enable_language (C) include(CheckCompilerFlag) set(C 1) # test that this is tolerated # test that the check uses an isolated locale set(_env_LC_ALL "${LC_ALL}") set(ENV{LC_ALL} "BAD") check_compiler_flag(C "-_this_is_not_a_flag_" SHOULD_FAIL) if(SHOULD_FAIL) message(SEND_ERROR "invalid C compile flag didn't fail.") endif() if(CMAKE_C_COMPILER_ID MATCHES "GNU|LCC|Clang" AND NOT "x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC") check_compiler_flag(C "-x c" SHOULD_WORK) if(NOT SHOULD_WORK) message(SEND_ERROR "${CMAKE_C_COMPILER_ID} compiler flag '-x c' check failed") endif() endif() if(CMAKE_C_COMPILER_ID STREQUAL "GNU") # LCC C compiler silently ignore -frtti instead of failing, so skip it here. check_compiler_flag(C "-frtti" SHOULD_FAIL_RTTI) if(SHOULD_FAIL_RTTI) message(SEND_ERROR "${CMAKE_C_COMPILER_ID} compiler flag '-frtti' check passed but should have failed") endif() endif() if(NOT "$ENV{LC_ALL}" STREQUAL "BAD") message(SEND_ERROR "ENV{LC_ALL} was not preserved by check_compiler_flag") endif() set(ENV{LC_ALL} ${_env_LC_ALL})