Macro constant that expands to a positive expression of type double.
A function returns this value when the result of a mathematical operation yields a value that is too large in magnitude to be representable with its return type. This is one of the possible range errors, and is signaled by setting errno to ERANGE.
Actually, functions may either return a positive or a negative HUGE_VAL (HUGE_VAL or -HUGE_VAL) to indicate the sign of the result.