diff options
| author | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
|---|---|---|
| committer | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
| commit | bd0f3345a938b35ce6a12f6150373b0955b8dd12 (patch) | |
| tree | 7a520322212d48ebcb9fbe1087e7fca28b76185c /doc/html/qiodevice.html | |
| download | qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.tar.gz qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.zip | |
Add Qt3 development HEAD version
Diffstat (limited to 'doc/html/qiodevice.html')
| -rw-r--r-- | doc/html/qiodevice.html | 553 |
1 files changed, 553 insertions, 0 deletions
diff --git a/doc/html/qiodevice.html b/doc/html/qiodevice.html new file mode 100644 index 0000000..b937514 --- /dev/null +++ b/doc/html/qiodevice.html @@ -0,0 +1,553 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/src/tools/qiodevice.cpp:40 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>QIODevice Class</title> +<style type="text/css"><!-- +fn { margin-left: 1cm; text-indent: -1cm; } +a:link { color: #004faf; text-decoration: none } +a:visited { color: #672967; text-decoration: none } +body { background: #ffffff; color: black; } +--></style> +</head> +<body> + +<table border="0" cellpadding="0" cellspacing="0" width="100%"> +<tr bgcolor="#E5E5E5"> +<td valign=center> + <a href="index.html"> +<font color="#004faf">Home</font></a> + | <a href="classes.html"> +<font color="#004faf">All Classes</font></a> + | <a href="mainclasses.html"> +<font color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped Classes</font></a> + | <a href="functions.html"> +<font color="#004faf">Functions</font></a> +</td> +<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QIODevice Class Reference</h1> + +<p>The QIODevice class is the base class of I/O devices. +<a href="#details">More...</a> +<p>All the functions in this class are <a href="threads.html#reentrant">reentrant</a> when Qt is built with thread support.</p> +<p><tt>#include <<a href="qiodevice-h.html">qiodevice.h</a>></tt> +<p>Inherited by <a href="qbuffer.html">QBuffer</a>, <a href="qfile.html">QFile</a>, <a href="qsocket.html">QSocket</a>, and <a href="qsocketdevice.html">QSocketDevice</a>. +<p><a href="qiodevice-members.html">List of all member functions.</a> +<h2>Public Members</h2> +<ul> +<li class=fn>typedef Q_ULONG <a href="#Offset"><b>Offset</b></a></li> +<li class=fn><a href="#QIODevice"><b>QIODevice</b></a> ()</li> +<li class=fn>virtual <a href="#~QIODevice"><b>~QIODevice</b></a> ()</li> +<li class=fn>int <a href="#flags"><b>flags</b></a> () const</li> +<li class=fn>int <a href="#mode"><b>mode</b></a> () const</li> +<li class=fn>int <a href="#state"><b>state</b></a> () const</li> +<li class=fn>bool <a href="#isDirectAccess"><b>isDirectAccess</b></a> () const</li> +<li class=fn>bool <a href="#isSequentialAccess"><b>isSequentialAccess</b></a> () const</li> +<li class=fn>bool <a href="#isCombinedAccess"><b>isCombinedAccess</b></a> () const</li> +<li class=fn>bool <a href="#isBuffered"><b>isBuffered</b></a> () const</li> +<li class=fn>bool <a href="#isRaw"><b>isRaw</b></a> () const</li> +<li class=fn>bool <a href="#isSynchronous"><b>isSynchronous</b></a> () const</li> +<li class=fn>bool <a href="#isAsynchronous"><b>isAsynchronous</b></a> () const</li> +<li class=fn>bool <a href="#isTranslated"><b>isTranslated</b></a> () const</li> +<li class=fn>bool <a href="#isReadable"><b>isReadable</b></a> () const</li> +<li class=fn>bool <a href="#isWritable"><b>isWritable</b></a> () const</li> +<li class=fn>bool <a href="#isReadWrite"><b>isReadWrite</b></a> () const</li> +<li class=fn>bool <a href="#isInactive"><b>isInactive</b></a> () const</li> +<li class=fn>bool <a