getting authentication information from apache

Hello, I'm new to php and I have am running php on apache. I already have ldap authentication set up in apache would rather not create a separate system for php. What would be ideal would be to get the current authenticated user from the apache environment. At this point I'm grabbing at straws, but so far I've tried.... $ret = apache_getenv("LDAP_USER"); echo $ret; echo $_SERVER['PHP_AUTH_DIGEST']; $ret = apache_getenv('PHP_AUTH_DIGEST'); echo $HTTP_SERVER_VARS['PHP_AUTH_USER']; echo $_SERVER['REMOTE_USER']; None of these work (all of the variables are empty). Has anyone done this?? Thanks, Ryan