-int o2hb_register_callback(struct o2hb_callback_func *hc);
-int o2hb_unregister_callback(struct o2hb_callback_func *hc);
+int o2hb_register_callback(const char *region_uuid,
+ struct o2hb_callback_func *hc);
+void o2hb_unregister_callback(const char *region_uuid,
+ struct o2hb_callback_func *hc);