bug#20927: 24.5; Cygwin Emacs completely blocks for 5+ seconds

[Eli Zaretskii <eliz@gnu.org>]

> From: Sebastien Vauban <sva-news@mygooglest.com>
> Cc: 20927@debbugs.gnu.org
> Date: Tue, 30 Jun 2015 10:30:02 +0200
> 
> >> I've tracked down this problem in Cygwin Emacs, and it's due to this
> >> line:
> >> 
> >> --8<---------------cut here---------------start------------->8---
> >>   (global-auto-revert-mode 1)           ; Auto refresh buffers.
> >> --8<---------------cut here---------------end--------------->8---
> >> 
> >> When it's commented, Cygwin Emacs behaves normally.
> >
> > Probably because you use glib's notifications,
> 
> If you say so (I'm not even aware of what that is)...

It's a library which implements file notifications.

> Would you advice me to put:
> 
> --8<---------------cut here---------------start------------->8---
>   ;; Don't use file notification functions.
>   (setq auto-revert-use-notify nil)
> --8<---------------cut here---------------end--------------->8---
> 
> just for Cygwin Emacs (where the problem was visible)

Since Ken cannot reproduce this in his Emacs, I'd suggest to try and
figure out why you are hit by this problem, while he is not.

For starters, does the problem happen in "emacs -Q"?

If so, I suggest to compare the versions of glib you and Ken use.

> or for both Windows and Cygwin Emacs?

No, the native Windows build of Emacs doesn't use glib (it can be
built like that, but when I tried this, file notifications simply
didn't work at all).  It uses a native Windows API for receiving file
notifications.  So this is definitely not needed in the native Windows
build.