fetestexcept()

Arguments:

excepts

A bitwise OR of the flags that you want to check; zero or more of the following:

• FE_ALL_EXCEPT — all the bits
• FE_DENORMAL — the result of a floating-point expression is a denormalized number
• FE_DIVBYZERO — pole error
• FE_INEXACT — the result can't be exactly represented as a floating-point number
• FE_INVALID — domain error
• FE_OVERFLOW — result is too large to be representable
• FE_UNDERFLOW — result is subnormal with a loss of precision

Library:

libm

Use the -l m option to qcc to link against this library.

Description:

The fetestexcept() function determines which of the specified floating-point exceptions are currently set.

Returns:

A bitwise OR of the flags that are in excepts and that correspond to floating-point exceptions that are currently set.

Examples:

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

int main( void )
{
    int except_flags;

    /* acos(2) should raise a "domain error" exception. */

    feclearexcept(FE_ALL_EXCEPT);
    printf( "acos(2) is %f\n", acos(2) );
    except_flags = fetestexcept(FE_ALL_EXCEPT);
    if(except_flags & FE_INVALID)
        puts("FE_INVALID (domain error) reported");

    return EXIT_SUCCESS;
}

Classification:

C99, POSIX 1003.1