Was this... #if !defined MISDNUSER_VERSION_CODE || (MISDNUSER_VERSION_CODE < MISDNUSER_VERSION(1, 0, 3)) #error "You need a newer version of mISDNuser ..." #endif #ifndef MISDNUSER_VERSION_CODE #error "You need a newer version of mISDNuser ..." #elif MISDNUSER_VERSION_CODE < MISDNUSER_VERSION(1, 0, 3) #error "You need a newer version of mISDNuser ..." #endif