Path: utzoo!attcan!uunet!lll-winken!csd4.milw.wisc.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!DSYS.ICST.NBS.GOV!rbj
From: rbj@DSYS.ICST.NBS.GOV (Root Boy Jim)
Newsgroups: comp.windows.x
Subject: Why does X not use SO_KEEPALIVE?
Message-ID: <8905252135.AA05839@dsys.icst.nbs.gov>
Date: 25 May 89 21:35:08 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Organization: National Institute of Standards and Technology
	formerly National Bureau of Standards
Lines: 36

? From: rws@expo.lcs.mit.edu

?     This implies that there needs to
?     be an option to the X stream-creation routine to specify this.

? At present, there appears to be enough contention about use of keepalives
? that I would prefer to "ignore" them at the Xlib level entirely.  Clients
? that wish to (ab)use SO_KEEPALIVE and other OS "features" can use the
? XConnectionNumber() directly.

RWS,
	I saw your query on the TCP/IP list. There seemed to be several
heavyweights aligned against keep-alives, and I don't really know
enuf to oppose them. However, I do have several comments.

1) As to the objection that KA's would interact poorly with long-haul
networks, I agree. However, quite a few X clients talk to a server on the
same network, and many of these talk to the same machine (note: I am
hereby cautioning people against using UNIX domain sockets, i.e. unix:0,
until they work perfectly. Use "localhost:0" or "`$hostname`:0" instead).
In this case, KA's might be appropriate.

2) In the case of an xclock that is producing frequent output (especially
with a second hand), are KA's sent anyway? My SunOS 3.5 says the KA
timer value is 45 seconds. Pretty long time.

3) Several people have mentioned that this feature might be nice on
xterms. Perhaps a "-keepalive" option could be added either to xterm
or as a standard option. At least then everyone can do it the same way.

4) I am not sure that Barmar's idea of mapping KA failure into an
X event helps. Doesn't the OS kill the connection? Or is that left
up to the guy who receives the SIGPIPE?

	Root Boy Jim is what I am
	Are you what you are or what?