GNU bug report logs -
#12450
Remove configure's --without-sync-input option.
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Reported by: Paul Eggert <eggert <at> cs.ucla.edu>
Date: Sat, 15 Sep 2012 07:57:02 UTC
Severity: normal
Done: Paul Eggert <eggert <at> cs.ucla.edu>
Bug is archived. No further changes may be made.
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Message #38 received at 12450 <at> debbugs.gnu.org (full text, mbox):
> Date: Sat, 15 Sep 2012 20:15:36 -0700
> From: Paul Eggert <eggert <at> cs.ucla.edu>
> Cc: lekktu <at> gmail.com, 12450 <at> debbugs.gnu.org
>
> On 09/15/2012 03:18 PM, Richard Stallman wrote:
> > I have a vague memory that the sync input code had an important flaw
> > -- that for certain display-updating tasks (perhaps
> > mouse-highlighting) it could cause a delay until Emacs was read to
> > accept input, which the other code could do instantly.
> >
> > I don't know if this is true now, and I'm not sure of the memory at all.
> > But it would be good to investigate this question.
>
> Yes, that topic came up in 2008 when SYNC_INPUT was made the
> default on non-Windows hosts. That discussion concluded that it's
> not a problem in practice, because SYNC_INPUT does not postpone
> X11 event processing indefinitely; it postpones it only until the
> next QUIT or UNBLOCK_INPUT. Please see Stefan's comment in
> <http://lists.gnu.org/archive/html/emacs-devel/2008-03/msg01368.html>,
> along with the surrounding thread. The remaining issues noted in
> that thread all seem to have been fixed since then, for the
> SYNC_INPUT case.
That thread left the MS-Windows case indeterminate.
And I still would like to have BLOCK_INPUT in xmalloc and friends,
conditioned on some global variable being non-zero. That way, if some
strange problems come up, we can ask people to set that variable to a
non-zero value in a debugger and see if the problems persist. Given
that no one here actually understands all the aspects of the related
issues, that is a prudent thing to do, especially with code freeze and
Emacs 24.3 release looming.
This bug report was last modified 12 years and 249 days ago.
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