cmake-qt(7)¶
Contents
Introduction¶
CMake can find and use Qt 4 and Qt 5 libraries. The Qt 4 libraries are found
by the FindQt4 find-module shipped with CMake, whereas the
Qt 5 libraries are found using “Config-file Packages” shipped with Qt 5. See
cmake-packages(7) for more information about CMake packages, and
see the Qt cmake manual
for your Qt version.
Qt 4 and Qt 5 may be used together in the same
CMake buildsystem:
cmake_minimum_required(VERSION 3.8.0 FATAL_ERROR)
project(Qt4And5)
set(CMAKE_AUTOMOC ON)
find_package(Qt5 COMPONENTS Widgets DBus REQUIRED)
add_executable(publisher publisher.cpp)
target_link_libraries(publisher Qt5::Widgets Qt5::DBus)
find_package(Qt4 REQUIRED)
add_executable(subscriber subscriber.cpp)
target_link_libraries(subscriber Qt4::QtGui Qt4::QtDBus)
A CMake target may not link to both Qt 4 and Qt 5. A diagnostic is issued if this is attempted or results from transitive target dependency evaluation.
Qt Build Tools¶
Qt relies on some bundled tools for code generation, such as moc for
meta-object code generation, uic for widget layout and population,
and rcc for virtual filesystem content generation. These tools may be
automatically invoked by cmake(1) if the appropriate conditions
are met. The automatic tool invocation may be used with both Qt 4 and Qt 5.
The tools are executed as part of a synthesized custom target generated by
CMake. Target dependencies may be added to that custom target by adding them
to the AUTOGEN_TARGET_DEPENDS target property.
AUTOMOC¶
The AUTOMOC target property controls whether cmake(1)
inspects the C++ files in the target to determine if they require moc to
be run, and to create rules to execute moc at the appropriate time.
If a macro from AUTOMOC_MACRO_NAMES is found in a header file,
moc will be run on the file. The result will be put into a file named
according to moc_<basename>.cpp.
If the macro is found in a C++ implementation
file, the moc output will be put into a file named according to
<basename>.moc, following the Qt conventions. The <basename>.moc must
be included by the user in the C++ implementation file with a preprocessor
#include.
Included moc_*.cpp and *.moc files will be generated in the
<AUTOGEN_BUILD_DIR>/include directory which is
automatically added to the target’s INCLUDE_DIRECTORIES.
- This differs from CMake 3.7 and below; see their documentation for details.
- For
multi configuration generators, the include directory is<AUTOGEN_BUILD_DIR>/include_<CONFIG>. - See
AUTOGEN_BUILD_DIR.
Not included moc_<basename>.cpp files will be generated in custom
folders to avoid name collisions and included in a separate
<AUTOGEN_BUILD_DIR>/mocs_compilation.cpp file which is compiled
into the target.
- See
AUTOGEN_BUILD_DIR.
The moc command line will consume the COMPILE_DEFINITIONS and
INCLUDE_DIRECTORIES target properties from the target it is being
invoked for, and for the appropriate build configuration.
The AUTOMOC target property may be pre-set for all
following targets by setting the CMAKE_AUTOMOC variable. The
AUTOMOC_MOC_OPTIONS target property may be populated to set
options to pass to moc. The CMAKE_AUTOMOC_MOC_OPTIONS
variable may be populated to pre-set the options for all following targets.
Additional macro names to search for can be added to AUTOMOC_MACRO_NAMES.
Additional moc dependency file names can be extracted from source code
by using AUTOMOC_DEPEND_FILTERS.
Source C++ files can be excluded from AUTOMOC processing by
enabling SKIP_AUTOMOC or the broader SKIP_AUTOGEN.
AUTOUIC¶
The AUTOUIC target property controls whether cmake(1)
inspects the C++ files in the target to determine if they require uic to
be run, and to create rules to execute uic at the appropriate time.
If a preprocessor #include directive is found which matches
<path>ui_<basename>.h, and a <basename>.ui file exists,
then uic will be executed to generate the appropriate file.
The <basename>.ui file is searched for in the following places
<source_dir>/<basename>.ui<source_dir>/<path><basename>.ui<AUTOUIC_SEARCH_PATHS>/<basename>.ui<AUTOUIC_SEARCH_PATHS>/<path><basename>.ui
where <source_dir> is the directory of the C++ file and
AUTOUIC_SEARCH_PATHS is a list of additional search paths.
