diff --git a/vm.c b/vm.c
index 22ade689fc..d79d38a8d9 100644
--- a/vm.c
+++ b/vm.c
@@ -1124,6 +1124,7 @@ rb_source_location(int *pline)
 	return cfp->iseq->body->location.path;
     }
     else {
+	if (pline) *pline = 0;
 	return 0;
     }
 }