From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,d9e66bfe9beb10b9
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: g2news1.google.com!postnews2.google.com!not-for-mail
From: fjloma@andaluciajunta.es (Francisco Javier Loma Daza)
Newsgroups: comp.lang.ada
Subject: Re: C array to ada record interface
Date: 22 Jul 2004 11:02:39 -0700
Organization: http://groups.google.com
Message-ID: <404ee0af.0407221002.1cfdc21e@posting.google.com>
References: <404ee0af.0407141517.30cacac7@posting.google.com>
 <W%kJc.3320$Qu5.3121@newsread2.news.pas.earthlink.net>
NNTP-Posting-Host: 80.102.44.14
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Trace: posting.google.com 1090519360 22550 127.0.0.1 (22 Jul 2004 18:02:40
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Thu, 22 Jul 2004 18:02:40 +0000 (UTC)
Xref: g2news1.google.com comp.lang.ada:2350
Date: 2004-07-22T11:02:39-07:00
List-Id: <comp.lang.ada>

Jeffrey Carter <spam@spam.com> wrote in message news:<W%kJc.3320$Qu5.3121@newsread2.news.pas.earthlink.net>...
> Francisco Javier Loma Daza wrote:
> 
> > struct
> > {
> >    int a,b,c:
> >    int len;
> >    struct b* arr;
> > } A;
> > 
> > And I would love to interface in Ada with a record with a discriminant
> > 
> > type B_array(len: Positive) is record
> >     arr: array of B(1..len);
> > end record;
> > 
> > type A(len: Positive) is
> >    a,b,c: Integer;
> >    arr:   A(len);
> > end record;
> 
> Assuming you meant
> 
>     Arr : B_Array (Len => Len);
> 
> this won't work. What you have from C is a pointer; the actual array may 
>   not even be contiguous with the struct. You'll have to do something like
> 
> type B_Ptr is access all B;
> pragma Convention (C, B_Ptr);
> 
> type A_Info is record
>     A, B, C : Interfaces.C.Int;
>     Len     : Interfaces.C.Int;
>     Arr     : B_Ptr;
> end record;
> pragma Convention (C, A_Info);
> 
> You only use these types when talking directly to C. For the rest of 
> your application, you use something like the record you presented, and 
> have your operations that talk to C convert between the 2.


Thanks, I think you understood well

I would want to use some more ada like array, you suggest to implement
that with accesors functions ... I was just wondering if it can be
done, the Len + Arr part, to be set up as an Ada array ...