From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Juanma Barranquero Newsgroups: gmane.emacs.bugs Subject: bug#8545: issues with recent doprnt-related changes Date: Thu, 28 Apr 2011 05:42:32 +0200 Message-ID: References: <4DB50AB9.6060100@cs.ucla.edu> <83tydmaeo3.fsf@gnu.org> <4DB65FF1.5010003@cs.ucla.edu> <83aafb8p4a.fsf@gnu.org> <4DB8ABEA.3080503@cs.ucla.edu> <4DB8DAF8.7070408@cs.ucla.edu> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1303963622 26275 80.91.229.12 (28 Apr 2011 04:07:02 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Thu, 28 Apr 2011 04:07:02 +0000 (UTC) Cc: 8545@debbugs.gnu.org To: Paul Eggert Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Thu Apr 28 06:06:58 2011 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1QFIVF-0003Il-KC for geb-bug-gnu-emacs@m.gmane.org; Thu, 28 Apr 2011 06:06:57 +0200 Original-Received: from localhost ([::1]:51915 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QFIVB-0002Ac-Az for geb-bug-gnu-emacs@m.gmane.org; Thu, 28 Apr 2011 00:06:53 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:46377) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QFIV9-0002AT-3C for bug-gnu-emacs@gnu.org; Thu, 28 Apr 2011 00:06:51 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QFIV7-0005QE-U6 for bug-gnu-emacs@gnu.org; Thu, 28 Apr 2011 00:06:51 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:54849) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QFIV7-0005Q8-RI for bug-gnu-emacs@gnu.org; Thu, 28 Apr 2011 00:06:49 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.69) (envelope-from ) id 1QFI93-0002MK-TP; Wed, 27 Apr 2011 23:44:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Juanma Barranquero Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 28 Apr 2011 03:44:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 8545 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 8545-submit@debbugs.gnu.org id=B8545.13039622039020 (code B ref 8545); Thu, 28 Apr 2011 03:44:01 +0000 Original-Received: (at 8545) by debbugs.gnu.org; 28 Apr 2011 03:43:23 +0000 Original-Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1QFI8R-0002LR-EM for submit@debbugs.gnu.org; Wed, 27 Apr 2011 23:43:23 -0400 Original-Received: from mail-gy0-f172.google.com ([209.85.160.172]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1QFI8L-0002L9-Lz for 8545@debbugs.gnu.org; Wed, 27 Apr 2011 23:43:22 -0400 Original-Received: by gyf3 with SMTP id 3so884337gyf.3 for <8545@debbugs.gnu.org>; Wed, 27 Apr 2011 20:43:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type:content-transfer-encoding; bh=ImKPrf6upaMe9dEx9GrWQvsix8YCCfBabOGoGKtGVUA=; b=IkNY35uL682xDtyl7UkYKHlZ8jfEyVQisnuuP6f46mzlxq3cQ4O9jOHo1NFsc0iipo WyRkFvdbWt2pLQowTK4BBsUJRrnjmwXEXh1v1Re4Tesyq5WXeYsTJRpD608vSJ0G6IUj PtuEb7dA3FlG7lZhEhIbtOe0uWuW3+NVgxSnY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=qTH1fFg82khgA2dpvcQ60wn3FMntayPs+9yQ2C5uxTRaN97iIbP6eB5FqTKgoTS0R+ TcrDSKvA4Rd+2JWdQxo8TyUW7WFa2YuRUPJC76AqQDIQNe81t9h/b2d6Ysw3HARne6Cs 6rUQ8+Vbx2SBWS8xNkcwS15EIVtmn6JO3khDM= Original-Received: by 10.236.176.6 with SMTP id a6mr3490692yhm.428.1303962192090; Wed, 27 Apr 2011 20:43:12 -0700 (PDT) Original-Received: by 10.147.182.5 with HTTP; Wed, 27 Apr 2011 20:42:32 -0700 (PDT) In-Reply-To: <4DB8DAF8.7070408@cs.ucla.edu> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list Resent-Date: Wed, 27 Apr 2011 23:44:01 -0400 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:46050 Archived-At: On Thu, Apr 28, 2011 at 05:11, Paul Eggert wrote: >> would it be undefined behavior, >> as long as the pointer has not been dereferenced? > > Yes. =C2=A0A portable C program is not allowed to create a pointer that > doesn't point to an object, with the two exceptions of a null pointer > and a pointer to the address immediately after an object. That's weird, because it would mean that every pointer variable must be initialized (either explicitly to some value, or implicitly to the null pointer), or else the program will have undefined behavior. Anyway, in this case fmt =3D=3D format_end + 1 would point to the address immediately after an object, wouldn't it? > On > some architectures, attempting to point to random addresses can cause > exceptions or other undefined behavior. On dereferencing, sure. But just on assignment to the pointer variable? =C2=A0 =C2=A0 Juanma