href="#isOpen"><b>isOpen</b></a> () const</li> +<li class=fn>int <a href="#status"><b>status</b></a> () const</li> +<li class=fn>void <a href="#resetStatus"><b>resetStatus</b></a> ()</li> +<li class=fn>virtual bool <a href="#open"><b>open</b></a> ( int mode ) = 0</li> +<li class=fn>virtual void <a href="#close"><b>close</b></a> () = 0</li> +<li class=fn>virtual void <a href="#flush"><b>flush</b></a> () = 0</li> +<li class=fn>virtual Offset <a href="#size"><b>size</b></a> () const = 0</li> +<li class=fn>virtual Offset <a href="#at"><b>at</b></a> () const</li> +<li class=fn>virtual bool <a href="#at-2"><b>at</b></a> ( Offset pos )</li> +<li class=fn>virtual bool <a href="#atEnd"><b>atEnd</b></a> () const</li> +<li class=fn>bool <a href="#reset"><b>reset</b></a> ()</li> +<li class=fn>virtual Q_LONG <a href="#readBlock"><b>readBlock</b></a> ( char * data, Q_ULONG maxlen ) = 0</li> +<li class=fn>virtual Q_LONG <a href="#writeBlock"><b>writeBlock</b></a> ( const char * data, Q_ULONG len ) = 0</li> +<li class=fn>virtual Q_LONG <a href="#readLine"><b>readLine</b></a> ( char * data, Q_ULONG maxlen )</li> +<li class=fn>Q_LONG <a href="#writeBlock-2"><b>writeBlock</b></a> ( const QByteArray & data )</li> +<li class=fn>virtual QByteArray <a href="#readAll"><b>readAll</b></a> ()</li> +<li class=fn>virtual int <a href="#getch"><b>getch</b></a> () = 0</li> +<li class=fn>virtual int <a href="#putch"><b>putch</b></a> ( int ch ) = 0</li> +<li class=fn>virtual int <a href="#ungetch"><b>ungetch</b></a> ( int ch ) = 0</li> +</ul> +<h2>Protected Members</h2> +<ul> +<li class=fn>void <a href="#setFlags"><b>setFlags</b></a> ( int flags )</li> +<li class=fn>void <a href="#setType"><b>setType</b></a> ( int type )</li> +<li class=fn>void <a href="#setMode"><b>setMode</b></a> ( int mode )</li> +<li class=fn>void <a href="#setState"><b>setState</b></a> ( int state )</li> +<li class=fn>void <a href="#setStatus"><b>setStatus</b></a> ( int s )</li> +</ul> +<hr><a name="details"></a><h2>Detailed Description</h2> + + + +<p> The QIODevice class is the base class of I/O devices. +<p> +<p> An I/O device represents a medium that one can read bytes from +and/or write bytes to. The QIODevice class is the abstract +superclass of all such devices; classes such as <a href="qfile.html">QFile</a>, <a href="qbuffer.html">QBuffer</a> and +<a href="qsocket.html">QSocket</a> inherit QIODevice and implement virtual functions such as +write() appropriately. +<p> Although applications sometimes use QIODevice directly, it is +usually better to use <a href="qtextstream.html">QTextStream</a> and <a href="qdatastream.html">QDataStream</a>, which provide +stream operations on any QIODevice subclass. QTextStream provides +text-oriented stream functionality (for human-readable ASCII +files, for example), whereas QDataStream deals with binary data in +a totally platform-independent manner. +<p> The public member functions in QIODevice roughly fall into two +groups: the action functions and the state access functions. The +most important action functions are: +<p> <ul> +<p> <li> <a href="#open">open</a>() opens a device for reading and/or writing, depending on +the mode argument. +<p> <li> <a href="#close">close</a>() closes the device and tidies up (e.g. flushes buffered +data) +<p> <li> <a href="#readBlock">readBlock</a>() reads a block of data from the device. +<p> <li> <a href="#writeBlock">writeBlock</a>() writes a block of data to the device. +<p> <li> <a href="#readLine">readLine</a>() reads a line (of text, usually) from the device. +<p> <li> <a href="#flush">flush</a>() ensures that all buffered data are written to the real device. +<p> </ul> +<p> There are also