Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ATHENA.MIT.EDU!rfrench
From: rfrench@ATHENA.MIT.EDU ("Robert S. French")
Newsgroups: gnu.emacs
Subject: Re: XNoOp packets in GNU emacs
Message-ID: <8902212053.AA13039@BINKLEY.MIT.EDU>
Date: 21 Feb 89 20:53:08 GMT
References: <8902202010.AA19603@convexc>
Sender: daemon@tut.cis.ohio-state.edu
Distribution: gnu
Organization: GNUs Not Usenet
Lines: 13


The XNoOp calls are buried in the history of Emacs and X.  It has been
used because emacs didn't behave properly when the X socket closed
when the used logged out and the X server died.  Emacs would simply
sit and loop due to a bug in the X library.  This bug started in X10
and has carried over to X11 despite our best efforts to get people to
fix it.  I'm not sure if it's still present in X11R2 and X11R3.  The
XNoOp and XFlush are done whenever the screen is refreshed even if
nothing else needs to be done.  This will cause Emacs to die with an X
error if the X server has been killed.  Under X10, since no XNoOp
existed, a 1x1 pixmap was retrieved, or something like that.

			Rob