problem in drupal

alsulm alikom

i use drupal cms and i build small external chat script based on drupal database (for egjug ish),  i want to get the current user name or user id from the current users in drupal to use it in the chat script i use this code but no result returned

<?php
global $user;

echo $user->name;
?>

 and i try to inlcude page like "drupal /inlcudes / session.inc " and try to call some functions to get the user id also but no return result !

 i hope to get help for this problem

thx

wael mohamed

web developer