function get_rd($sess_id = 0) {
$rd = (!empty($_SESSION['rd'])) ? $_SESSION['rd'] : 'index.php';

if (!$sess_id)
return $rd;

preg_match('#([^\?]+|)(\?([^\#]+)|)(\#(.*)|)#s', $rd, $rd);

if ($rd[3] === '')
$rd[3] = '?'._SESSION_ID;
else
$rd[3] = $rd[2].'&'._SESSION_ID;

if ($rd[4] !== '')
{
$rd[5] = $rd[4];
} else {
$rd[5] = '';
}

return $rd = $rd[1].$rd[3].$rd[5];
}