{"id":2226294,"url":"http://patchwork.ozlabs.org/api/1.2/covers/2226294/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/cover/bmm.hhubrmqub2.gcc.gcc-TEST.redi.31.1.0@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":"2026-04-22T10:44:15","name":"[v1,00/16] atomic wait/notify ABI stabilization","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.hhubrmqub2.gcc.gcc-TEST.redi.31.1.0@forge-stage.sourceware.org/mbox/","series":[{"id":500987,"url":"http://patchwork.ozlabs.org/api/1.2/series/500987/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=500987","date":"2026-04-22T10:44:17","name":"atomic wait/notify ABI stabilization","version":1,"mbox":"http://patchwork.ozlabs.org/series/500987/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/covers/2226294/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=2620:52:6:3111::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\n [IPv6:2620:52:6:3111::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 4g0xXg14pKz1y2d\n\tfor ; Wed, 22 Apr 2026 21:17:55 +1000 (AEST)","from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 235E948FE0A2\n\tfor ; Wed, 22 Apr 2026 11:17:53 +0000 (GMT)","from forge-stage.sourceware.org (vm08.sourceware.org [38.145.34.39])\n by sourceware.org (Postfix) with ESMTPS id A1BE140959A3\n for ; Wed, 22 Apr 2026 10:46:01 +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 7630242BAE\n for ; Wed, 22 Apr 2026 10:46:01 +0000 (UTC)"],"DKIM-Filter":["OpenDKIM Filter v2.11.0 sourceware.org 235E948FE0A2","OpenDKIM Filter v2.11.0 sourceware.org A1BE140959A3"],"DMARC-Filter":"OpenDMARC Filter v1.4.2 sourceware.org A1BE140959A3","ARC-Filter":"OpenARC Filter v1.0.0 sourceware.org A1BE140959A3","ARC-Seal":"i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1776854761; cv=none;\n b=UsQIgkQP2qofRQ33biZQ5RLUEl6S/AboWwp1Ra9vrKwwSexRaw7HueL7MN/hA5pZHkVcv/Wk2QH+WLdZ+9R5W6yir+2oxbCfzJZ3N285xDSp7EZxolUH9rKlU7I/gVNOugnPxZ6tOA4ytqC5xlTuACl6MyXyxkhVVsT+ynBVkvg=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1776854761; c=relaxed/simple;\n bh=UwoVBCjYJ16pxYHwJQLdSWY/xOrkSz8eLLrGB24QU1s=;\n h=From:Date:Subject:To:Message-ID;\n b=ceHwsPM5UFKbsN0VNq3W9AOJZzw595EX+LWZCNRw1VWW4JBoR7yeUv48AK7sRye5pn+Cq142QzyXl2m5sWw3r0phgE5mxgRKlvLbVeCLrxlHtThdaPyuqUduxQAUdfRcG+SJqq8pf+kdwmHO7GWDp7fsb9VWQeBnhqdgI58smRA=","ARC-Authentication-Results":"i=1; server2.sourceware.org","From":"Jonathan Wakely via Sourceware Forge\n ","Date":"Wed, 22 Apr 2026 10:44:15 +0000","Subject":"[PATCH v1 00/16] atomic wait/notify ABI stabilization","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/31","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: 2025-01-10 00:38:00+00:00\nLatest update: 2025-08-13 03:29:35+00:00\nChanges: 19 changed files, 1030 additions, 1111 deletions\nHead revision: redi/gcc ref atomic-patches commit 2ecceadcbe231874053dc40943a112aad0778d82\nBase revision: gcc/gcc-TEST ref trunk commit ae2912748b9913fe9cd198db1b3fa704d0cbc728 r15-9121-gae2912748b9913\nMerge base: ae2912748b9913fe9cd198db1b3fa704d0cbc728\nFull diff url: https://forge.sourceware.org/gcc/gcc-TEST/pulls/31.diff\nDiscussion: https://forge.sourceware.org/gcc/gcc-TEST/pulls/31\nRequested Reviewers:\n\n\nRefactoring of C++20 atomic wait/notify and related synchronization types. The goal is to make the implementation ready for some pieces to be moved into libstdc++.so instead of defining everything inline in the headers (see [PR 99277](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99277)).\n\nThis fixes:\n\n- [104928 - std::counting_semaphore on Linux can sleep forever](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104928)\n- [99572 - std::counting_semaphore coalescing wakes](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99572)\n- [118395 - Constructor of std::barrier is not constexpr](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118395)\n\nPartially fixed:\n- [98749 - No precondition checks in ``, `` and ``](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98749)\n\n**Not** fixed yet:\n- [115955 - `atomic::wait _S_for` uses a poor hash function](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115955)\n- [110854 - constructor of std::counting_semaphore is not constexpr](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110854)\n- std::barrier waits on 1-byte value, so can't use futex directly (see [PR 99277](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99277)).