ReleaseNotes.rst (2374B)
1 ========================== 2 Libc++ 8.0.0 Release Notes 3 ========================== 4 5 .. contents:: 6 :local: 7 :depth: 2 8 9 Written by the `Libc++ Team <https://libcxx.llvm.org>`_ 10 11 Introduction 12 ============ 13 14 This document contains the release notes for the libc++ C++ Standard Library, 15 part of the LLVM Compiler Infrastructure, release 8.0.0. Here we describe the 16 status of libc++ in some detail, including major improvements from the previous 17 release and new feature work. For the general LLVM release notes, see `the LLVM 18 documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM releases may 19 be downloaded from the `LLVM releases web site <https://releases.llvm.org/>`_. 20 21 For more information about libc++, please see the `Libc++ Web Site 22 <https://libcxx.llvm.org>`_ or the `LLVM Web Site <https://llvm.org>`_. 23 24 What's New in Libc++ 8.0.0? 25 =========================== 26 27 API Changes 28 ----------- 29 - Building libc++ for Mac OSX 10.6 is not supported anymore. 30 - Starting with LLVM 8.0.0, users that wish to link together translation units 31 built with different versions of libc++'s headers into the same final linked 32 image MUST define the _LIBCPP_HIDE_FROM_ABI_PER_TU macro to 1 when building 33 those translation units. Not defining _LIBCPP_HIDE_FROM_ABI_PER_TU to 1 and 34 linking translation units built with different versions of libc++'s headers 35 together may lead to ODR violations and ABI issues. On the flipside, code 36 size improvements should be expected for everyone not defining the macro. 37 - Starting with LLVM 8.0.0, std::dynarray has been removed from the library. 38 std::dynarray was a feature proposed for C++14 that was pulled from the 39 Standard at the last minute and was never standardized. Since there are no 40 plans to standardize this facility it is being removed. 41 - Starting with LLVM 8.0.0, std::bad_array_length has been removed from the 42 library. std::bad_array_length was a feature proposed for C++14 alongside 43 std::dynarray, but it never actually made it into the C++ Standard. There 44 are no plans to standardize this feature at this time. Formally speaking, 45 this removal constitutes an ABI break because the symbols were shipped in 46 the shared library. However, on macOS systems, the feature was not usable 47 because it was hidden behind availability annotations. We do not expect 48 any actual breakage to happen from this change.