From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Matt Armstrong Newsgroups: gmane.emacs.devel Subject: Re: question about Qnil representation Date: Wed, 26 Oct 2022 09:16:53 -0700 Message-ID: <87ilk6a7be.fsf@rfc20.org> References: <5a560265-fa81-42d2-945b-ab85d72df9e6@Spark> <5a00e93e-5f44-4865-aeeb-51f0aced9996@Spark> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="31469"; mail-complaints-to="usenet@ciao.gmane.io" To: Troy Hinckley , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Oct 26 18:18:16 2022 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1onj6e-0007u5-1r for ged-emacs-devel@m.gmane-mx.org; Wed, 26 Oct 2022 18:18:16 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1onj5m-0001wo-Mc; Wed, 26 Oct 2022 12:17:22 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1onj5W-0000bA-3v for emacs-devel@gnu.org; Wed, 26 Oct 2022 12:17:18 -0400 Original-Received: from relay9-d.mail.gandi.net ([217.70.183.199]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1onj5R-0005gZ-CB for emacs-devel@gnu.org; Wed, 26 Oct 2022 12:17:04 -0400 Original-Received: (Authenticated sender: matt@rfc20.org) by mail.gandi.net (Postfix) with ESMTPSA id 826B9FF804; Wed, 26 Oct 2022 16:16:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rfc20.org; s=gm1; t=1666801017; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aTRAaARnQmxIDi641TrqX31rDpwsW2Qv0YarS0+QY7U=; b=JJckYcgiKVrjxAZob0E2UY0uF61UTkXhDyF56uhq2paUy2N6j/bFK+NgBOla+PHoLgcMqK 1tNi/eTgQYP+J1jVQVxGM9y5VbE7/DxbF8v4D+1ZuqG1DiikZIH8qElG1BHmnzrLt7dWSc sVZwW+smctan6ef2bEbbKjtAWejYm6LPt/Ts+yaJzL74w6vGu4z1EG+C4B77fw9AdcpHXO dButY207YJ55BLzymI0w9LTx1n7HXNZ2t3H8J4SxuvkMAJemEUJk2DUTVapAPtk4gZ6nVW qbVuYfzRH4FjP611895HIfs8Y1SBDFa0jSw3zbMlLzhXkT7Gdm5dOHjDA96okg== Original-Received: from matt by naz with local (Exim 4.96) (envelope-from ) id 1onj5J-000OKC-2C; Wed, 26 Oct 2022 09:16:53 -0700 In-Reply-To: <5a00e93e-5f44-4865-aeeb-51f0aced9996@Spark> Received-SPF: pass client-ip=217.70.183.199; envelope-from=matt@rfc20.org; helo=relay9-d.mail.gandi.net X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: "Emacs-devel" Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:298559 Archived-At: Troy Hinckley writes: > but 0 would not be a valid pointer. I am a confused by this. 0 is a valid value for a C pointer. This is what NULL is, etc. You must not dereference it, but it is a valid value.