Commit d60f1ddc authored by Sebastian Holtermann's avatar Sebastian Holtermann Committed by Brad King
Browse files

Autogen: Documentation update

Closes #15254
parent cdb72127
......@@ -63,20 +63,24 @@ If a ``Q_OBJECT`` or ``Q_GADGET`` macro 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 ``moc file`` may be
included by the user in the C++ implementation file with a preprocessor
``#include``. If it is not so included, it will be added to a separate file
which is compiled into the target.
``<basename>.moc``, following the Qt conventions. The ``<basename>.moc`` must
be included by the user in the C++ implementation file with a preprocessor
``#include``.
The ``moc`` command line will consume the :prop_tgt:`COMPILE_DEFINITIONS` and
:prop_tgt:`INCLUDE_DIRECTORIES` target properties from the target it is being
invoked for, and for the appropriate build configuration.
The generated ``moc_*.cpp`` and ``*.moc`` files are placed in the
Included ``moc_*.cpp`` and ``*.moc`` files will be generated in the
``<CMAKE_CURRENT_BINARY_DIR>/<TARGETNAME>_autogen/include`` directory which is
automatically added to the target's :prop_tgt:`INCLUDE_DIRECTORIES`.
(This differs from CMake 3.7 and below; see their documentation for details.)
Not included ``moc_<basename>.cpp`` files will be generated in custom
folders to avoid name collisions and included in a separate
``<CMAKE_CURRENT_BINARY_DIR>/<TARGETNAME>_autogen/moc_compilation.cpp``
file which is compiled into the target.
The ``moc`` command line will consume the :prop_tgt:`COMPILE_DEFINITIONS` and
:prop_tgt:`INCLUDE_DIRECTORIES` target properties from the target it is being
invoked for, and for the appropriate build configuration.
The :prop_tgt:`AUTOMOC` target property may be pre-set for all
following targets by setting the :variable:`CMAKE_AUTOMOC` variable. The
:prop_tgt:`AUTOMOC_MOC_OPTIONS` target property may be populated to set
......
......@@ -8,31 +8,41 @@ preprocessor automatically, i.e. without having to use the
:module:`QT4_WRAP_CPP() <FindQt4>` or QT5_WRAP_CPP() macro. Currently Qt4 and Qt5 are
supported.
When this property is set ``ON``, CMake will scan the
When this property is set ``ON``, CMake will scan the header and
source files at build time and invoke moc accordingly.
* If an ``#include`` statement like ``#include "moc_foo.cpp"`` is found,
the ``Q_OBJECT`` class declaration is expected in the header, and
``moc`` is run on the header file. A ``moc_foo.cpp`` file will be
generated from the source's header into the
``<CMAKE_CURRENT_BINARY_DIR>/<TARGETNAME>_autogen/include``
directory which is automatically added to the target's
* If an ``#include`` statement like ``#include "moc_<basename>.cpp"`` is found,
the ``Q_OBJECT`` or ``Q_GADGET`` macros are expected in an otherwise empty
line of the ``<basename>.h(xx)`` header file. ``moc`` is run on the header file to
generate ``moc_<basename>.cpp`` in the
``<CMAKE_CURRENT_BINARY_DIR>/<TARGETNAME>_autogen/include`` directory
which is automatically added to the target's
:prop_tgt:`INCLUDE_DIRECTORIES`. This allows the compiler to find the
included ``moc_foo.cpp`` file regardless of the location the original source.
However, if multiple source files in different directories do this then their
generated moc files would collide. In this case a diagnostic will be issued.
* If an ``#include`` statement like ``#include "foo.moc"`` is found,
then a ``Q_OBJECT`` is expected in the current source file and ``moc``
is run on the file itself. Additionally, header files with the same
base name (like ``foo.h``) or ``_p`` appended to the base name (like
``foo_p.h``) are parsed for ``Q_OBJECT`` macros, and if found, ``moc``
is also executed on those files. ``AUTOMOC`` checks multiple header
alternative extensions, such as ``hpp``, ``hxx`` etc when searching
for headers. The resulting moc files, which are not included as shown
above in any of the source files are included in a generated
``moc_compilation.cpp`` file, which is compiled as part of the
target.
included ``moc_<basename>.cpp`` file regardless of the location the
original source.
* If an ``#include`` statement like ``#include "<basename>.moc"`` is found,
then ``Q_OBJECT`` or ``Q_GADGET`` macros are expected in the current source
file and ``moc`` is run on the source file itself.
* Header files that are not included by an ``#include "moc_<basename>.cpp"``
statement are nonetheless scanned for ``Q_OBJECT`` or ``Q_GADGET`` macros.
The resulting ``moc_<basename>.cpp`` files are generated in custom
directories and automatically included in the generated
``<CMAKE_CURRENT_BINARY_DIR>/<TARGETNAME>_autogen/moc_compilation.cpp`` file,
which is compiled as part of the target. The custom directories help to
avoid name collisions for moc files with the same ``<basename>``.
* Additionally, header files with the same base name as a source file,
(like ``<basename>.h``) or ``_p`` appended to the base name (like
``<basename>_p.h``), are parsed for ``Q_OBJECT`` or ``Q_GADGET`` macros,
and if found, ``moc`` is also executed on those files.
* ``AUTOMOC`` always checks multiple header alternative extensions,
such as ``hpp``, ``hxx``, etc. when searching for headers.
* ``AUTOMOC`` looks for the ``Q_PLUGIN_METADATA`` macro and reruns the
``moc`` when the file addressed by the ``FILE`` argument of the macro changes.
This property is initialized by the value of the :variable:`CMAKE_AUTOMOC`
variable if it is set when a target is created.
......
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