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 8B1823858D33 for ; Wed, 13 Mar 2024 23:52:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 8B1823858D33 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 8B1823858D33 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1710373946; cv=none; b=DPNFkzMtIvGbNN9ESwf8IjYRJ5E6ZZ1hwUKf6sbAtLjCcU3R1ArSjUKRhSPwoxf6h2XMP94otr5g9QvKlxY+TM39gwRsCxmGGGw8OaHl3XI1go+JGwJrq3e6n/nm3HbmMt1E59PR5nNCanaRfV9Sb+GvbVzWCUCidsb/euzUfd4= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1710373946; c=relaxed/simple; bh=zk76Nc2vWK01x2EXuyYSGQZrKa4G1AoIVeukwm9kwBQ=; h=DKIM-Signature:MIME-Version:From:Date:Message-ID:Subject:To; b=pMrnotALkT6/tNEaSnHeb6c/zqOLpmauMIoy8RKwsvGMCOwq6AUf4lbpg1ynClAwBnRfHR45Lvl4zYwFf25EwteSebskZ4j+cNYtzWp+JDTCFNIc2yve5eVq2Bp6APMVPQFAVnbHx1jYwRFBrqKNr59gJfSkQhCrgOQ7dN9WGyw= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710373943; 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=EuYjCNFuguUhiox9C2pASON2HCC4noKYMbu+pLXq2Ck=; b=YcjlBrlZDzcNa65H3eJxMfavtm8j0neACUcji3V11RWuRnIWB7VQV1XLgIoRuw+nDykMJa u5+LoXZzGrZVAQtxi2NIiNWVW6g77EGD2od8OTIlKOnEERW6pPuR1sXSNNIhmKBUCqmfwN NHUmY/teey4OiM1SM8RnC7fCcbapEuw= Received: from mail-yw1-f200.google.com (mail-yw1-f200.google.com [209.85.128.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-635-xK1grFJFP2awEe1CWJMLlA-1; Wed, 13 Mar 2024 19:52:21 -0400 X-MC-Unique: xK1grFJFP2awEe1CWJMLlA-1 Received: by mail-yw1-f200.google.com with SMTP id 00721157ae682-60a5374f3bcso6984197b3.0 for ; Wed, 13 Mar 2024 16:52:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710373941; x=1710978741; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=EuYjCNFuguUhiox9C2pASON2HCC4noKYMbu+pLXq2Ck=; b=DQHTWxIMpQTNsvjLZMATkepNEWgCZ86+5c/BJQKuRyAEuxYR0dBcQhirleNBDCP+jW znI0jipvwgUcO3sRtmfpg8wMe3fu+Dm2RCrHA8GRZzBGsiv/LtHhazxug6YtqZJ7qFNr sS+Q7B5cyrccpFSRVk7UbwcFl7r1IfMJ5Js6vd2Zn1vRRA2RJ+UsPhAc/JgEYlyNWLxo 0KMQCwKXlFh0RFXJt9zfu8TfA+i6DqYiS9gH0ivI/s+OTeIlW8gYWA8Je5CQBkdQgChu ZWNfmZTzfe3E5KttV63W53vDDr6bwI95AijppcJ/mjWA8Q1cVq02u+f1Ngton7Ar6uM7 eV+A== X-Gm-Message-State: AOJu0Yz5HdLoHQpOtD1xiwaxxo1zsVHyan4oim6e0eim+y+5JilMP6S6 Tntn0g5paOGm7FPDrOL3pGoDPh40StJZZ+BJFssOt9oIuVI9Qfmq8R3C+wnsI8h4v73ssctzNP2 Hi70eNlsXe41GNZZfsVDRa/fmXeG7BxnfJzviPWPwmacjD/qfAts+vsmFr0A/12KW6MvGWicpb2 rq7spMew/xeZLDNn3Uc7Wsd/ObFr0FnidCJqQ= X-Received: by 2002:a05:6902:1889:b0:dc6:17d2:3b89 with SMTP id cj9-20020a056902188900b00dc617d23b89mr194196ybb.61.1710373941193; Wed, 13 Mar 2024 16:52:21 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHATQDPE90w34/Go1bF43udTU6j0roGEBwVf9sRlXo2m/hX7HD1GYxvyJcNDU6X/OzjSUhFWa1GI6IwXr0ZwXM= X-Received: by 2002:a05:6902:1889:b0:dc6:17d2:3b89 with SMTP id cj9-20020a056902188900b00dc617d23b89mr194185ybb.61.1710373940869; Wed, 13 Mar 2024 16:52:20 -0700 (PDT) MIME-Version: 1.0 References: <20240307120630.482384-1-jwakely@redhat.com> In-Reply-To: <20240307120630.482384-1-jwakely@redhat.com> From: Jonathan Wakely Date: Wed, 13 Mar 2024 23:52:04 +0000 Message-ID: Subject: Re: [PATCH] libstdc++: Document that _GLIBCXX_CONCEPT_CHECKS might be removed in future To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-12.9 