Re: Calling Lisp from undo.c's record_* functions

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: phillip.lord@russet.org.uk (Phillip Lord),  emacs-devel@gnu.org
> Date: Tue, 17 Nov 2015 11:51:25 -0500
> 
> > Would it work to have a non-idle timer that is started once at
> > startup, and then never shut down, and have its job be put on some
> > list that the timer will examine?
> 
> I ruled that out early on in the design cycle because I think it's wrong
> for an application to have such constant background activity.

OK, but then the same considerations should prohibit using an idle
timer, no?

How about the following idea: we don't start the timer from
run_undoable_change; instead, we set a flag there that will be checked
by the command loop when it finishes execution of a command, and the
call to start the timer will be made then?  We don't really need to
attempt to start the timer for each and every change of every buffer,
do we?