affiliate ID tag

Hi,

Today i need a little information :wink:

Because i'm working with external partners, i need the php code wo can give me this tag on a wordpress sale page : Affiliate alias or affiliate ID

Example: When i want to replace an ending link by a wordpress user ID, i use that :
<?php
global $current_user;
get_currentuserinfo();
echo $current_user->user_login;
?>

Someone know what i need to use to have the alias or affiliate member ID like that ?

Thank you,
Bertrand