{"id":2226101,"url":"http://patchwork.ozlabs.org/api/1.2/covers/2226101/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/cover/bmm.hhu8u7e3ks.gcc.gcc-TEST.redi.4.2.0@forge-stage.sourceware.org/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/1.2/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"","list_archive_url":null,"date":"2026-04-22T08:58:14","name":"[v2,0/1] libstdc++: Deprecate useless compatibility headers for C++17","submitter":{"id":93210,"url":"http://patchwork.ozlabs.org/api/1.2/people/93210/?format=json","name":"Jonathan Wakely via Sourceware Forge","email":"forge-bot+redi@forge-stage.sourceware.org"},"mbox":"http://patchwork.ozlabs.org/project/gcc/cover/bmm.hhu8u7e3ks.gcc.gcc-TEST.redi.4.2.0@forge-stage.sourceware.org/mbox/","series":[{"id":500950,"url":"http://patchwork.ozlabs.org/api/1.2/series/500950/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=500950","date":"2026-04-22T08:58:14","name":"libstdc++: Deprecate useless compatibility headers for C++17","version":2,"mbox":"http://patchwork.ozlabs.org/series/500950/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/covers/2226101/comments/","headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; helo=vm01.sourceware.org;\n envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org;\n receiver=patchwork.ozlabs.org)","sourceware.org; dmarc=none (p=none dis=none)\n header.from=forge-stage.sourceware.org","sourceware.org;\n spf=pass smtp.mailfrom=forge-stage.sourceware.org","server2.sourceware.org;\n arc=none smtp.remote-ip=38.145.34.39"],"Received":["from vm01.sourceware.org (vm01.sourceware.org [38.145.34.32])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g0tTJ1Cypz1yD5\n\tfor ; Wed, 22 Apr 2026 18:59:48 +1000 (AEST)","from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 574BA4B9DB75\n\tfor ; Wed, 22 Apr 2026 08:59:46 +0000 (GMT)","from forge-stage.sourceware.org (vm08.sourceware.org [38.145.34.39])\n by sourceware.org (Postfix) with ESMTPS id 518B24B9DB59\n for ; Wed, 22 Apr 2026 08:59:19 +0000 (GMT)","from forge-stage.sourceware.org (localhost [IPv6:::1])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256)\n (No client certificate requested)\n by forge-stage.sourceware.org (Postfix) with ESMTPS id 24B814052E\n for ; Wed, 22 Apr 2026 08:59:19 +0000 (UTC)"],"DKIM-Filter":["OpenDKIM Filter v2.11.0 sourceware.org 574BA4B9DB75","OpenDKIM Filter v2.11.0 sourceware.org 518B24B9DB59"],"DMARC-Filter":"OpenDMARC Filter v1.4.2 sourceware.org 518B24B9DB59","ARC-Filter":"OpenARC Filter v1.0.0 sourceware.org 518B24B9DB59","ARC-Seal":"i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1776848359; cv=none;\n b=akqCsJvuDnn0E3xp06NOkANiJnTI77xsUFc0sObsTn+vvbCnB160vBXm7kzQ7Rkk3WOu/9ZZbBjYZdk01Iie7YaVplLnyDGyPAJyw1uWGBn/THfQavrVHopXLQv0tOBcAgT/VpeXeirDNpon4kR6tx02wZsNMx+5GDOtYjnqf2U=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1776848359; c=relaxed/simple;\n bh=HavtEEpGo/t9JJ5+YN4gdfs77RC5pE3I2NtS5Ad801c=;\n h=From:Date:Subject:To:Message-ID;\n b=rrgflXLySGaRIbFLT0bdDiGdFU7WwUZuHwnp5DVEt6lU2/0majVWGtbrmSTFYf+ILcvomaq6sW1lR15A3PgB0ZLiBaFrZLW2sIGke04xiRD6KYAhzRV3obEqcp4/a8ndF2b9AfQqHkoi55JR5NpM6cZbXK2Xce5J20s6gb6bmfI=","ARC-Authentication-Results":"i=1; server2.sourceware.org","From":"Jonathan Wakely via Sourceware Forge\n ","Date":"Wed, 22 Apr 2026 08:58:14 +0000","Subject":"[PATCH v2 0/1] libstdc++: Deprecate useless compatibility\n headers for C++17","To":"gcc-patches mailing list ","Message-ID":"\n ","X-Mailer":"batrachomyomachia","X-Pull-Request-Organization":"gcc","X-Pull-Request-Repository":"gcc-TEST","X-Pull-Request":"https://forge.sourceware.org/gcc/gcc-TEST/pulls/4","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Reply-To":"gcc-patches mailing list , redi@gcc.gnu.org","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"},"content":"Hi gcc-patches mailing list,\nJonathan Wakely via Sourceware Forge has requested that the following forgejo pull request\nbe published on the mailing list.