(PECL zookeeper >= 0.1.0)
Zookeeper::getClientId — Return the client session id, only valid if the connections is currently connected (ie. last watcher state is ZOO_CONNECTED_STATE)
此函数没有参数。
Returns the client session id on success, and false on failure.
This method emits PHP error/warning when it could not get client session id.
Since version 0.3.0, this method emits ZookeeperException and it's derivatives.