From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: ludo@gnu.org (Ludovic =?UTF-8?Q?Court=C3=A8s?=) Newsgroups: gmane.lisp.guile.bugs Subject: bug#12095: Protecting pointer on bytevector with guardian does not protect memory Date: Sun, 07 Oct 2012 22:38:33 +0200 Message-ID: <87y5ji2f1y.fsf@gnu.org> References: <20502.44997.295661.951990@vagabond.local> <878vdskmde.fsf@Kagami.home> <874nm75le8.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1349642386 18880 80.91.229.3 (7 Oct 2012 20:39:46 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 7 Oct 2012 20:39:46 +0000 (UTC) Cc: 12095@debbugs.gnu.org, Ian Price To: Daniel Hartwig Original-X-From: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Sun Oct 07 22:39:50 2012 Return-path: Envelope-to: guile-bugs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1TKxdc-0003Np-ID for guile-bugs@m.gmane.org; Sun, 07 Oct 2012 22:39:48 +0200 Original-Received: from localhost ([::1]:50792 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TKxdW-0004nE-L1 for guile-bugs@m.gmane.org; Sun, 07 Oct 2012 16:39:42 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:56089) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TKxdU-0004n9-BK for bug-guile@gnu.org; Sun, 07 Oct 2012 16:39:41 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TKxdT-0001Cu-DT for bug-guile@gnu.org; Sun, 07 Oct 2012 16:39:40 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:50140) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TKxdT-0001Co-9k for bug-guile@gnu.org; Sun, 07 Oct 2012 16:39:39 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.72) (envelope-from ) id 1TKxdq-0005Ne-Et for bug-guile@gnu.org; Sun, 07 Oct 2012 16:40:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: ludo@gnu.org (Ludovic =?UTF-8?Q?Court=C3=A8s?=) Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-CC: bug-guile@gnu.org Resent-Date: Sun, 07 Oct 2012 20:40:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 12095 X-GNU-PR-Package: guile X-GNU-PR-Keywords: Original-Received: via spool by 12095-submit@debbugs.gnu.org id=B12095.134964234520614 (code B ref 12095); Sun, 07 Oct 2012 20:40:02 +0000 Original-Received: (at 12095) by debbugs.gnu.org; 7 Oct 2012 20:39:05 +0000 Original-Received: from localhost ([127.0.0.1]:60391 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.72) (envelope-from ) id 1TKxcv-0005MR-4U for submit@debbugs.gnu.org; Sun, 07 Oct 2012 16:39:05 -0400 Original-Received: from xanadu.aquilenet.fr ([88.191.123.111]:48939) by debbugs.gnu.org with esmtp (Exim 4.72) (envelope-from ) id 1TKxcp-0005Lx-VT for 12095@debbugs.gnu.org; Sun, 07 Oct 2012 16:39:02 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by xanadu.aquilenet.fr (Postfix) with ESMTP id 7E92B2E9A; Sun, 7 Oct 2012 22:38:34 +0200 (CEST) Original-Received: from xanadu.aquilenet.fr ([127.0.0.1]) by localhost (xanadu.aquilenet.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tlBTbM1VESFs; Sun, 7 Oct 2012 22:38:34 +0200 (CEST) Original-Received: from pluto (reverse-83.fdn.fr [80.67.176.83]) by xanadu.aquilenet.fr (Postfix) with ESMTPSA id D99DD2826; Sun, 7 Oct 2012 22:38:33 +0200 (CEST) X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 16 =?UTF-8?Q?Vend=C3=A9miaire?= an 221 de la =?UTF-8?Q?R=C3=A9volution?= X-PGP-Key-ID: 0xEA52ECF4 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 83C4 F8E5 10A3 3B4C 5BEA D15D 77DD 95E2 EA52 ECF4 X-OS: x86_64-unknown-linux-gnu In-Reply-To: (Daniel Hartwig's message of "Sun, 7 Oct 2012 10:56:55 +0800") User-Agent: Gnus/5.130005 (Ma Gnus v0.5) Emacs/24.2 (gnu/linux) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.13 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 140.186.70.43 X-BeenThere: bug-guile@gnu.org List-Id: "Bug reports for GUILE, GNU's Ubiquitous Extension Language" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Original-Sender: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.bugs:6545 Archived-At: Hi, Daniel Hartwig skribis: > On 7 October 2012 05:41, Ludovic Court=C3=A8s wrote: >> Hi, >> >> Daniel Hartwig skribis: >> >>> (define x (bytevector->pointer (make-bytevector len 1))) >>> (define a (pointer-address x)) >>> (display x)(newline) >>> (my-guardian x) >>> ;(my-guardian (pointer->bytevector x len)) >>> (set! x #f) >>> >>> (define (dump-struct) >>> (write (pointer->bytevector (make-pointer a) len))(newline)) >> >> This is expected to fail: =E2=80=98bytevector->pointer=E2=80=99 creates = a weak reference >> from the returned pointer object to the given bytevector. So when the >> pointer object is reclaimed, the bytevector can be reclaimed too, hence >> the problem you=E2=80=99re observing. (And no, guardians don=E2=80=99t = protect objects >> from garbage collection.) > > If I understand correctly, there is never any non-weak reference to > the bv above and so it can be collected at any time. There=E2=80=99s a weak reference from the pointer object to the bytevector. Once that pointer object has been collected (as in the example above), the bytevector can be collected anytime. Thanks, Ludo=E2=80=99.