diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index dde6b47..7f4c312 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -6464,7 +6464,7 @@
 		PyErr_Format(PyExc_ValueError,
 			     "unsupported format character '%c' (0x%x) "
 			     "at index %i",
-			     (31<=c && c<=126) ? c : '?', 
+			     (31<=c && c<=126) ? (char)c : '?', 
                              c,
 			     (int)(fmt -1 - PyUnicode_AS_UNICODE(uformat)));
 		goto onError;