[ANNOUNCEMENT] Uploads for 12 August

Corinna Vinschen corinna-cygwin@cygwin.com
Wed Aug 14 14:05:00 GMT 2013

On Aug 14 08:28, Ryan Johnson wrote:
> On 14/08/2013 7:59 AM, Corinna Vinschen wrote:
> >On Aug 14 13:33, Corinna Vinschen wrote:
> >>On Aug 14 12:53, Corinna Vinschen wrote:
> >>>On Aug 14 06:28, Ken Brown wrote:
> >>>>On 8/14/2013 5:16 AM, Corinna Vinschen wrote:
> >>>>>On Aug 14 10:10, Corinna Vinschen wrote:
> >>>>>>On Aug 13 18:00, Ken Brown wrote:
> >>>>>>>On 8/13/2013 2:26 PM, Corinna Vinschen wrote:
> >>>>>>>>What function is not implemented?  Is that something we can fix,
> >>>>>>>>perhaps in the Cygwin DLL?
> >>>>>>>It's memalign, or at least that's what it was in 2007.  See
> >>>>>>>
> >>>>>>>   http://cygwin.com/ml/cygwin/2007-02/msg00678.html
> >>>>>>So it's using its own malloc but we don't support overriding other
> >>>>>>functions besides malloc/realloc/calloc/free.
> >>>>>>
> >>>>>>In theory we could do that in future.  We still have room for 10 (x86)
> >>>>>>resp. 12 (x86_64) pointers in the per_process structure, which could be
> >>>>>>used for this purpose.  This would only require applications which need
> >>>>>>this feature to be rebuilt with the next Cygwin version providing these
> >>>>>>pointers.
> >>>>>More precisely, they have to be rebuild using crt0.o from the next
> >>>>>Cygwin release, and they would have to run under the next Cygwin
> >>>>>release.  If you omit one step, you're back to the current behaviour.
> >>>>>
> >>>>>>But we shouldn't waste those unused slots either, so the number of
> >>>>>>overridable functions should be kept small.  In theory we have mallopt,
> >>>>>>mallinfo, posix_memalign, memalign, and valloc.
> >>>>>>
> >>>>>>I guess we can skip mallopt and mallinfo since they are pretty
> >>>>>>seldomly used in user-provided malloc implementations.
> >>>>>>
> >>>>>>Memalign is an old, deprecated function, so I wonder why it's used at
> >>>>>>all.  GSlice should use posix_memalign instead.  Yaakov, is there an
> >>>>>>option to use posix_memalign rather than memalign?
> >>>>I just checked the glib source, and it does use posix_memalign if
> >>>>it's available.  I was quoting a 2007 discussion when I said it was
> >>>>memalign that GSlice wanted to use.
> >>>Given that, we should perhaps skip the memalign override.
> >>On second (third? fourth?) thought, I think we should do this with
> >>posix_memalign only.  valloc is just as obsolete as posix_memalign.
> >I applied the patch to allow overriding posix_memalloc only, and I'm

> >building snapshots right now.  For testing, this requires to rebuild
> >either emacs, or glib, or both, I'm not sure.  Make sure to link against
> >the new crt0.o/libcygwin.a and use the new Cygwin DLL for testing.
> Wait, it's "memalign" that's obsolete and "posix_memalign" that you
> added a patch for, right? The last couple of paragraphs were a
> little confusing...


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