Drupal hook_user_login not redirecting

I tried using  hook_user_login in my custom module it was not redirecting. use $_GET['destination'] and it works like a charm eg function mymodule_user_login(&$edit, $account) {//drupal_set_message('user logged in'.$_COOKIE["cart"]); // Unless there is already a redirection going, or the user is trying to reset his password, we redirect to $redirection.   if (empty($_GET['destination'])     && isset($_COOKIE["cart"])     […]