n         set -defer to n ms,same as deferupdate:n
-                       wait:n          set -wait to n ms.
-                       extra_fbur:n    set -extra_fbur to n.
-                       wait_ui:f       set -wait_ui factor to f.
-                       setdefer:n      set -setdefer to -2,-1,0,1, or 2.
-                       wait_bog        disable -nowait_bog mode.
-                       nowait_bog      enable  -nowait_bog mode.
-                       slow_fb:f       set -slow_fb to f seconds.
-                       xrefresh:f      set -xrefresh to f seconds.
-                       readtimeout:n   set read timeout to n seconds.
-                       nap             enable  -nap mode.
-                       nonap           disable -nap mode.
-                       sb:n            set -sb to n s, same as screen_blank:n
-                       fbpm            disable -nofbpm mode.
-                       nofbpm          enable  -nofbpm mode.
-                       dpms            disable -nodpms mode.
-                       nodpms          enable  -nodpms mode.
-                       forcedpms       enable  -forcedpms mode.
-                       noforcedpms     disable -forcedpms mode.
-                       clientdpms      enable  -clientdpms mode.
-                       noclientdpms    disable -clientdpms mode.
-                       noserverdpms    enable  -noserverdpms mode.
-                       serverdpms      disable -noserverdpms mode.
-                       noultraext      enable  -noultraext mode.
-                       ultraext        disable -noultraext mode.
-                       chatwindow      enable  local chatwindow mode.
-                       nochatwindow    disable local chatwindow mode.
-                       chaton          begin chat using local window.
-                       chatoff         end   chat using local window.
-                       xdamage         enable  xdamage polling hints.
-                       noxdamage       disable xdamage polling hints.
-                       xd_area:A       set -xd_area max pixel area to "A"
-                       xd_mem:f        set -xd_mem remembrance to "f"
-                       fs:frac         set -fs fraction to "frac", e.g. 0.5
-                       gaps:n          set -gaps to n.
-                       grow:n          set -grow to n.
-                       fuzz:n          set -fuzz to n.
-                       snapfb          enable  -snapfb mode.
-                       nosnapfb        disable -snapfb mode.
-                       rawfb:str       set -rawfb mode to "str".
-                       uinput_accel:f  set uinput_accel to f.
-                       uinput_thresh:n set uinput_thresh to n.
-                       uinput_reset:n  set uinput_reset to n ms.
-                       uinput_always:n set uinput_always to 1/0.
-                       progressive:n   set LibVNCServer -progressive slice
-                                       height parameter to n.
-                       desktop:str     set -desktop name to str for new clients
-.
-                       rfbport:n       set -rfbport to n.
-                       macnosaver      enable  -macnosaver mode.
-                       macsaver        disable -macnosaver mode.
-                       macnowait       enable  -macnowait  mode.
-                       macwait         disable -macnowait  mode.
-                       macwheel:n      set -macwheel to n.
-                       macnoswap       enable  -macnoswap mouse button mode.
-                       macswap         disable -macnoswap mouse button mode.
-                       macnoresize     enable  -macnoresize mode.
-                       macresize       disable -macnoresize mode.
-                       maciconanim:n   set -maciconanim to n.
-                       macmenu         enable  -macmenu  mode.
-                       macnomenu       disable -macmenu  mode.
-                       macuskbd        enable  -macuskbd mode.
-                       macnouskbd      disable -macuskbd mode.
-                       httpport:n      set -httpport to n.
-                       httpdir:dir     set -httpdir to dir (and enable http).
-                       enablehttpproxy   enable  -enablehttpproxy mode.
-                       noenablehttpproxy disable -enablehttpproxy mode.
-                       alwaysshared     enable  -alwaysshared mode.
-                       noalwaysshared   disable -alwaysshared mode.
-                                        (may interfere with other options)
-                       nevershared      enable  -nevershared mode.
-                       nonevershared    disable -nevershared mode.
-                                        (may interfere with other options)
-                       dontdisconnect   enable  -dontdisconnect mode.
-                       nodontdisconnect disable -dontdisconnect mode.
