You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
65 lines
2.6 KiB
65 lines
2.6 KiB
=========================================
|
|
Libc++ 12.0.0 (In-Progress) Release Notes
|
|
=========================================
|
|
|
|
.. contents::
|
|
:local:
|
|
:depth: 2
|
|
|
|
Written by the `Libc++ Team <https://libcxx.llvm.org>`_
|
|
|
|
.. warning::
|
|
|
|
These are in-progress notes for the upcoming libc++ 12 release.
|
|
Release notes for previous releases can be found on
|
|
`the Download Page <https://releases.llvm.org/download.html>`_.
|
|
|
|
Introduction
|
|
============
|
|
|
|
This document contains the release notes for the libc++ C++ Standard Library,
|
|
part of the LLVM Compiler Infrastructure, release 12.0.0. Here we describe the
|
|
status of libc++ in some detail, including major improvements from the previous
|
|
release and new feature work. For the general LLVM release notes, see `the LLVM
|
|
documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM releases may
|
|
be downloaded from the `LLVM releases web site <https://llvm.org/releases/>`_.
|
|
|
|
For more information about libc++, please see the `Libc++ Web Site
|
|
<https://libcxx.llvm.org>`_ or the `LLVM Web Site <https://llvm.org>`_.
|
|
|
|
Note that if you are reading this file from a Git checkout or the
|
|
main Libc++ web page, this document applies to the *next* release, not
|
|
the current one. To see the release notes for a specific release, please
|
|
see the `releases page <https://llvm.org/releases/>`_.
|
|
|
|
What's New in Libc++ 12.0.0?
|
|
============================
|
|
|
|
New Features
|
|
------------
|
|
|
|
- ...
|
|
|
|
API Changes
|
|
-----------
|
|
- By default, libc++ will _not_ include the definition for new and delete,
|
|
since those are provided in libc++abi. Vendors wishing to provide new and
|
|
delete in libc++ can build the library with ``-DLIBCXX_ENABLE_NEW_DELETE_DEFINITIONS=ON``
|
|
to get back the old behavior. This was done to avoid providing new and delete
|
|
in both libc++ and libc++abi, which is technically an ODR violation. Also
|
|
note that we couldn't decide to put the operators in libc++ only, because
|
|
they are needed from libc++abi (which would create a circular dependency).
|
|
- During the C++20 standardization process some new low-level bit functions
|
|
have been renamed. Libc++ has renamed these functions to match the C++20
|
|
Standard.
|
|
- ``ispow2`` has been renamed to ``has_single_bit``
|
|
- ``ceil2`` has been renamed to ``bit_ceil``
|
|
- ``floor2`` has been renamed to ``bit_floor``
|
|
- ``log2p1`` has been renamed to ``bit_width``
|
|
|
|
- In C++20 mode, ``std::filesystem::path::u8string()`` and
|
|
``generic_u8string()`` now return ``std::u8string`` according to P0428,
|
|
while they return ``std::string`` in C++17. This can cause source
|
|
incompatibility, which is discussed and acknowledged in P1423, but that
|
|
paper doesn't suggest any remediation for this incompatibility.
|