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 D65D63858432 for ; Tue, 7 Dec 2021 21:52:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org D65D63858432 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-275-IetolKYeOaO-0xol-GNTOQ-1; Tue, 07 Dec 2021 16:52:13 -0500 X-MC-Unique: IetolKYeOaO-0xol-GNTOQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4DD3E8015CD; Tue, 7 Dec 2021 21:52:12 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.193.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EDB675C1D5; Tue, 7 Dec 2021 21:52:10 +0000 (UTC) From: Florian Weimer To: Jonathan Wakely Cc: "Jonathan Wakely via Libstdc++" , Jonathan Wakely , gcc-patches Subject: Re: [PATCH] libstdc++: Allow std::condition_variable waits to be cancelled [PR103382] References: <20211207205803.1142706-1-jwakely@redhat.com> <871r2onmfg.fsf@oldenburg.str.redhat.com> Date: Tue, 07 Dec 2021 22:52:08 +0100 In-Reply-To: (Jonathan Wakely's message of "Tue, 7 Dec 2021 21:38:26 +0000") Message-ID: <87tufkm6bb.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 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-6.5 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=ham 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, 07 Dec 2021 21:52:16 -0000 * Jonathan Wakely: > On Tue, 7 Dec 2021, 21:20 Florian Weimer via Libstdc++, > wrote: > > * Jonathan Wakely via Libstdc: > > > If necessary we could keep the terminate-on-cancellation behaviour as > > _ZNSt18condition_variable4waitERSt11unique_lockISt5mutexE@GLIBCXX_3.4.= 11 > > and export the new behaviour as @@GLIBCXX_3.4.30, although this patch > > doesn't do that. > > Note that if this fix escapes into the wild and then you have to make > the symbol version change, you will break newer applications. In a few > cases in glibc, we proactively added aliases at a different symbol > version, but with the same implementation (at first). > > To be safe, we probably should preserve the old behaviour for the old > version of the symbol. If we decide that the new behaviour is always > preferable, we could change that later by making the old symbol an > alias for the new. If we don't decide that, we'll be glad we made it a > separate symbol. On the other hand, with separate versions, it's possible to reintroduce the old behavior at a later date, as a bugfix. It's not strictly necessary to do that work upfront. It's just nice to have this option. > I'll see if I can get it working with two versioned symbols. We don't > actually do that in libstdc++ currently, we only have a single version > of every symbol. Ping me if you want to discuss options. 8-> Out of curiosity=E2=80=94do you support building libstdc++ (the shared obje= ct) with a different compiler than the included GCC? Thanks, Florian