Mike Ash: gcc provides two built-in functions which can be useful for building macros. The first is __builtin_types_compatible_p. You pass two types to this function (__typeof__ comes in handy here) and it produces 1 if the two types are “compatible” (roughly, if they’re equal) and 0 if they aren’t. The second is __builtin_choose_expr. This works … Continue reading C Macro Tips and Tricks