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From: danny@calgary.UUCP (Danny Levinson)
Newsgroups: comp.emacs
Subject: Re: Emacs Version 18.41 Bug?
Message-ID: <935@vaxb.calgary.UUCP>
Date: Fri, 29-May-87 18:23:08 EDT
Article-I.D.: vaxb.935
Posted: Fri May 29 18:23:08 1987
Date-Received: Tue, 2-Jun-87 01:45:08 EDT
References: <223@nih-csl.UUCP>
Organization: U. of Calgary, Calgary, Ab.
Lines: 25
Keywords: emacs, shell, suspend, dbx
Summary: "emacs" bug is actually in sun unix tty driver

In article <223@nih-csl.UUCP>, connie@nih-csl.UUCP (connie eppich) writes:
> I am having an intermittent problem with the new Emacs. When I test a
> program I will often suspend the Emacs session to run something
> in the c-shell outside of Emacs. I have been having Emacs "get stuck"
> after I issue the "foreground" command, "fg", to the shell; my terminal
> is completely locked up.  My only recourse is to disconnect.

I have indeed had this problem, but not just with gnu emacs.  My guess is
that you, like myself, are working on a sun (bsd4.2, v3.2?) and that we are
experiencing a bug in the Unix tty driver.  Perhaps it arises because doing
certain "ioctl"s before the tty driver has had a chance to flush the echo of
the <return> following the "fg" command has side effects.

At any rate, putting a "sleep(1)" before the ioctl in question (and, for
safety's sake, after it too) worked for me in Gosling emacs.  I haven't
actually fixed it in Gnu as (1) it occurs far less regularly (perhaps gosmacs
does less work twixt ioctl and generating output), and (2) the ioctl calls
are harder to find in the Gnu code.

I am given to understand that a fuller description of the Unix bug and a
prescription for its cure appeared in SunSpots (or a related group).  Try
your local guru for a definitive fix!

-- danny levinson
   university of calgary