Emergency Escape and EXWM

Emergency Escape and EXWM

[port19]

Hi all,

while reading the emacs manual I stumbled across a little inaccuracy in
(info "(emacs) Emergency Escape")

> Emergency escape is active only for text terminals.  On graphical
> displays, you can use the mouse to kill Emacs or switch to another
> program.

While this is true for the vast majority of graphical sessions, one major exception exists.
On EXWM, not least due to the single threaded nature of emacs, the graphical session can indeed hang because of emacs.
In this case it's not possible to kill emacs with a mouse or switch to another program.

This has only affected me a few times in the 10 months I'm using that window manager.
For me, not having emergency escape is acceptable, as I know to switch ttys via e.g. C-M-F2.

Should this be documented? 
Should emergency escape be available via a customization option to graphical sessions?
Or is this minor enough to ignore?

Your call.

Best,
port19

Re: Emergency Escape and EXWM

[Eli Zaretskii]

> Date: Fri, 06 Sep 2024 08:02:47 +0000
> From: port19 <port19@port19.xyz>
> 
> while reading the emacs manual I stumbled across a little inaccuracy in
> (info "(emacs) Emergency Escape")
> 
> > Emergency escape is active only for text terminals.  On graphical
> > displays, you can use the mouse to kill Emacs or switch to another
> > program.
> 
> While this is true for the vast majority of graphical sessions, one major exception exists.
> On EXWM, not least due to the single threaded nature of emacs, the graphical session can indeed hang because of emacs.
> In this case it's not possible to kill emacs with a mouse or switch to another program.

There's always "kill -9", no?

> Should this be documented? 

Which part?

> Should emergency escape be available via a customization option to graphical sessions?

Is it even possible?  On a text terminal, we configure the terminal to
generate SIGINT when C-g is pressed, and that's why we can provide
this feature: if we see a nested SIGINT, we know the user pressed C-g
more than once without Emacs being able to handle it.  But in a GUI
session, this is impossible, AFAIK.

Re: Emergency Escape and EXWM

[port19]

> There's always "kill -9", no?

Yes, which is why I'm not too bothered by this

> Which part?

"On graphical displays, you can use the mouse to kill Emacs" could be reworded to include the EXWM caveat.
But I have no idea how, without degrading the quality of the writing.

I had no idea how the emergency escape is implemented.
It relying on the tty is a good reason to not bend over backwards to make it possible in graphical sessions, if it even is possible

I propose we ignore this.


On Friday, 6 September 2024 at 13:46, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Fri, 06 Sep 2024 08:02:47 +0000
> > From: port19 port19@port19.xyz
> > 
> > while reading the emacs manual I stumbled across a little inaccuracy in
> > (info "(emacs) Emergency Escape")
> > 
> > > Emergency escape is active only for text terminals. On graphical
> > > displays, you can use the mouse to kill Emacs or switch to another
> > > program.
> > 
> > While this is true for the vast majority of graphical sessions, one major exception exists.
> > On EXWM, not least due to the single threaded nature of emacs, the graphical session can indeed hang because of emacs.
> > In this case it's not possible to kill emacs with a mouse or switch to another program.
> 
> 
> There's always "kill -9", no?
> 
> > Should this be documented?
> 
> 
> Which part?
> 
> > Should emergency escape be available via a customization option to graphical sessions?
> 
> 
> Is it even possible? On a text terminal, we configure the terminal to
> generate SIGINT when C-g is pressed, and that's why we can provide
> this feature: if we see a nested SIGINT, we know the user pressed C-g
> more than once without Emacs being able to handle it. But in a GUI
> session, this is impossible, AFAIK.