Argh
#include <stdio.h>
#include <math.h>
#include <fenv.h>
int main () {
// don’t set rounding here
double ten0 = sin(pow(10.0,22));
fesetround(FE_DOWNWARD);
double ten1 = sin(pow(10.0,22));
fesetround(FE_UPWARD);
double ten2 = sin(pow(10.0,22));
fesetround(FE_TONEAREST);
double ten3 = sin(pow(10.0,22));
fesetround(FE_TOWARDZERO);
double ten4 = sin(pow(10.0,22));
printf(
"Default: %f\n"
"Downward: %f\n"
"Upward: %f\n"
"ToNearest: %f\n"
"TowardZero: %f\n",
ten0, ten1,
ten2, ten3, ten4);
return 0;
}
$ gcc test.c -lm -fno-builtin && ./a.out
Default: [...]
