diff --git a/src/proto/dict.pro b/src/proto/dict.pro
index 94ed2a0..b09a647 100644
--- a/src/proto/dict.pro
+++ b/src/proto/dict.pro
@@ -15,6 +15,7 @@
 int dict_add(dict_T *d, dictitem_T *item);
 int dict_add_number(dict_T *d, char *key, varnumber_T nr);
 int dict_add_string(dict_T *d, char *key, char_u *str);
+int dict_add_string_len(dict_T *d, char *key, char_u *str, int len);
 int dict_add_list(dict_T *d, char *key, list_T *list);
 int dict_add_dict(dict_T *d, char *key, dict_T *dict);
 long dict_len(dict_T *d);