Strict Standards: Only variables should be passed by reference in m_auth

Question

I am working on a login system for a project using MVC programming and ran into this error. Here is the code, the problem line is #31

This login system is a tutoria

Answer 1

bind_param's params are references to variables. You can't use md5() there. You need to save it to a variable first.

$userPass = md5($pass . $this->salt);
$stmt->bind_param("ss", $user, $userPass);