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From: peterson@SW.MCC.COM (James Peterson)
Newsgroups: comp.windows.x
Subject: Replies and Errors
Message-ID: <8809121717.AA11866@cleo.sw.mcc.com>
Date: 12 Sep 88 17:17:12 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 19

At the Protocol level, I can generate Requests which expect replies.
A Reply identifies the request that it is a reply to by its sequence
number.  I can generate many requests before waiting for the replies.
Since the format of a reply depends upon the type of request that was
made, I must keep a list of all outstanding requests, their sequence
numbers and the type of the reply. 

If a Request generates an Error, the Error identifies the Request
by its sequence number.

Is it always the case that if a Request expects a Reply, and an
Error is received for the sequence number of that Request, then
there will be no Reply?  That is, I can remove the sequence number
from my list of pending replies if I get either the expected reply
or an Error.

Also, I notice that Events have sequence numbers, but can find nothing
in the Protocol document explaining what they are for.

jim