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 DB8293858D37 for ; Wed, 20 Jul 2022 13:54:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org DB8293858D37 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-621-ezhFjWiVM0WedWoourFq3Q-1; Wed, 20 Jul 2022 09:54:33 -0400 X-MC-Unique: ezhFjWiVM0WedWoourFq3Q-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 65D1E811E75; Wed, 20 Jul 2022 13:54:32 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.143]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DD8EE141511A; Wed, 20 Jul 2022 13:54:30 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella Netto via Libc-alpha Cc: Joseph Myers , Adhemerval Zanella Netto , Tom Honermann Subject: Re: [PATCH v4 2/3] stdlib: Implement mbrtoc8(), c8rtomb(), and the char8_t typedef. References: <20220630125215.6052-1-tom@honermann.net> <20220630125215.6052-3-tom@honermann.net> <5bcf2650-0cf0-6f67-a532-b47e3daffdda@linaro.org> Date: Wed, 20 Jul 2022 15:54:29 +0200 In-Reply-To: <5bcf2650-0cf0-6f67-a532-b47e3daffdda@linaro.org> (Adhemerval Zanella Netto via Libc-alpha's message of "Wed, 20 Jul 2022 09:04:02 -0300") Message-ID: <878ronlwiy.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-5.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Jul 2022 13:54:38 -0000 * Adhemerval Zanella Netto via Libc-alpha: > On 19/07/22 18:08, Joseph Myers wrote: >> This change appears to introduce a failure of >> wcsmbs/check-installed-headers-cxx with GCC mainline, because uchar.h now >> produces: >> >> ../wcsmbs/uchar.h:38:23: error: identifier 'char8_t' is a keyword in C++20 [-Werror=c++20-compat] >> 38 | typedef unsigned char char8_t; >> >> (recall we want our installed headers to avoid warnings *without* relying >> on the default disabling of warnings in system headers). >> >> Unfortunately, GCC for C++ doesn't disable -Wc++20-compat inside >> __extension__ (unlike what the C front end does), so simply adding >> __extension__ to that declaration wouldn't help, but we could use >> diagnostic disabling pragmas (as already done in some installed headers). > My understanding is compiler will define __cpp_char8_t exactly to avoid > such redefinition. But it seems from gcc documentation that it is only > actually enabled with -fchar8_t. Do we a preprocessor flag to indicate > it? I think __cpp_char8_t is only defined if the language mode is active. The warning is independent of the language mode, though. Thanks, Florian