bool Memcache::add ( string key, mixed var [, int flag [, int expire]] )
Memcache::add() stores variable
var with key only if such
key doesn't exist at the server yet.
Also you can use memcache_add() function.
Parameters
key
The key that will be associated with the item.
var
The variable to store. Strings and integers are stored as is, other
types are stored serialized.
flag
Use MEMCACHE_COMPRESSED to store the item
compressed (uses zlib).
expire
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).
Return Values
Returns TRUE on success or FALSE on failure.
Returns FALSE if such key already exist. For the rest
Memcache::add() behaves similarly to
Memcache::set().
