code: private function setCookieParamsInternal()
      {
          $data = $this->getCookieParams();
          extract($data);
          if (isset($lifetime, $path, $domain, $secure, $httponly)) {
              session_set_cookie_params($lifetime, $path, $domain, $secure, $httponly);
          } else {
              throw new InvalidParamException('Please make sure cookieParams contains these elements: lifetime, path, domain, secure and httponly.');
          }
      }
docs: Sets the session cookie parameters.
  This method is called by [[open()]] when it is about to open the session.
  @throws InvalidParamException if the parameters are incomplete.
  @see http://us2.php.net/manual/en/function.session-set-cookie-params.php