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Date: Tue, 9 Aug 2011 10:26:52 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
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Subject: Re: emacs and large-address awareness under recent snapshots
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On Aug  8 19:07, Eliot Moss wrote:
> On 8/8/2011 5:17 PM, Ken Brown wrote:
> 
> >do
> >newsize *= 2;
> >while ((__malloc_size_t) BLOCK ((char *) result + size) > newsize);
> >
> >My guess now is that there was some invalid pointer arithmetic somewhere that led to this, but I
> >don't have time at the moment to look for it. I'll do it later (or tomorrow) if no one beats me to it.
> 
> Possibly, Ken. I also wonder about signed vs unsigned calculations
> and such. We are looking at the higher end of the address space,
> which means negative addresses when considered as signed numbers.
> 
> I'm not sure what the above is doing, but if it is trying to
> double its understanding of the heap size, based on using the
> current end of the heap (result?) as a measure of size, then
> if the heap is at 0x80000000, doubling that gives 0 in a 32-bit
> address space ...

The question is, how could newsize ever become >= 0x80000000?
Ken, what are the values of result and size?  And what value has
heapsize?  Consider that the statement before the loop is

  newsize = heapsize;


Corinna

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

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