\n\nCreated on: 2024-10-23 18:51:55+00:00\nLatest update: 2026-04-21 21:24:26+00:00\nChanges: 586 changed files, 19943 additions, 5410 deletions\nHead revision: redi/gcc ref deprecate-cheaders commit 0740f7d2e5e1ba2ec93969675a6b9baa31e48c47\nBase revision: gcc/gcc-TEST ref trunk commit a00a0e34b8a7312bcf357bd0238d6d9711ca96b2 r15-4817-ga00a0e34b8a731\nMerge base: a00a0e34b8a7312bcf357bd0238d6d9711ca96b2\nFull diff url: https://forge.sourceware.org/gcc/gcc-TEST/pulls/4.diff\nDiscussion: https://forge.sourceware.org/gcc/gcc-TEST/pulls/4\nRequested Reviewers:\n\nThese headers make no sense for C++ programs, because they either define\ndifferent content to the corresponding `` C header, or define\nnothing at all in namespace std. They were all deprecated in C++17, so\nadd deprecation warnings to them, which can be disabled with\n`-Wno-deprecated`. For C++20 and later these headers are no longer in the\nstandard at all, so compiling with `_GLIBCXX_USE_DEPRECATED` defined to 0\nwill give an error when they are included.\n\nBecause `#warning` is non-standard before C++23 we need to use pragmas to\nignore `-Wc++23-extensions` for the `-Wsystem-headers -pedantic` case.\n\nOne g++ test needs adjustment because it includes ``, but that\ncan be made conditional on the `__cplusplus` value without any reduction\nin test coverage.\n\n```\nlibstdc++-v3/ChangeLog:\n\n * doc/xml/manual/evolution.xml: Document deprecations.\n * doc/html/*: Regenerate.\n * include/c_compatibility/complex.h (_GLIBCXX_COMPLEX_H): Move\n include guard to start of file. Include directly\n instead of .\n * include/c_compatibility/tgmath.h: Include and\n directly, instead of .\n * include/c_global/ccomplex: Add deprecated #warning for C++17\n and #error for C++20 if _GLIBCXX_USE_DEPRECATED == 0.\n * include/c_global/ciso646: Likewise.\n * include/c_global/cstdalign: Likewise.\n * include/c_global/cstdbool: Likewise.\n * include/c_global/ctgmath: Likewise.\n * include/c_std/ciso646: Likewise.\n * include/precompiled/stdc++.h: Do not include ccomplex,\n ciso646, cstdalign, cstdbool, or ctgmath in C++17 and later.\n * testsuite/18_support/headers/cstdalign/macros.cc: Check for\n warnings and errors for unsupported dialects.\n * testsuite/18_support/headers/cstdbool/macros.cc: Likewise.\n * testsuite/26_numerics/headers/ctgmath/complex.cc: Likewise.\n * testsuite/27_io/objects/char/1.cc: Do not include .\n * testsuite/27_io/objects/wchar_t/1.cc: Likewise.\n * testsuite/18_support/headers/cstdbool/std_c++0x_neg.cc: Removed.\n * testsuite/18_support/headers/cstdalign/std_c++0x_neg.cc: Removed.\n * testsuite/26_numerics/headers/ccomplex/std_c++0x_neg.cc: Removed.\n * testsuite/26_numerics/headers/ctgmath/std_c++0x_neg.cc: Removed.\n * testsuite/18_support/headers/ciso646/macros.cc: New test.\n * testsuite/18_support/headers/ciso646/macros.h.cc: New test.\n * testsuite/18_support/headers/cstdbool/macros.h.cc: New test.\n * testsuite/26_numerics/headers/ccomplex/complex.cc: New test.\n * testsuite/26_numerics/headers/ccomplex/complex.h.cc: New test.\n * testsuite/26_numerics/headers/ctgmath/complex.h.cc: New test.\n\ngcc/testsuite/ChangeLog:\n\n * g++.old-deja/g++.other/headers1.C: Do not include ciso646 for\n C++17 and later.