SUSv2 and POSIX 1003.1-2001 contain text about overflow (which might set
errno to ERANGE, or raise an exception). In practice, the result cannot
overflow on any current machine, so this error-handling stuff is just
nonsense. (More precisely, overflow can happen only when the maximum value of
the exponent is smaller than the number of mantissa bits. For the IEEE-754
standard 32-bit and 64-bit floating point numbers the maximum value of the
exponent is 128 (resp. 1024), and the number of mantissa bits is 24 (resp.