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Re: [64bit] Problem with emacs and shared memory under X11
- From: Ken Brown <kbrown at cornell dot edu>
- To: cygwin-apps at cygwin dot com
- Date: Sat, 20 Jul 2013 08:02:32 -0400
- Subject: Re: [64bit] Problem with emacs and shared memory under X11
- References: <51D82992 dot 5010402 at dronecode dot org dot uk> <51E70D37 dot 5020600 at dronecode dot org dot uk> <20130718083748 dot GA9628 at calimero dot vinschen dot de> <51E858E2 dot 7050802 at dronecode dot org dot uk> <20130718213455 dot GC30542 at calimero dot vinschen dot de> <51E91378 dot 6060402 at dronecode dot org dot uk> <20130719113509 dot GF20871 at calimero dot vinschen dot de> <51E96374 dot 4080308 at cornell dot edu> <20130719171104 dot GI20871 at calimero dot vinschen dot de> <51E974D9 dot 30906 at dronecode dot org dot uk> <20130720050608 dot GA4134 at ednor dot casa dot cgf dot cx>
On 7/20/2013 1:06 AM, Christopher Faylor wrote:
On Fri, Jul 19, 2013 at 06:18:17PM +0100, Jon TURNEY wrote:
On 19/07/2013 18:11, Corinna Vinschen wrote:
On Jul 19 12:04, Ken Brown wrote:
On 7/19/2013 7:35 AM, Corinna Vinschen wrote:
On Jul 19 11:22, Jon TURNEY wrote:
Oh yes, that works, and is a bit clearer.
Thanks for testing. I applied the patch and attributed it to you in
the ChangeLog since you did all the work anyway.
There's still the x86 issue that I mentioned earlier. With
cygwin-1.7.21 (as well as today's snapshot), I'm getting a return
value of 0 from shmtest on x86. This is with cygserver not running.
(In fact, cygserver has never been configured on this system, so
there's no /etc/cygserver.conf). Jon reported getting a return
value of 1 using cygwin-1.7.20.
I don't recall seeing this testcase. Any chance you can extract an STC
to help fixing this? I wonder how this happened anyway. There were no
changes in terms of XSI IPC between 1.7.20 and 1.7.21, except for tiny
changes for porting to x86_64. What on earth did I screw up this
shmtest.c was attached to my mail a couple of days ago 
This seems to be an unrelated issue. When cygserver is not running, this
program should receive a SIGSYS and terminate with exit code 140 (128 + signal)
This works correctly on x86_64, but on x86, although the signal is raised,
something goes wrong and the exit code is 0...
The exit 0 behavior (which I think was introduced in 1.7.20) should now
be fixed in CVS and, soon, in a snapshot.
Confirmed. I now get "Bad system call", as expected, and an exit code
of 140. This is from running shmtest with cygserver not running.
There's still a difference between the x86 behavior and the x86_64
behavior. It's not relevant to the bug being discussed in this thread,
and maybe it's to be expected, but I'll report it anyway:
On x86_64 the error message is "Bad system call (core dumped)", and
there is in fact a stackdump. On x86 the error message doesn't say
"core dumped", but there is nevertheless a stackdump file created, which
is essentially empty:
$ cat shmtest32.exe.stackdump
Frame Function Args