function group_users($group_name=NUL){
        $result = array();
        if ($group_name==NULL){ return (false); }
        if (!$this->_bind){ return (false); }
        $filter="(&(|(objectClass=posixGroup)(objectClass=groupofNames))(".$this->_group_cn_identifier."=".$this->ldap_search_encode($group_name)."))";

        $fields=array("member","memberuid");
        $sr=ldap_search($this->_conn,$this->_base_dn,$filter,$fields);
        $entries = $this->ldap_get_entries_raw($sr);

        // DEBUG
        if (0 == count($entries)) {
            $this->_warning_message = "group_users: No entry for the specified filter $filter";
            echo "DEBUG: ".$this->_warning_message;
        }

        if (isset($entries[0]["member"][0]))
        {
            $result = $this->nice_names($entries[0]["member"]);
            /*
            for ($i=0; $i++; $i < $entries[0]["member"][count])
            {
                $result[] == ($entries[0]["member"][$i]);
            }
            */
        }
        elseif (isset($entries[0]["memberuid"][0]))
        {
            $result = $this->nice_names($entries[0]["memberuid"]);
        }
        else
        {
            $result = array();
        }
        return ($result);
    }