>(a) there exists a C-preprocessor instruction as per the above There's no day-of-week but you could cause mayhem with __DATE__ >(2) if the compiler will noti

>(a) there exists a C-preprocessor instruction as per the above There's no day-of-week but you could cause mayhem with __DATE__ >(2) if the compiler will notice errors in the unexecuted branch of an #if Compiler only gets to see preprocessor output, it won't. >if printf; would give a syntax error Perhaps surprisingly but no, it's just statement without effect (containing expression returning function pointer to printf).