\n\n\nChanged files:\n- A: libstdc++-v3/src/c++20/atomic.cc\n- A: libstdc++-v3/testsuite/30_threads/barrier/cons.cc\n- A: libstdc++-v3/testsuite/30_threads/barrier/lwg3898.cc\n- A: libstdc++-v3/testsuite/30_threads/semaphore/cons.cc\n- D: libstdc++-v3/testsuite/30_threads/semaphore/platform_try_acquire_for.cc\n- D: libstdc++-v3/testsuite/30_threads/semaphore/try_acquire_posix.cc\n- M: libstdc++-v3/config/abi/pre/gnu.ver\n- M: libstdc++-v3/include/bits/atomic_timed_wait.h\n- M: libstdc++-v3/include/bits/atomic_wait.h\n- M: libstdc++-v3/include/bits/semaphore_base.h\n- M: libstdc++-v3/include/std/barrier\n- M: libstdc++-v3/include/std/latch\n- M: libstdc++-v3/include/std/semaphore\n- M: libstdc++-v3/src/c++20/Makefile.am\n- M: libstdc++-v3/src/c++20/Makefile.in\n- M: libstdc++-v3/testsuite/17_intro/headers/c++1998/49745.cc\n- M: libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/100334.cc\n- M: libstdc++-v3/testsuite/29_atomics/atomic_integral/wait_notify.cc\n- M: libstdc++-v3/testsuite/30_threads/semaphore/100806.cc\n\n\nJonathan Wakely (14):\n libstdc++: Whitespace fixes in atomic wait/notify code\n libstdc++: Various fixes for atomic wait/notify code\n libstdc++: Fix race condition in new atomic notify code\n libstdc++: Fix time_point conversion in atomic timed waits\n libstdc++: Simplify futex wrapper functions for atomic wait/notify\n libstdc++: Remove reinterpret_cast uses in atomic wait/notify\n libstdc++: Rename __atomic_compare to __atomic_eq\n libstdc++: Rename __waiter_pool_impl to __waitable_state\n libstdc++: Move atomic wait/notify entry points into the library\n libstdc++: Optimise std::latch::arrive_and_wait\n libstdc++: Fix std::barrier for constant initialization [PR118395]\n libstdc++: Create new base class of std::barrier for non-dependent\n code\n libstdc++: Rewrite std::counting_semaphore base class [PR118494]\n libstdc++: Define __wait_result_type for atomic waiting\n\nThomas Rodgers (2):\n libstdc++: Atomic wait/notify ABI stabilization\n libstdc++: Pass __wait_args to internal API by const pointer\n\n libstdc++-v3/config/abi/pre/gnu.ver | 6 +\n libstdc++-v3/include/bits/atomic_timed_wait.h | 436 ++++------------\n libstdc++-v3/include/bits/atomic_wait.h | 483 ++++++-----------\n libstdc++-v3/include/bits/semaphore_base.h | 229 +++------\n libstdc++-v3/include/std/barrier | 199 ++++---\n libstdc++-v3/include/std/latch | 26 +-\n libstdc++-v3/include/std/semaphore | 32 +-\n libstdc++-v3/src/c++20/Makefile.am | 2 +-\n libstdc++-v3/src/c++20/Makefile.in | 4 +-\n libstdc++-v3/src/c++20/atomic.cc | 485 ++++++++++++++++++\n .../17_intro/headers/c++1998/49745.cc | 2 -\n .../29_atomics/atomic/wait_notify/100334.cc | 7 +-\n .../29_atomics/atomic_integral/wait_notify.cc | 8 +-\n .../testsuite/30_threads/barrier/cons.cc | 6 +\n .../testsuite/30_threads/barrier/lwg3898.cc | 45 ++\n .../testsuite/30_threads/semaphore/100806.cc | 2 +-\n .../testsuite/30_threads/semaphore/cons.cc | 7 +\n .../semaphore/platform_try_acquire_for.cc | 9 -\n .../30_threads/semaphore/try_acquire_posix.cc | 153 ------\n 19 files changed, 1030 insertions(+), 1111 deletions(-)\n create mode 100644 libstdc++-v3/src/c++20/atomic.cc\n create mode 100644 libstdc++-v3/testsuite/30_threads/barrier/cons.cc\n create mode 100644 libstdc++-v3/testsuite/30_threads/barrier/lwg3898.cc\n create mode 100644 libstdc++-v3/testsuite/30_threads/semaphore/cons.cc\n delete mode 100644 libstdc++-v3/testsuite/30_threads/semaphore/platform_try_acquire_for.cc\n delete mode 100644 libstdc++-v3/testsuite/30_threads/semaphore/try_acquire_posix.cc"}