#include #include #pragma STDC FENV_ACCESS ON double inverse(double x) { return 1.0 / x; } int main() { if (fesetround(FE_DOWNWARD)) { printf("fesetround(FE_DOWNWARD) unsuccessful\n"); } double low = inverse(3.0); if (fesetround(FE_UPWARD)) { printf("fesetround(FE_UPWARD) unsuccessful\n"); } double high = inverse(3.0); printf("%d %a\n", low==high, high-low); }