some other, less used, action functions: +<p> <ul> +<p> <li> <a href="#getch">getch</a>() reads a single character. +<p> <li> <a href="#ungetch">ungetch</a>() forgets the last call to getch(), if possible. +<p> <li> <a href="#putch">putch</a>() writes a single character. +<p> <li> <a href="#size">size</a>() returns the size of the device, if there is one. +<p> <li> <a href="#at">at</a>() returns the current read/write pointer's position, if there +is one for this device, or it moves the pointer if given an offset. +<p> <li> <a href="#atEnd">atEnd</a>() indicates whether there is more to read, if this is +meaningful for this device. +<p> <li> <a href="#reset">reset</a>() moves the read/write pointer to the start of the +device, if that is possible for this device. +<p> </ul> +<p> The state access are all "get" functions. The QIODevice subclass +calls <a href="#setState">setState</a>() to update the state, and simple access functions +tell the user of the device what the device's state is. Here are +the settings, and their associated access functions: +<p> <ul> +<p> <li> Access type. Some devices are direct access (it is possible +to read/write anywhere), whereas others are sequential. QIODevice +provides the access functions (<a href="#isDirectAccess">isDirectAccess</a>(), +<a href="#isSequentialAccess">isSequentialAccess</a>(), and <a href="#isCombinedAccess">isCombinedAccess</a>()) to tell users what a +given I/O device supports. +<p> <li> Buffering. Some devices are accessed in raw mode, whereas +others are buffered. Buffering usually provides greater +efficiency, particularly for small read/write operations. +<a href="#isBuffered">isBuffered</a>() tells the user whether a given device is buffered. +(This can often be set by the application in the call to <a href="#open">open</a>().) +<p> <li> Synchronicity. Synchronous devices work immediately (for +example, files). When you read from a file, the file delivers its +data straight away. Other kinds of device, such as a socket +connected to a HTTP server, may not deliver the data until seconds +after you ask to read it. <a href="#isSynchronous">isSynchronous</a>() and <a href="#isAsynchronous">isAsynchronous</a>() +tell the user how this device operates. +<p> <li> CR/LF translation. For simplicity, applications often like to +see just a single CR/LF style, and QIODevice subclasses can +provide this. <a href="#isTranslated">isTranslated</a>() returns TRUE if this object +translates CR/LF to just LF. (This can often be set by the +application in the call to open().) +<p> <li> Permissions. Some files cannot be written. For example, +<a href="#isReadable">isReadable</a>(), <a href="#isWritable">isWritable</a>() and <a href="#isReadWrite">isReadWrite</a>() tell the application +whether it can read from and write to a given device. (This can +often be set by the application in the call to <a href="#open">open</a>().) +<p> <li> Finally, <a href="#isOpen">isOpen</a>() returns TRUE if the device is open, i.e. +after an open() call. +<p> </ul> +<p> QIODevice provides numerous pure virtual functions that you need +to implement when subclassing it. Here is a skeleton subclass with +all the members you are sure to need and some that you will +probably need: +<p> <pre> + class MyDevice : public QIODevice + { + public: + MyDevice(); + ~MyDevice(); + + bool open( int mode ); + void close(); + void flush(); + + uint size() const; + int at() const; // non-pure virtual + bool at( int ); // non-pure virtual + bool atEnd() const; // non-pure virtual + + int readBlock( char *data, uint maxlen ); + int writeBlock( const char *data, uint len ); + int readLine( char *data, uint maxlen ); + + int