NAME

fetestexcept — test floating-point exception flags

SYNOPSIS

#include <fenv.h>

int fetestexcept(int excepts);


DESCRIPTION

^[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2024 defers to the ISO C standard.

The fetestexcept() function shall determine which of a specified subset of the floating-point exception flags are currently set. The excepts argument specifies the floating-point status flags to be queried.

RETURN VALUE

The fetestexcept() function shall return the value of the bitwise-inclusive OR of the floating-point exception macros corresponding to the currently set floating-point exceptions included in excepts.

ERRORS

No errors are defined.

EXAMPLES

The following example calls function f() if an invalid exception is set, and then function g() if an overflow exception is set:

#include <fenv.h>
/* ... */
{
    #pragma STDC FENV_ACCESS ON
    int set_excepts;
    feclearexcept(FE_INVALID | FE_OVERFLOW);
    // maybe raise exceptions
    set_excepts = fetestexcept(FE_INVALID | FE_OVERFLOW);
    if (set_excepts & FE_INVALID) f();
    if (set_excepts & FE_OVERFLOW) g();
    /* ... */
}

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

feclearexcept, fegetexceptflag, feraiseexcept

XBD <fenv.h>

CHANGE HISTORY

First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.