The _chkdouble_ function checks the status of the floating-point number val.

The _chkdouble_ function returns the status of the floating-point number val:

_chkfloat_

#include <intrins.h>
#include <stdio.h> /* for printf */

float f1, f2, f3;

void tst_chkdouble (void) {
  f1 = f2 * f3;

  switch (_chkdouble_ (f1)) {
    case 0:
      printf ("result is a number\n"); break;
    case 1:
      printf ("result is zero\n"); break;
    case 2:
      printf ("result is +INF\n"); break;
    case 3:
      printf ("result is -INF\n"); break;
    case 4:
      printf ("result is NaN\n"); break;
  }
}