CheckCXXCompilerFlag

Check whether the CXX compiler supports a given flag.

check_cxx_compiler_flag

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 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.