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Thu, 7 Mar 2024 at 12:07, Jonathan Wakely wrote: > > Any objection to this update to make the docs reflect reality? Pushed to trunk now. > > -- >8 -- > > The macro-based concept checks are unmaintained and do not support C++11 > or later, so reject valid code. If nobody plans to update them we should > consider removing them. Alternatively, we could ignore the macro for > C++11 and later, so they have no effect and don't reject valid code. > > libstdc++-v3/ChangeLog: > > * doc/xml/manual/debug.xml: Document that concept checking might > be removed in future. > * doc/xml/manual/extensions.xml: Likewise. > --- > libstdc++-v3/doc/xml/manual/debug.xml | 2 ++ > libstdc++-v3/doc/xml/manual/extensions.xml | 18 ++++++++++++------ > 2 files changed, 14 insertions(+), 6 deletions(-) > > diff --git a/libstdc++-v3/doc/xml/manual/debug.xml b/libstdc++-v3/doc/xml/manual/debug.xml > index 42d4d32aa29..7f6d0876fc6 100644 > --- a/libstdc++-v3/doc/xml/manual/debug.xml > +++ b/libstdc++-v3/doc/xml/manual/debug.xml > @@ -351,6 +351,8 @@ > > The Compile-Time > Checks extension has compile-time checks for many algorithms. > + These checks were designed for C++98 and have not been updated to work > + with C++11 and later standards. They might be removed at a future date. > > > > diff --git a/libstdc++-v3/doc/xml/manual/extensions.xml b/libstdc++-v3/doc/xml/manual/extensions.xml > index d4fe2f509d4..490a50cc331 100644 > --- a/libstdc++-v3/doc/xml/manual/extensions.xml > +++ b/libstdc++-v3/doc/xml/manual/extensions.xml > @@ -77,8 +77,7 @@ extensions, be aware of two things: > object file. The checks are also cleaner and easier to read and > understand. > > - They are off by default for all versions of GCC from 3.0 to 3.4 (the > - latest release at the time of writing). > + They are off by default for all GCC 3.0 and all later versions. > They can be enabled at configure time with > --enable-concept-checks. > You can enable them on a per-translation-unit basis with > @@ -89,10 +88,17 @@ extensions, be aware of two things: > > > Please note that the concept checks only validate the requirements > - of the old C++03 standard. C++11 was expected to have first-class > - support for template parameter constraints based on concepts in the core > - language. This would have obviated the need for the library-simulated concept > - checking described above, but was not part of C++11. > + of the old C++03 standard and reject some valid code that meets the relaxed > + requirements of C++11 and later standards. > + C++11 was expected to have first-class support for template parameter > + constraints based on concepts in the core language. > + This would have obviated the need for the library-simulated concept checking > + described above, but was not part of C++11. > + C++20 adds a different model of concepts, which is now used to constrain > + some new parts of the C++20 library, e.g. the > + <ranges> header and the new overloads in the > + <algorithm> header for working with ranges. > + The old library-simulated concept checks might be removed at a future date. > > > > -- > 2.43.2 >