$user_id = get_user_id();
if (is_authenticated() && get_user_id() == 5) { // show confidential content to user with ID 5 } else { // redirect to login page or show error message }In this example, we are checking if the current user is authenticated and has a user ID of 5. If so, we will display confidential content to that user. Otherwise, the user will be redirected to the login page or shown an error message. The get_user_id() function is not part of a standard PHP package or library. It is typically part of a custom authentication library or framework that is used to handle user authentication for a particular web application or website.