# Test if compile errors are produced where necessary. include(CheckCXXSourceCompiles) set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR}/..) # Writing a wide character to a character stream Writer is forbidden. check_cxx_source_compiles(" #include \"format.cc\" int main() { fmt::Writer() << L'a'; } " WRITE_WCHAR_COMPILES) if (WRITE_WCHAR_COMPILES) error("No compile error for: fmt::Writer() << L'a'") endif ()