Re: How to debug problems during temacs?

[Eli Zaretskii]

On Mon, 26 Nov 2001, Simon Josefsson wrote:

> I have made some C level changes to my Emacs, which worked fine up
> until I did cvs update a few days ago.  How would I debug a error like
> the below?  "debug.el" doesn't seem available in temacs, so toggling
> debug-on-error doesn't work.  Using gdb to find the cause for this
> lisp error is beyond me right now.

For some problems, you will have no other choice but to use GDB.  It's 
not that hard, really; and you can get help here if you get stuck.

Anyway, here's some hints about debugging this on the Lisp level:

  - byte-compile all the *.el files for which temacs says it is loading 
    the (stale) .elc file.  You might be having trouble because old *.elc 
    files conflict with the new C code.

  - If "make" still produces the same error after you byte-compile all 
    the new *.el files, try this:

        cd src
        ./temacs -q
        M-x set-variable RET debug-on-error RET t RET
        M-x load-library RET loadup RET

This will load all the packages specified by loadup.el, but 
interactively.  With any luck, you will get a backtrace when it hits the 
problem.

If the above doesn't help, I'd suggest to run temacs under GDB, set a 
breakpoint in Fsignal, type "run -batch -l loadup", and examine things 
when that breakpoint breaks.  See etc/DEBUG for some useful techniques 
about accessing Lisp information from GDB.