The generated generated ui_*.h files are placed in the
<AUTOGEN_BUILD_DIR>/include directory which is
automatically added to the target’s INCLUDE_DIRECTORIES.
- This differs from CMake 3.7 and below; see their documentation for details.
- For
multi configuration generators, the include directory is<AUTOGEN_BUILD_DIR>/include_<CONFIG>. - See
AUTOGEN_BUILD_DIR.
The AUTOUIC target property may be pre-set for all following
targets by setting the CMAKE_AUTOUIC variable. The
AUTOUIC_OPTIONS target property may be populated to set options
to pass to uic. The CMAKE_AUTOUIC_OPTIONS variable may be
populated to pre-set the options for all following targets. The
AUTOUIC_OPTIONS source file property may be set on the
<basename>.ui file to set particular options for the file. This
overrides options from the AUTOUIC_OPTIONS target property.
A target may populate the INTERFACE_AUTOUIC_OPTIONS target
property with options that should be used when invoking uic. This must be
consistent with the AUTOUIC_OPTIONS target property content of the
depender target. The CMAKE_DEBUG_TARGET_PROPERTIES variable may
be used to track the origin target of such
INTERFACE_AUTOUIC_OPTIONS. This means that a library which
provides an alternative translation system for Qt may specify options which
should be used when running uic:
add_library(KI18n klocalizedstring.cpp)
target_link_libraries(KI18n Qt5::Core)
# KI18n uses the tr2i18n() function instead of tr(). That function is
# declared in the klocalizedstring.h header.
set(autouic_options
-tr tr2i18n
-include klocalizedstring.h
)
set_property(TARGET KI18n APPEND PROPERTY
INTERFACE_AUTOUIC_OPTIONS ${autouic_options}
)
A consuming project linking to the target exported from upstream automatically
uses appropriate options when uic is run by AUTOUIC, as a
result of linking with the IMPORTED target:
set(CMAKE_AUTOUIC ON)
# Uses a libwidget.ui file:
add_library(LibWidget libwidget.cpp)
target_link_libraries(LibWidget
KF5::KI18n
Qt5::Widgets
)
Source files can be excluded from AUTOUIC processing by
enabling SKIP_AUTOUIC or the broader SKIP_AUTOGEN.
AUTORCC¶
The AUTORCC target property controls whether cmake(1)
creates rules to execute rcc at the appropriate time on source files
which have the suffix .qrc.
add_executable(myexe main.cpp resource_file.qrc)
The AUTORCC target property may be pre-set for all following targets
by setting the CMAKE_AUTORCC variable. The
AUTORCC_OPTIONS target property may be populated to set options
to pass to rcc. The CMAKE_AUTORCC_OPTIONS variable may be
populated to pre-set the options for all following targets. The
AUTORCC_OPTIONS source file property may be set on the
<name>.qrc file to set particular options for the file. This
overrides options from the AUTORCC_OPTIONS target property.
Source files can be excluded from AUTORCC processing by
enabling SKIP_AUTORCC or the broader SKIP_AUTOGEN.
Visual Studio Generators¶
When using the Visual Studio generators
CMake tries to use a PRE_BUILD
custom command instead
of a custom target for autogen.
PRE_BUILD can’t be used when the autogen target depends on files.
This happens when
AUTOMOCorAUTOUICis enabled and the origin target depends onGENERATEDfiles which aren’t excluded from autogen bySKIP_AUTOMOC,SKIP_AUTOUIC,SKIP_AUTOGENorCMP0071AUTORCCis enabled and a.qrcfile is listed in the origin target sourcesAUTOGEN_TARGET_DEPENDSlists a source file
qtmain.lib on Windows¶
The Qt 4 and 5 IMPORTED targets for the QtGui libraries specify
that the qtmain.lib static library shipped with Qt will be linked by all
dependent executables which have the WIN32_EXECUTABLE enabled.
To disable this behavior, enable the Qt5_NO_LINK_QTMAIN target property for
Qt 5 based targets or QT4_NO_LINK_QTMAIN target property for Qt 4 based
targets.
add_executable(myexe WIN32 main.cpp)
target_link_libraries(myexe Qt4::QtGui)
add_executable(myexe_no_qtmain WIN32 main_no_qtmain.cpp)
set_property(TARGET main_no_qtmain PROPERTY QT4_NO_LINK_QTMAIN ON)
target_link_libraries(main_no_qtmain Qt4::QtGui)