Re: [Stephen.Berman@gmx.net: Re: redisplay]

["Jan Djärv" <jan.h.d@swipnet.se>]

Chong Yidong skrev:
> Richard Stallman <rms@gnu.org> writes:
> 
>> Would someone please debug this, then ack?
>>
>> From: Stephen Berman <Stephen.Berman@gmx.net>
>> Subject: Re: redisplay
>> To: emacs-pretest-bug@gnu.org
>>
>> On Sat, 21 Apr 2007 20:47:19 -0400 Richard Stallman <rms@gnu.org> 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.