From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70D20C10F27 for ; Tue, 10 Mar 2020 18:19:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3FEBE21D7E for ; Tue, 10 Mar 2020 18:19:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=pobox.com header.i=@pobox.com header.b="eXtYWKQF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726391AbgCJSTl (ORCPT ); Tue, 10 Mar 2020 14:19:41 -0400 Received: from pb-smtp21.pobox.com ([173.228.157.53]:59974 "EHLO pb-smtp21.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726269AbgCJSTl (ORCPT ); Tue, 10 Mar 2020 14:19:41 -0400 Received: from pb-smtp21.pobox.com (unknown [127.0.0.1]) by pb-smtp21.pobox.com (Postfix) with ESMTP id 10532BC9F6; Tue, 10 Mar 2020 14:19:39 -0400 (EDT) (envelope-from junio@pobox.com) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=+v+RsNB0Rg7i3ZG+fBvhsHgJzkA=; b=eXtYWK QFnQHNODtV55iLScGiUg7YE671u0PvG/pZ3IrmqIj/cTux3/0H/lZRmIVMCdV9jk rvfeZ97lLLzply9cOmvX/e+6ux6xlMq9Tx0DdOvGHUS7we0z20pRpExcp/4fqD71 BDNp3xXN+oIdasCs1nmgbfPuJTJvl7olbWnEE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=mdJrMbQAtD4uS/KWErtmYbjtkr6QDMk7 wB0pBqaQCQAPwVmSgQM8lldqzGPgdqbcl8L3BSaX9oqtbRfdZNhOZN44RbMyh9G0 b01lSCM/9xNhcYjgKu4VwKEkp8cTjd35ZJs8cJRlNTYFr8IxyngbiVZ56/K8veea JtA3q3K+UnY= Received: from pb-smtp21.sea.icgroup.com (unknown [127.0.0.1]) by pb-smtp21.pobox.com (Postfix) with ESMTP id 0921ABC9F5; Tue, 10 Mar 2020 14:19:39 -0400 (EDT) (envelope-from junio@pobox.com) Received: from pobox.com (unknown [34.74.119.39]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp21.pobox.com (Postfix) with ESMTPSA id 4E0B8BC9F2; Tue, 10 Mar 2020 14:19:36 -0400 (EDT) (envelope-from junio@pobox.com) From: Junio C Hamano To: Jeff King Cc: SZEDER =?utf-8?Q?G=C3=A1bor?= , git@vger.kernel.org Subject: Re: [PATCH] commit-slab: clarify slabname##_peek()'s return value References: <20200310153049.3482-1-szeder.dev@gmail.com> <20200310175446.GB549010@coredump.intra.peff.net> Date: Tue, 10 Mar 2020 11:19:33 -0700 In-Reply-To: <20200310175446.GB549010@coredump.intra.peff.net> (Jeff King's message of "Tue, 10 Mar 2020 13:54:46 -0400") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: B2BDFEE6-62FB-11EA-8BAD-8D86F504CC47-77302942!pb-smtp21.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jeff King writes: > But that would get a bit awkward, because peek() returns a pointer, not > a value (as it should, because the type we're storing may be a compound > type, which we generally avoid passing or returning by value). So we'd > actually need to return a pointer to a zero-initialized dummy value. Not > impossible, but getting a bit odd. Do we have a guarantee that callers of the peek only look at, never touch, the location? As long as we make it return a "const *", it might be OK, but a quick look at commit-slab.h tells me that we do not say "const".