Removing/unsetting session variables.

I have several variables that I set in a session - to record that a user is logged in. I want to be able to unset them - when they log out. $_SESSION['PERMS_USER'] = 'fred'; Sets the variable quite nicely, I can also change it and the change is recorded. I cannot unset it. I have tried (in various combinations): unset($_SESSION['PERMS_USER']); unset($HTTP_SESSION_VARS['PERMS_USER']); session_unregister($SESSION['PERMS_USER']); session_unregister($HTTP_SESSION_VARS['PERMS_USER']); None of which have any effect. What should I do ? Thanks Merry Christmas. -- Alain Williams #include <std_disclaimer.h> FATHERS-4-JUSTICE - Campaigning for equal rights for parents and the best interests of our children. See http://www.fathers-4-justice.org