(PECL zookeeper >= 0.1.0)
Zookeeper::setWatcher — Set a watcher function.
watcher_cb
A watch will be set at the server to notify the client if the node changes.
成功时返回 TRUE
, 或者在失败时返回 FALSE
。
This method emits PHP error/warning when parameters count or types are wrong or fail to set watcher.