[64bit] Problem with emacs and shared memory under X11

[Jon TURNEY]

On 06/07/2013 12:46, Ken Brown wrote:
> On 64bit Cygwin, if I try to run emacs under X11 while cygserver is running,
> emacs fails to connect to the X server.  The error message from the X server is
> 
>   BadShmSeg (invalid shared segment parameter) on protocol request 131
> 
> To reproduce:
> 
> 1. Install the current version of emacs-X11 (24.3-4).
> 
> 2. Start the (64bit) cygserver service.
> 
> 3. Start the (64bit) X server, e.g., by typing "startxwin" in a Cygwin Terminal.
> 
> 4. In the resulting xterm, try to start emacs:
> 
>   $ emacs-X11.exe -Q &
> 
> The result is that emacs displays the error message above and then aborts.
> 
> emacs-X11 works fine if the X server is started when cygserver is not running.

Yup, there's some kind of bug which affects SHM use by the X server on 64bit.
I am looking into it.

You can also work around this by starting the X server with '-extension MIT-SHM'

-- 
Jon TURNEY
Volunteer Cygwin/X X Server maintainer