Return the integer value that respresents the floating point classification of the specified x value as follows:
* if x is NaN, return FP_NAN; * otherwise if x is positive or negative infinity, return FP_INFINITE; * otherwise if x is a subnormal value, return FP_SUBNORMAL * otherwise if x is a zero value, return FP_ZERO * otherwise return FP_NORMAL
Note that the mention FP_XXX constants are C99 standard macros and they are defined in the math.h (cmath) standard header. On systems that fail to define those standard macros we define the in this component as public macros.