CMake/Modules/CheckCCompilerFlag.cmake
Brad King 3e79d656da Check*CompilerFlag: Document use of CMAKE_REQUIRED_DEFINITIONS (#14309)
Explain how CMAKE_REQUIRED_DEFINITIONS is set before calling the
check_*_source_compiles macros.
2013-07-25 08:25:15 -04:00

59 lines
2.7 KiB
CMake

# - Check whether the C compiler supports a given flag.
# CHECK_C_COMPILER_FLAG(<flag> <var>)
# <flag> - the compiler flag
# <var> - variable to store the result
# This internally calls the check_c_source_compiles macro and
# sets CMAKE_REQUIRED_DEFINITIONS to <flag>.
# See help for CheckCSourceCompiles for a listing of variables
# that can otherwise modify the build.
#=============================================================================
# Copyright 2006-2011 Kitware, Inc.
# Copyright 2006 Alexander Neundorf <neundorf@kde.org>
# Copyright 2011 Matthias Kretz <kretz@kde.org>
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
# License text for the above reference.)
include(CheckCSourceCompiles)
macro (CHECK_C_COMPILER_FLAG _FLAG _RESULT)
set(SAFE_CMAKE_REQUIRED_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS}")
set(CMAKE_REQUIRED_DEFINITIONS "${_FLAG}")
# Normalize locale during test compilation.
set(_CheckCCompilerFlag_LOCALE_VARS LC_ALL LC_MESSAGES LANG)
foreach(v ${_CheckCCompilerFlag_LOCALE_VARS})
set(_CheckCCompilerFlag_SAVED_${v} "$ENV{${v}}")
set(ENV{${v}} C)
endforeach()
CHECK_C_SOURCE_COMPILES("int main(void) { return 0; }" ${_RESULT}
# Some compilers do not fail with a bad flag
FAIL_REGEX "command line option .* is valid for .* but not for C" # GNU
FAIL_REGEX "unrecognized .*option" # GNU
FAIL_REGEX "unknown .*option" # Clang
FAIL_REGEX "ignoring unknown option" # MSVC
FAIL_REGEX "warning D9002" # MSVC, any lang
FAIL_REGEX "option.*not supported" # Intel
FAIL_REGEX "invalid argument .*option" # Intel
FAIL_REGEX "ignoring option .*argument required" # Intel
FAIL_REGEX "[Uu]nknown option" # HP
FAIL_REGEX "[Ww]arning: [Oo]ption" # SunPro
FAIL_REGEX "command option .* is not recognized" # XL
FAIL_REGEX "WARNING: unknown flag:" # Open64
)
foreach(v ${_CheckCCompilerFlag_LOCALE_VARS})
set(ENV{${v}} ${_CheckCCompilerFlag_SAVED_${v}})
unset(_CheckCCompilerFlag_SAVED_${v})
endforeach()
unset(_CheckCCompilerFlag_LOCALE_VARS)
set (CMAKE_REQUIRED_DEFINITIONS "${SAFE_CMAKE_REQUIRED_DEFINITIONS}")
endmacro ()