Description:
------------
I tried to implement a class with the Singleton pattern. However, static variables do not seem to tie to the class, but rather to the instance of the class.

Looking at bug 16245
  http://bugs.php.net/bug.php?id=16245&edit=2
I see that Mr. Flying and I have sort of 'exchanged' bugs. He got the result I expected and I got the result he expected.
Notice 2 things: first, he assigned a primitive type to his variable, whereas my variable holds an object; second, his variable is declared inside the function, and mine is declared inside the class.

Reproduce code:
---------------
<?php
class IntegerFactory {
    private static $int = NULL;
    function __construct() {}
    public function getInstance() {
        if ( !isset($this->int) ) {
            echo 'null !', "\n"; $this->int = new IntegerFactory;
        }
        return $this->int;
    }
}
$tmp1 = new IntegerFactory;
$d1 = $tmp1->getInstance();
var_dump($d1);
$tmp2 = new IntegerFactory;
$d2 = $tmp2->getInstance();
var_dump($d2);
$d3 = $tmp1->getInstance();
var_dump($d3);
?>

Expected result:
----------------
null !
object(IntegerFactory)#2 (0) {
}
object(IntegerFactory)#2 (0) {
}
object(IntegerFactory)#2 (0) {
}


Actual result:
--------------
null !
object(IntegerFactory)#2 (0) {
}
null !
object(IntegerFactory)#4 (0) {
}
object(IntegerFactory)#2 (0) {
}