Re: poor handling of multiple C-g with multi-tty (apparent hangs)

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 15 Sep 2008 16:00:39 -0700
> From: "Ami Fischman" <ami@fischman.org>
> Cc: emacs-devel@gnu.org
> 
> On Mon, Aug 11, 2008 at 10:40 AM, Chong Yidong <cyd@stupidchicken.com>wrote:
> 
> > "Ami Fischman" <ami@fischman.org> writes:
> >
> > > Emacs has code to deal with C-g being entered while a quit is already
> > > in progress, meant to suspend emacs and drop the user to the superior
> > > shell or debugger (see section 59.7 Emergency Escape of the emacs
> > > info).  This is done if emacs believes it's a good idea, which
> > > criteria includes "running in tty mode".  Unfortunately this was never
> > > updated to work correctly with the multi-tty patch.
> >
> > Thanks for pointing this out.
> >
> > IIUC, the "emergency C-g" behavior is geared towards the traditional
> > setup where there's only one text-only terminal available.  There, the
> > emergency C-g is the only way to drop back to the shell if Emacs gets
> > stuck.
> >
> > It's disabled for graphical terminals because there, you can open up a
> > separate terminal to kill/suspend the Emacs process.
> >
> > This implies that we should disable the emergency C-g if Emacs is
> > running on more than one terminal, as in the following patch.

I don't understand the problem(s) with the current code, nor the
reason why the emergency shutdown should only work when there's only
one terminal.  Perhaps the intent was to check if some of the other
terminals are non-tty's?  Could someone explain the problem and the
reasoning for the proposed solution?