qt_wrap_cpp.qdoc

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// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\page qt-wrap-cpp.html
\ingroup cmake-commands-qtcore
 
\title qt_wrap_cpp
\keyword qt6_wrap_cpp
 
\summary {Creates .moc files from sources.}
 
\include cmake-find-package-core.qdocinc
 
\cmakecommandsince 5.0
 
\section1 Synopsis
 
\c{qt_wrap_cpp} supports two signatures. The first signature was added in Qt 6.8
and has the following form:
 
\badcode
qt_wrap_cpp(<TARGET> src_file1 [src_file2 ...]
            [OPTIONS ...]
            [DEPENDS ...])
\endcode
 
\note The signature above is recommended over the older signature.
 
\badcode
qt_wrap_cpp(<VAR> src_file1 [src_file2 ...]
            [TARGET target]
            [OPTIONS ...]
            [DEPENDS ...])
\endcode
 
\versionlessCMakeCommandsNote qt6_wrap_cpp()
 
\section1 Description
 
Creates rules for calling the \l{moc}{Meta-Object Compiler (moc)} on the given
source files. For each input file, an output file is generated in the build
directory.
 
With the target-based signature, generated files are added as sources to
\c{<TARGET>}. With the older signature, the paths of the generated files are
added to \c{<VAR>}.
 
\note This is a low-level macro. See the \l{CMake AUTOMOC Documentation} for a
more convenient way to let source files be processed with \c{moc}.
 
\section1 Arguments
 
You can set an explicit \c{TARGET}. This will make sure that the target
properties \c{INCLUDE_DIRECTORIES} and \c{COMPILE_DEFINITIONS} are also used
when scanning the source files with \c{moc}.
 
Since Qt 6.8, when a source file is passed to \c{qt_wrap_cpp} instead of a
header file to generate a \c{.moc} file for a target, the \c{TARGET} parameter
is needed to set the correct include path for the generated \c{.moc} file in
the source file.
 
If you're calling \c qt_wrap_cpp in a directory scope that's different from the
directory scope of the target, you must use the target-based signature of \c
qt_wrap_cpp or pass the target with the \c TARGET argument.
 
You can set additional \c{OPTIONS} that should be added to the \c{moc} calls.
You can find possible options in the \l{moc}{moc documentation}.
 
The \c{OPTIONS} can evaluate generator expressions when \c{TARGET} is set.
\note If the \c{OPTIONS} include both generator expressions and special
characters, use variables to implement them. For example, use \c{$<ANGLE-R>},
\c{$<COMMA>} and \c{$<SEMICOLON>} instead of \c{>}, \c{,} and \c{:}. Otherwise,
the generator expression will not be evaluated correctly. \c {OPTIONS} are
wrapped in generator expressions, so you must escape special characters in
them.
 
\c{DEPENDS} allows you to add additional dependencies for recreation of the
generated files. This is useful when the sources have implicit dependencies,
like code for a Qt plugin that includes a \c{.json} file using the
Q_PLUGIN_METADATA() macro.
 
\section1 Examples
 
Since Qt 6.8:
 
\snippet cmake-macros/examples.cmake qt_wrap_cpp_4
\br
\snippet cmake-macros/examples.cpp qt_wrap_cpp_4
 
In the above file, \c{myapp.moc} is included in \c{myapp.cpp}.
To generate the \c{myapp.moc} file, the \c{qt_wrap_cpp} macro is used with the
\c{TARGET} parameter. The \c{.moc} file and its path will be added to the
target's sources and include directories by the \c{qt_wrap_cpp} macro.
 
The old version:
\snippet cmake-macros/examples.cmake qt_wrap_cpp_1
 
In the following example, the generator expressions passed to \c{OPTIONS}
will be evaluated since \c{TARGET} is set. The argument is specified this way to
avoid syntax errors in the generator expressions.
 
\snippet cmake-macros/examples.cmake qt_wrap_cpp_2
 
The following example uses \l{https://cmake.org/cmake/help/latest/command/target_compile_definitions.html}{target_compile_definitions}
to set \l{https://cmake.org/cmake/help/latest/prop_tgt/COMPILE_DEFINITIONS.html}{COMPILE_DEFINITIONS} which will be added to
\c{OPTIONS}.
\snippet cmake-macros/examples.cmake qt_wrap_cpp_3
 
*/