(PHP 4, PHP 5 < 5.1.0)
yp_order — Returns the order number for a map
$domain
   , string $map
   ) : intGets the order number for a map.
domain
map
   Returns the order number for a map or FALSE on error.
  
Example #1 Example for the NIS order
<?php
    $number = yp_order($domain, $mapname);
    echo "Order number for this map is: " . $number;
?>