cencellazione directory a fine sessione

[mrtyler81]

dovrei scrivere una cosa del genre nel file .php?

function gc($maxlifetime)
{
   global $sess_save_path;

   foreach (glob("$sess_save_path/sess_*") as $filename) 
   {
      if (filemtime($filename) + $maxlifetime < time()) 
      {
         @unlink($filename);
      }
   }
   return true;
}

session_set_save_handler("gc");

session_start(); 

gracias