(PECL memcache >= 0.2.0)
Memcache::replace — Replace value of the existing item
Memcache::replace() should be used to replace value of existing item with key . In case if item with such key doesn't exists, Memcache::replace() returns FALSE. For the rest Memcache::replace() behaves similarly to Memcache::set(). Also you can use memcache_replace() function.
The key that will be associated with the item.
The variable to store. Strings and integers are stored as is, other types are stored serialized.
Use MEMCACHE_COMPRESSED to store the item compressed (uses zlib).
Expiration time of the item. If it's equal to zero, the item will never expire. You can also use Unix timestamp or a number of seconds starting from current time, but in the latter case the number of seconds may not exceed 2592000 (30 days).
如果成功则返回 TRUE，失败则返回 FALSE。
Example #1 Memcache::replace() example
<?php
$memcache_obj = memcache_connect('memcache_host', 11211);
/* procedural API */
memcache_replace($memcache_obj, "test_key", "some variable", false, 30);
/* OO API */
$memcache_obj->replace("test_key", "some variable", false, 30);
?>