From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: windows build help Date: Sun, 15 Oct 2017 23:49:49 -0700 Organization: UCLA Computer Science Department Message-ID: References: <84o9pyim1a.fsf@AigleRoyal> <83r2up976t.fsf@gnu.org> <83bmlblfca.fsf@gnu.org> <877evyev8o.fsf_-_@russet.org.uk> <86a80udeid.fsf@stephe-leake.org> <87376m9edg.fsf@russet.org.uk> <86wp3xbw0y.fsf@stephe-leake.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1508136635 22555 195.159.176.226 (16 Oct 2017 06:50:35 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 16 Oct 2017 06:50:35 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 Cc: stephen_leake@stephe-leake.org, emacs-devel@gnu.org To: rms@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Oct 16 08:50:31 2017 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e3zEJ-0004iN-Cz for ged-emacs-devel@m.gmane.org; Mon, 16 Oct 2017 08:50:27 +0200 Original-Received: from localhost ([::1]:59593 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e3zEQ-00080h-M2 for ged-emacs-devel@m.gmane.org; Mon, 16 Oct 2017 02:50:34 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41463) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e3zDo-00080X-Er for emacs-devel@gnu.org; Mon, 16 Oct 2017 02:49:57 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e3zDl-00076y-B1 for emacs-devel@gnu.org; Mon, 16 Oct 2017 02:49:56 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:44380) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e3zDl-00074s-5R; Mon, 16 Oct 2017 02:49:53 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 3F8BD160062; Sun, 15 Oct 2017 23:49:51 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id IFoIWuBAmPm1; Sun, 15 Oct 2017 23:49:50 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 85DBF160E2A; Sun, 15 Oct 2017 23:49:50 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id lzhNl9jz7t_F; Sun, 15 Oct 2017 23:49:50 -0700 (PDT) Original-Received: from [192.168.1.9] (unknown [47.154.18.85]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 3720B160062; Sun, 15 Oct 2017 23:49:50 -0700 (PDT) In-Reply-To: Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:219568 Archived-At: > > one can write Elisp code that compiles to different .elc files > > depending whether the compiling Emacs is built for a 32 or 64 bit = machine, >=20 > Just for curiosity's sake, would anyone like to tell me what circumstan= ces > this happens in? For example, given this source code: (defconst x (* 32768 32768)) On a 64-bit machine, byte-compiling generates an .elc file containing thi= s: (defconst x 1073741824) On a 32-bit machine, byte-compiling the same source code generates an .el= c file=20 containing this instead: (defconst x 0) due to multiplication overflow in this Emacs's integers, which use 30-bit= two's=20 complement. Each .elc file is correct for the Emacs it is built with, but= =20 incorrect for the other Emacs. GNU Emacs source code should not do this sort of thing, since the .elc fi= les=20 distributed in its tarballs are supposed to be portable.