+/* Return a list of all tags found in the database.
+ *
+ * This function creates a list of all tags found in the database. The
+ * resulting list contains all tags from all messages found in the database.
+ *
+ * On error this function returns NULL.
+ */
+notmuch_tags_t *
+notmuch_database_get_all_tags (notmuch_database_t *db);
+