getch(); + int putch( int ); + int ungetch( int ); + }; + </pre> + +<p> The three non-pure virtual functions need not be reimplemented for +sequential devices. +<p> <p>See also <a href="qdatastream.html">QDataStream</a>, <a href="qtextstream.html">QTextStream</a>, and <a href="io.html">Input/Output and Networking</a>. + +<hr><h2>Member Type Documentation</h2> +<h3 class=fn><a name="Offset"></a>QIODevice::Offset</h3> + +<p> The offset within the device. + +<hr><h2>Member Function Documentation</h2> +<h3 class=fn><a name="QIODevice"></a>QIODevice::QIODevice () +</h3> +Constructs an I/O device. + +<h3 class=fn><a name="~QIODevice"></a>QIODevice::~QIODevice ()<tt> [virtual]</tt> +</h3> +Destroys the I/O device. + +<h3 class=fn><a href="qiodevice.html#Offset">Offset</a> <a name="at"></a>QIODevice::at () const<tt> [virtual]</tt> +</h3> +Virtual function that returns the current I/O device position. +<p> This is the position of the data read/write head of the I/O +device. +<p> <p>See also <a href="#size">size</a>(). + +<p>Example: <a href="distributor-example.html#x2666">distributor/distributor.ui.h</a>. +<p>Reimplemented in <a href="qsocket.html#at">QSocket</a>. +<h3 class=fn>bool <a name="at-2"></a>QIODevice::at ( <a href="qiodevice.html#Offset">Offset</a> pos )<tt> [virtual]</tt> +</h3> +Virtual function that sets the I/O device position to <em>pos</em>. +Returns TRUE if the position was successfully set, i.e. <em>pos</em> is +within range and the seek was successful; otherwise returns FALSE. +<p> <p>See also <a href="#size">size</a>(). + +<p>Reimplemented in <a href="qsocket.html#at-2">QSocket</a>. +<h3 class=fn>bool <a name="atEnd"></a>QIODevice::atEnd () const<tt> [virtual]</tt> +</h3> +Virtual function that returns TRUE if the I/O device position is +at the end of the input; otherwise returns FALSE. + +<p>Reimplemented in <a href="qfile.html#atEnd">QFile</a> and <a href="qsocket.html#atEnd">QSocket</a>. +<h3 class=fn>void <a name="close"></a>QIODevice::close ()<tt> [pure virtual]</tt> +</h3> + +<p> Closes the I/O device. +<p> This virtual function must be reimplemented by all subclasses. +<p> <p>See also <a href="#open">open</a>(). + +<p>Example: <a href="grapher-nsplugin-example.html#x2742">grapher/grapher.cpp</a>. +<p>Reimplemented in <a href="qfile.html#close">QFile</a> and <a href="qsocket.html#close">QSocket</a>. +<h3 class=fn>int <a name="flags"></a>QIODevice::flags () const +</h3> + +<p> Returns the current I/O device flags setting. +<p> Flags consists of mode flags and state flags. +<p> <p>See also <a href="#mode">mode</a>() and <a href="#state">state</a>(). + +<h3 class=fn>void <a name="flush"></a>QIODevice::flush ()<tt> [pure virtual]</tt> +</h3> + +<p> Flushes an open I/O device. +<p> This virtual function must be reimplemented by all subclasses. + +<p>Reimplemented in <a href="qfile.html#flush">QFile</a> and <a href="qsocket.html#flush">QSocket</a>. +<h3 class=fn>int <a name="getch"></a>QIODevice::getch ()<tt> [pure virtual]</tt> +</h3> + +<p> Reads a single byte/character from the I/O device. +<p> Returns the byte/character read, or -1 if the end of the I/O +device has been reached. +<p> This virtual function must be reimplemented by all subclasses. +<p> <p>See also <a href="#putch">putch</a>() and <a href="#ungetch">ungetch</a>(). + +<p>Reimplemented in <a href="qfile.html#getch">QFile</a> and <a href="qsocket.html#getch">QSocket</a>. +<h3 class=fn>bool <a name="isAsynchronous"></a>QIODevice::isAsynchronous () const +</h3> + +<p> Returns TRUE if the device is an asynchronous device; otherwise +returns FALSE, i.e. if the device is a synchronous device. +<p> This mode is currently not in use. +<p> <p>See