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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
CheckCXXSourceCompiles
----------------------
This module provides a command to check whether a C++ source can be built.
Load this module in a CMake project with:
.. code-block:: cmake
include(CheckCXXSourceCompiles)
Commands
^^^^^^^^
This module provides the following command:
.. command:: check_cxx_source_compiles
Checks once whether the given C++ source code can be built:
.. code-block:: cmake
check_cxx_source_compiles(<code> <variable> [FAIL_REGEX <regexes>...])
This command checks once that the source supplied in ``<code>`` can be
compiled (and linked into an executable). The result of the check is
stored in the internal cache variable specified by ``<variable>``.
The arguments are:
``<code>``
C++ source code to check. This must be an entire program, as written
in a file containing the body block. All symbols used in the source code
are expected to be declared as usual in their corresponding headers.
``<variable>``
Variable name of an internal cache variable to store the result of the
check, with boolean true for success and boolean false for failure.
``FAIL_REGEX <regexes>...``
If one or more regular expression patterns are provided, then failure is
determined by checking if anything in the compiler output matches any of
the specified regular expressions.
.. rubric:: Variables Affecting the Check
The following variables may be set before calling this command to modify
the way the check is run:
.. include:: /module/include/CMAKE_REQUIRED_FLAGS.rst
.. include:: /module/include/CMAKE_REQUIRED_DEFINITIONS.rst
.. include:: /module/include/CMAKE_REQUIRED_INCLUDES.rst
.. include:: /module/include/CMAKE_REQUIRED_LINK_OPTIONS.rst
.. include:: /module/include/CMAKE_REQUIRED_LIBRARIES.rst
.. include:: /module/include/CMAKE_REQUIRED_LINK_DIRECTORIES.rst
.. include:: /module/include/CMAKE_REQUIRED_QUIET.rst
.. include:: /module/include/CMAKE_TRY_COMPILE_TARGET_TYPE.rst
Examples
^^^^^^^^
The following example demonstrates how to check whether the C++ compiler
supports a specific language feature. In this case, the check verifies if
the compiler supports ``C++11`` lambda expressions. The result is stored
in the internal cache variable ``HAVE_CXX11_LAMBDAS``:
.. code-block:: cmake
include(CheckCXXSourceCompiles)
check_cxx_source_compiles("
int main()
{
auto lambda = []() { return 42; };
return lambda();
}
" HAVE_CXX11_LAMBDAS)
See Also
^^^^^^^^
* The :module:`CheckSourceCompiles` module for a more general command to
check whether source can be built.
* The :module:`CheckSourceRuns` module to check whether source can be built
and run.
#]=======================================================================]
include_guard(GLOBAL)
include(Internal/CheckSourceCompiles)
macro(CHECK_CXX_SOURCE_COMPILES SOURCE VAR)
cmake_check_source_compiles(CXX "${SOURCE}" ${VAR} ${ARGN})
endmacro()
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