diff --git a/bin/tests/serial_test.c b/bin/tests/serial_test.c
index a6a2f9ece9..3a9da6892b 100644
--- a/bin/tests/serial_test.c
+++ b/bin/tests/serial_test.c
@@ -42,5 +42,5 @@ main() {
 			isc_serial_ge(a,b), isc_serial_le(a,b),
 			isc_serial_eq(a,b), isc_serial_ne(a,b));
 	}
-	exit (0);
+	return (0);
 }