1.. _cxx20-status: 2 3================================ 4libc++ C++20 Status 5================================ 6 7.. include:: ../Helpers/Styles.rst 8 9.. contents:: 10 :local: 11 12 13Overview 14================================ 15 16In July 2017, the C++ standard committee created a draft for the next version of the C++ standard, initially known as "C++2a". 17In September 2020, the C++ standard committee approved this draft, and sent it to ISO for approval as C++20. 18 19This page shows the status of libc++; the status of clang's support of the language features is `here <https://clang.llvm.org/cxx_status.html#cxx20>`__. 20 21.. attention:: Features in unreleased drafts of the standard are subject to change. 22 23The groups that have contributed papers: 24 25- CWG - Core Language Working group 26- LWG - Library working group 27- SG1 - Study group #1 (Concurrency working group) 28 29.. note:: "Nothing to do" means that no library changes were needed to implement this change. 30 31.. _paper-status-cxx20: 32 33Paper Status 34==================================== 35 36.. csv-table:: 37 :file: Cxx20Papers.csv 38 :header-rows: 1 39 :widths: auto 40 41.. note:: 42 43 .. [#note-P0591] P0591: The changes in [mem.poly.allocator.mem] are missing. 44 .. [#note-P0645] P0645: The paper is implemented but still marked as an incomplete feature 45 (the feature-test macro is not set). 46 .. [#note-P0966] P0966: It was previously erroneously marked as complete in version 8.0. See `bug 45368 <https://llvm.org/PR45368>`__. 47 .. [#note-P0619] P0619: Only sections D.8, D.9, D.10 and D.13 are implemented. Sections D.4, D.7, D.11, and D.12 remain undone. 48 .. [#note-P0883.1] P0883: shared_ptr and floating-point changes weren't applied as they themselves aren't implemented yet. 49 .. [#note-P0883.2] P0883: ``ATOMIC_FLAG_INIT`` was marked deprecated in version 14.0, but was undeprecated with the implementation of LWG3659 in version 15.0. 50 .. [#note-P2231] P2231: Optional is complete. The changes to variant haven't been implemented yet. 51 .. [#note-P0660] P0660: The paper is implemented but the features are experimental and can be enabled via ``-fexperimental-library``. 52 .. [#note-P0355] P0355: The implementation status is: 53 54 * ``Calendars`` mostly done in Clang 7 55 * ``Input parsers`` not done 56 * ``Stream output`` Obsolete due to `P1361R2 <https://wg21.link/P1361R2>`_ "Integration of chrono with text formatting" 57 * ``Time zone and leap seconds`` In Progress 58 * ``TAI clock`` not done 59 * ``GPS clock`` not done 60 * ``UTC clock`` not done 61 62.. _issues-status-cxx20: 63 64Library Working Group Issues Status 65==================================== 66 67.. csv-table:: 68 :file: Cxx20Issues.csv 69 :header-rows: 1 70 :widths: auto 71