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,c76d41708bf94f23
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news2.google.com!goblin2!goblin1!goblin.stu.neva.ru!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail
From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: c2ada bug report filed
Date: Thu, 31 Mar 2011 22:03:52 +0100
Organization: A noiseless patient Spider
Message-ID: <m24o6jovd3.fsf@pushface.org>
References: <3a657bf9-89ed-45c8-bd4d-f226cb3bc5fa@w7g2000pre.googlegroups.com>
	<4d94c18b$0$4966$a8266bb1@postbox2.readnews.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: mx03.eternal-september.org;
 posting-host="dFCm8HWntFqmDIilBLqEJQ";
	logging-data="8321"; mail-complaints-to="abuse@eternal-september.org";
	posting-account="U2FsdGVkX1/ADSFv6JoSWs4CNCuIjXFJEJSkx8hoiKQ="
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (darwin)
Cancel-Lock: sha1:8RWPNTeUj42e2txrFRH+zPBM9w4=
	sha1:CllsVTlnG3vnvoxnbLhfeypjZDU=
Xref: g2news2.google.com comp.lang.ada:19602
Date: 2011-03-31T22:03:52+01:00
List-Id: <comp.lang.ada>

Per Sandberg <per.sandberg@bredband.net> writes:

> So i expect c2ada to be obsolete at least when GNAT GPL 2011 is
> released.

GNAT GPL 2010 certainly tries; I don't know how good it is.

Just tried on <tcl.h>; GPL 2010 is better than FSF 4.6.0, which didn't
understand
  #define TCL_MAJOR_VERSION 8
for example.

Both made a - to my eyes - strange choice about parameter passing:

   typedef struct Tcl_Interp {
       ...
   } Tcl_Interp;

translated as

   type Tcl_Interp is record
      ...
   end record;
   pragma Convention (C_Pass_By_Copy, Tcl_Interp);

Now, the C code that's being called most certainly doesn't expect
pass-by-copy; and the generated binding always says (eg)

   function Tcl_AppInit (arg1 : access Tcl_Interp) return int;

Wouldn't pragma Convention (C) have done?


For interest, the tcladashell equivalent (which, I believe, was
originally generated using c2ada, but has since been heavily
hand-amended) is

   type Tcl_Interp_Rec (<>) is private;
   type Tcl_Interp is access all Tcl_Interp_Rec;
   pragma Convention (C, Tcl_Interp);

   function Tcl_AppInit (interp : in Tcl_Interp) return C.int;

I shall have a think about this, the 'access' approach is certainly
neat. There's the question of whether null is allowed; if it is, and
customers are using Ada95, 'access' is ruled out.