+.. function:: memcached_return_t memcached_set_encoding_key (memcached_st *ptr, const char *str, const size_t length)
+
+ :param ptr: pointer to initialized `memcached_st` struct
+ :param str: the key to use
+ :param length: the length of `key` without any terminating zero
+ :returns: `memcached_return_t` indicating success