#include <fenv.h>
#include <math.h>
-/*
-rint may raise inexact (and it should not alter the fenv otherwise)
-nearbyint must not raise inexact
+/* nearbyint is the same as rint, but it must not raise the inexact exception */
-(according to ieee754r section 7.9 both functions should raise invalid
-when the input is signaling nan, but c99 does not define snan so saving
-and restoring the entire fenv should be fine)
-*/
+double nearbyint(double x)
+{
+#ifdef FE_INEXACT
+ #pragma STDC FENV_ACCESS ON
+ int e;
-double nearbyint(double x) {
- fenv_t e;
-
- fegetenv(&e);
+ e = fetestexcept(FE_INEXACT);
+#endif
x = rint(x);
- fesetenv(&e);
+#ifdef FE_INEXACT
+ if (!e)
+ feclearexcept(FE_INEXACT);
+#endif
return x;
}