also <a href="#isSynchronous">isSynchronous</a>(). + +<h3 class=fn>bool <a name="isBuffered"></a>QIODevice::isBuffered () const +</h3> + +<p> Returns TRUE if the I/O device is a buffered device; otherwise +returns FALSE, i.e. the device is a raw device. +<p> <p>See also <a href="#isRaw">isRaw</a>(). + +<h3 class=fn>bool <a name="isCombinedAccess"></a>QIODevice::isCombinedAccess () const +</h3> + +<p> Returns TRUE if the I/O device is a combined access (both direct +and sequential) device; otherwise returns FALSE. +<p> This access method is currently not in use. + +<h3 class=fn>bool <a name="isDirectAccess"></a>QIODevice::isDirectAccess () const +</h3> + +<p> Returns TRUE if the I/O device is a direct access device; +otherwise returns FALSE, i.e. if the device is a sequential access +device. +<p> <p>See also <a href="#isSequentialAccess">isSequentialAccess</a>(). + +<h3 class=fn>bool <a name="isInactive"></a>QIODevice::isInactive () const +</h3> + +<p> Returns TRUE if the I/O device state is 0, i.e. the device is not +open; otherwise returns FALSE. +<p> <p>See also <a href="#isOpen">isOpen</a>(). + +<h3 class=fn>bool <a name="isOpen"></a>QIODevice::isOpen () const +</h3> + +<p> Returns TRUE if the I/O device has been opened; otherwise returns +FALSE. +<p> <p>See also <a href="#isInactive">isInactive</a>(). + +<p>Example: <a href="networkprotocol-example.html#x670">network/networkprotocol/nntp.cpp</a>. +<h3 class=fn>bool <a name="isRaw"></a>QIODevice::isRaw () const +</h3> + +<p> Returns TRUE if the device is a raw device; otherwise returns +FALSE, i.e. if the device is a buffered device. +<p> <p>See also <a href="#isBuffered">isBuffered</a>(). + +<h3 class=fn>bool <a name="isReadWrite"></a>QIODevice::isReadWrite () const +</h3> + +<p> Returns TRUE if the I/O device was opened using <a href="qfile.html#open">IO_ReadWrite</a> +mode; otherwise returns FALSE. +<p> <p>See also <a href="#isReadable">isReadable</a>() and <a href="#isWritable">isWritable</a>(). + +<h3 class=fn>bool <a name="isReadable"></a>QIODevice::isReadable () const +</h3> + +<p> Returns TRUE if the I/O device was opened using <a href="qfile.html#open">IO_ReadOnly</a> or +<a href="qfile.html#open">IO_ReadWrite</a> mode; otherwise returns FALSE. +<p> <p>See also <a href="#isWritable">isWritable</a>() and <a href="#isReadWrite">isReadWrite</a>(). + +<h3 class=fn>bool <a name="isSequentialAccess"></a>QIODevice::isSequentialAccess () const +</h3> + +<p> Returns TRUE if the device is a sequential access device; +otherwise returns FALSE, i.e. if the device is a direct access +device. +<p> Operations involving <a href="#size">size</a>() and <a href="#at">at</a>(int) are not valid on +sequential devices. +<p> <p>See also <a href="#isDirectAccess">isDirectAccess</a>(). + +<h3 class=fn>bool <a name="isSynchronous"></a>QIODevice::isSynchronous () const +</h3> + +<p> Returns TRUE if the I/O device is a synchronous device; otherwise +returns FALSE, i.e. the device is an asynchronous device. +<p> <p>See also <a href="#isAsynchronous">isAsynchronous</a>(). + +<h3 class=fn>bool <a name="isTranslated"></a>QIODevice::isTranslated () const +</h3> + +<p> Returns TRUE if the I/O device translates carriage-return and +linefeed characters; otherwise returns FALSE. +<p> A <a href="qfile.html">QFile</a> is translated if it is opened with the <a href="qfile.html#open">IO_Translate</a> +mode flag. + +<h3 class=fn>bool <a name="isWritable"></a>QIODevice::isWritable () const +</h3> + +<p> Returns TRUE if the I/O device was opened using <a href="qfile.html#open">IO_WriteOnly</a> or +<a href="qfile.html#open">IO_ReadWrite</a> mode; otherwise returns FALSE. +<p> <p>See also <a