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

#pragma STDC FENV_ACCESS ON
int main(void)
{
    double pi = acos(-1);
    // typical usage
    printf("cos(pi/3) = %fn", cos(pi/3));
    printf("cos(pi/2) = %fn", cos(pi/2));
    printf("cos(-3*pi/4) = %fn", cos(-3*pi/4));
    // special values
    printf("cos(+0) = %fn", cos(0.0));
    printf("cos(-0) = %fn", cos(-0.0));
    // error handling
    feclearexcept(FE_ALL_EXCEPT);
    printf("cos(INFINITY) = %fn", cos(INFINITY));
    if(fetestexcept(FE_INVALID)) puts("    FE_INVALID raised");
}