Weirdness with Emacs' X window id

Weirdness with Emacs' X window id

[Peter Heslin]

In Debian GNU/Linux:

If I do emacs -q --no-site-file with a month-old CVS checkout, and
then M-x eshell:

~ $ xdpyinfo |grep -i focus
focus:  window 0x1400015, revert to Parent
~ $ wmctrl -l |grep -i emacs
0x01400014 1 aideen Emacs *eshell*

where wmctrl is a command-line program and the -l switch makes it list
all current windows.  Note that xdpyinfo and wmctrl disagree as to
what should be the ID number for the single Emacs frame.  One says a
number ending in 14, the other in 15.

wmctrl -l does not know of any window with the ID 0x1400015.

Is this expected?  I don't know anything about these IDs -- I'm just
trying to write a script to manipulate windows on my desktop, and
it's quite difficult with this ID schizophrenia.

Emacs is the only application I run that behaves like this.

If it's not expected behavior, then it could be a bug in wmctrl,
xdpyinfo, my X server, Emacs, or who knows where, so it would be
interesting to see if anyone else sees this.

Peter

Re: Weirdness with Emacs' X window id

[Lennart Borgman]

----- Original Message ----- 
From: "Peter Heslin" <public@heslin.eclipse.co.uk>

> wmctrl -l does not know of any window with the ID 0x1400015.
>
> Is this expected?  I don't know anything about these IDs -- I'm just
> trying to write a script to manipulate windows on my desktop, and
> it's quite difficult with this ID schizophrenia.
>
> Emacs is the only application I run that behaves like this.
>
> If it's not expected behavior, then it could be a bug in wmctrl,
> xdpyinfo, my X server, Emacs, or who knows where, so it would be
> interesting to see if anyone else sees this.

I do not know about GNU/Linux but it sounds to me like Emacs have a
background window (maybe for managing multiple frames?) and this is found by
one of the programs you use. So maybe there is a bug in one of those
programs?

But this is just a guess from what I have seen on w32.

Re: Weirdness with Emacs' X window id

[Jan D.]

Peter Heslin wrote:

>In Debian GNU/Linux:
>
>If I do emacs -q --no-site-file with a month-old CVS checkout, and
>then M-x eshell:
>
>~ $ xdpyinfo |grep -i focus
>focus:  window 0x1400015, revert to Parent
>~ $ wmctrl -l |grep -i emacs
>0x01400014 1 aideen Emacs *eshell*
>
>where wmctrl is a command-line program and the -l switch makes it list
>all current windows.  Note that xdpyinfo and wmctrl disagree as to
>what should be the ID number for the single Emacs frame.  One says a
>number ending in 14, the other in 15.
>
>wmctrl -l does not know of any window with the ID 0x1400015.
>
>Is this expected?  I don't know anything about these IDs -- I'm just
>trying to write a script to manipulate windows on my desktop, and
>it's quite difficult with this ID schizophrenia.
>
>Emacs is the only application I run that behaves like this.
>
>If it's not expected behavior, then it could be a bug in wmctrl,
>xdpyinfo, my X server, Emacs, or who knows where, so it would be
>interesting to see if anyone else sees this.
>

It is normal.  The window manager may set windows between the Emacs 
window and the root window.  Also, there is a special window called the 
client leader window used for session handling.  I don't know which 
window wmctrl  returns, it can be any of these.  To see all windows 
Emacs has, use:

% xwininfo -tree -id 0x1400015

(or 14).

    Jan D.

Re: Weirdness with Emacs' X window id

[Robert J. Chassell]

Peter Heslin <public@heslin.eclipse.co.uk> wrote,

   If I do emacs -q --no-site-file with a month-old CVS checkout, and
   then M-x eshell:

   ~ $ xdpyinfo |grep -i focus
   focus:  window 0x1400015, revert to Parent
   ~ $ wmctrl -l |grep -i emacs
   0x01400014 1 aideen Emacs *eshell*

   where wmctrl is a command-line program and the -l switch makes it list
   all current windows.  Note that xdpyinfo and wmctrl disagree as to
   what should be the ID number for the single Emacs frame.  

   ... Emacs is the only application I run that behaves like this.

This also happens with

Today's GNU Emacs CVS snapshot, Mon, 2005 Feb  7  14:18 UTC
GNU Emacs 21.3.50.51 (i686-pc-linux-gnu, GTK+ Version 2.4.14)
started with

    emacs -Q

Very strange.  I did not expect it.  I do not know what is going on.

-- 
    Robert J. Chassell                         
    bob@rattlesnake.com                         GnuPG Key ID: 004B4AC8
    http://www.rattlesnake.com                  http://www.teak.cc

Re: Weirdness with Emacs' X window id

[Jan D.]

Robert J. Chassell wrote:

>Peter Heslin <public@heslin.eclipse.co.uk> wrote,
>
>   If I do emacs -q --no-site-file with a month-old CVS checkout, and
>   then M-x eshell:
>
>   ~ $ xdpyinfo |grep -i focus
>   focus:  window 0x1400015, revert to Parent
>   ~ $ wmctrl -l |grep -i emacs
>   0x01400014 1 aideen Emacs *eshell*
>
>   where wmctrl is a command-line program and the -l switch makes it list
>   all current windows.  Note that xdpyinfo and wmctrl disagree as to
>   what should be the ID number for the single Emacs frame.  
>
>   ... Emacs is the only application I run that behaves like this.
>
>This also happens with
>
>Today's GNU Emacs CVS snapshot, Mon, 2005 Feb  7  14:18 UTC
>GNU Emacs 21.3.50.51 (i686-pc-linux-gnu, GTK+ Version 2.4.14)
>started with
>
>    emacs -Q
>
>Very strange.  I did not expect it.  I do not know what is going on.
>  
>

xdpyinfo apparently prints the client leader window id, but wmctrl 
prints the top level id.  It is normal to have the client leader window 
the same as the top level window, but Emacs does not really have one top 
level window that can be used for that purpose.  Frames come and go, and 
the client leader window is expected to exist as long as the application 
exists.  So the Emacs client leader window is a hidden window not seen.

    Jan D.