From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id A9E873858402 for ; Tue, 30 Nov 2021 08:57:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A9E873858402 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-557-JO3Wc9eCNVe0ERBkC6UrPg-1; Tue, 30 Nov 2021 03:56:56 -0500 X-MC-Unique: JO3Wc9eCNVe0ERBkC6UrPg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C84E9100C660; Tue, 30 Nov 2021 08:56:55 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.194.188]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 73BB95D9D5; Tue, 30 Nov 2021 08:56:55 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.16.1/8.16.1) with ESMTPS id 1AU8uqwR2920897 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 30 Nov 2021 09:56:53 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.16.1/8.16.1/Submit) id 1AU8uqcf2920896; Tue, 30 Nov 2021 09:56:52 +0100 Date: Tue, 30 Nov 2021 09:56:52 +0100 From: Jakub Jelinek To: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org Subject: [PATCH] libstdc++: Add [[nodiscard]] to std::byteswap Message-ID: <20211130085652.GK2646553@tucnak> Reply-To: Jakub Jelinek MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=unavailable autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Nov 2021 08:57:02 -0000 Hi! This patch adds [[nodiscard]] to std::byteswap, because the function template doesn't do anything useful if the result isn't used. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2021-11-30 Jakub Jelinek * include/std/bit (byteswap): Add [[nodiscard]]. --- libstdc++-v3/include/std/bit.jj 2021-11-28 16:32:15.204524854 +0100 +++ libstdc++-v3/include/std/bit 2021-11-29 17:40:00.781074520 +0100 @@ -83,6 +83,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Reverse order of bytes in the object representation of `value`. template + [[nodiscard]] constexpr enable_if_t::value, _Tp> byteswap(_Tp __value) noexcept { Jakub