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Craig Scott
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The references to the <ORIGIN>_autogen and <ORIGIN>_autogen_timestamp_deps anchors were being replaced by the section heading text that immediately followed the anchors. But in most cases, the text where the cross-referencing was placed was expecting the anchor text to be used instead. Add custom text for such cross-references so that the text reads as originally intended.
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9.7 KiB
ReStructuredText
267 lines
9.7 KiB
ReStructuredText
AUTOMOC
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-------
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Should the target be processed with auto-moc (for Qt projects).
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``AUTOMOC`` is a boolean specifying whether CMake will handle the Qt ``moc``
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preprocessor automatically, i.e. without having to use commands like
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:module:`qt4_wrap_cpp() <FindQt4>`, `qt5_wrap_cpp()`_, etc.
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Currently, Qt versions 4 to 6 are supported.
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.. _qt5_wrap_cpp(): https://doc.qt.io/archives/qt-5.15/qtcore-cmake-qt5-wrap-cpp.html
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This property is initialized by the value of the :variable:`CMAKE_AUTOMOC`
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variable if it is set when a target is created.
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When this property is set ``ON``, CMake will scan the header and
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source files at build time and invoke ``moc`` accordingly.
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Header file processing
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^^^^^^^^^^^^^^^^^^^^^^
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At configuration time, a list of header files that should be scanned by
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``AUTOMOC`` is computed from the target's sources.
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- All header files in the target's sources are added to the scan list.
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- For all C++ source files ``<source_base>.<source_extension>`` in the
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target's sources, CMake searches for
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- a regular header with the same base name
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(``<source_base>.<header_extension>``) and
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- a private header with the same base name and a ``_p`` suffix
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(``<source_base>_p.<header_extension>``)
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and adds these to the scan list.
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- The :prop_tgt:`AUTOMOC_INCLUDE_DIRECTORIES` target property may be set
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to explicitly tell ``moc`` what include directories to search. If not
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set, the default is to use the include directories from the target and
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its transitive closure of dependencies.
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At build time, CMake scans each unknown or modified header file from the
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list and searches for
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- a Qt macro from :prop_tgt:`AUTOMOC_MACRO_NAMES`,
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- additional file dependencies from the ``FILE`` argument of a
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``Q_PLUGIN_METADATA`` macro and
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- additional file dependencies detected by filters defined in
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:prop_tgt:`AUTOMOC_DEPEND_FILTERS`.
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If a Qt macro is found, then the header will be compiled by the ``moc`` to the
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output file ``moc_<base_name>.cpp``. The complete output file path is
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described in the section `Output file location`_.
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The header will be ``moc`` compiled again if a file from the additional file
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dependencies changes.
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Header ``moc`` output files ``moc_<base_name>.cpp`` can be included in source
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files. In the section `Including header moc files in sources`_ there is more
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information on that topic.
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Source file processing
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^^^^^^^^^^^^^^^^^^^^^^
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At build time, CMake scans each unknown or modified C++ source file from the
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target's sources for
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- a Qt macro from :prop_tgt:`AUTOMOC_MACRO_NAMES`,
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- includes of header ``moc`` files
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(see `Including header moc files in sources`_),
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- additional file dependencies from the ``FILE`` argument of a
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``Q_PLUGIN_METADATA`` macro and
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- additional file dependencies detected by filters defined in
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:prop_tgt:`AUTOMOC_DEPEND_FILTERS`.
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If a Qt macro is found, then the C++ source file
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``<base>.<source_extension>`` is expected to as well contain an include
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statement
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.. code-block:: c++
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#include <<base>.moc> // or
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#include "<base>.moc"
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The source file then will be compiled by the ``moc`` to the output file
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``<base>.moc``. A description of the complete output file path is in section
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`Output file location`_.
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The source will be ``moc`` compiled again if a file from the additional file
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dependencies changes.
