You want to link two objects, so when you update one, you also update the other.
Use = to assign one object to another by reference:
$adam = new user; $dave = $adam;
When you do an object assignment using =, you don't create a new copy of an object, but a reference to the first. So, modifying one alters the other.
This is different from how PHP 5 treats other types of variables, where it does a copy-by-value. It is also different from PHP 4, where all variables are copied by value, regardless of their type.
So where you used to use =& in PHP 4 to make two objects point at each other, you can now use only =:
$adam = new user; $adam->load_info('adam'); $dave = $adam;
Now $dave and $adam are two names for the exact same object.
7.9.4. See Also
Recipe 7.10 for more on cloning objects; documentation on references at http://www.php.net/references.