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_chkdouble_

Summary
#include <math.h>

unsigned char _chkdouble_ (
  double val);       /* number to check */
Description

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

Return Value

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

Return Value Meaning
0 Standard floating-point number.
1 Floating-point value 0.
2 +INF (positive overflow).
3 -INF (negative overflow).
4 NaN (Not a Number) error status.
See Also

_chkfloat_

Example
#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;
  }
}
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