-                                        (may interfere with other options)
-                       debug_xevents   enable  debugging X events.
-                       nodebug_xevents disable debugging X events.
-                       debug_xdamage   enable  debugging X DAMAGE mechanism.
-                       nodebug_xdamage disable debugging X DAMAGE mechanism.
-                       debug_wireframe enable   debugging wireframe mechanism.
-                       nodebug_wireframe disable debugging wireframe mechanism.
-                       debug_scroll    enable  debugging scrollcopy mechanism.
-                       nodebug_scroll  disable debugging scrollcopy mechanism.
-                       debug_tiles     enable  -debug_tiles
-                       nodebug_tiles   disable -debug_tiles
-                       debug_grabs     enable  -debug_grabs
-                       nodebug_grabs   disable -debug_grabs
-                       debug_sel       enable  -debug_sel
-                       nodebug_sel     disable -debug_sel
-                       debug_ncache    enable  -debug_ncache
-                       nodebug_ncache  disable -debug_ncache
-                       dbg             enable  -dbg crash shell
-                       nodbg           disable -dbg crash shell
-
-                       noremote        disable the -remote command processing,
-                                       it cannot be turned back on.
-
-                       bcx_xattach:str  This remote control command is for
-                       use with the BARCO xattach program or the x2x program.
-                       Both of these programs are for 'pointer and keyboard'
-                       sharing between separate X displays.  In general the
-                       two displays are usually nearby, e.g. on the same desk,
-                       and this allows the user to share a single pointer and
-                       keyboard between them.  The user moves the mouse to
-                       an edge and then the mouse pointer appears to 'jump'
-                       to the other display screen.  Thus it emulates what a
-                       single X server would do for two screens (e.g. :0.0 and
-                       :0.1) The illusion of a single Xserver with multiple
-                       screens is achieved by forwarding events to the 2nd
-                       one via the XTEST extension.
-
-                       What the x11vnc bcx_xattach command does is to perform
-                       some pointer movements to try to INDUCE xattach/x2x
-                       to 'jump' to the other display.  In what follows the
-                       'master' display refers to the one that when it has
-                       'focus' it is basically doing nothing besides watching
-                       for the mouse to go over an edge.  The 'slave'
-                       display refers to the one to which the mouse and
-                       keyboard is redirected to once an edge in the master
-                       has been crossed.  Note that the x11vnc executing the
-                       bcx_xattach command MUST be the one connected to the
-                       *master* display.
-
-                       Also note that when input is being redirected (via
-                       XTEST) from the master display to the slave display,
-                       the master display's pointer and keyboard are *grabbed*
-                       by xattach/x2x.  x11vnc can use this info to verify that
-                       the master/slave mode change has taken place correctly.
-                       If you specify the "ifneeded" option (see below)
-                       and the initial grab state is that of the desired
-                       final state, then no pointer movements are injected
-                       and "DONE,GRAB_OK" is returned.
-
-                       "str" must contain one of "up", "down", "left",
-                       or "right" to indicate the direction of the 'jump'.
-                       "str" must also contain one of "master_to_slave"
-                       or "slave_to_master" to indicate the type of mode
-                       change induced by the jump.  Use "M2S" and "S2M"
-                       as shorter aliases.
-
-                       "str" may be a "+" separated list of additional
-                       tuning options.  The "shift=n" option indicates an
-                       offset shift position away from (0,0) (default 20).
-                       "final=x+y" specifies the final position of the cursor
-                       at the end of the normal move sequence; default 30+30.
-                       "extra_move=x+y" means to do one more pointer move
-                       after "final" to x+y.  "dt=n" sets the sleep time
-                       in milliseconds between pointer moves (default: 40ms)
-                       "retry=n" specifies the maximum number of retries if
-                       the grab state change fails. "ifneeded" means to not
-                       apply the pointer movements if the initial grab state is
-                       that of the desired final state. "nograbcheck" means
-                       to not check if the grab state changed as expected and
-                       only apply the pointer movements (default is to check
-                       the grab states.)
