# Zookeeper::setWatcher

(PECL zookeeper >= 0.1.0)

Zookeeper::setWatcher — Set a watcher function

### Description

public Zookeeper::setWatcher ( callable `$watcher_cb` ) : bool

### Parameters

`watcher_cb`

  A watch will be set at the server to notify the client if the node changes.

### Return Values

Returns `TRUE` on success or `FALSE` on failure.

### Errors/Exceptions

This method emits PHP error/warning when parameters count or types are wrong or fail to set watcher.

Caution

Since version 0.3.0, this method emits ZookeeperException and it's derivatives.

### See Also

- Zookeeper::exists() - Checks the existence of a node in zookeeper synchronously
- Zookeeper::get() - Gets the data associated with a node synchronously
- ZookeeperException