CMake/Modules/CheckCXXCompilerFlag.cmake
Robert Maynard d192918586 Modules: Do not implicitly add new functions via old Check Modules
The conversion of Check<Lang>CompilerFlag, SourceCompiles, and
SourceRuns over to the new functions has the possibility of breaking
projects that had functions with those existing names.

To reduce the possibility of collisions we now have all the
legacy code call functions that start with `cmake_`, and users
will need to explicitly include the new modules to get the
non-prefixed versions

Fixes: #21359
2020-10-26 10:57:55 -04:00

42 lines
1.5 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
CheckCXXCompilerFlag
------------------------
Check whether the CXX compiler supports a given flag.
.. command:: check_cxx_compiler_flag
.. code-block:: cmake
check_cxx_compiler_flag(<flag> <var>)
Check that the ``<flag>`` is accepted by the compiler without
a diagnostic. Stores the result in an internal cache entry
named ``<var>``.
This command temporarily sets the ``CMAKE_REQUIRED_DEFINITIONS`` variable
and calls the ``check_cxx_source_compiles`` macro from the
:module:`CheckCXXSourceCompiles` module. See documentation of that
module for a listing of variables that can otherwise modify the build.
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.
.. note::
Since the :command:`try_compile` command forwards flags from variables
like :variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>`, unknown flags
in such variables may cause a false negative for this check.
#]=======================================================================]
include_guard(GLOBAL)
include(CheckCXXSourceCompiles)
include(Internal/CheckCompilerFlag)
macro (CHECK_CXX_COMPILER_FLAG _FLAG _RESULT)
cmake_check_compiler_flag(CXX "${_FLAG}" ${_RESULT})
endmacro ()