(PECL memcached >= 0.1.0)
Memcached::add — Add an item under a new key
Memcached::add() is similar to
Memcached::set(), but the operation fails if the
key
already exists on the server.
성공 시 TRUE
를, 실패 시 FALSE
를 반환합니다.
The Memcached::getResultCode() will return
Memcached::RES_NOTSTORED
if the key already exists.