MY_controller problem

[eluser]Near[/eluser]
here is my_controller

Code:

class base_c extends ci_controller{
protected $is_login;
function __construct(){
parent::__construct();
$this->load->library('auth');
$this->is_login = (bool) $this->auth->is_login();
}
}

welcome controller

Code:

class welcome extends base_c{

function __contruct(){
parent::__construct();
var_dump($this->is_login);
}

}

class auth

Code:

function is_login(){
return true;
}