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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Any way of persuading GNAT/GCC to implement a true overlay and
 not a pointer?
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Date: Sat, 1 Apr 2006 20:04:35 +0200
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Date: 2006-04-01T20:04:30+02:00
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On Sat, 1 Apr 2006 17:52:46 +0100, Doobs wrote:

> ">> I was under the impression that code of the following form :
>>>
>>> X : <Some Type>;
>>> Y : <Some Type>;
>>> for Y'Address use X'Address;
>>>
>>> would result in an overlay in the resulting code.
> 
> Tried Pragma volatile - had no effect.....
> 
> What I am seeing is that in the map file X and Y are located at different 
> addresses.  Even though Y is a large array in my implementation, the linker 
> has only reserved four bytes for it.  When examining the contents of Y at 
> run time it contains the address of X - i.e. it is a pointer to X

Is it possible that the object's type is unconstrained and what you see is
the array dope allocated at the address specified, rather than the array
body?

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de