ci-pt1-my_controller.php

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');

class MY_Controller extends Controller
{

	function MY_Controller()
	{
		parent::Controller();
		
		$this->auth_logged_in();
	}
	
	function auth_logged_in()
	{
		if ( ! $this->session->userdata('user_id'))
		{
			// Remember what page the user was on
			redirect('/users/login');
		}
	}
}