Re: how to debug an emacs hang?

[John Owens]

John Owens <address@hidden> writes:

> I've been running the same emacs (the released version of NT emacs
> 21.3) for quite some time, but recently it started hanging while I'm
> composing a mail message (via vm-mail), and I made it also hang when
> editing a HTML file. It hangs for about a minute (to the point where
> it doesn't even refresh) and eventually all my text suddenly appears
> and it's all back to normal. Hitting C-g does not seem to do anything
> while it is hanging.
>
> I'd like to figure out how/where it's hanging, but I don't know how I
> might do so. Suggestions?

Thank you all for the kind replies. I am using a precompiled version
from Ted Jump ["GNU Emacs 21.3.1 (i386-msvc-nt5.1.2600) of 2003-03-25
on TJUMP20"], clearly a MSVC compile and not a debug one. I've never
actually built one myself on Windows (but have on OS X). 

The hope was that it would be possible to set a variable that would
actually catch some signal and give a backtrace, but that does not
seem to be available (or such is my understanding from your replies).
Also it happens infrequently enough that running a debug build would
probably annoy me. :) However, I appreciate the pointer to the
etc/DEBUG docs and will give those a try.

The codebase has probably progressed enough since 21.3 was released
that I'm probably better off just getting a new CVS build and seeing
if the problem is still present, and if so, debugging it instead. (I'm
running a CVS build on OS X currently.) One difficulty with that
approach is that if I'm getting source from CVS it's always a little
dicey to make sure I have a stable version, since I might have got new
files in the middle of a checkin. Given the maturity of the 21.3.50
tree, maybe it's getting about time to at least mark a set of files as
"alpha1", "alpha2", etc. just to make sure they're stable.

Thanks again for the replies.

JDO