Classifies the real floating-point type.

    Format

       #include <math.h>
       int fpclassify (real-floating x);

1  –  Argument

 x

    Value to classify.

2  –  Description

    The fpclassify macro classifies its argument value as NaN, infinite,
    normal, subnormal, zero, or into another implementation-defined
    category.

    First, an argument represented in a format wider than its semantic
    type is converted to its semantic type. Then classification is based
    on the type of the argument.

3  –  Return Value

    The fpclassify macro returns the value of the number classification
    macro appropriate to the value of its argument.