Memcached::replace

(PECL memcached >= 0.1.0)

Memcached::replace — Replace the item under an existing key

public bool Memcached::replace ( string $key , mixed $value [, int $expiration ] )

Memcached::replace() is similar to Memcached::set, but the operation fails if the key does not exist on the server.

key: The key under which to store the value.
value: The value to store.
expiration: The expiration time, defaults to 0. See Expiration Times for more info.

如果成功则返回 TRUE，失败则返回 FALSE。 The Memcached::getResultCode will return Memcached::RES_NOTSTORED if the key does not exist.

Memcached::replaceByKey - Replace the item under an existing key on a specific server
Memcached::set - Store an item
Memcached::add - Add an item under a new key