C question: off_t (and other signed integer types) minimum and maximum values

Question

I occasionally will come across an integer type (e.g. POSIX signed integer type off_t) where it would be helpful to have a macro for its minimum and maximum val

Answer 1

For sign-magnitude representations, it's fairly easy (for types at least as wide as int, anyway):

#define SM_TYPE_MAX(type) (~(type)-1 + 1)
#define SM_TYPE_MIN(type) (-TYPE_MAX(type))

Unfortunately, sign-magnitude representations are rather thin on the ground ;)