Modules/CheckCompilerFlag.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
CheckCompilerFlag
---------------------

.. versionadded:: 3.19

Check whether the compiler supports a given flag.

.. command:: check_compiler_flag

  .. code-block:: cmake

    check_compiler_flag(<lang> <flag> <resultVar>)

Check that the ``<flag>`` is accepted by the compiler without a diagnostic.
Stores the result in an internal cache entry named ``<resultVar>``.

A positive result from this check indicates only that the compiler did not
issue a diagnostic message when given the flag.  Whether the flag has any
effect or even a specific one is beyond the scope of this module.

The check is only performed once, with the result cached in the variable named
by ``<resultVar>``. Every subsequent CMake run will re-use this cached value
rather than performing the check again, even if the ``<code>`` changes. In
order to force the check to be re-evaluated, the variable named by
``<resultVar>`` must be manually removed from the cache.

The compile and link commands can be influenced by setting any of the
following variables prior to calling ``check_compiler_flag()``

.. include:: /module/CMAKE_REQUIRED_FLAGS.txt

.. include:: /module/CMAKE_REQUIRED_DEFINITIONS.txt

.. include:: /module/CMAKE_REQUIRED_INCLUDES.txt

.. include:: /module/CMAKE_REQUIRED_LINK_OPTIONS.txt

.. include:: /module/CMAKE_REQUIRED_LIBRARIES.txt

.. include:: /module/CMAKE_REQUIRED_QUIET.txt

#]=======================================================================]

include_guard(GLOBAL)
include(Internal/CheckCompilerFlag)

function(CHECK_COMPILER_FLAG _lang _flag _var)
  cmake_check_compiler_flag(${_lang} "${_flag}" ${_var})
endfunction()