NAME

       cmake-qt - CMake Qt Features Reference

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

       1. <source_dir>/<basename>.ui

       2. <source_dir>/<path><basename>.ui

       3. <AUTOUIC_SEARCH_PATHS>/<basename>.ui

       4. <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

       • AUTOMOC or AUTOUIC is enabled and the origin target depends  on  GENERATED  files  which
         aren’t excluded from autogen by SKIP_AUTOMOC, SKIP_AUTOUIC, SKIP_AUTOGEN or CMP0071

       • AUTORCC is enabled and a .qrc file is listed in the origin target sources

       • AUTOGEN_TARGET_DEPENDS lists 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)

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