diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 68977f4..74fb7ce 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -654,6 +654,7 @@
         int overflow;
 
         maxchar = 0;
+        overflow = 0;
         for (i=0; i < how_many; i++) {
             ch = PyUnicode_READ(from_kind, from_data, from_start + i);
             if (ch > maxchar) {