Configuring qmake's Environment

Customizing Makefile Output

qmake tries to do everything expected of a cross-platform build tool. This is often less than ideal when you really need to run special platform-dependent commands. This can be achieved with specific instructions to the different qmake backends.

Customization of the Makefile output is performed through an object-style API as found in other places in qmake. Objects are defined automatically by specifying their members; for example:

 mytarget.target = .buildfile
 mytarget.commands = touch $$mytarget.target
 mytarget.depends = mytarget2

 mytarget2.commands = @echo Building $$mytarget.target

The definitions above define a qmake target called mytarget, containing a Makefile target called .buildfile which in turn is generated with the touch command. Finally, the .depends member specifies that mytarget depends on mytarget2, another target that is defined afterwards. mytarget2 is a dummy target; it is only defined to echo some text to the console.

The final step is to instruct qmake that this object is a target to be built:

 QMAKE_EXTRA_TARGETS += mytarget mytarget2

This is all you need to do to actually build custom targets. Of course, you may want to tie one of these targets to the qmake build target. To do this, you simply need to include your Makefile target in the list of PRE_TARGETDEPS.

The following tables are an overview of the options available to you with the QMAKE_EXTRA_TARGETS variable.

List of members specific to the CONFIG option:

For convenience, there is also a method of customizing projects for new compilers or preprocessors:

 new_moc.output  = moc_${QMAKE_FILE_BASE}.cpp
 new_moc.commands = moc ${QMAKE_FILE_NAME} -o ${QMAKE_FILE_OUT}
 new_moc.depend_command = g++ -E -M ${QMAKE_FILE_NAME} | sed "s,^.*: ,,"
 new_moc.input = NEW_HEADERS
 QMAKE_EXTRA_COMPILERS += new_moc

With the above definitions, you can use a drop-in replacement for moc if one is available. The commands is executed on all arguments given to the NEW_HEADERS variable (from the input member), and the result is written to the file defined by the output member; this file is added to the other source files in the project. Additionally, qmake will execute depend_command to generate dependency information, and place this information in the project as well.

These commands can easily be placed into a cache file, allowing subsequent project files to add arguments to NEW_HEADERS.

The following tables are an overview of the options available to you with the QMAKE_EXTRA_COMPILERS variable.

List of members specific to the CONFIG option:

List of members specific to the CONFIG option:

Note: Symbian platform specific: Generating objects to be linked in is not supported on the Symbian platform, so either the CONFIG option no_link or variable variable_out should always be defined for extra compilers.