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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Interfacing to C: big structures
Date: Tue, 26 Feb 2008 20:40:09 -0500
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2008-02-26T20:40:09-05:00
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"Randy Brukardt" <randy@rrsoftware.com> writes:

> "Simon Wright" <simon.j.wright@mac.com> wrote in message
> news:m27igr4i0b.fsf@mac.com...
>> Adam Beneschan <adam@irvine.com> writes:
>>
>> > I thought of something like this, but Maciej said something about
>> > wanting to avoid dynamic memory, and it seems that you're defining a
>> > type whose size isn't going to be known until runtime, and therefore
>> > if you declare an Ada variable of that type, it will have to be
>> > allocated dynamically in some way.
>>
>> That was the cunning trick: the size is known at *elaboration* time!
>>
>> procedure Main_Program is
>>   type T is Ada.Streams.Stream_Element_Array (1 .. Size_Returned_From_C);
>>   V : aliased T;
>
> But at least some compilers will allocate V on the heap (under the covers,
> of course) because the size of the object is not know at compile-time.

I the compiler does that, I presume it would (under the covers)
deallocate the heap object on leaving the relevant scope.

> Janus/Ada works this way, for instance. For high-integrity applications,
> that's still unacceptable.
>
> But the OP didn't provide enough information to know if this is acceptable
> to him or not.

Indeed.

- Bob