#include <errno.h>
#include <fenv.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#ifndef __GNUC__
#pragma STDC FENV_ACCESS ON
#endif
int main(void)
{
printf("acos(-1) = %f\n", acos(-1));
printf("acos(0.0) = %f 2*acos(0.0) = %f\n", acos(0), 2 * acos(0));
printf("acos(0.5) = %f 3*acos(0.5) = %f\n", acos(0.5), 3 * acos(0.5));
printf("acos(1) = %f\n", acos(1));
errno = 0; feclearexcept(FE_ALL_EXCEPT);
printf("acos(1.1) = %f\n", acos(1.1));
if (errno == EDOM)
perror(" errno == EDOM");
if (fetestexcept(FE_INVALID))
puts(" FE_INVALID raised");
}