Re: Revise etc/DEBUG documentation

[Alain Schneble <a.s@realize.ch>]

Eli Zaretskii <eliz@gnu.org> writes:

>> > It is actually more complicated than that, because the same Emacs
>> > session could have some GUI frames and some text-mode frames (though
>> > not on MS-Windows).  That's why saying "Emacs executes as GUI" is
>> > problematic at best.
>> 
>> I didn't even know that this is possible.  Thanks for pointing it out.
>
> See keyboard.c:handle_interrupt_signal for how that complication is
> handled.

Thanks.  Now I think I finally understand what the comment about
multiple display types and SIGINT in init_keyboard.c:10886 (cfaf18a)
really means :)

> Btw, I found that the MS-Windows build wasn't catching SIGINT in GUI
> sessions like the Posix platforms do, and I will fix that in a few
> moments.

That was exactly one of the things that confused me and what I tried to
document in my initial patch by saying

"On MS-Windows, [...].  GDB treats them as a SIGINT, but Emacs
won't terminate as it ignores these events."
                      ^^^^^^^^^^^^^^^^^^^^
With this fix, this confusion is gone.  Thanks.

Just one small thing: After sending a SIGINT, it might take some time
until Emacs actually terminates as it might be blocked in pselect
emulation (sys_select) in the call to MsgWaitForMultipleObjects.  Just
wonder if there is an easy way to send a message or such to get out of
the blocking call without having to wait for a timeout or another event
to happen.  I guess that does not happen on POSIX as the corresponding
syscall will be interrupted anyway, right?