struct timerequest *create_timer(ULONG unit)
{
	LONG error;
	struct MsgPort *timerport;
	struct timerequest *TimerIO;

	timerport = CreatePort(0, 0);
	if (timerport == NULL)
	{
		return(NULL);
	}

	TimerIO = (struct timerequest *);
	CreateExtIO(timerport, sizeof(struct timerequest));
	if (TimerIO == NULL)
	{
		DeletePort(timerport);
		return(NULL);
	}

	error = OpenDevice(TIMERNAME, unit,(struct IORequest *) TimerIO, 0L);
	if (error != 0)
	{
		delete_timer(TimerIO);
		return(NULL);
	}
	return( TimerIO );
}

void wait_for_timer(struct timerequest *tr, struct timeval *tv)
{
	tr->tr_node.io_Command = TR_ADDREQUEST;
	tr->tr_time = *tv;
	DoIO((struct IORequest *) tr);
}

void delete_timer(struct timerequest *tr )
{
	struct MsgPort *tp;

	if (tr != 0 )
	{
		tp = tr->tr_node.io_Message.mn_ReplyPort;

		if (tp != 0)
		{
			DeletePort(tp);
		}

		CloseDevice( (struct IORequest *) tr);
		DeleteExtIO( (struct IORequest *) tr);
	}
}

LONG time_delay(struct timeval *tv, LONG unit)
{
	struct timerequest *tr;

	tr = create_timer(unit);
	if (tr == NULL)
	{
		return(-1L);
	}
	wait_for_timer(tr, tv);

	delete_timer(tr);
	return (0L);
}