[64bit] emacs is unable to call subprocesses if display-time-mode is set

Corinna Vinschen corinna-cygwin@cygwin.com
Tue Apr 2 09:11:00 GMT 2013

On Apr  1 12:04, Ken Brown wrote:
> On 4/1/2013 8:48 AM, Ken Brown wrote:
> >On 3/30/2013 7:17 AM, Corinna Vinschen wrote:
> >>On Mar 30 06:54, Ken Brown wrote:
> >>>When you set display-time-mode in emacs, the mode line near the
> >>>bottom of the screen shows the current time.  The code that does
> >>>this involves setting itimers.
> >>
> >>Can you extrace a simple testcase from the itimer code?  That would help
> >>a lot to track down this case.  I'm a bit scared of emacs...
> >
> >I was wrong about itimers.  It turns out that emacs uses two different
> >kinds of timers.  One type is defined in C code and uses itimers, and
> >the other type is defined in Lisp code.  It's the latter that's involved
> >here.  So it won't be easy to make a test case in plain C.
> >
> >I'm also finding that the order in which I do things affects whether or
> >not the bug shows up.  For example, if I start a shell within emacs
> >before setting display-time-mode, the bug disappears.  I'll keep looking
> >at the emacs code, but maybe you'll be able to see something in the
> >strace output.
> Sorry for yet another email, but I just wanted to let you know that
> you shouldn't put much time into this unless something jumps out at
> you.
> I just looked at this with gdb again and noticed that the function
> `Fcall_process' [which is the C function that implements the lisp
> function `call-process'] is being called with an argument nargs =
> 4305072226, which is 0x1009A3062; the value should be 4.  nargs is
> of type ptrdiff_t.  I'll try to figure out why this is happening.

Thanks, Ken!  I hold myself back for the time being.  Btw., your
copyright assignment has arrived.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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