diff --git a/src/rc.h b/src/rc.h
index 8bb8a4f3..b43d2d29 100644
--- a/src/rc.h
+++ b/src/rc.h
@@ -203,6 +203,8 @@ char *rc_strlist_addsort (char ***list, const char *item);
 char *rc_strlist_addsortc (char ***list, const char *item);
 char *rc_strlist_addsortu (char ***list, const char *item);
 int rc_strlist_delete (char ***list, const char *item);
+/* rc_strlist_list_join does a shallow copy of list2 onto list1
+ * and then frees the pointer for list2 (but not the contents) */
 int rc_strlist_join (char ***list1, char **list2);
 void rc_strlist_reverse (char **list);
 void rc_strlist_free (char **list);