Re: Interfacing to C: big structures

[Robert A Duff <bobduff@shell01.TheWorld.com>]

"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