6.5.8 fegetexceptflag Function

Stores the floating-point exception flags represented by the argument excepts into an object.

Include

<fenv.h>

Prototype

void fegetexceptflag(fexcept_t * flagp, int excepts);

Arguments

flagp

a pointer to the object in which the flag representation will be stored

excepts

a value being the bitwise OR of one or more floating-point exception macros, representing the exceptions to store

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

void showExceptions(void)
{
  printf("Exceptions currently raised: ");
  if(fetestexcept(FE_DIVBYZERO))
    printf("FE_DIVBYZERO ");
  if(fetestexcept(FE_INEXACT))
    printf("FE_INEXACT ");
  if(fetestexcept(FE_INVALID))
    printf("FE_INVALID ");
  if(fetestexcept(FE_OVERFLOW))
    printf("FE_OVERFLOW ");
  if(fetestexcept(FE_UNDERFLOW))
    printf("FE_UNDERFLOW ");
  printf("\n");
}

volatile double result = 0.0;

int main(void)
{
  fexcept_t excepts;

  result = 1.0 / result;                        // raise FE_DIVBYZERO
  showExceptions();
  fegetexceptflag(&excepts, FE_ALL_EXCEPT);     // save state
  feraiseexcept(FE_INVALID|FE_OVERFLOW);        // raise exceptions without operation
  showExceptions();
  fesetexceptflag(&excepts, FE_ALL_EXCEPT);     // restore state
  showExceptions();
}

Example Output

Exceptions currently raised: FE_DIVBYZERO 
Exceptions currently raised: FE_DIVBYZERO FE_INEXACT FE_INVALID FE_OVERFLOW 
Exceptions currently raised: FE_DIVBYZERO