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Including header moc files in sources
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"""""""""""""""""""""""""""""""""""""
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A source file can include the ``moc`` output file of a header
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``<header_base>.<header_extension>`` by using an include statement of
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the form
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.. code-block:: c++
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#include <moc_<header_base>.cpp> // or
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#include "moc_<header_base>.cpp"
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If the ``moc`` output file of a header is included by a source, it will
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be generated in a different location than if it was not included. This is
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described in the section `Output file location`_.
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Output file location
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^^^^^^^^^^^^^^^^^^^^
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Included moc output files
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"""""""""""""""""""""""""
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``moc`` output files that are included by a source file will be generated in
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- ``<AUTOGEN_BUILD_DIR>/include``
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for single configuration generators or in
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- ``<AUTOGEN_BUILD_DIR>/include_<CONFIG>``
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for :prop_gbl:`multi configuration <GENERATOR_IS_MULTI_CONFIG>` generators.
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Where ``<AUTOGEN_BUILD_DIR>`` is the value of the target property
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:prop_tgt:`AUTOGEN_BUILD_DIR`.
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The include directory is automatically added to the target's
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:prop_tgt:`INCLUDE_DIRECTORIES`.
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Not included moc output files
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"""""""""""""""""""""""""""""
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``moc`` output files that are not included in a source file will be generated
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in
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- ``<AUTOGEN_BUILD_DIR>/<SOURCE_DIR_CHECKSUM>``
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for single configuration generators or in,
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- ``<AUTOGEN_BUILD_DIR>/include_<CONFIG>/<SOURCE_DIR_CHECKSUM>``
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for :prop_gbl:`multi configuration <GENERATOR_IS_MULTI_CONFIG>` generators.
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Where ``<SOURCE_DIR_CHECKSUM>`` is a checksum computed from the relative
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parent directory path of the ``moc`` input file. This scheme allows to have
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``moc`` input files with the same name in different directories.
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All not included ``moc`` output files will be included automatically by the
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CMake generated file
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- ``<AUTOGEN_BUILD_DIR>/mocs_compilation.cpp``, or
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- ``<AUTOGEN_BUILD_DIR>/mocs_compilation_$<CONFIG>.cpp``,
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which is added to the target's sources.
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Qt version detection
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^^^^^^^^^^^^^^^^^^^^
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``AUTOMOC`` enabled targets need to know the Qt major and minor
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version they're working with. The major version usually is provided by the
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``INTERFACE_QT_MAJOR_VERSION`` property of the ``Qt[456]Core`` library,
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that the target links to. To find the minor version, CMake builds a list of
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available Qt versions from
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- ``Qt6Core_VERSION_MAJOR`` and ``Qt6Core_VERSION_MINOR`` variables
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(usually set by ``find_package(Qt6...)``)
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- ``Qt6Core_VERSION_MAJOR`` and ``Qt6Core_VERSION_MINOR`` directory properties
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- ``Qt5Core_VERSION_MAJOR`` and ``Qt5Core_VERSION_MINOR`` variables
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(usually set by ``find_package(Qt5...)``)
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- ``Qt5Core_VERSION_MAJOR`` and ``Qt5Core_VERSION_MINOR`` directory properties
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- ``QT_VERSION_MAJOR`` and ``QT_VERSION_MINOR`` variables
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(usually set by ``find_package(Qt4...)``)
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- ``QT_VERSION_MAJOR`` and ``QT_VERSION_MINOR`` directory properties
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in the context of the :command:`add_executable` or :command:`add_library` call.
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Assumed ``INTERFACE_QT_MAJOR_VERSION`` is a valid number, the first
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entry in the list with a matching major version is taken. If no matching major
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version was found, an error is generated.
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If ``INTERFACE_QT_MAJOR_VERSION`` is not a valid number, the first
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entry in the list is taken.
