RE: [GD-Windows] More timer fun!

[Jon W. <hp...@mi...>]

> Could you share some insight as to doing this with some 
> reliability? In most

Well, the source code for NTP is rather more authoritative than I 
could ever be :-)

However, a quick-and-dirty way (which I've used privately in the 
past) might include setting up your packets such that, from the 
clients point of view:

- tack on current time when sending
- server returns your-send-time + server-reply-time on the reply
- you receive a packet containing your-send-time, and at this point 
  compare server-reply-time to your-receive-time, your-send-time

Note that the round-trip time is now known. The server's time must 
be in the range of your-send-time through your-receive-time, with a 
tendency towards the center of that range (assuming symmetric round 
trips). You can know to immediately adjust your clock if the server's 
own notion of time is outside this range; a good place to adjust to 
is such that the center of your window lines up with the server-reply-
time.

But, as I said, for a less quick-and-dirty way to do it, you should 
go to some authoritative source. (Maybe a pun was intended there :-)

Cheers,

				/ h+