AUTOMOC | |
------- | |
Should the target be processed with auto-moc (for Qt projects). | |
:prop_tgt:`AUTOMOC` is a boolean specifying whether CMake will handle the Qt | |
``moc`` preprocessor automatically, i.e. without having to use commands like | |
:module:`QT4_WRAP_CPP() <FindQt4>`, ``QT5_WRAP_CPP()``, etc. | |
Currently, Qt versions 4 to 6 are supported. | |
This property is initialized by the value of the :variable:`CMAKE_AUTOMOC` | |
variable if it is set when a target is created. | |
When this property is set ``ON``, CMake will scan the header and | |
source files at build time and invoke ``moc`` accordingly. | |
Header file processing | |
^^^^^^^^^^^^^^^^^^^^^^ | |
At configuration time, a list of header files that should be scanned by | |
:prop_tgt:`AUTOMOC` is computed from the target's sources. | |
- All header files in the target's sources are added to the scan list. | |
- For all C++ source files ``<source_base>.<source_extension>`` in the | |
target's sources, CMake searches for | |
- a regular header with the same base name | |
(``<source_base>.<header_extention>``) and | |
- a private header with the same base name and a ``_p`` suffix | |
(``<source_base>_p.<header_extention>``) | |
and adds these to the scan list. | |
At build time, CMake scans each unknown or modified header file from the | |
list and searches for | |
- a Qt macro from :prop_tgt:`AUTOMOC_MACRO_NAMES`, | |
- additional file dependencies from the ``FILE`` argument of a | |
``Q_PLUGIN_METADATA`` macro and | |
- additional file dependencies detected by filters defined in | |
:prop_tgt:`AUTOMOC_DEPEND_FILTERS`. | |
If a Qt macro is found, then the header will be compiled by the ``moc`` to the | |
output file ``moc_<base_name>.cpp``. The complete output file path is | |
described in the section `Output file location`_. | |
The header will be ``moc`` compiled again if a file from the additional file | |
dependencies changes. | |
Header ``moc`` output files ``moc_<base_name>.cpp`` can be included in source | |
files. In the section `Including header moc files in sources`_ there is more | |
information on that topic. | |
Source file processing | |
^^^^^^^^^^^^^^^^^^^^^^ | |
At build time, CMake scans each unknown or modified C++ source file from the | |
target's sources for | |
- a Qt macro from :prop_tgt:`AUTOMOC_MACRO_NAMES`, | |
- includes of header ``moc`` files | |
(see `Including header moc files in sources`_), | |
- additional file dependencies from the ``FILE`` argument of a | |
``Q_PLUGIN_METADATA`` macro and | |
- additional file dependencies detected by filters defined in | |
:prop_tgt:`AUTOMOC_DEPEND_FILTERS`. | |
If a Qt macro is found, then the C++ source file | |
``<base>.<source_extension>`` is expected to as well contain an include | |
statement | |
.. code-block:: c++ | |
#include <<base>.moc> // or | |
#include "<base>.moc" | |
The source file then will be compiled by the ``moc`` to the output file | |
``<base>.moc``. A description of the complete output file path is in section | |
`Output file location`_. | |
The source will be ``moc`` compiled again if a file from the additional file | |
dependencies changes. | |
Including header moc files in sources | |
""""""""""""""""""""""""""""""""""""" | |
A source file can include the ``moc`` output file of a header | |
``<header_base>.<header_extension>`` by using an include statement of | |
the form | |
.. code-block:: c++ | |
#include <moc_<header_base>.cpp> // or | |
#include "moc_<header_base>.cpp" | |
If the ``moc`` output file of a header is included by a source, it will | |
be generated in a different location than if it was not included. This is | |
described in the section `Output file location`_. | |
Output file location | |
^^^^^^^^^^^^^^^^^^^^ | |
Included moc output files | |
""""""""""""""""""""""""" | |
``moc`` output files that are included by a source file will be generated in | |
- ``<AUTOGEN_BUILD_DIR>/include`` | |
for single configuration generators or in | |
- ``<AUTOGEN_BUILD_DIR>/include_<CONFIG>`` | |
for :prop_gbl:`multi configuration <GENERATOR_IS_MULTI_CONFIG>` generators. | |
Where ``<AUTOGEN_BUILD_DIR>`` is the value of the target property | |
:prop_tgt:`AUTOGEN_BUILD_DIR`. | |
The include directory is automatically added to the target's | |
:prop_tgt:`INCLUDE_DIRECTORIES`. | |
Not included moc output files | |
""""""""""""""""""""""""""""" | |
``moc`` output files that are not included in a source file will be generated | |
in | |
- ``<AUTOGEN_BUILD_DIR>/<SOURCE_DIR_CHECKSUM>`` | |
for single configuration generators or in, | |
- ``<AUTOGEN_BUILD_DIR>/include_<CONFIG>/<SOURCE_DIR_CHECKSUM>`` | |
for :prop_gbl:`multi configuration <GENERATOR_IS_MULTI_CONFIG>` generators. | |
Where ``<SOURCE_DIR_CHECKSUM>`` is a checksum computed from the relative | |
parent directory path of the ``moc`` input file. This scheme allows to have | |
