* if ($idx == -3 && ret == FALSE) => wrong password
* if ($idx == -1 && ret == FALSE) => no space left
* if ($idx == 0 && ret == user) => SUCCESS
- * if ($idx == -$idx && ret == user) => SUCCESS (but the login exists in the auth db)
+ * if ($idx == -($idx + 1) && ret == user) => SUCCESS (but the login exists in the auth db)
*/
function add_user(&$sess, &$idx, $name, $pass, $ip, $header, $cookie)