https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104593
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- #include <functional> #include <cstdarg> extern std::function<void( void*, int, const char*, va_list )> g_msgFnc; Does not warn for me on x86_64-linux-gnu.