\brief checks the existence of a node in zookeeper synchronously.
This function is similar to \ref zoo_exists except it allows one specify
a watcher object rather than a boolean watch flag.
\param zh the zookeeper handle obtained by a call to \ref zookeeper_init
\param path the name of the node. Expressed as a file name with slashes
separating ancestors of the node.
\param watcher if non-null a watch will set on the specified znode on the server.
The watch will be set even if the node does not exist. This allows clients
to watch for nodes to appear.
\param watcherCtx user specific data, will be passed to the watcher callback.
Unlike the global context set by \ref zookeeper_init, this watcher context
is associated with the given instance of the watcher only.
\param the return stat value of the node.
\return return code of the function call.
ZOK operation completed successfully
ZNONODE the node does not exist.
ZNOAUTH the client does not have permission.
ZBADARGUMENTS - invalid input parameters
ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
\brief checks the existence of a node in zookeeper synchronously.
This function is similar to \ref zoo_exists except it allows one specify a watcher object rather than a boolean watch flag.
\param zh the zookeeper handle obtained by a call to \ref zookeeper_init \param path the name of the node. Expressed as a file name with slashes separating ancestors of the node. \param watcher if non-null a watch will set on the specified znode on the server. The watch will be set even if the node does not exist. This allows clients to watch for nodes to appear. \param watcherCtx user specific data, will be passed to the watcher callback. Unlike the global context set by \ref zookeeper_init, this watcher context is associated with the given instance of the watcher only. \param the return stat value of the node. \return return code of the function call. ZOK operation completed successfully ZNONODE the node does not exist. ZNOAUTH the client does not have permission. ZBADARGUMENTS - invalid input parameters ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory