Re: Debugging Emacs

[phillip.lord@russet.org.uk (Phillip Lord)]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Nicolas Richard <nrichard@ulb.ac.be>
>> Date: Mon, 30 Nov 2015 14:33:00 +0100
>> Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
>> 
>> phillip.lord@russet.org.uk (Phillip Lord) writes:
>> > Now, if we had a command, say `break', implemented in C, then added a
>> > "breakpoint Fbreak" into .gdbinit, then all of this would happen
>> > automatically. Under GDB, then "M-x break" or (break) Emacs would halt.
>> > Outside M-x break would do nothing.
>> 
>> FWIW I use "killall -TSTP emacs", at which point gdb kicks in. (IIUC.)
>
> This was in etc/DEBUG, of course.

Actually, it wasn't!

etc/DEBUG

has a section called "Getting Control to the Debugger". The section
BEFORE that mentions

kill -TSTP PID

Getting the PID of emacs is somewhat painful because I normally run two.
And three when debugging. It didn't occur to me that I could safely run
killall -TSTP emacs without trashing my other Emacs'

Again, this all sounds small, but getting to the debug "Hello World"
needs to be as simple as possible.

> Anyway, I added a "Preliminaries" section to etc/DEBUG, based on
> Phillip's text, please take a look.


It's good. Slightly more detail that I would have added (less is more in
a brief tutorial).

I would put back my short "run through". Also, the section on "pp" needs
to mention that this prints to standard out (this is true right?). I
spend a long time trying to get "pp" to work and failing because I
expected the output to appear in the GDB window (like "print" does).

Probably, etc/DEBUG needs to be replaced with a section in the elisp
manual. Which probably needs to be renamed (Programming Emacs Manual?)
-- I noticed the section on modules going in the other day which isn't
very lispy!

Phil