href="#isReadable">isReadable</a>() and <a href="#isReadWrite">isReadWrite</a>(). + +<h3 class=fn>int <a name="mode"></a>QIODevice::mode () const +</h3> + +<p> Returns bits OR'ed together that specify the current operation +mode. +<p> These are the flags that were given to the <a href="#open">open</a>() function. +<p> The flags are <a href="qfile.html#open">IO_ReadOnly</a>, <a href="qfile.html#open">IO_WriteOnly</a>, <a href="qfile.html#open">IO_ReadWrite</a>, +<a href="qfile.html#open">IO_Append</a>, <a href="qfile.html#open">IO_Truncate</a> and <a href="qfile.html#open">IO_Translate</a>. + +<h3 class=fn>bool <a name="open"></a>QIODevice::open ( int mode )<tt> [pure virtual]</tt> +</h3> + +<p> Opens the I/O device using the specified <em>mode</em>. Returns TRUE if +the device was successfully opened; otherwise returns FALSE. +<p> The mode parameter <em>mode</em> must be an OR'ed combination of the +following flags. +<center><table cellpadding="4" cellspacing="2" border="0"> +<tr bgcolor="#a2c511"> <th valign="top">Mode flags <th valign="top">Meaning +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qfile.html#open">IO_Raw</a> <td valign="top">specifies raw (unbuffered) file access. +<tr bgcolor="#d0d0d0"> <td valign="top"><a href="qfile.html#open">IO_ReadOnly</a> <td valign="top">opens a file in read-only mode. +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qfile.html#open">IO_WriteOnly</a> <td valign="top">opens a file in write-only mode. +<tr bgcolor="#d0d0d0"> <td valign="top"><a href="qfile.html#open">IO_ReadWrite</a> <td valign="top">opens a file in read/write mode. +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qfile.html#open">IO_Append</a> <td valign="top">sets the file index to the end of the file. +<tr bgcolor="#d0d0d0"> <td valign="top"><a href="qfile.html#open">IO_Truncate</a> <td valign="top">truncates the file. +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qfile.html#open">IO_Translate</a> <td valign="top">enables carriage returns and linefeed +translation for text files under MS-DOS, Windows and Macintosh. On +Unix systems this flag has no effect. Use with caution as it will +also transform every linefeed written to the file into a CRLF +pair. This is likely to corrupt your file if you write write +binary data. Cannot be combined with <a href="qfile.html#open">IO_Raw</a>. +</table></center> +<p> This virtual function must be reimplemented by all subclasses. +<p> <p>See also <a href="#close">close</a>(). + +<p>Example: <a href="grapher-nsplugin-example.html#x2743">grapher/grapher.cpp</a>. +<p>Reimplemented in <a href="qfile.html#open">QFile</a> and <a href="qsocket.html#open">QSocket</a>. +<h3 class=fn>int <a name="putch"></a>QIODevice::putch ( int ch )<tt> [pure virtual]</tt> +</h3> + +<p> Writes the character <em>ch</em> to the I/O device. +<p> Returns <em>ch</em>, or -1 if an error occurred. +<p> This virtual function must be reimplemented by all subclasses. +<p> <p>See also <a href="#getch">getch</a>() and <a href="#ungetch">ungetch</a>(). + +<p>Example: <a href="grapher-nsplugin-example.html#x2744">grapher/grapher.cpp</a>. +<p>Reimplemented in <a href="qfile.html#putch">QFile</a> and <a href="qsocket.html#putch">QSocket</a>. +<h3 class=fn><a href="qbytearray.html">QByteArray</a> <a name="readAll"></a>QIODevice::readAll ()<tt> [virtual]</tt> +</h3> +This convenience function returns all of the remaining data in the +device. + +<h3 class=fn>Q_LONG <a name="readBlock"></a>QIODevice::readBlock ( char * data, Q_ULONG maxlen )<tt> [pure virtual]</tt> +</h3> + +<p> Reads at most <em>maxlen</em> bytes from the I/O device into <em>data</em> and +returns the number of bytes actually