From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS22989 209.51.188.0/24 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 598C41F463 for ; Mon, 16 Dec 2019 10:03:00 +0000 (UTC) Received: from localhost ([::1]:49468 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ignDO-0001af-W7 for normalperson@yhbt.net; Mon, 16 Dec 2019 05:02:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43181) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ignDG-0001aX-Rz for bug-gnulib@gnu.org; Mon, 16 Dec 2019 05:02:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ignDF-0003rH-OF for bug-gnulib@gnu.org; Mon, 16 Dec 2019 05:02:50 -0500 Received: from zimbra.cs.ucla.edu ([131.179.128.68]:54572) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ignDF-0003pv-IQ for bug-gnulib@gnu.org; Mon, 16 Dec 2019 05:02:49 -0500 Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 92E381600FC; Mon, 16 Dec 2019 02:02:47 -0800 (PST) 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 AbsuMF6xhHBW; Mon, 16 Dec 2019 02:02:46 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id E0FF01605CA; Mon, 16 Dec 2019 02:02:46 -0800 (PST) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu 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 vDZRi80o7SZL; Mon, 16 Dec 2019 02:02:46 -0800 (PST) Received: from [192.168.1.9] (cpe-23-242-74-103.socal.res.rr.com [23.242.74.103]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id BF57E1600FC; Mon, 16 Dec 2019 02:02:46 -0800 (PST) Subject: Re: intptr_t vs. uintptr_t To: Bruno Haible References: <20190323080618.E6EB.27F6AC2D@kcn.ne.jp> <2783436.Tsuh4lOfYa@omega> <362ef4f4-83b7-1630-9ad3-4453ae2b5e64@cs.ucla.edu> <1794872.dtbK2spBG1@omega> From: Paul Eggert Organization: UCLA Computer Science Department Message-ID: <3d6aefa2-b23a-903c-99a5-9c3e3c262094@cs.ucla.edu> Date: Mon, 16 Dec 2019 02:02:46 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <1794872.dtbK2spBG1@omega> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 X-BeenThere: bug-gnulib@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Gnulib discussion list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: bug-gnulib@gnu.org Errors-To: bug-gnulib-bounces+normalperson=yhbt.net@gnu.org Sender: "bug-gnulib" On 12/14/19 4:35 PM, Bruno Haible wrote: > the advice can be simplified: If pointer arithmetic > is involved, uintptr_t is better suited than intptr_t. And if pointer arithmetic > is not involved, uintptr_t and intptr_t are equivalent and equally good. It's more complicated in Emacs, because Emacs sometimes converts small integers to pointers and then back again, and these integers can be negative. (The C standard doesn't guarantee that this works, but Emacs is deliberately nonportable in this low-level area and it does work on Emacs's current platforms.) For such conversions, signed integers are more convenient. It is a messy area, admittedly.