Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!sco!mikep
From: mikep@sco.COM (Mike Patnode)
Newsgroups: comp.windows.x
Subject: FIONREAD on a closed connection
Message-ID: <7523@scolex.sco.COM>
Date: 21 Aug 90 08:30:43 GMT
Sender: news@sco.COM
Reply-To: mikep@sco.COM (Mike Patnode)
Distribution: na
Organization: The Santa Cruz Operation, Inc.
Lines: 32


It looks to me like BytesReadable() in Xlibos.h (AKA: FIONREAD) is
expected to return -1 if the connection is closed.  In Lachman TCP/IP
this isn't so, and I can't find anything that says it should.  I also
took a quick look at the BSD 4.3 kernel, and I couldn't find it being
done there.

Now this may not be a problem at all.  Xlib may check the return
value of BytesReadable() just for a sanity check, but it looks to me
like _XEventsQueued() is expecting this to be an indicator of the
connection status.

So this leads to a few questions:

	What are the functional specs for BytesReadable()?

	If a connection is broken, when and how should a client find out?

	Does anybody's FIONREAD return -1 on a closed connection?


And the bonus question:

	Does anybody know what I_NREAD is supposed to do when there is a
	M_HANGUP on the stream?  (Take a wild guess at the answer I want)


-- 
Mike Patnode					The Santa Cruz Operation 
SCO Software Engineer				400 Encinal Street
{ucscc,uunet}!sco!mikep	 mikep@sco.COM  	P.O. Box 1900
(408) 458-1422                                  Santa Cruz, CA 95061