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From: "Alex R. Mosteo" <devnull@mailinator.com>
Newsgroups: comp.lang.ada
Subject: Re: Robert Dewar's great article about the Strengths of Ada over
 other langauges in multiprocessing!
Date: Fri, 14 Mar 2008 11:16:09 +0100
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Date: 2008-03-14T11:16:09+01:00
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Randy Brukardt wrote:

> "Alex R. Mosteo" <devnull@mailinator.com> wrote in message
> news:63sn1tF29a5oiU1@mid.individual.net...
> ...
>> Although in Ada I don't see much (or any?) use for volatile, non-atomic
> shared
>> variables outside of protected objects.
>>
>> Some flaw in my understanding?
> 
> Yes, sort of. You're not considering non-tasking uses. The canonical example
> for Volatile is reading/writing a memory-mapped hardware device. In that
> case, optimizing out the reads/writes can be fatal. It doesn't directly have
> anything to do with tasking. (I suppose one could consider the hardware
> device as a sort of task, but it would be done with unusual properties.)

Ah, of course. I was so bent on looking for strange uses that I missed the
obvious one.

> Another purpose is for debugging. You can monitor the memory location of a
> Volatile object to see what is going on, without the pragma the compiler can
> optimize the entire object away leaving nothing to monitor. (Of course, the
> pragma also changes the code, which might change the bug you are trying to
> find.)

Hehe. Happily I only need the debugger once in a trimester or so :)

> (...)

Thanks!