Add basic regression test for modf() issue.

encouraged by deraadt and miod

1 files changed, 35 insertions, 0 deletions

diff --git a/regress/lib/libc/modf/modf_test.c b/regress/lib/libc/modf/modf_test.c
new file mode 100644
index 00000000000..f732533635a
--- /dev/null
+++ b/regress/lib/libc/modf/modf_test.c
@@ -0,0 +1,35 @@
+/* Public domain, 2014, Tobias Ulmer <tobiasu@tmux.org> */
+
+/* Test for bug introduced in 4.4BSD modf() on sparc */
+
+#include <math.h>
+
+#define BIGFLOAT (5e15) /* Number large enough to trigger the "big" case */
+
+int
+main(void)
+{
+	double f, i;
+
+	f = modf(BIGFLOAT, &i);
+	if (i != BIGFLOAT)
+		return 1;
+	if (f != 0.0)
+		return 1;
+
+	/* Repeat, maybe we were lucky */
+	f = modf(BIGFLOAT, &i);
+	if (i != BIGFLOAT)
+		return 1;
+	if (f != 0.0)
+		return 1;
+
+	/* With negative number, for good measure */
+	f = modf(-BIGFLOAT, &i);
+	if (i != -BIGFLOAT)
+		return 1;
+	if (f != 0.0)
+		return 1;
+
+	return 0;
+}