From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <goswin-v-b@web.de>
X-Original-To: caml-list@sympa.inria.fr
Delivered-To: caml-list@sympa.inria.fr
Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83])
	by sympa.inria.fr (Postfix) with ESMTPS id D8D947EEF8
	for <caml-list@sympa.inria.fr>; Tue, 11 Aug 2015 11:36:27 +0200 (CEST)
Received-SPF: None (mail2-smtp-roc.national.inria.fr: no sender
  authenticity information available from domain of
  goswin-v-b@web.de) identity=pra; client-ip=212.227.17.12;
  receiver=mail2-smtp-roc.national.inria.fr;
  envelope-from="goswin-v-b@web.de";
  x-sender="goswin-v-b@web.de"; x-conformance=sidf_compatible
Received-SPF: Pass (mail2-smtp-roc.national.inria.fr: domain of
  goswin-v-b@web.de designates 212.227.17.12 as permitted
  sender) identity=mailfrom; client-ip=212.227.17.12;
  receiver=mail2-smtp-roc.national.inria.fr;
  envelope-from="goswin-v-b@web.de";
  x-sender="goswin-v-b@web.de"; x-conformance=sidf_compatible;
  x-record-type="v=spf1"
Received-SPF: None (mail2-smtp-roc.national.inria.fr: no sender
  authenticity information available from domain of
  postmaster@mout.web.de) identity=helo;
  client-ip=212.227.17.12;
  receiver=mail2-smtp-roc.national.inria.fr;
  envelope-from="goswin-v-b@web.de";
  x-sender="postmaster@mout.web.de";
  x-conformance=sidf_compatible
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: A0A9AQCUwclVnAwR49RdhFjFXQKBNkwBAQEBAQESAQEBAQEGDQkJIS6EJAEBBCcTPxALDgoJJQ8FDRshE4gYAQMWyHQfKw2FRgEBAQEGAQEBAR6LUYJPgjoHgxiBFAEElRCKfoFpiFoMiXSHM4QmbwGCSwEBAQ
X-IPAS-Result: A0A9AQCUwclVnAwR49RdhFjFXQKBNkwBAQEBAQESAQEBAQEGDQkJIS6EJAEBBCcTPxALDgoJJQ8FDRshE4gYAQMWyHQfKw2FRgEBAQEGAQEBAR6LUYJPgjoHgxiBFAEElRCKfoFpiFoMiXSHM4QmbwGCSwEBAQ
X-IronPort-AV: E=Sophos;i="5.15,652,1432591200"; 
   d="scan'208";a="173268698"
Received: from mout.web.de ([212.227.17.12])
  by mail2-smtp-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-SHA; 11 Aug 2015 11:36:27 +0200
Received: from frosties.localnet ([95.208.221.151]) by smtp.web.de (mrweb102)
 with ESMTPSA (Nemesis) id 0M2dg1-1YYvKp1SUP-00sNV0; Tue, 11 Aug 2015 11:36:26
 +0200
Received: from mrvn by frosties.localnet with local (Exim 4.84)
	(envelope-from <goswin-v-b@web.de>)
	id 1ZP5yr-0001cZ-FI; Tue, 11 Aug 2015 11:36:25 +0200
Date: Tue, 11 Aug 2015 11:36:25 +0200
From: Goswin von Brederlow <goswin-v-b@web.de>
To: Malcolm Matalka <mmatalka@gmail.com>
Cc: Nicolas Ojeda Bar <n.oje.bar@gmail.com>, caml-list@inria.fr
Message-ID: <20150811093625.GA5949@frosties>
References: <20150806094030.GE16477@frosties>
 <CAPunWhApy98_3Oyb+FkQLr7xdETAu33YpzGk2R6m9=cPBQF2tg@mail.gmail.com>
 <864mkcci29.fsf@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <864mkcci29.fsf@gmail.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
X-Provags-ID:  V03:K0:v97CzRKp1ymCK7X6kMAyMoH7SfKCZXQHlV9Kqr9aonex5AnQ2xP
 tJQcKbPgrW724pjkXGpl2+x5VjeU0RtZCBYtrEsBmwUObckd57RvJHulf1zv4XJkFNrlIci
 pJvIYXlAkwcWDmfM0bHLd4zJmfUW44ImYsx6pZDJycRxGI+bb/k2K5FYKuKLLpBqpnJH/xz
 AhrGTUe1tRZCZKrMfnxZQ==
X-UI-Out-Filterresults: notjunk:1;V01:K0:bBkOdsXp6p8=:eb5WysHtiYRNaZ+p2bEZLS
 lVqx1FP8Qikna7WgE3AScuty+lJfjPqImixBXH5AV595Y8mnNM2HWsYjz7aZxJlPZzGJHdxEC
 1sc+ekUQNWP5n9UbROkiq96rZ2QdMjSgksHGDgXq+hFwxqNypZ9MtVaZeHWJH+Zj8AdDfJS0m
 8yveUpihxgMFwVIk+iBSPjHa14DjdzxyIf8hVZBV04XPlBvH1IYgujblJxMc537eTDmuNrrUd
 XGNnp2THL04+USuYDR08xptKiQdAsyTZaJZEWIxEXl3cEThQahK8Jj3mjEiwue6Ui16GHtqxo
 heyfDvCY/oaPPX9mAgGf1vIa/sJ+HXsDLcj9Pu3RV0yoJmdgMsjG8ufEH/3e3oCg8srEuXd1P
 /li6xbKzHZfMmpxIKpy3eU1bKLjRgbWQUY1sn5LJSA3tv5uW+PtEMJjNkv8/dyNgDjn48/01h
 z6vevs60sDvDZ/7gtLZabpzSXPFGZ8MJT4M3FGyC9zzcHucW6FokPV24L1W0JucBZ6Akn41Rq
 39uN2elcDqEsktVV3QVRpueUxLSGFjj0yfu/WjRWREP8qi9FFHsmwzBwGFDUE4PrcRuYbjII1
 yAMcV4umzsiiewt9irMDNzWNs271Xae4+nFA6v30hZim/ti2YJCuYOvuzLp3jXkdtMfbrXF18
 hAnj7cFn6nbYkpA9dzkxXMpjf7F7bOHz7ALjhv8lZBN43qLUmYWdd1u51M8cUQestEaUwWX9g
 EAQ4AeQadeqnYQpc
Subject: Re: [Caml-list] Destructive use of file descriptors

On Thu, Aug 06, 2015 at 07:50:38PM +0000, Malcolm Matalka wrote:
> Nicolas Ojeda Bar <n.oje.bar@gmail.com> writes:
> 
> > Hi,
> >
> > No magic needed in OCaml:
> >
> >   let with_open path f =
> >     let oc = open_out path in
> >     match f oc with
> >     | x -> close_out_noerr oc; x
> >     | exception e -> close_out_noerr oc; raise e
> >
> > and then use it as
> >
> >   with_open "foo" (fun oc -> output_string oc str)
> >
> > Cheers
> >
> > Nicolas
> >
> 
> The weakness with this (which I'm not sure if Python offers protection)
> is returning something that references the file created.  It can lead to
> some confusing error messages.

Yeah. I was thinking that that might be avoided. Something on the line
of putting the file descriptor into a local module so ocaml would
complain about it escaping its scope or something.

At least unlike the other suggestion this one closes the FD on exception.

MfG
	Goswin