From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-return-170735-listarch-gcc=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 3818 invoked by alias); 18 Oct 2011 18:39:20 -0000
Received: (qmail 3809 invoked by uid 22791); 18 Oct 2011 18:39:19 -0000
X-SWARE-Spam-Status: No, hits=-2.4 required=5.0	tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW
X-Spam-Check-By: sourceware.org
Received: from mail-wy0-f175.google.com (HELO mail-wy0-f175.google.com) (74.125.82.175)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 18 Oct 2011 18:39:04 +0000
Received: by wyg19 with SMTP id 19so1029493wyg.20        for <gcc@gcc.gnu.org>; Tue, 18 Oct 2011 11:39:03 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.216.229.30 with SMTP id g30mr1277165weq.51.1318963143142; Tue, 18 Oct 2011 11:39:03 -0700 (PDT)
Received: by 10.216.36.78 with HTTP; Tue, 18 Oct 2011 11:39:03 -0700 (PDT)
In-Reply-To: <20111018200320.d842f5352bbdccf961125857@starynkevitch.net>
References: <20111018171201.361304028ab94f102f827bd2@starynkevitch.net>	<CAH6eHdQLu6fJGBdY5PQbBLJj2MWdmM5YZVMUPJmMShLdWQtr+Q@mail.gmail.com>	<20111018200320.d842f5352bbdccf961125857@starynkevitch.net>
Date: Tue, 18 Oct 2011 19:42:00 -0000
Message-ID: <CAH6eHdQ4rSVeb0tiPgtALOK=k7ZpSKX5LyP=x39n53TFE5H1eQ@mail.gmail.com>
Subject: Re: adding destroyable objects into Ggc
From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: Basile Starynkevitch <basile@starynkevitch.net>
Cc: gcc@gcc.gnu.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-IsSubscribed: yes
Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc/>
List-Post: <mailto:gcc@gcc.gnu.org>
List-Help: <http://gcc.gnu.org/ml/>
Sender: gcc-owner@gcc.gnu.org
X-SW-Source: 2011-10/txt/msg00293.txt.bz2

On 18 October 2011 19:03, Basile Starynkevitch wrote:
> On Tue, 18 Oct 2011 18:53:07 +0100
> Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
>
>> On 18 October 2011 16:12, Basile Starynkevitch wrote:
>> >
>> > Of course, with C++, the destructor routine is really what C++ calls a=
 destructor, e.g
>> > something like extern "C" void my_destructor_for_class_C (class C* p)
>> > { delete (p) p; // call the placement version of operator delete, from=
 <new> C++ library
>> > header. }
>>
>> Why not just call the destructor?
>>
>> =A0 =A0p->~C()
>
> You are right. But I was also thinking of giving a C ABI to these destruc=
tors.

Yes, I understand that, I wasn't talking about the C interface.

I assume you haven't tried to compile your suggested code, because
1) your destructor function doesn't match the ggc_destructor_t signature.
2) you can't call placement delete like that
3) the placement delete in <new> is a no-op

You probably want something like this:

extern "C" void my_destructor_for_class_C (void* p)
{ static_cast<C*>(p)->~C(); }