Returns the status word containing information about the floating-point class.
_fpclass returns an integer value that indicates the floating-point class of its argument x. The status word might have one of the following values, defined in Float.h.
Negative infinity ( –INF)
Negative normalized non-zero
Negative zero ( – 0)
Positive 0 (+0)
Positive normalized non-zero
Positive infinity (+INF)
For more compatibility information, see Compatibility in the Introduction.