-
-                       If you do not specify "up", etc., to bcx_xattach
-                       nothing will be attempted and the command returns
-                       the string FAIL,NO_DIRECTION_SPECIFIED.  If you do
-                       not specify "master_to_slave" or "M2S", etc., to
-                       bcx_xattach nothing will be attempted and the command
-                       returns the string FAIL,NO_MODE_CHANGE_SPECIFIED.
-
-                       Otherwise, the returned string will contain "DONE".
-                       It will be "DONE,GRAB_OK" if the grab state changed
-                       as expected (or if "ifneeded" was supplied and
-                       the initial grab state was already the desired
-                       one.)  If the initial grab state was incorrect,
-                       but the final grab state was correct then it is
-                       "DONE,GRAB_FAIL_INIT".  If the initial grab state
-                       was correct, but the final grab state was incorrect
-                       then it is "DONE,GRAB_FAIL_FINAL".  If both are
-                       incorrect it will be "DONE,GRAB_FAIL".  Under grab
-                       failure the string will be followed by ":p1,k1-p2,k2"
-                       where  p1,k1 indicates the initial pointer and keyboard
-                       grab states and p2,k2 the final ones. If GRAB_FAIL or
-                       GRAB_FAIL_FINAL occurs, the action will be retried up
-                       to 3 times; trying to reset the state and sleeping a
-                       bit between each try.  Set retry=n to adjust the number
-                       of retries, zero to disable retries.
-
-                       Examples:
-                           -R bcx_xattach:down+M2S
-                           -R bcx_xattach:up+S2M
-                           -R bcx_xattach:up+S2M+nograbcheck+dt=30
-                           -R bcx_xattach:down+M2S+extra_move=100+100
-
-                       or use -Q instead of -R to retrieve the result text.
-
-                       End of the bcx_xattach:str description.
-
-                       The vncconnect(1) command from standard VNC
-                       distributions may also be used if string is prefixed
-                       with "cmd=" E.g. 'vncconnect cmd=stop'.  Under some
-                       circumstances xprop(1) can used if it supports -set
-                       (see the FAQ).
-
-                       If "-connect /path/to/file" has been supplied to the
-                       running x11vnc server then that file can be used as a
-                       communication channel (this is the only way to remote
-                       control one of many x11vnc's polling the same X display)
-                       Simply run: 'x11vnc -connect /path/to/file -remote ...'
-                       or you can directly write to the file via something
-                       like: "echo cmd=stop > /path/to/file", etc.
-
--query variable        Like -remote, except just query the value of
-                       "variable".  "-Q" is an alias for "-query".
-                       Multiple queries can be done by separating variables
-                       by commas, e.g. -query var1,var2. The results come
-                       back in the form ans=var1:value1,ans=var2:value2,...
-                       to the standard output.  If a variable is read-only,
-                       it comes back with prefix "aro=" instead of "ans=".
-
-                       Some -remote commands are pure actions that do not make
-                       sense as variables, e.g. "stop" or "disconnect", in
-                       these cases the value returned is "N/A".  To direct a
-                       query straight to the X11VNC_REMOTE property or connect
-                       file use "qry=..." instead of "cmd=..."
