6.11.77 fpclassify Macro

Classifies its argument as one of several floating-point categories.

Include

<math.h>

Prototype

int fpclassify(floating-point x);

Argument

x

any floating-point number

Return Value

Classifies its argument as one of several floating-point categories, such as NaN, infinite, normal, subnormal, zero, or as another implementation-defined category, represented by the floating-point classification macros discussed in Floating-point Classification Macros.

Example

See the notes at the beginning of this chapter or section for information on using printf() or scanf() (and other functions reading and writing the stdin or stdout streams) in the example code.

#include <math.h>
#include <stdio.h>

int main(void)
{
  double x;
  int b;
  x = 0.0;
  b = fpclassify(x);
  if(b == FP_ZERO)
    printf("The value %f has been classified as a floating-point zero\n", x);
}

Example Output

The value 0.000000 has been classified as a floating-point zero