The fpclassify() macro shall classify its argument value as NaN, infinite, normal, subnormal, or zero.

#include <math.h>

int fpclassify (double x);

Return Values

• 0 if the value of x is normal.
• Returns one of the following for special values of x
  • FP_ZERO
  • FP_SUBNORMAL
  • FP_NAN
  • FP_INFINITE

Requirements

See Also

isinf, isnan finite