User::userOnline

static function userOnline()
{
	$dbRes = UserTable::getList(array(
		'filter' => array(
			'IS_ONLINE' => 'Y',
		),
		'select' => array('ID')
	));

	$onlineUsers = array();
	while($userData = $dbRes->fetch())
	{
		$onlineUsers[] = $userData['ID'];
	}

	return $onlineUsers;
}