Re: Ada Address = C pointer ?

["M. A. Alves" <maa@liacc.up.pt>]

On Tue, 30 Oct 2001, Mark Johnson wrote:
> "M. A. Alves" wrote:
> > I am in fact using Address and Access_To_Address_Conversions(*) because I
> > simply did not find out how to do the trick otherwise.  For example, the C
> > function is returning an array of unsigned long.  I want to access that
> > array without copying it.  How can you do that with Interfaces.C.Strings
> > or even Interfaces.C.Pointers ?
>
> Reread the implementation advice in B.3....
>  An Ada parameter of an array type with component type T, of any mode, is passed
> as a t* argument to a C function, where t is the C type corresponding to the Ada
> type T.

Yes, a very sensible _advice_ indeed. Somehow I feel more assured with
Address_To_Access_Conversions. Actually it is more than just a feeling,
according to http://adapower.com/lang/accessmem.html .

But adhering to the advice surely makes for the most elegant coding.

Note that by now, thanks to all, this thread has tutored all possible
idioms of C-interfacing namely:

  * using Address_To_Access_Conversions

  * using Interfaces.C.Pointers

  * commiting to implementation advice in B.3...

Well done guys!

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