how to logout from a php session - session_destroy doesn't seem to be enough

Question

I\'m trying to learn PHP and using sessions. I seen examples about using session_destroy on logout, but I see this in the php documentation:

In order

Answer 1

At the first: use the unset() function. So if you have a $_SESSION['user_id'], and you wanne destroy it: unset($_SESSION['user_id'])

You can also use the unset() for cookies or other vars

Second: can we have some code?