Re: How to debug hang?

[martin rudalics <rudalics@gmx.at>]

 > I'm trying to debug some kind of a hang that occurs when I try to use
 > a font-lock mode I'm developing.  I can't get control back by hitting
 > `C-g'.  I suspected it was a bad (combinatoric) regexp, but I added
 > advice before and after re-search-forward that emitted enter/exit
 > messages, and when the hang occurs I am seeing an exit message, so I'm
 > guessing that's not it.  I'm quite stumped now; hoping someone can
 > offer a clue.

If a (presumed) bug in font-locking makes Emacs hang during redisplay,
the latter won't be able to display your message.  You could try to
write your messages to a dribble file.