Core PHP Programming, Third Edition

6.5. Cloning

The object model in PHP 5 treats objects in a unique way by implementing an implicit by-reference paradigm. In some situations, you may wish to create a replica of an object so that changes to the replica are not reflected in the original object. For that purpose, PHP defines a special method, named __clone. As with __construct and __destruct, use two underscores for the first two characters of the method name.

Every object has a default implementation for __clone. The default implementation creates a new object containing the same values and resources as the original object. If you wish to override this default implementation, you may declare your own version of __clone in your class.

The clone method accepts no arguments, but it ...