Path: utzoo!attcan!uunet!bloom-beacon!watson.ibm.COM!dan
From: dan@watson.ibm.COM (Walt Daniels)
Newsgroups: comp.windows.x
Subject: XIOErrorHandler
Message-ID: <100689.093908.dan@watson.ibm.com>
Date: 6 Oct 89 13:39:08 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 27

Submitting for a friend (Walt)
Is this an IBM problem, or is it a genetic defect?
------------
I'm installing an XIOErrorHandler so that my application can do some
reasonable clean-up and shutdown if the connection to the window
fails.  (I'm running AIX/RT - latest updates to X) My XIOErrorHandler
gets control just fine when I run the client on one node and the
server on another and I kill the server.  But if I run the client and
server on the same machine and I kill the server (or cancel the
window), the default AIX SIGPIPE signal handler gets control, prints
"Broken pipe" and then exits.  My handler never gets called.  The
reason why this happens is that Xlib is writing to a pipe, and if the
pipe gets broken, the AIX SIGPIPE handler gets control and never gives
Xlib the chance to check the error code from the write and invoke the
XIOErrorHandler.  I really think that Xlib should do something with
SIGPIPE signals other than letting the default action take place.
This would allow the XIOErrorHandler (Xlib's default, or user
specified) to get invoked.  I can get around the problem by saying
"signal(SIGPIPE, SIG_IGN);" in my application, but I think this call
should be in Xlib.

I'm not totally sure why it worked for the remote case.  But I would
guess that TCP/IP (or whatever the transport mechanism is for remote
pipes) is handling SIGPIPE.

Karl Schultz
Engineering Graphics Products