Re: Fix for Cygwin/GSlice problem

[Jan D.]

On 2009-12-09 04:06, Ken Brown wrote:
> On 12/8/2009 8:33 PM, Stefan Monnier wrote:
> > > +/* Emacs supplies its own malloc, but glib (part of Gtk+) calls
> > > + memalign and on Cygwin, that becomes the Cygwin supplied memalign.
> > > + As malloc is not the Cygwin malloc, the Cygwin memalign always
> > > + returns ENOSYS. A workaround is to set G_SLICE=always-malloc. */
> > > +#define G_SLICE_ALWAYS_MALLOC
> >
> > Why does Cygwin-Emacs use its own malloc rather than the system malloc?

Emacs prefers its own malloc when the system malloc doesn't have the 
required hooks.  If this is critical or not I don't know.

> There was a long thread about this on the Cygwin list in 2007, in which
> Jan Djärv tried to sort this out. It starts at
>
> http://cygwin.com/ml/cygwin/2007-02/threads.html#00469
>
> and continues at
>
> http://cygwin.com/ml/cygwin/2007-02/threads.html#00503
>
> I'm afraid a lot of that discussion is over my head. All I can say is
> that the Emacs build brings in the Emacs malloc and friends, but when
> glib calls memalign, the Cygwin memalign gets called instead of the one
> supplied by Emacs. Maybe Jan can explain why it wasn't possible to
> change this or to simply use Cygwin's malloc and friends. He seemed
> optimistic at the end of thread, but then the discussion stopped.

I think it stopped because it came down to the way Cygwin handles 
linking of malloc and friends.  I don't understand why Cygwin doesn't 
allow an application to have its own memalign, but do allow it to have 
its own malloc.

        Jan D.