PHPBB and website integration

I needed to integrate a website login with a phpBB3 forum recently, and this blog post came in really useful:  http://www.3cc.org/blog/2010/03/integrating-your-existing-site-into-phpbb3/

The only issue with it was the logout section – it uses $_GET, but when I implement this I get a message saying that this is an ‘illegal use of $_GET’.

Instead, the logout code that worked for me was this – it uses request_var() instead:

<?php
$cp = request_var('cp', '');
if ($cp == "logout") {
$user->session_kill();
$user->session_begin();
echo "Logged out";
}
?>