session_unregister() unregisters the global variable
   named name from the current session.
  
Note: If
$_SESSION(or$HTTP_SESSION_VARSfor PHP 4.0.6 or less) is used, use unset() to unregister a session variable. Do not unset()$_SESSIONitself as this will disable the special function of the$_SESSIONsuperglobal.
| Caution | 
    This function does not unset the corresponding global variable for
      | 
| Caution | 
    If you are using   |