1========================================= 2Libc++ 13.0.0 (In-Progress) Release Notes 3========================================= 4 5.. contents:: 6 :local: 7 :depth: 2 8 9Written by the `Libc++ Team <https://libcxx.llvm.org>`_ 10 11.. warning:: 12 13 These are in-progress notes for the upcoming libc++ 13 release. 14 Release notes for previous releases can be found on 15 `the Download Page <https://releases.llvm.org/download.html>`_. 16 17Introduction 18============ 19 20This document contains the release notes for the libc++ C++ Standard Library, 21part of the LLVM Compiler Infrastructure, release 13.0.0. Here we describe the 22status of libc++ in some detail, including major improvements from the previous 23release and new feature work. For the general LLVM release notes, see `the LLVM 24documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM releases may 25be downloaded from the `LLVM releases web site <https://llvm.org/releases/>`_. 26 27For more information about libc++, please see the `Libc++ Web Site 28<https://libcxx.llvm.org>`_ or the `LLVM Web Site <https://llvm.org>`_. 29 30Note that if you are reading this file from a Git checkout or the 31main Libc++ web page, this document applies to the *next* release, not 32the current one. To see the release notes for a specific release, please 33see the `releases page <https://llvm.org/releases/>`_. 34 35What's New in Libc++ 13.0.0? 36============================ 37 38New Features 39------------ 40 41- ... 42 43API Changes 44----------- 45 46- There has been several changes in the tuple constructors provided by libc++. 47 Those changes were made as part of an effort to regularize libc++'s tuple 48 implementation, which contained several subtle bugs due to these extensions. 49 If you notice a build breakage when initializing a tuple, make sure you 50 properly initialize all the tuple elements - this is probably the culprit. 51 52 In particular, the extension allowing tuples to be constructed from fewer 53 elements than the number of elements in the tuple (in which case the remaining 54 elements would be default-constructed) has been removed. See https://godbolt.org/z/sqozjd. 55 56 Also, the extension allowing a tuple to be constructed from an array has been 57 removed. See https://godbolt.org/z/5esqbW. 58 59- The ``std::pointer_safety`` utility and related functions are not available 60 in C++03 anymore. Furthermore, in other standard modes, it has changed from 61 a struct to a scoped enumeration, which is an ABI break. Finally, the 62 ``std::get_pointer_safety`` function was previously in the dylib, but it 63 is now defined as inline in the headers. 64 65 While this is technically both an API and an ABI break, we do not expect 66 ``std::pointer_safety`` to have been used at all in real code, since we 67 never implemented the underlying support for garbage collection. 68