-
-                       ans= stop quit exit shutdown ping resend_cutbuffer
-                       resend_clipboard resend_primary blacken zero refresh
-                       reset close disconnect id_cmd id sid waitmapped
-                       nowaitmapped clip flashcmap noflashcmap shiftcmap
-                       truecolor notruecolor overlay nooverlay overlay_cursor
-                       overlay_yescursor nooverlay_nocursor nooverlay_cursor
-                       nooverlay_yescursor overlay_nocursor 8to24 no8to24
-                       8to24_opts 24to32 no24to32 visual scale scale_cursor
-                       viewonly noviewonly shared noshared forever noforever
-                       once timeout tightfilexfer notightfilexfer ultrafilexfer
-                       noultrafilexfer rfbversion deny lock nodeny unlock avahi
-                       mdns zeroconf noavahi nomdns nozeroconf connect proxy
-                       allowonce allow noipv6 ipv6 noipv4 ipv4 no6 6 localhost
-                       nolocalhost listen lookup nolookup accept afteraccept
-                       gone shm noshm flipbyteorder noflipbyteorder onetile
-                       noonetile solid_color solid nosolid blackout xinerama
-                       noxinerama xtrap noxtrap xrandr noxrandr xrandr_mode
-                       rotate padgeom quiet q noquiet modtweak nomodtweak xkb
-                       noxkb capslock nocapslock skip_lockkeys noskip_lockkeys
-                       skip_keycodes sloppy_keys nosloppy_keys skip_dups
-                       noskip_dups add_keysyms noadd_keysyms clear_mods
-                       noclear_mods clear_keys noclear_keys clear_all
-                       clear_locks keystate remap repeat norepeat fb nofb bell
-                       nobell sendbell sel nosel primary noprimary setprimary
-                       nosetprimary clipboard noclipboard setclipboard
-                       nosetclipboard seldir cursorshape nocursorshape
-                       cursorpos nocursorpos cursor_drag nocursor_drag cursor
-                       show_cursor noshow_cursor nocursor arrow xfixes noxfixes
-                       xdamage noxdamage xd_area xd_mem alphacut alphafrac
-                       alpharemove noalpharemove alphablend noalphablend
-                       xwarppointer xwarp noxwarppointer noxwarp always_inject
-                       noalways_inject buttonmap dragging nodragging ncache_cr
-                       noncache_cr ncache_no_moveraise noncache_no_moveraise
-                       ncache_no_dtchange noncache_no_dtchange
-                       ncache_no_rootpixmap noncache_no_rootpixmap
-                       ncache_reset_rootpixmap ncrp ncache_keep_anims
-                       noncache_keep_anims ncache_old_wm noncache_old_wm
-                       ncache_pad ncache noncache ncache_size debug_ncache
-                       nodebug_ncache wireframe_mode wireframe wf nowireframe
-                       nowf wireframelocal wfl nowireframelocal nowfl
-                       wirecopyrect wcr nowirecopyrect nowcr scr_area
-                       scr_skip scr_inc scr_keys scr_term scr_keyrepeat
-                       scr_parms scrollcopyrect scr noscrollcopyrect
-                       noscr fixscreen noxrecord xrecord reset_record
-                       pointer_mode pm input_skip allinput noallinput
-                       input_eagerly noinput_eagerly input grabkbd nograbkbd
-                       grabptr nograbptr grabalways nograbalways grablocal
-                       client_input ssltimeout speeds wmdt debug_pointer dp
-                       nodebug_pointer nodp debug_keyboard dk nodebug_keyboard
-                       nodk keycode keysym ptr fakebuttonevent sleep get_xprop
-                       set_xprop wininfo bcx_xattach deferupdate defer
-                       setdefer extra_fbur wait_ui wait_bog nowait_bog
-                       slow_fb xrefresh wait readtimeout nap nonap sb
-                       screen_blank fbpm nofbpm dpms nodpms clientdpms
-                       noclientdpms forcedpms noforcedpms noserverdpms
-                       serverdpms noultraext ultraext chatwindow nochatwindow
-                       chaton chatoff fs gaps grow fuzz snapfb nosnapfb
-                       rawfb uinput_accel uinput_thresh uinput_reset
-                       uinput_always progressive rfbport http nohttp httpport
-                       httpdir enablehttpproxy noenablehttpproxy alwaysshared
-                       noalwaysshared nevershared noalwaysshared dontdisconnect
-                       nodontdisconnect desktop debug_xevents nodebug_xevents
-                       debug_xevents debug_xdamage nodebug_xdamage
-                       debug_xdamage debug_wireframe nodebug_wireframe
-                       debug_wireframe debug_scroll nodebug_scroll debug_scroll
-                       debug_tiles dbt nodebug_tiles nodbt debug_tiles
-                       debug_grabs nodebug_grabs debug_sel nodebug_sel dbg
-                       nodbg macnosaver macsaver nomacnosaver macnowait macwait
-                       nomacnowait macwheel macnoswap macswap nomacnoswap
