I can't use cookie in Codeigniter

[eluser]Unknown[/eluser]
I want to keep login status with cookie in Codeigniter, but I can't set cookie in Codeigniter. This is my code in Controller. when I click submit button in the login form it call chk_login() function to check username and password in DB. After that, it go to this line echo "You are not log in". That mean cookie not set yet. how to use cookie in Codeigniter.

Code:

<?php
class Login extends CI_Controller
{

    public function __construct()
    {
        parent::__construct();
                $this->load->helper('cookie');
    }

    function index()
    {
        redirect('login/form_login');
    }

    function form_login()
    {
        $data['title'] = 'Login';
        $this->load->view('form_login_view', $data);
    }

    function goto_test()
    {
            if($this->input->cookie('login')){
               echo "You are logged in";
            }
            else{

                echo "You are not log in";  // It show string in this line every time. that mean cookie not set yet. how to use cookie in Codeigniter.
            }
    }


function chk_login()
{
$this->load->model('login_model', 'login');
$this->login->username = $this->input->post('username');
$this->login->password = $this->input->post('password');

$user_login = $this->login->get_by_user_pass();

         if($user_login==null){
                $data['errors']  = 'Username Not found.<br />';
                $this->load->view('form_login_view', $data);

    }else{

        // I set directed data in cookie but I can't get this cookie in goto_test().

        $this->input->set_cookie(array(
                               'login'=>TRUE,
                'username'=>"aaa",
                'password'=>"123",
                'status'=>"user"));


            redirect('login/goto_test');  // Go to function goto_test in this class
    }  
}
}
?&gt;