_status87, _statusfp

Remonter à float.h - Index

Header File

float.h

Category

Math Routines

Prototype

unsigned int _status87(void);

unsigned int _statusfp(void);

Description

Gets floating-point status.

_status87 gets the floating-point status word, which is a combination of the 80x87 status word and other conditions detected by the 80x87 exception handler.

_statusfp is identical to _status87 and is for Microsoft compatibility.

Return Value

The bits in the return value give the floating-point status. See float.h for a complete definition of the bits returned by _status87 and _status87.

Example

#include <float.h>

/* Prints the status of the FPU */
void print_fp_status()
{
  /* Obtain the FPU status word */
  int fp_status = _status87();
  printf("Status = %d", fp_status);

  /* Write the statuses */
  if (fp_status & SW_DENORMAL)
    printf(" denormalized");

  if (fp_status & SW_UNDERFLOW)
    printf(" underflow");

  if (fp_status & SW_INEXACT)
    printf(" inexact");

  printf("\n");
}

int _tmain(int argc, _TCHAR* argv[])
{
  double big_value = 1e-40;
  float short_value;

  /* Print the default status */
  print_fp_status();

  /* Force FP status change */
  short_value = big_value;
  print_fp_status();

  /* Clear FPU status word */
  _clear87();

  /* Force FP status change */
  big_value = short_value;
  print_fp_status();
}

Portability

	POSIX	Win32	ANSI C	ANSI C++
_status87		+
_statusfp		+