php - Facebook SDK logout not working -

i'm using facebook php-sdk sign in users , works fine. i'm having problem logging users out correctly. after clicking logout button , clicking sign in button not redirect user facebook's sign in page, instead logs them site if logout wasn't successful. here code sign in user:

function authenticate_user() {     $ci = & get_instance();     $ci->config->load("facebook",true);     $config = $ci->config->item('facebook');     $ci->load->library('facebook', $config);      $user = $ci->facebook->getuser();      if ($user)     {         try         {             $user_profile = $ci->facebook->api('/me');             return $user_profile;         }         catch (facebookapiexception $e)         {             error_log($e);         }     }      return false;  }  public function signin() {     $user_profile = authenticate_user();     if (!$user_profile)     {            $loginurl = $this->facebook->getloginurl(array('scope' => 'email'));         redirect($loginurl);     }      $this->load->model("user_model");      if ($userrow = $this->user_model->user_exists($user_profile["id"]))     {         set_session($user_profile, $userrow->privileges);         redirect("member_controller/members");     } } 

this logout code:

public function fb_signout() {     $params = array( 'next' => 'http://www.' + $host + '/index.php/authentication_controller/signout');     redirect($this->facebook->getlogouturl($params)); // $params optional. }  public function signout() {     $this->session->sess_destroy();     redirect("http://www." + $host + "/"); } 

update:

the sdk using native php sessions , calling $this->session->sess_destroy() not destroy it, needed include session_destroy() in signout function.

the facebook sdk uses native php sessions codeigniter doesn't. want add session_destroy(); in signout controller kill php native session.

hope helps!