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diff --git a/qmake/book/qmake-advanced.leaf b/qmake/book/qmake-advanced.leaf deleted file mode 100644 index e4d7621b1..000000000 --- a/qmake/book/qmake-advanced.leaf +++ /dev/null @@ -1,401 +0,0 @@ -\chapter qmake's Advanced Concepts - -\section1 qmake's Advanced Concepts - -The \e qmake project files we've seen up to now have been very simple, -just a list of \e{name = value} and \e{name += value} lines. \e qmake -provides a lot more power, for example you can use a single project -file to produce makefiles for multiple platforms. - -\section1 Operators - -So far, you have seen the \e = operator and \e += operator being used -in a project file. There are more operators available for use; but -some of these should be used carefully as they may change more than -you expect them to. - -\section2 The '=' operator - -This operator simply assigns a value to a variable, it is used like -this: - -\code - TARGET = myapp -\endcode - -This sets the TARGET variable to \e myapp. This will remove any -previously set TARGET. - -\section2 The '+=' operator - -This operator appends a value to the list of values in a variable. It -is used like this: - -\code - DEFINES += QT_DLL -\endcode - -This appends QT_DLL to the list of pre-processor defines to be put in the -makefile. - -\section2 The '-=' operator - -This operator removes a value from the list of values in a variable. -It is used like this: - -\code - DEFINES -= QT_DLL -\endcode - -This removes QT_DLL from the list of pre-processor defines to be put -in the makefile. - -\section2 The '*=' operator - -This operator only adds a value to the list of values in a variable if -it doesn't already exist. It is used like this: - -\code - DEFINES *= QT_DLL -\endcode - -QT_DLL will only be added to the list of pre-processor defines if it -is not already defined. - -\section2 The '~=' operator - -This operator replaces any values that match the regexp with the -specified value. It is used like this: - -\code - DEFINES ~= s/QT_[DT].+/QT -\endcode - -This removes any values in the list that start with QT_D or QT_T with -QT. - -\section1 Scopes - -A scope are similar to 'if' statements, if a certain condition is -true, the settings inside the scope are processed. A scope is written -like this: - -\code - win32 { - DEFINES += QT_DLL - } -\endcode - -The above code will add the QT_DLL define to the makefile if \e qmake -is used on a Windows platform. If \e qmake is used on a different -platform than Windows, the define will be ignored. You may also perform -single line conditionals/assignments with qmake like this: - -\code - win32:DEFINES += QT_DLL -\endcode - -For example, suppose we want to process something on all platforms -\e except for Windows. We can achieve this by negating the scope like -this: - -\code - !win32 { - DEFINES += QT_DLL - } -\endcode - -Any entry on the CONFIG line is also a scope. For example, if you -write this: -\code - CONFIG += warn_on -\endcode -you will have a scope called 'warn_on'. This makes it easy to change -the configuration for a project without losing all the custom settings -that might be needed for a specific configuration. Since it is -possible to put your own values on the CONFIG line, this provides you -with a very powerful configuration tool for your makefiles. For -example: - -\code - CONFIG += qt warn_on debug - debug { - TARGET = myappdebug - } - release { - TARGET = myapp - } -\endcode - -In the above code, two scopes are created which depend on what -is put on the CONFIG line. In the example, \e debug is on the config -line, so the TARGET variable is set to \e myappdebug. If \e release -was on the config line, then the TARGET variable would be set to \e -myapp. - -It is also possible to check for two things before processing some -settings. For instance, if you want to check if the platform is -Windows and that the thread configuration is set, you would write -this: - -\code - win32 { - thread { - DEFINES += TQT_THREAD_SUPPORT - } - } -\endcode - -To save writing many nested scopes, you can nest scopes using a colon -like this: - -\code - win32:thread { - DEFINES += TQT_THREAD_SUPPORT - } -\endcode - -Once a test has been performed you may also do else/elseif operations. With -this you may easily write complicated tests. This can be done with the -special 'else' scope, it can be combined with other scopes (separated by -colons as above) for example: - -\code - win32:thread { - DEFINES += TQT_THREAD_SUPPORT - } else:debug { - DEFINES += QT_NOTHREAD_DEBUG - } else { - message("Unknown configuration") - } -\endcode - -\section1 Variables - -The variables that we have encountered so far are system variables, -such as \e DEFINES, \e SOURCES and \e HEADERS. It is possible for you -to create your own variables so that you use them in scopes. It's -easy to create your own variable; just name it and assign something to -it. For example: - -\code - MY_VARIABLE = value -\endcode - -There are no restricitions on what you do to your own variables, as \e -qmake will just ignore them unless it needs to look at them for a -scope. - -You can also assign the value of a current variable to another -variable by prefixing $$ to the variable name. For example: - -\code - MY_DEFINES = $$DEFINES -\endcode - -Now the MY_DEFINES variable contains what is in the DEFINES variable at -this point in the project file. This is also equivalent to: - -\code - MY_DEFINES = $${DEFINES} -\endcode - -The second notation allows you to adjoin the variable expansion to another -value without separating by space. \e qmake will allow a variable to -contain anything (including $(VALUE), which will be placed directly into -the Makefile, and allow it to expand as