function user_confirm($username, $confirmsecret = null) {
        global $DB;

        $user = get_complete_user_data('username', $username);

        if (!empty($user)) {
            if ($user->confirmed) {
                return AUTH_CONFIRM_ALREADY;
            } else {
                $DB->set_field("user", "confirmed", 1, array("id"=>$user->id));
                return AUTH_CONFIRM_OK;
            }
        } else  {
            return AUTH_CONFIRM_ERROR;
        }
    }