53 lines
1.9 KiB
CMake
53 lines
1.9 KiB
CMake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
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# file Copyright.txt or https://cmake.org/licensing for details.
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#.rst:
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# CheckCCompilerFlag
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# ------------------
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#
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# Check whether the C compiler supports a given flag.
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#
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# CHECK_C_COMPILER_FLAG(<flag> <var>)
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#
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# ::
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#
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# <flag> - the compiler flag
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# <var> - variable to store the result
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# Will be created as an internal cache variable.
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#
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# This internally calls the check_c_source_compiles macro and sets
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# CMAKE_REQUIRED_DEFINITIONS to <flag>. See help for
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# CheckCSourceCompiles for a listing of variables that can otherwise
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# modify the build. The result only tells that the compiler does not
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# give an error message when it encounters the flag. If the flag has
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# any effect or even a specific one is beyond the scope of this module.
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include(CheckCSourceCompiles)
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include(CMakeCheckCompilerFlagCommonPatterns)
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macro (CHECK_C_COMPILER_FLAG _FLAG _RESULT)
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set(SAFE_CMAKE_REQUIRED_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS}")
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set(CMAKE_REQUIRED_DEFINITIONS "${_FLAG}")
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# Normalize locale during test compilation.
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set(_CheckCCompilerFlag_LOCALE_VARS LC_ALL LC_MESSAGES LANG)
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foreach(v ${_CheckCCompilerFlag_LOCALE_VARS})
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set(_CheckCCompilerFlag_SAVED_${v} "$ENV{${v}}")
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set(ENV{${v}} C)
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endforeach()
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CHECK_COMPILER_FLAG_COMMON_PATTERNS(_CheckCCompilerFlag_COMMON_PATTERNS)
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CHECK_C_SOURCE_COMPILES("int main(void) { return 0; }" ${_RESULT}
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# Some compilers do not fail with a bad flag
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FAIL_REGEX "command line option .* is valid for .* but not for C" # GNU
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${_CheckCCompilerFlag_COMMON_PATTERNS}
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)
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foreach(v ${_CheckCCompilerFlag_LOCALE_VARS})
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set(ENV{${v}} ${_CheckCCompilerFlag_SAVED_${v}})
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unset(_CheckCCompilerFlag_SAVED_${v})
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endforeach()
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unset(_CheckCCompilerFlag_LOCALE_VARS)
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unset(_CheckCCompilerFlag_COMMON_PATTERNS)
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set (CMAKE_REQUIRED_DEFINITIONS "${SAFE_CMAKE_REQUIRED_DEFINITIONS}")
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endmacro ()
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