What is the opposite of Access Callback user_is_anonymous?

Question

I know that is used in a drupal module to specify that only anonymous users can see that module. What would be the callback that specifies only logged in users ?

I have a page that I only want accessible to logged in users.

Thank You

Answer 1

It is the user_is_logged_in() function, which basically checks that the user's ID ($GLOBALS['user']->uid) is greater than zero.

The function converts the uid into a Boolean type and returns TRUE for any user that is logged in, because they would have a uid that is a positive number. Drupal assigns anonymous users a uid of 0, which is FALSE when converted into a Boolean.