session header error!!!

[eluser]bang_dayat[/eluser]
[quote author="JanDoToDo" date="1268525996"]if you are using the native php sessions then you need to call session_start() to start the php session. If youve done that then cart variable doesnt exist and you should do

$cart = isset($_SESSION[‘cart’]) ? $_SESSION[‘cart’] : array();[/quote]

yeaa,..that's work,,..I have allready call session_start() in the parent::controller();
but how do you explain bout that code

$cart = isset($_SESSION[‘cart’]) ? $_SESSION[‘cart’] : array();

It's Really work!!how the way it can work like that??
Thanx,...