function user_all_groups($username, $groups_filtering = '') {
        if ($username==NULL){ return (false); }
        if (!$this->_bind){ return (false); }
        $filter = "(&(objectCategory=group)(member:1.2.840.113556.1.4.1941:=".$username.")".$groups_filtering.")";
        // $fields = array($this->_group_cn_identifier,$this->_group_attribute,"distinguishedname");
        $fields = array("cn");
        $sr = ldap_search($this->_conn,$this->_base_dn,$filter, $fields);
        $group_entries = $this->rCountRemover(ldap_get_entries($this->_conn, $sr));

//echo "DEBUG: info group_entries\n";
//print_r($group_entries);
        
        $group_array = array();
        foreach ($group_entries as $group_entry) {
            $group_array[] = $group_entry['cn'][0];
        }
//echo "DEBUG: group_array\n";
//print_r($group_array);

        return ($group_array);
    }