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Date: Fri, 5 Jan 2007 11:07:55 -0600
From: Brian Ford <Brian DOT Ford AT FlightSafety DOT com>
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Subject: Re: 1.7.0 CVS mmap failure
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On Fri, 5 Jan 2007, Christopher Faylor wrote:
> On Fri, Jan 05, 2007 at 10:55:09AM -0600, Brian Ford wrote:
> >One more tidbit before I have time to find the real problem.  Compiling
> >the test case with -Wl,large-address-aware makes the test pass on a
> >/3GB system.
>
> Does that mean that this is a solution for you, Brian?

It's a work around.  I wouldn't exactly call it a solution.

> If the MEM_TOP_DOWN problem is just allocating memory in a place that
> an app isn't prepared to deal with that seems like a lurking problem
> with the app, anyway, since even without MEM_TOP_DOWN there is no
> guarantee that the address from mmap will not show up in a problematic
> range of memory.

On the contrary, I'd say this says something more like Windows is
allocating memory in a place that it knows a non-large address aware
application is not supposed to have access to.  If you look at my test
app, you'll see it doesn't even use the mapped pointer.  The mmap just
fails, so in this case, Cygwin would be the "app" with the lurking
problem ;-).

I'm looking into the issue myself, BTW.

-- 
Brian Ford
Lead Realtime Software Engineer
VITAL - Visual Simulation Systems
FlightSafety International
the best safety device in any aircraft is a well-trained crew...



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