(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.
The key under which to store the value.
The value to store.
The expiration time, defaults to 0. See Expiration Times for more info.
Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки. The Memcached::getResultCode will return Memcached::RES_NOTSTORED if the key already exists.