> Personally, I would just conditionalise the local definitions, e.g.: > > #ifndef M_PI > #define M_PI 3.14159265358979323846 > #endif why not go straight to the long? 3.1415926535897932384626433832795029 or 3.1415926535897932384626433832795029L (but don't call that M_PI) ? Hamish