function session_begin($user_id, $user_ip, $page_id, $auto_create = 0, $enable_autologin = 0)

function session_begin($user_id, $user_ip, $page_id, $auto_create = 0, $enable_autologin = 0, $admin = 0)

		SET session_user_id = $user_id, session_start = $current_time, session_time = $current_time, session_page = $page_id, session_logged_in = $login
		WHERE session_id = '" . $session_id . "' 
			AND session_ip = '$user_ip'";
	if ( !$db->sql_query($sql) || !$db->sql_affectedrows() )
	{
		$session_id = md5(uniqid($user_ip));

		$sql = "INSERT INTO " . SESSIONS_TABLE . "
			(session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in)
			VALUES ('$session_id', $user_id, $current_time, $current_time, '$user_ip', $page_id, $login)";

		SET session_user_id = $user_id, session_start = $current_time, session_time = $current_time, session_page = $page_id, session_logged_in = $login, session_admin = $admin
		WHERE session_id = '" . $session_id . "' 
			AND session_ip = '$user_ip'";
	if ( !$db->sql_query($sql) || !$db->sql_affectedrows() )
	{
		list($sec, $usec) = explode(' ', microtime());
		mt_srand((float) $sec + ((float) $usec * 100000));
		$session_id = md5(uniqid(mt_rand(), true));

		$sql = "INSERT INTO " . SESSIONS_TABLE . "
			(session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin)
			VALUES ('$session_id', $user_id, $current_time, $current_time, '$user_ip', $page_id, $login, $admin)";

	{// ( $userdata['user_session_time'] > $expiry_time && $auto_create ) ? $userdata['user_lastvisit'] : ( 
		$last_visit = ( $userdata['user_session_time'] > 0 ) ? $userdata['user_session_time'] : $current_time; 

		if (!$admin)
		{

		$userdata['user_lastvisit'] = $last_visit;

		$sessiondata['autologinid'] = ( $enable_autologin && $sessionmethod == SESSION_METHOD_COOKIE ) ? $auto_login_key : '';

		}

		$userdata['user_lastvisit'] = $last_visit;

		$sessiondata['autologinid'] = (!$admin) ? (( $enable_autologin && $sessionmethod == SESSION_METHOD_COOKIE ) ? $auto_login_key : '') : $sessiondata['autologinid'];

	$userdata['session_page'] = $page_id;
	$userdata['session_start'] = $current_time;
	$userdata['session_time'] = $current_time;

	$userdata['session_admin'] = $admin;

					$sql = "UPDATE " . SESSIONS_TABLE . " 
						SET session_time = $current_time, session_page = $thispage_id 

					// A little trick to reset session_admin on session re-usage
					$update_admin = (!defined('IN_ADMIN') && $current_time - $userdata['session_time'] > ($board_config['session_length']+60)) ? ', session_admin = 0' : '';

					$sql = "UPDATE " . SESSIONS_TABLE . " 
						SET session_time = $current_time, session_page = $thispage_id$update_admin

		message_die(GENERAL_MESSAGE, $message);
	}
}
else if ( ( $mode == 'user' && ( isset($HTTP_POST_VARS['username']) || $user_id ) ) || ( $mode == 'group' && $group_id ) )

		$sql = 'SELECT user_id FROM ' . USER_GROUP_TABLE . "
			WHERE group_id = $group_id";
		$result = $db->sql_query($sql);

		$group_user = array();
		while ($row = $db->sql_fetchrow($result))
		{
			$group_user[$row['user_id']] = $row['user_id'];
		}
		$db->sql_freeresult($result);

		$sql = "SELECT ug.user_id, COUNT(auth_mod) AS is_auth_mod 
			FROM " . AUTH_ACCESS_TABLE . " aa, " . USER_GROUP_TABLE . " ug 
			WHERE ug.user_id IN (" . implode(', ', $group_user) . ") 
				AND aa.group_id = ug.group_id 
				AND aa.auth_mod = 1
			GROUP BY ug.user_id";
		if ( !($result = $db->sql_query($sql)) )
		{
			message_die(GENERAL_ERROR, 'Could not obtain moderator status', '', __LINE__, __FILE__, $sql);
		}

		while ($row = $db->sql_fetchrow($result))
		{
			if ($row['is_auth_mod'])
			{
				unset($group_user[$row['user_id']]);
			}
		}
		$db->sql_freeresult($result);

		if (sizeof($group_user))
		{
			$sql = "UPDATE " . USERS_TABLE . " 
				SET user_level = " . USER . " 
				WHERE user_id IN (" . implode(', ', $group_user) . ")";
			if ( !($result = $db->sql_query($sql)) )
			{
				message_die(GENERAL_ERROR, 'Could not update user level', '', __LINE__, __FILE__, $sql);
			}
		}