1 files changed, 2 insertions, 1 deletions
diff --git a/error.c b/error.c
index aeacc4d130..f97452941b 100644
--- a/error.c
+++ b/error.c
@@ -1261,12 +1261,13 @@ Init_syserr(void)
 char *
 rb_strerrno(int err)
 {
+    if (err == 0) return "NOERROR";
 #define defined_error(name, num) if (err == num) return name;
 #define undefined_error(name) 
 #include "known_errors.inc"
 #undef defined_error
 #undef undefined_error
-    return "NOERROR";
+    return "UNKNOWNERROR";
 }
 
 static void