\n```\n\n\nChanged files:\n- A: libstdc++-v3/testsuite/18_support/headers/ciso646/macros.cc\n- A: libstdc++-v3/testsuite/18_support/headers/ciso646/macros.h.cc\n- A: libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.h.cc\n- A: libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.h.cc\n- A: libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.cc\n- A: libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.h.cc\n- A: libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.h.cc\n- D: libstdc++-v3/testsuite/18_support/headers/cstdalign/std_c++0x_neg.cc\n- D: libstdc++-v3/testsuite/18_support/headers/cstdbool/std_c++0x_neg.cc\n- D: libstdc++-v3/testsuite/26_numerics/headers/ccomplex/std_c++0x_neg.cc\n- D: libstdc++-v3/testsuite/26_numerics/headers/ctgmath/std_c++0x_neg.cc\n- M: gcc/testsuite/g++.old-deja/g++.other/headers1.C\n- M: libstdc++-v3/doc/html/manual/api.html\n- M: libstdc++-v3/doc/xml/manual/evolution.xml\n- M: libstdc++-v3/include/c_compatibility/complex.h\n- M: libstdc++-v3/include/c_compatibility/tgmath.h\n- M: libstdc++-v3/include/c_global/ccomplex\n- M: libstdc++-v3/include/c_global/ciso646\n- M: libstdc++-v3/include/c_global/cstdalign\n- M: libstdc++-v3/include/c_global/cstdbool\n- M: libstdc++-v3/include/c_global/ctgmath\n- M: libstdc++-v3/include/c_std/ciso646\n- M: libstdc++-v3/include/precompiled/stdc++.h\n- M: libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.cc\n- M: libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.cc\n- M: libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.cc\n- M: libstdc++-v3/testsuite/27_io/objects/char/1.cc\n- M: libstdc++-v3/testsuite/27_io/objects/wchar_t/1.cc\n\n\nJonathan Wakely (1):\n libstdc++: Deprecate useless compatibility headers for C++17\n\n .../g++.old-deja/g++.other/headers1.C | 2 +\n libstdc++-v3/doc/html/manual/api.html | 8 +++\n libstdc++-v3/doc/xml/manual/evolution.xml | 10 ++++\n .../include/c_compatibility/complex.h | 10 ++--\n libstdc++-v3/include/c_compatibility/tgmath.h | 11 ++--\n libstdc++-v3/include/c_global/ccomplex | 9 ++++\n libstdc++-v3/include/c_global/ciso646 | 9 ++++\n libstdc++-v3/include/c_global/cstdalign | 8 +++\n libstdc++-v3/include/c_global/cstdbool | 8 +++\n libstdc++-v3/include/c_global/ctgmath | 14 +++--\n libstdc++-v3/include/c_std/ciso646 | 10 ++++\n libstdc++-v3/include/precompiled/stdc++.h | 13 +++--\n .../18_support/headers/ciso646/macros.cc | 51 +++++++++++++++++++\n .../18_support/headers/ciso646/macros.h.cc | 49 ++++++++++++++++++\n .../18_support/headers/cstdalign/macros.cc | 10 +++-\n .../18_support/headers/cstdalign/macros.h.cc | 25 +++++++++\n .../headers/cstdalign/std_c++0x_neg.cc | 24 ---------\n .../18_support/headers/cstdbool/macros.cc | 9 +++-\n .../18_support/headers/cstdbool/macros.h.cc | 21 ++++++++\n .../headers/cstdbool/std_c++0x_neg.cc | 26 ----------\n .../26_numerics/headers/ccomplex/complex.cc | 10 ++++\n .../26_numerics/headers/ccomplex/complex.h.cc | 10 ++++\n .../headers/ccomplex/std_c++0x_neg.cc | 26 ----------\n .../26_numerics/headers/ctgmath/complex.cc | 9 +++-\n .../26_numerics/headers/ctgmath/complex.h.cc | 10 ++++\n .../headers/ctgmath/std_c++0x_neg.cc | 26 ----------\n .../testsuite/27_io/objects/char/1.cc | 1 -\n .../testsuite/27_io/objects/wchar_t/1.cc | 1 -\n 28 files changed, 294 insertions(+), 126 deletions(-)\n create mode 100644 libstdc++-v3/testsuite/18_support/headers/ciso646/macros.cc\n create mode 100644 libstdc++-v3/testsuite/18_support/headers/ciso646/macros.h.cc\n create mode 100644 libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.h.cc\n delete mode 100644 libstdc++-v3/testsuite/18_support/headers/cstdalign/std_c++0x_neg.cc\n create mode 100644 libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.h.cc\n delete mode 100644 libstdc++-v3/testsuite/18_support/headers/cstdbool/std_c++0x_neg.cc\n create mode 100644 libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.cc\n create mode 100644 libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.h.cc\n delete mode 100644 libstdc++-v3/testsuite/26_numerics/headers/ccomplex/std_c++0x_neg.cc\n create mode 100644 libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.h.cc\n delete mode 100644 libstdc++-v3/testsuite/26_numerics/headers/ctgmath/std_c++0x_neg.cc\n\nRange-diff against v1:"}