From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <basile@starynkevitch.net>
Received: from mail1-relais-roc.national.inria.fr (mail1-relais-roc.national.inria.fr [192.134.164.82])
	by yquem.inria.fr (Postfix) with ESMTP id 50218BBAF
	for <caml-list@yquem.inria.fr>; Sat,  9 Jan 2010 00:53:53 +0100 (CET)
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: ApoDAN9UR0s+BBFpe2dsb2JhbACBRIIal30BARYkA6xRjQmBK4IuVgQ
X-IronPort-AV: E=Sophos;i="4.49,245,1262559600"; 
   d="scan'208";a="44494581"
Received: from smtp-105-friday.noc.nerim.net (HELO mallaury.nerim.net) ([62.4.17.105])
  by mail1-smtp-roc.national.inria.fr with ESMTP; 09 Jan 2010 00:53:53 +0100
Received: from hector.lesours (ours.starynkevitch.net [213.41.244.95])
	by mallaury.nerim.net (Postfix) with ESMTP id 1A7CEA1062;
	Sat,  9 Jan 2010 00:53:51 +0100 (CET)
Received: from glinka.lesours ([192.168.0.1])
	by hector.lesours with esmtp (Exim 4.71)
	(envelope-from <basile@starynkevitch.net>)
	id 1NTOeO-00041E-Hz; Sat, 09 Jan 2010 00:53:52 +0100
Message-ID: <4B47C59C.9080505@starynkevitch.net>
Date: Sat, 09 Jan 2010 00:54:04 +0100
From: Basile STARYNKEVITCH <basile@starynkevitch.net>
User-Agent: Mozilla-Thunderbird 2.0.0.22 (X11/20091109)
MIME-Version: 1.0
To: guillaume.yziquel@citycable.ch
Cc: Damien Doligez <damien.doligez@inria.fr>,
	caml-list List <caml-list@yquem.inria.fr>
Subject: Re: [Caml-list] problem creating .cma library
References: <56670.41.177.16.252.1262195331.squirrel@41.177.16.252>	<4B3BE288.4030701@citycable.ch>	<3EE07409-9559-4B91-BA3E-8787D1378275@inria.fr> <4B47C201.7090201@citycable.ch>
In-Reply-To: <4B47C201.7090201@citycable.ch>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Spam: no; 0.00; basile:01 basile:01 guillaume:01 ocaml:01 byterun:01 camlprim:01 debugger:01 val:01 val:01 camlprim:01 camlparam:01 camlreturn:01 ocaml:01 damien:01 camlparam:01 

Guillaume Yziquel wrote:
> 
> However, I had a look at
> 
>     https://yquem.inria.fr/caml/svn/ocaml/version/3.09/byterun/sys.c
> 
> and more specifically at the function
> 
>> CAMLprim value caml_sys_exit(value retcode)
>> {
>> #ifndef NATIVE_CODE
>>   caml_debugger(PROGRAM_EXIT);
>> #endif
>>   exit(Int_val(retcode));
>>   return Val_unit;
>> }
> 
> or the function
> 
>> CAMLprim value caml_sys_close(value fd)
>> {
>>   close(Int_val(fd));
>>   return Val_unit;
>> }
> 
> Why do these functions not follow the usual CAMLparam/CAMLreturn macro 
> stuff?
> 

Because they are written by the Ocaml guys (Damien knows really well the Ocaml garbage collector; he wrote it). And 
also, because these particular functions do not do any allocation of Ocaml values (either directly or indirectly).

My advice for people coding C code for ocaml is the following:

1. *always* use the CAMLparam/CAMLreturn/... macros.

2. if you dare not using them for some very few functions (because they don't allocate, ...) add a big fat comment with 
a warning inside.

Regards


-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
8, rue de la Faiencerie, 92340 Bourg La Reine, France
*** opinions {are only mines, sont seulement les miennes} ***