C in a Nutshell

Name

fegetexceptflag

Synopsis

Stores the floating-point environment’s exception status flags

#include <fenv.h>
intfegetexceptflag( fexcept_t *flagp, int excepts );

The fegetexceptflag() function saves the current state of specified status flags in the floating-point environment, which indicate specific floating-point processing exceptions, in the object referenced by the pointer argument. The object type that represents the floating-point status flags, fexcept_t, is defined in fenv.h. Unlike the integer argument that represents the floating-point exception status flags in this and other functions that manipulate the floating-point environment, the object with type fexcept_t cannot be directly modified by user programs.

The integer argument is a bitwise OR of the values of macros defined in fenv.h to represent the floating-point exception flags. The macros are listed under feraiseexcept() in this chapter. fegetexceptflag() stores the state of those flags which correspond to the values that are set in this mask.

The function returns 0 if successful; a nonzero return value indicates that an error occurred.

Example

/* Temporarily store the state of the FE_INEXACT, FE_UNDERFLOW
 * and FE_OVERFLOW flags
 */
fexcept_t fpexcepts;

#pragma STDC FENV_ACCESS ON
/* Save state: */fegetexceptflag( &fpexcepts, FE_INEXACT | FE_UNDERFLOW | FE_OVERFLOW ); feclearexcept( FE_INEXACT | FE_UNDERFLOW | FE_OVERFLOW ); /* ... Perform some calculations that might raise those exceptions ... */ /* ... Handle (or ignore) ...