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.

成功时返回 TRUE，或者在失败时返回 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() - 向一个新的key下面增加一个元素