What’s the meaning of __sleep and __wakeup?

[shilpamg]

Please anybody tell me the meaning of __sleep and __wakeup.

[R0bb0b]

__sleep() and __wakeup() run prior to serialize() and unserialize() respectively.
http://us.php.net/oop5.magic
__sleep() returns an array of all variables prior to serializing an object
__wakeup() also runs prior to unserializing an object to reestablish any database connections etc... for that object prior to unserialization