appropriate, usually an environment -variable). However, if you require an environment variable to be replaced -immediately then you may use the $$() notation. For example: - -\code - MY_DEFINES = $$(ENV_DEFINES) -\endcode - -This will set MY_DEFINES to the value of the evironment variable -ENV_DEFINES as it parses the .pro file. Additionally you may call built-in -functions in variable replacing. These functions (not to be confused with -Test Functions as enumerated in the next section) are listed below: - -\section2 join( variablename, glue, before, after ) - -This will join the value of \e variablename with glue. If this value is -non-empty it will prefix the value with \e before and suffix it with \e -after. \e variablename is the only required field, the others will default -to empty strings. If you need to encode spaces in \e glue, \e before, or \e -after you must quote them. - -\section2 prompt( question ) - -This will display \e question, and read from stdin as a return value. - -\section2 member( variablename, position ) - -This will place the value in \e variablename in position \e position of the -list. If the value of \e variablename is not long this will return an empty -string. \e variablename is the only required field, if not specified -position will default to the first value in the list (0). - -\section2 find( variablename, substr ) - -This will place all the values in \e variablename that match \e substr. \e -substr may be a regular expression as well, and will be matched -accordingly. - -\code - MY_VAR = one two three four - MY_VAR2 = $$join(MY_VAR, " -L", -L) -Lfive - MY_VAR3 = $$member(MY_VAR, 2) $$find(MY_VAR, t.*) -\endcode - -MY_VAR2 will contain '-Lone -Ltwo -Lthree -Lfour -Lfive', and MYVAR3 will -contains 'three two three'. - -\section2 system( program_and_args ) - -This will return the stdout/stderr of the program executed, and parse it as -normally expected. You can use this to interrogate information about the -platform for example. - -\code - UNAME = $$system(uname -s) - contains( UNAME, [lL]inux ):message( This looks like Linux ($$UNAME) to me ) -\endcode - -\section1 Test Functions - -\e qmake provides built-in functions that perform simple, yet powerful -tests. These tests may be used in place of scopes (as described above), in -some cases it is more usefull to use the test function by itself ignoring -its test value. - -\section2 contains( variablename, value ) - -If \e value is in the list of values stored in the variable called \e -variablename, then the settings inside the scope will be processed. -For example: - -\code - contains( CONFIG, thread ) { - DEFINES += TQT_THREAD_SUPPORT - } -\endcode - -If \e thread is in the list of values for the \e CONFIG variable, then -TQT_THREAD_SUPPORT will be added to the list of values in the \e -DEFINES variable. - -\section2 count( variablename, number ) - -If \e number matches the number of values stored in the variable -called \e variablename, then the settings inside the scope will be -processed. For example: - -\code - count( DEFINES, 5 ) { - CONFIG += debug - } -\endcode - -\section2 error( string ) - -This function outputs the string given and then makes \e qmake exit. -For example: - -\code - error( "An error has occured" ) -\endcode - -The text "An error has occured" will be displayed on the console and -\e qmake will exit. - -\section2 exists( filename ) - -If the specified file exists, then the settings inside the scope will -be processed. For example: - -\code - exists( /local/qt/qmake/main.cpp ) { - SOURCES += main.cpp - } -\endcode - -If \e /local/qt/qmake/main.cpp exists then main.cpp is added to the -list of source files. - -Note that "/" can be used as a directory separator regardless of the -platform. - - -\section2 equals( variable, value ) - -If the specified variable is equal to the value passed the scope will -be processed. For example: - -\code - NUMBERS = 1 2 3 - equals( NUMBERS, 3 4 5 ) { - message("The numbers are equal") - } -\endcode - -The message will not be displayed because "1 2 3" does not equal "1 2 -3". As with all functions you can pass an expanded variable as the -value argument (ie, $$NUMBERS). - -\section2 include( filename ) - -The contents of filename are included at this point in the project -file, so any settings in the specified file will be processed. An -example of this is: - -\code - include( myotherapp.pro ) -\endcode - -Any settings in the \e myotherapp.pro project file are now processed. - -\section2 isEmpty( variablename ) - -This is the equivalent of using count( variablename, 0 ). If the -variable called \e variablename has no elements, then the settings -inside the scope will be processed. An example of this is: - -\code - isEmpty( CONFIG ) { - CONFIG += qt warn_on debug - } -\endcode - -\section2 message( string ) - -This function simply outputs a message on the console. - -\code - message( "This is a message" ) -\endcode - -The text "This is a message" is output to the console and -processing of the project file carries on. - -\section2 system( command ) - -The specified command is performed and if it returns an exit code of -1, the settings inside the scope are processed. For example: - -\code - system( ls /bin ) { - SOURCES += bin/main.cpp - HEADERS += bin/main.h - } -\endcode - -So if the command \e {ls /bin} returns 1 then \e bin/main.cpp is added -to the list of sources and \e bin/main.h is added to the list of -headers. - -\section2 infile( filename, var, val ) - -This function will succeed if the file \e filename (when parsed -by qmake itself) contains the variable \e var with a value of -\e val. You may also not pass in a third argument (\e val) and the -function will only test if \e var has been assigned to in the file. |