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A ``find_package(Qt[456]...)`` call sets the ``QT/Qt[56]Core_VERSION_MAJOR/MINOR``
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variables. If the call is in a different context than the
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:command:`add_executable` or :command:`add_library` call, e.g. in a function,
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then the version variables might not be available to the ``AUTOMOC``
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enabled target.
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In that case the version variables can be forwarded from the
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``find_package(Qt[456]...)`` calling context to the :command:`add_executable`
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or :command:`add_library` calling context as directory properties.
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The following Qt5 example demonstrates the procedure.
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.. code-block:: cmake
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function (add_qt5_client)
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find_package(Qt5 REQUIRED QUIET COMPONENTS Core Widgets)
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...
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set_property(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
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PROPERTY Qt5Core_VERSION_MAJOR "${Qt5Core_VERSION_MAJOR}")
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set_property(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
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PROPERTY Qt5Core_VERSION_MINOR "${Qt5Core_VERSION_MAJOR}")
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...
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endfunction ()
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...
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add_qt5_client()
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add_executable(myTarget main.cpp)
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target_link_libraries(myTarget Qt5::QtWidgets)
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set_property(TARGET myTarget PROPERTY AUTOMOC ON)
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Modifiers
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^^^^^^^^^
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:prop_tgt:`AUTOMOC_EXECUTABLE`:
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The ``moc`` executable will be detected automatically, but can be forced to
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a certain binary using this target property.
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:prop_tgt:`AUTOMOC_MOC_OPTIONS`:
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Additional command line options for ``moc`` can be set in this target property.
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:prop_tgt:`AUTOMOC_MACRO_NAMES`:
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This list of Qt macro names can be extended to search for additional macros in
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headers and sources.
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:prop_tgt:`AUTOMOC_DEPEND_FILTERS`:
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``moc`` dependency file names can be extracted from headers or sources by
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defining file name filters in this target property.
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:prop_tgt:`AUTOMOC_COMPILER_PREDEFINES`:
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Compiler pre definitions for ``moc`` are written to the ``moc_predefs.h`` file.
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The generation of this file can be enabled or disabled in this target property.
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:prop_tgt:`AUTOMOC_INCLUDE_DIRECTORIES`:
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Specifies one or more include directories for ``AUTOMOC`` to pass explicitly to ``moc``
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instead of automatically discovering a target’s include directories.
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:prop_sf:`SKIP_AUTOMOC`:
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Sources and headers can be excluded from ``AUTOMOC`` processing by
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setting this source file property.
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:prop_sf:`SKIP_AUTOGEN`:
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Source files can be excluded from ``AUTOMOC``,
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:prop_tgt:`AUTOUIC` and :prop_tgt:`AUTORCC` processing by
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setting this source file property.
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:prop_gbl:`AUTOGEN_SOURCE_GROUP`:
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This global property can be used to group files generated by
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``AUTOMOC`` or :prop_tgt:`AUTORCC` together in an IDE, e.g. in MSVS.
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:prop_gbl:`AUTOGEN_TARGETS_FOLDER`:
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This global property can be used to group ``AUTOMOC``,
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:prop_tgt:`AUTOUIC` and :prop_tgt:`AUTORCC` targets together in an IDE,
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e.g. in MSVS.
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:variable:`CMAKE_GLOBAL_AUTOGEN_TARGET`:
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A global ``autogen`` target, that depends on all ``AUTOMOC`` or
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:prop_tgt:`AUTOUIC` generated :ref:`<ORIGIN>_autogen <<ORIGIN>_autogen>`
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targets in the project, will be generated when this variable is ``ON``.
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:prop_tgt:`AUTOGEN_PARALLEL`:
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This target property controls the number of ``moc`` or ``uic`` processes to
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start in parallel during builds.
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:prop_tgt:`AUTOGEN_COMMAND_LINE_LENGTH_MAX`:
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This target property controls the limit when to use response files for
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``moc`` or ``uic`` processes on Windows.
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See the :manual:`cmake-qt(7)` manual for more information on using CMake
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with Qt.
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