different explanation

Posted by Delirium tremens on Stack Overflow See other posts from Stack Overflow or by Delirium tremens
Published on 2010-04-24T22:38:40Z Indexed on 2010/04/24 22:43 UTC
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The following code echoes 5, not 10:

$global_obj = null;
class my_class
{
       var $value;
       function my_class()
       {
               global $global_obj;
               $global_obj = &$this;
       }
}
$a = new my_class;
$a->my_value = 5;
$global_obj->my_value = 10;
echo $a->my_value;

"Upon first examination, it would seem that the constructor of my_class stores a reference to itself inside the $global_obj variable. Therefore, one would expect that, when we later change the value of $global_obj->my_value to 10, the corresponding value in $a would change as well. Unfortunately, the new operator does not return a reference, but a copy of the newly created object."

Please, give me a different explanation.

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