#include "cxx_std.h" #if defined(CXX_STD) && CXX_STD > CXX_STD_23 && !defined(CXX_STD_LATEST) # error "CXX_STANDARD 23 honored as higher standard" #endif #if defined(CXX_STD) && CXX_STD <= CXX_STD_20 # error "CXX_STANDARD 23 not honored" #endif