diff --git a/newlib/libc/ctype/categories.c b/newlib/libc/ctype/categories.c
index 85328ef2e..a8de1f129 100644
--- a/newlib/libc/ctype/categories.c
+++ b/newlib/libc/ctype/categories.c
@@ -19,7 +19,7 @@ bisearch_cat(wint_t ucs, const struct _category *table, int max)
   int mid;
 
   if (ucs < table[0].first || ucs > table[max].first + table[max].delta)
-    return 0;
+    return -1;
   while (max >= min)
     {
       mid = (min + max) / 2;