``moc`` input files with the same name in different directories. | |
All not included ``moc`` output files will be included automatically by the | |
CMake generated file | |
- ``<AUTOGEN_BUILD_DIR>/mocs_compilation.cpp``, or | |
- ``<AUTOGEN_BUILD_DIR>/mocs_compilation_$<CONFIG>.cpp``, | |
which is added to the target's sources. | |
Qt version detection | |
^^^^^^^^^^^^^^^^^^^^ | |
:prop_tgt:`AUTOMOC` enabled targets need to know the Qt major and minor | |
version they're working with. The major version usually is provided by the | |
``INTERFACE_QT_MAJOR_VERSION`` property of the ``Qt[456]Core`` library, | |
that the target links to. To find the minor version, CMake builds a list of | |
available Qt versions from | |
- ``Qt6Core_VERSION_MAJOR`` and ``Qt6Core_VERSION_MINOR`` variables | |
(usually set by ``find_package(Qt6...)``) | |
- ``Qt6Core_VERSION_MAJOR`` and ``Qt6Core_VERSION_MINOR`` directory properties | |
- ``Qt5Core_VERSION_MAJOR`` and ``Qt5Core_VERSION_MINOR`` variables | |
(usually set by ``find_package(Qt5...)``) | |
- ``Qt5Core_VERSION_MAJOR`` and ``Qt5Core_VERSION_MINOR`` directory properties | |
- ``QT_VERSION_MAJOR`` and ``QT_VERSION_MINOR`` variables | |
(usually set by ``find_package(Qt4...)``) | |
- ``QT_VERSION_MAJOR`` and ``QT_VERSION_MINOR`` directory properties | |
in the context of the :command:`add_executable` or :command:`add_library` call. | |
Assumed ``INTERFACE_QT_MAJOR_VERSION`` is a valid number, the first | |
entry in the list with a matching major version is taken. If no matching major | |
version was found, an error is generated. | |
If ``INTERFACE_QT_MAJOR_VERSION`` is not a valid number, the first | |
entry in the list is taken. | |
A ``find_package(Qt[456]...)`` call sets the ``QT/Qt[56]Core_VERSION_MAJOR/MINOR`` | |
variables. If the call is in a different context than the | |
:command:`add_executable` or :command:`add_library` call, e.g. in a function, | |
then the version variables might not be available to the :prop_tgt:`AUTOMOC` | |
enabled target. | |
In that case the version variables can be forwarded from the | |
``find_package(Qt[456]...)`` calling context to the :command:`add_executable` | |
or :command:`add_library` calling context as directory properties. | |
The following Qt5 example demonstrates the procedure. | |
.. code-block:: cmake | |
function (add_qt5_client) | |
find_package(Qt5 REQUIRED QUIET COMPONENTS Core Widgets) | |
... | |
set_property(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}" | |
PROPERTY Qt5Core_VERSION_MAJOR "${Qt5Core_VERSION_MAJOR}") | |
set_property(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}" | |
PROPERTY Qt5Core_VERSION_MINOR "${Qt5Core_VERSION_MAJOR}") | |
... | |
endfunction () | |
... | |
add_qt5_client() | |
add_executable(myTarget main.cpp) | |
target_link_libraries(myTarget Qt5::QtWidgets) | |
set_property(TARGET myTarget PROPERTY AUTOMOC ON) | |
Modifiers | |
^^^^^^^^^ | |
:prop_tgt:`AUTOMOC_EXECUTABLE`: | |
The ``moc`` executable will be detected automatically, but can be forced to | |
a certain binary using this target property. | |
:prop_tgt:`AUTOMOC_MOC_OPTIONS`: | |
Additional command line options for ``moc`` can be set in this target property. | |
:prop_tgt:`AUTOMOC_MACRO_NAMES`: | |
This list of Qt macro names can be extended to search for additional macros in | |
headers and sources. | |
:prop_tgt:`AUTOMOC_DEPEND_FILTERS`: | |
``moc`` dependency file names can be extracted from headers or sources by | |
defining file name filters in this target property. | |
:prop_tgt:`AUTOMOC_COMPILER_PREDEFINES`: | |
Compiler pre definitions for ``moc`` are written to the ``moc_predefs.h`` file. | |
The generation of this file can be enabled or disabled in this target property. | |
:prop_sf:`SKIP_AUTOMOC`: | |
Sources and headers can be excluded from :prop_tgt:`AUTOMOC` processing by | |
setting this source file property. | |
:prop_sf:`SKIP_AUTOGEN`: | |
Source files can be excluded from :prop_tgt:`AUTOMOC`, | |
:prop_tgt:`AUTOUIC` and :prop_tgt:`AUTORCC` processing by | |
setting this source file property. | |
:prop_gbl:`AUTOGEN_SOURCE_GROUP`: | |
This global property can be used to group files generated by | |
:prop_tgt:`AUTOMOC` or :prop_tgt:`AUTORCC` together in an IDE, e.g. in MSVS. | |
:prop_gbl:`AUTOGEN_TARGETS_FOLDER`: | |
This global property can be used to group :prop_tgt:`AUTOMOC`, | |
:prop_tgt:`AUTOUIC` and :prop_tgt:`AUTORCC` targets together in an IDE, | |
e.g. in MSVS. | |
:variable:`CMAKE_GLOBAL_AUTOGEN_TARGET`: | |
A global ``autogen`` target, that depends on all :prop_tgt:`AUTOMOC` or | |
:prop_tgt:`AUTOUIC` generated ``<ORIGIN>_autogen`` targets in the project, | |
will be generated when this variable is ``ON``. | |
:prop_tgt:`AUTOGEN_PARALLEL`: | |
This target property controls the number of ``moc`` or ``uic`` processes to | |
start in parallel during builds. | |
See the :manual:`cmake-qt(7)` manual for more information on using CMake | |
with Qt. |