In article <775 at axis.UUCP> philip at axis.UUCP (Philip Peake) writes: >How can I know, when trying to write portable code, if the 'library' >function I am going to use is a real function or a macro ? The only time it can matter is if it's a macro and you need a function. In this case, #undef it first (this is harmless if it's not a macro).