read. +<p> This function should return -1 if a fatal error occurs and should +return 0 if there are no bytes to read. +<p> The device must be opened for reading, and <em>data</em> must not be 0. +<p> This virtual function must be reimplemented by all subclasses. +<p> <p>See also <a href="#writeBlock">writeBlock</a>(), <a href="#isOpen">isOpen</a>(), and <a href="#isReadable">isReadable</a>(). + +<p>Example: <a href="distributor-example.html#x2667">distributor/distributor.ui.h</a>. +<p>Reimplemented in <a href="qsocket.html#readBlock">QSocket</a> and <a href="qsocketdevice.html#readBlock">QSocketDevice</a>. +<h3 class=fn>Q_LONG <a name="readLine"></a>QIODevice::readLine ( char * data, Q_ULONG maxlen )<tt> [virtual]</tt> +</h3> +Reads a line of text, (or up to <em>maxlen</em> bytes if a newline isn't +encountered) plus a terminating '\0' into <em>data</em>. If there is a +newline at the end if the line, it is not stripped. +<p> Returns the number of bytes read including the terminating '\0', +or -1 if an error occurred. +<p> This virtual function can be reimplemented much more efficiently +by the most subclasses. +<p> <p>See also <a href="#readBlock">readBlock</a>() and <a href="qtextstream.html#readLine">QTextStream::readLine</a>(). + +<p>Reimplemented in <a href="qfile.html#readLine">QFile</a>. +<h3 class=fn>bool <a name="reset"></a>QIODevice::reset () +</h3> + +<p> Sets the device index position to 0. +<p> <p>See also <a href="#at">at</a>(). + +<h3 class=fn>void <a name="resetStatus"></a>QIODevice::resetStatus () +</h3> + +<p> Sets the I/O device status to <a href="qiodevice.html#status">IO_Ok</a>. +<p> <p>See also <a href="#status">status</a>(). + +<h3 class=fn>void <a name="setFlags"></a>QIODevice::setFlags ( int flags )<tt> [protected]</tt> +</h3> + +<p> Used by subclasses to set the device flags to the <em>flags</em> specified. + +<h3 class=fn>void <a name="setMode"></a>QIODevice::setMode ( int mode )<tt> [protected]</tt> +</h3> + +<p> Used by subclasses to set the device mode to the <em>mode</em> specified. + +<h3 class=fn>void <a name="setState"></a>QIODevice::setState ( int state )<tt> [protected]</tt> +</h3> + +<p> Used by subclasses to set the device state to the <em>state</em> specified. + +<h3 class=fn>void <a name="setStatus"></a>QIODevice::setStatus ( int s )<tt> [protected]</tt> +</h3> +Used by subclasses to set the device status (not state) to <em>s</em>. + +<h3 class=fn>void <a name="setType"></a>QIODevice::setType ( int type )<tt> [protected]</tt> +</h3> + +<p> Used by subclasses to set the device type to the <em>type</em> specified. + +<h3 class=fn><a href="qiodevice.html#Offset">Offset</a> <a name="size"></a>QIODevice::size () const<tt> [pure virtual]</tt> +</h3> + +<p> Virtual function that returns the size of the I/O device. +<p> <p>See also <a href="#at">at</a>(). + +<p>Reimplemented in <a href="qfile.html#size">QFile</a> and <a href="qsocket.html#size">QSocket</a>. +<h3 class=fn>int <a name="state"></a>QIODevice::state () const +</h3> + +<p> Returns bits OR'ed together that specify the current state. +<p> The flags are: <tt>IO_Open</tt>. +<p> Subclasses may define additional flags. + +<h3 class=fn>int <a name="status"></a>QIODevice::status () const +</h3> + +<p> Returns the I/O device status. +<p> The I/O device status returns an error code. If <a href="#open">open</a>() returns +FALSE or <a href="#readBlock">readBlock</a>() or <a href="#writeBlock">writeBlock</a>() return -1, this function can +be called to find out the reason why the operation failed. +<p> <!-- index IO_Ok --><!-- index IO_ReadError --><!-- index IO_WriteError --><!-- index IO_FatalError --><!-- index IO_OpenError --><!