fegetexceptflag, fesetexceptflag

Header: <fenv.h>

Attempts to obtain the full contents of the floating-point exception flags that are listed in the bitmask argument excepts, which is a bitwise OR of the floating-point exception macros.

# Declarations

int fegetexceptflag( fexcept_t* flagp, int excepts );

(since C99)

int fesetexceptflag( const fexcept_t* flagp, int excepts );

(since C99)

# Parameters

flagp: pointer to an fexcept_t object where the flags will be stored or read from
excepts: bitmask listing the exception flags to get/set

# Return value

0 on success, non-zero otherwise.

# Example

#include <stdio.h>
#include <fenv.h>
 
#pragma STDC FENV_ACCESS ON
 
void show_fe_exceptions(void)
{
    printf("current exceptions 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");
    if(fetestexcept(FE_ALL_EXCEPT)==0) printf(" none");
    printf("\n");
}
 
int main(void)
{
    fexcept_t excepts;
 
    /* Setup a "current" set of exception flags. */
    feraiseexcept(FE_INVALID);
    show_fe_exceptions();
 
    /* Save current exception flags. */
    fegetexceptflag(&excepts,FE_ALL_EXCEPT);
 
    /* Temporarily raise two other exceptions. */
    feclearexcept(FE_ALL_EXCEPT);
    feraiseexcept(FE_OVERFLOW | FE_INEXACT);
    show_fe_exceptions();
 
    /* Restore previous exception flags. */
    fesetexceptflag(&excepts,FE_ALL_EXCEPT);
    show_fe_exceptions();
 
    return 0;
}

# See also

C++ documentation