Re: [ANNOUNCEMENT] Uploads for 12 August

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

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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.


Corinna

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

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