Subject: Re: bug#9754: Issue with Emacs 23.4

From: Ken Brown <[email-masked]>
Date: Fri, 18 May 2012 13:09:34 -0400

On 5/18/2012 12:33 PM, Glenn Morris wrote:
> Ken Brown wrote:
>
>> I understand, and I'm no longer proposing the patch for the emacs-24
>> branch.  My question is about what should be done in the trunk.  It
>> seems to me that it would be better to use x_in_use, and I'm wondering
>> if knowledgeable people agree.
>
> More knowledgeable people != me; but I just want to ask what the actual
> issue is. You said:
>
>    The call of g_main_context_query in xgselect.c:62 still uses the
>    variables gfds and gfds_size, which are not initialized by
>    xgselect_initialize if we're running emacs -nw. But, more
>    fundamentally, it doesn't make sense for emacs -nw to be interacting
>    with GLib at all.
>
> This sort of makes it sound like the last sentence is a cosmetic issue,
> and it was the first bit (uninitialized variables; although they
> supposedly are initialized) that stopped your Cygwin crashes.

No, I shouldn't have made the last sentence sound like a cosmetic issue. 
  Paul correctly pointed out that the variables actually are 
initialized, so I don't understand what caused the crashes.  They only 
started after a recent GLib upgrade, and I wasn't able to figure out 
why.  But in the course of debugging, I began to wonder why emacs -nw 
was calling GLib functions in the first place.  So I applied my patch 
and found that the crashes stopped.

> Is the crash reproducible on any other platform besides Cygwin?

I don't know.  It would be useful for someone to try it on a GNU/Linux 
system with glib >= 2.32.

Prior to the patch to xgselect.c, I was able to reliably reproduce the 
crash by simply starting emacs -nw and then doing C-x C-f C-g.  But the 
problem seemed to only occur when Cygwin was running on Windows XP or 
Windows Vista, not on Windows 7.  This makes it seem likely that the 
issue is Cygwin specific.

Ken