-- index IO_ConnectError --><!-- index IO_AbortError --><!-- index IO_TimeOutError --><!-- index IO_UnspecifiedError --> +<p> The status codes are: +<center><table cellpadding="4" cellspacing="2" border="0"> +<tr bgcolor="#a2c511"> <th valign="top">Status code <th valign="top">Meaning +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qiodevice.html#status">IO_Ok</a> <td valign="top">The operation was successful. +<tr bgcolor="#d0d0d0"> <td valign="top"><a href="qiodevice.html#status">IO_ReadError</a> <td valign="top">Could not read from the device. +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qiodevice.html#status">IO_WriteError</a> <td valign="top">Could not write to the device. +<tr bgcolor="#d0d0d0"> <td valign="top"><a href="qiodevice.html#status">IO_FatalError</a> <td valign="top">A fatal unrecoverable error occurred. +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qiodevice.html#status">IO_OpenError</a> <td valign="top">Could not open the device. +<tr bgcolor="#d0d0d0"> <td valign="top"><a href="qiodevice.html#status">IO_ConnectError</a> <td valign="top">Could not connect to the device. +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qiodevice.html#status">IO_AbortError</a> <td valign="top">The operation was unexpectedly aborted. +<tr bgcolor="#d0d0d0"> <td valign="top"><a href="qiodevice.html#status">IO_TimeOutError</a> <td valign="top">The operation timed out. +<tr bgcolor="#f0f0f0"> <td valign="top"><a href="qiodevice.html#status">IO_UnspecifiedError</a> <td valign="top">An unspecified error happened on close. +</table></center> +<p> <p>See also <a href="#resetStatus">resetStatus</a>(). + +<h3 class=fn>int <a name="ungetch"></a>QIODevice::ungetch ( int ch )<tt> [pure virtual]</tt> +</h3> + +<p> Puts the character <em>ch</em> back into the I/O device and decrements +the index position if it is not zero. +<p> This function is normally called to "undo" a <a href="#getch">getch</a>() operation. +<p> Returns <em>ch</em>, or -1 if an error occurred. +<p> This virtual function must be reimplemented by all subclasses. +<p> <p>See also <a href="#getch">getch</a>() and <a href="#putch">putch</a>(). + +<p>Reimplemented in <a href="qfile.html#ungetch">QFile</a> and <a href="qsocket.html#ungetch">QSocket</a>. +<h3 class=fn>Q_LONG <a name="writeBlock"></a>QIODevice::writeBlock ( const char * data, Q_ULONG len )<tt> [pure virtual]</tt> +</h3> + +<p> Writes <em>len</em> bytes from <em>data</em> to the I/O device and returns the +number of bytes actually written. +<p> This function should return -1 if a fatal error occurs. +<p> This virtual function must be reimplemented by all subclasses. +<p> <p>See also <a href="#readBlock">readBlock</a>(). + +<p>Example: <a href="distributor-example.html#x2668">distributor/distributor.ui.h</a>. +<p>Reimplemented in <a href="qbuffer.html#writeBlock">QBuffer</a>, <a href="qsocket.html#writeBlock">QSocket</a>, and <a href="qsocketdevice.html#writeBlock">QSocketDevice</a>. +<h3 class=fn>Q_LONG <a name="writeBlock-2"></a>QIODevice::writeBlock ( const <a href="qbytearray.html">QByteArray</a> & data ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> This convenience function is the same as calling <a href="#writeBlock">writeBlock</a>( +data.data(), data.<a href="#size">size</a>() ). + +<!-- eof --> +<hr><p> +This file is part of the <a href="index.html">Qt toolkit</a>. +Copyright © 1995-2007 +<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center> +<table width=100% cellspacing=0 border=0><tr> +<td>Copyright © 2007 +<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> +<td align=right><div align=right>Qt 3.3.8</div> +</table></div></address></body> +</html> |