1 files changed, 9 insertions, 8 deletions
diff --git a/libc/misc/time/asctime_r.c b/libc/misc/time/asctime_r.c
index 823ab4f4d..215031949 100644
--- a/libc/misc/time/asctime_r.c
+++ b/libc/misc/time/asctime_r.c
@@ -1,15 +1,16 @@
 
 #include <time.h>
+#include <errno.h>
 
 extern void __asctime();
 
-char *asctime_r(timeptr, buf)
-__const struct tm *timeptr;
-char *buf;
+char *asctime_r(__const struct tm *timeptr, char *buf)
 {
-
-	if (timeptr == 0)
-		return 0;
-	__asctime(buf, timeptr);
-	return buf;
+    if (timeptr == NULL || buf == NULL) {
+	__set_errno (EINVAL);
+	return NULL;
+    }
+    __asctime(buf, timeptr);
+    return buf;
 }
+