nextafterf: trying to correct FP exception handling

1 files changed, 41 insertions, 0 deletions

diff --git a/docs/probe_math_exception.c b/docs/probe_math_exception.c
new file mode 100644
index 000000000..dbeccc5cc
--- /dev/null
+++ b/docs/probe_math_exception.c
@@ -0,0 +1,41 @@
+/* Small test program for probing how various math functions
+ * with specific operands set floating point exceptions
+ */
+
+#define _ISOC99_SOURCE 1
+#define _GNU_SOURCE    1
+
+#include <math.h>
+#include <fenv.h>
+#include <stdio.h>
+
+int main(int argc, char **argv)
+{
+	float infF = HUGE_VALF * 2;
+
+	feclearexcept(FE_ALL_EXCEPT);
+
+//	printf("%.40e\n", 1.0 / 0.0); // FE_DIVBYZERO
+//	printf("%.40e\n", nextafterf(HUGE_VALF, infF)); // no exceptions in glibc 2.4
+
+#define PREX(ex) do { if (fetestexcept(ex)) printf(#ex); } while(0)
+#ifdef FE_INEXACT
+	PREX(FE_INEXACT);
+#endif
+#ifdef FE_DIVBYZERO
+	PREX(FE_DIVBYZERO);
+#endif
+#ifdef FE_UNDERFLOW
+	PREX(FE_UNDERFLOW);
+#endif
+#ifdef FE_OVERFLOW
+	PREX(FE_OVERFLOW);
+#endif
+#ifdef FE_INVALID
+	PREX(FE_INVALID);
+#endif
+	if (fetestexcept(FE_ALL_EXCEPT))
+		printf("\n");
+	printf("done\n");
+	return 0;
+}