session_unset
  (PHP 4, PHP 5)
session_unset — Free all session variables
  
 
 
  Description
  
   void session_unset
    ( void
   )
  
  
 
  Return Values
  
   No value is returned.
  
  
 
  Notes
  Note: 
   
    If $_SESSION (or $HTTP_SESSION_VARS
    for PHP 4.0.6 or less) is used, use unset() to
    unregister a session variable, i.e.
    unset ($_SESSION['varname']);.
   
  
  Caution
   
    Do NOT unset the whole $_SESSION with
    unset($_SESSION) as this will disable the registering
    of session variables through the $_SESSION superglobal.