Re: Interfacing to C: big structures

[Stephen Leake <stephen_leake@stephe-leake.org>]

Robert A Duff <bobduff@shell01.TheWorld.com> writes:

> Maciej Sobczak <see.my.homepage@gmail.com> writes:
>
>> Consider the C API that contains some structure S and a couple of
>> functions that operate on the state that is stored in the Struct. A
>> typical usage in C might be:
>>
>> struct S s;
>>
>> init(&s);
>> foo(&s);
>> bar(&s);
>> baz(&s);
>>
>> Above, s is created with automatic storage duration.
>>
>> How to interface to this from Ada? I see two options:
>
> Something like:
>
>     type S is record ... end record;
>     pragma Convention (C, S);
>     
>     X : aliased S;
>     init (X'Access); -- or possibly 'Unchecked_Access
>     foo (X'Access); -- or ...

Why not:

procedure Init (X : in out S);
procedure Foo (X : in out S);

begin
    init (X);
    foo (X);
end;

-- 
-- Stephe