+ :param ptr: pointer to initialized `memcached_st` struct
+ :param callback: list of `memcached_server_fn` to be called for each server instance
+ :param context: pointer to user supplied context for the callback
+ :param number_of_callbacks: number of callbacks supplied
+ :returns: `memcached_return_t` indicating success
+
+.. type:: memcached_return_t (*memcached_server_fn)(const memcached_st *ptr, const memcached_instance_st * server, void *context)
+
+ :param ptr: pointer to the `memcached_st` struct
+ :param server: pointer to `memcached_instance_st`
+ :param context: pointer to user supplied context
+ :returns: `memcached_return_t` indicating success