-                       macnoresize macresize nomacnoresize maciconanim macmenu
-                       macnomenu nomacmenu macuskbd nomacuskbd noremote
-
-                       aro=  noop display vncdisplay icon_mode autoport
-                       loop loopbg desktopname guess_desktop guess_dbus
-                       http_url auth xauth users rootshift clipshift scale_str
-                       scaled_x scaled_y scale_numer scale_denom scale_fac_x
-                       scale_fac_y scaling_blend scaling_nomult4 scaling_pad
-                       scaling_interpolate inetd privremote unsafe safer nocmds
-                       passwdfile unixpw unixpw_nis unixpw_list ssl ssl_pem
-                       sslverify stunnel stunnel_pem https httpsredir usepw
-                       using_shm logfile o flag rmflag rc norc h help V version
-                       lastmod bg sigpipe threads readrate netrate netlatency
-                       pipeinput clients client_count pid ext_xtest ext_xtrap
-                       ext_xrecord ext_xkb ext_xshm ext_xinerama ext_overlay
-                       ext_xfixes ext_xdamage ext_xrandr rootwin num_buttons
-                       button_mask mouse_x mouse_y grab_state pointer_pos
-                       pointer_x pointer_y pointer_same pointer_root
-                       pointer_mask bpp depth indexed_color dpy_x dpy_y wdpy_x
-                       wdpy_y off_x off_y cdpy_x cdpy_y coff_x coff_y rfbauth
-                       passwd viewpasswd
-
--QD variable           Just like -query variable, but returns the default
-                       value for that parameter (no running x11vnc server
-                       is consulted)
-
--sync                  By default -remote commands are run asynchronously, that
-                       is, the request is posted and the program immediately
-                       exits.  Use -sync to have the program wait for an
-                       acknowledgement from the x11vnc server that command was
-                       processed (somehow).  On the other hand -query requests
-                       are always processed synchronously because they have
-                       to wait for the answer.
-
-                       Also note that if both -remote and -query requests are
-                       supplied on the command line, the -remote is processed
-                       first (synchronously: no need for -sync), and then
-                       the -query request is processed in the normal way.
-                       This allows for a reliable way to see if the -remote
-                       command was processed by querying for any new settings.
-                       Note however that there is timeout of a few seconds
-                       (see the next paragraph) so if the x11vnc takes longer
-                       than that to process the requests the requester will
-                       think that a failure has taken place.
-
-                       The default is to wait 3.5 seconds.  Or if cmd=stop
-                       only 1.0 seconds.  If cmd matches 'script:' then it
-                       will wait up to 10.0 seconds.  Set X11VNC_SYNC_TIMEOUT
-                       to the number of seconds you want it to wait.
-
--query_retries str     If a query fails to get a response from an x11vnc
-                       server, retry up to n times.  "str" is specified as
-                       n[:t][/match]  Optionally the delay between tries may
-                       be specified by "t" a floating point time (default
-                       0.5 seconds.)  Note: the response is not checked for
-                       validity or whether it corresponds to the query sent.
-                       The query "ping:mystring" may be used to help uniquely
-                       identify the query.  Optionally, a matching string after
-                       a "/" will be used to check the result text.  Up to
-                       n retries will take place until the matching string is
-                       found in the output text.  If the match string is never
-                       found the program's exit code is 1; if the match is
-                       found it exits with 0.  Note that there may be stdout
-                       printed for each retry (i.e. multiple lines printed
-                       out to stdout.)
-                       Example: -query_retries 4:1.5/grab_state
-
--remote_prefix str     Enable a remote-control communication channel for
-                       connected VNC clients.  str is a non-empty string. If a
-                       VNC client sends rfbCutText having the prefix "str"
-                       then the part after it is processed as though it were
-                       sent via 'x11vnc -remote ...'.  If it begins with
-                       neither 'cmd=' nor 'qry=' then 'qry=' is assumed.
-                       Any corresponding output text for that remote control
-                       command is sent back to all client as rfbCutText.
-                       The returned output is also prefixed with "str".
-                       Example: -remote_prefix DO_THIS:
-
-                       Note that enabling -remote_prefix allows the remote
-                       VNC viewers to run x11vnc -remote commands.  Do not
-                       use this option if they are not to be trusted.
-
--noremote              Do not process any remote control commands or queries.
--yesremote             Do process remote control commands or queries.
-                       Default: -yesremote
-
-                       A note about security wrt remote control commands.
-                       If someone can connect to the X display and change
-                       the property X11VNC_REMOTE, then they can remotely
-                       control x11vnc.  Normally access to the X display is
-                       protected.  Note that if they can modify X11VNC_REMOTE
-                       on the X server, they have enough permissions to also
-                       run their own x11vnc and thus have complete control
-                       of the desktop.  If the  "-connect /path/to/file"
-                       channel is being used, obviously anyone who can write
-                       to /path/to/file can remotely control x11vnc.  So be
-                       sure to protect the X display and that file's write
-                       permissions.  See -privremote below.
-
-                       If you are paranoid and do not think -noremote is
-                       enough, to disable the X11VNC_REMOTE property channel
-                       completely use -novncconnect, or use the -safer option
-                       that shuts many things off.
-
--unsafe                A few remote commands are disabled by default
-                       (currently: id:pick, accept:<cmd>, gone:<cmd>, and
-                       rawfb:setup:<cmd>) because they are associated with
-                       running external programs.  If you specify -unsafe, then
-                       these remote-control commands are allowed.  Note that
-                       you can still specify these parameters on the command
-                       line, they just cannot be invoked via remote-control.
--safer                 Equivalent to: -novncconnect -noremote and prohibiting
-                       -gui and the -connect file. Shuts off communcation
-                       channels.
--privremote            Perform some sanity checks and disable remote-control
-                       commands if it appears that the X DISPLAY and/or
-                       connectfile can be accessed by other users.  Once
-                       remote-control is disabled it cannot be turned back on.
--nocmds                No external commands (e.g. system(3), popen(3), exec(3))
-                       will be run at all.
--allowedcmds list      "list" contains a comma separated list of the only
-                       external commands that can be run.  The full list of
-                       associated options is:
-
-                        stunnel, ssl, unixpw, WAIT, zeroconf, id, accept,
-                        afteraccept, gone, pipeinput, v4l-info, rawfb-setup,
-                        dt, gui, ssh, storepasswd, passwdfile, custom_passwd,
-                        findauth, crash.
-
-                       See each option's help to learn the associated external
-                       command.  Note that the -nocmds option takes precedence
-                       and disables all external commands.
-
--deny_all              For use with -remote nodeny: start out denying all
-                       incoming clients until "-remote nodeny" is used to
-                       let them in.
-
-
-
-These options are passed to LibVNCServer:
-
--rfbport port          TCP port for RFB protocol
--rfbwait time          max time in ms to wait for RFB client
--rfbauth passwd-file   use authentication on RFB protocol
-                       (use 'storepasswd' to create a password file)
--rfbversion 3.x        Set the version of the RFB we choose to advertise
--permitfiletransfer    permit file transfer support
--passwd plain-password use authentication
-                       (use plain-password as password, USE AT YOUR RISK)
--deferupdate time      time in ms to defer updates (default 40)
--deferptrupdate time   time in ms to defer pointer updates (default none)
--desktop name          VNC desktop name (default "LibVNCServer")
--alwaysshared          always treat new clients as shared
--nevershared           never treat new clients as shared
--dontdisconnect        don't disconnect existing clients when a new non-shared
-                       connection comes in (refuse new connection instead)
--httpdir dir-path      enable http server using dir-path home
--httpport portnum      use portnum for http connection
--enablehttpproxy       enable http proxy support
--progressive height    enable progressive updating for slow links
--listen ipaddr         listen for connections only on network interface with
-                       addr ipaddr. '-listen localhost' and hostname work too.
-
-libvncserver-tight-extension options:
--disablefiletransfer   disable file transfer
--ftproot string        set ftp root
-
-   Pretty wild huh? Contact me if you have any questions or problems.
-
-   Personally, I use:
-x11vnc -rfbauth $HOME/.vnc/passwd -solid