This is an archive of the discontinued LLVM Phabricator instance.

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	- The comparison operators on ``thread::id`` are now defined as free-standing			- The comparison operators on ``thread::id`` are now defined as free-standing
	functions instead of as hidden friends, in conformance with the C++ standard.			functions instead of as hidden friends, in conformance with the C++ standard.
	Also see `issue 56187 <https://github.com/llvm/llvm-project/issues/56187>`_.			Also see `issue 56187 <https://github.com/llvm/llvm-project/issues/56187>`_.

	- ``_LIBCPP_ENABLE_NODISCARD`` and ``_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17`` are no longer respected.			- ``_LIBCPP_ENABLE_NODISCARD`` and ``_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17`` are no longer respected.
	Any standards-required ``[[nodiscard]]`` applications in C++20 are now always enabled. Any extended applications			Any standards-required ``[[nodiscard]]`` applications in C++20 are now always enabled. Any extended applications
	are now enabled by default and can be disabled by defining ``_LIBCPP_DISABLE_NODISCARD_EXT``.			are now enabled by default and can be disabled by defining ``_LIBCPP_DISABLE_NODISCARD_EXT``.

				- ``_LIBCPP_VERSION`` was previously defined to e.g. ``15001`` to represent LLVM 15.0.01, but this value had been
				left undocumented. Starting with LLVM 16, ``_LIBCPP_VERSION`` will contain the version of LLVM represented as
				``XXYYZZ``. In other words, ``_LIBCPP_VERSION`` is gaining a digit. This should not be an issue for existing
				code, since using e.g. ``_LIBCPP_VERSION > 15000`` will still give the right answer now that ``_LIBCPP_VERSION``
				is defined as e.g. ``160000`` (with one more digit).

	ABI Affecting Changes			ABI Affecting Changes
	---------------------			---------------------
	- In freestanding mode, ``atomic<small enum class>`` does not contain a lock byte anymore if the platform			- In freestanding mode, ``atomic<small enum class>`` does not contain a lock byte anymore if the platform
	can implement lockfree atomics for that size. More specifically, in LLVM <= 11.0.1, an ``atomic<small enum class>``			can implement lockfree atomics for that size. More specifically, in LLVM <= 11.0.1, an ``atomic<small enum class>``
	would not contain a lock byte. This was broken in LLVM >= 12.0.0, where it started including a lock byte despite			would not contain a lock byte. This was broken in LLVM >= 12.0.0, where it started including a lock byte despite
	the platform supporting lockfree atomics for that size. Starting in LLVM 15.0.1, the ABI for these types has been			the platform supporting lockfree atomics for that size. Starting in LLVM 15.0.1, the ABI for these types has been
	restored to what it used to be (no lock byte), which is the most efficient implementation.			restored to what it used to be (no lock byte), which is the most efficient implementation.

	This ABI break only affects users that compile with ``-ffreestanding``, and only for ``atomic<T>`` where ``T``			This ABI break only affects users that compile with ``-ffreestanding``, and only for ``atomic<T>`` where ``T``
	is a non-builtin type that could be lockfree on the platform. See https://llvm.org/D133377 for more details.			is a non-builtin type that could be lockfree on the platform. See https://llvm.org/D133377 for more details.

	Build System Changes			Build System Changes
	--------------------			--------------------

libcxx/include/__config

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	#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER			#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
	# pragma GCC system_header			# pragma GCC system_header
	#endif			#endif

	#ifdef __cplusplus			#ifdef __cplusplus

	// _LIBCPP_VERSION represents the version of libc++, which matches the version of LLVM.			// _LIBCPP_VERSION represents the version of libc++, which matches the version of LLVM.
	// Given a LLVM release LLVM XX.Y.ZZ (e.g. LLVM 16.0.1 == 16.0.01), _LIBCPP_VERSION is			// Given a LLVM release LLVM XX.YY.ZZ (e.g. LLVM 16.0.1 == 16.00.01), _LIBCPP_VERSION is
	// defined to XXYZZ.			// defined to XXYYZZ.
	# define _LIBCPP_VERSION 16000			# define _LIBCPP_VERSION 160000

	# define _LIBCPP_CONCAT_IMPL(_X, _Y) _X##_Y			# define _LIBCPP_CONCAT_IMPL(_X, _Y) _X##_Y
	# define _LIBCPP_CONCAT(_X, _Y) _LIBCPP_CONCAT_IMPL(_X, _Y)			# define _LIBCPP_CONCAT(_X, _Y) _LIBCPP_CONCAT_IMPL(_X, _Y)

	// Valid C++ identifier that revs with every libc++ version. This can be used to			// Valid C++ identifier that revs with every libc++ version. This can be used to
	// generate identifiers that must be unique for every released libc++ version.			// generate identifiers that must be unique for every released libc++ version.
	# define _LIBCPP_VERSIONED_IDENTIFIER _LIBCPP_CONCAT(v, _LIBCPP_VERSION)			# define _LIBCPP_VERSIONED_IDENTIFIER _LIBCPP_CONCAT(v, _LIBCPP_VERSION)

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This is an archive of the discontinued LLVM Phabricator instance.

[libc++] Use XXYYZZ instead of XXYZZ for _LIBCPP_VERSIONClosedPublic

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libcxx/docs/ReleaseNotes.rst

libcxx/include/__config

[libc++] Use XXYYZZ instead of XXYZZ for _LIBCPP_VERSION
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