Re: address@hidden: Re: redisplay]

[Jan Djärv]

Chong Yidong skrev:
> Richard Stallman <address@hidden> writes:
>
> > Would someone please debug this, then ack?
> >
> > From: Stephen Berman <address@hidden>
> > Subject: Re: redisplay
> > To: address@hidden
> >
> > On Sat, 21 Apr 2007 20:47:19 -0400 Richard Stallman <address@hidden> wrote:
> >
> > >     (progn (new-frame)
> > >            (redisplay t)
> > >            (x-popup-dialog t '("Foo" ("Bar" . 1))))
> > >
> > > I tried this but it didn't fail -- the new frame was not empty.
> > In my Emacs (GNU Emacs 22.0.98.2 (i686-pc-linux-gnu, GTK+ Version
> > 2.10.6) of 2007-04-20 on escher) I see two behaviors:
> >
> > 1. Evalling the above sexp in *scratch* with C-j or in any buffer with
> > M-: results in what the OP reported: "produces a blank frame while the
> > popup dialog is active, i.e., (redisplay t) fails to wait for
> > redisplay to finish."
> >
> > 2. Evalling the sexp with C-x C-e in any buffer results in what RMS
> > reported. 
>
> I believe this is because x-popup-dialog is handled with a GTK dialog
> when you build under GTK, instead of using the Emacs redisplay engine.

The redisplay engine don't handle any dialogs, Gtk+, Motif or otherwise.

> So the behaviors are slightly different.  I don't think this
> "problem"---if it's really a problem---is serious, and it certainly
> shouldn't block the Emacs 22 release.

I can't reproduce it with or without Gtk+, *scratch* or not.  I suspect it is 
a timing issue in X.  I don't think redisplay guarantees that all redisplay 
related events has been received and handeled by Emacs before it returns.  My 
guess is that it just makes the needed X calls and then returns.  For some 
reason or another, the dialog blocks the handling of other X events.  Can the 
OP try to move the dialog around a bit and see if the frame below it is 
redrawn at all?

        Jan D.