libcxx/include/__config

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___CONFIG
#define _LIBCPP___CONFIG

#include <__config_site>
#include <__configuration/abi.h>
#include <__configuration/availability.h>
#include <__configuration/compiler.h>
#include <__configuration/language.h>
#include <__configuration/platform.h>

#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#  pragma GCC system_header
#endif

#ifdef __cplusplus

// The attributes supported by clang are documented at https://clang.llvm.org/docs/AttributeReference.html

// _LIBCPP_VERSION represents the version of libc++, which matches the version of LLVM.
// Given a LLVM release LLVM XX.YY.ZZ (e.g. LLVM 17.0.1 == 17.00.01), _LIBCPP_VERSION is
// defined to XXYYZZ.
#  define _LIBCPP_VERSION 210000

#  define _LIBCPP_CONCAT_IMPL(_X, _Y) _X##_Y
#  define _LIBCPP_CONCAT(_X, _Y) _LIBCPP_CONCAT_IMPL(_X, _Y)
#  define _LIBCPP_CONCAT3(X, Y, Z) _LIBCPP_CONCAT(X, _LIBCPP_CONCAT(Y, Z))

#  if __STDC_HOSTED__ == 0
#    define _LIBCPP_FREESTANDING
#  endif

// HARDENING {

// TODO: Remove in LLVM 21. We're making this an error to catch folks who might not have migrated.
#  ifdef _LIBCPP_ENABLE_ASSERTIONS
#    error "_LIBCPP_ENABLE_ASSERTIONS has been removed, please use _LIBCPP_HARDENING_MODE instead"
#  endif

// The library provides the macro `_LIBCPP_HARDENING_MODE` which can be set to one of the following values:
//
// - `_LIBCPP_HARDENING_MODE_NONE`;
// - `_LIBCPP_HARDENING_MODE_FAST`;
// - `_LIBCPP_HARDENING_MODE_EXTENSIVE`;
// - `_LIBCPP_HARDENING_MODE_DEBUG`.
//
// These values have the following effects:
//
// - `_LIBCPP_HARDENING_MODE_NONE` -- sets the hardening mode to "none" which disables all runtime hardening checks;
//
// - `_LIBCPP_HARDENING_MODE_FAST` -- sets that hardening mode to "fast". The fast mode enables security-critical checks
//   that can be done with relatively little runtime overhead in constant time;
//
// - `_LIBCPP_HARDENING_MODE_EXTENSIVE` -- sets the hardening mode to "extensive". The extensive mode is a superset of
//   the fast mode that additionally enables checks that are relatively cheap and prevent common types of logic errors
//   but are not necessarily security-critical;
//
// - `_LIBCPP_HARDENING_MODE_DEBUG` -- sets the hardening mode to "debug". The debug mode is a superset of the extensive
//   mode and enables all checks available in the library, including internal assertions. Checks that are part of the
//   debug mode can be very expensive and thus the debug mode is intended to be used for testing, not in production.

// Inside the library, assertions are categorized so they can be cherry-picked based on the chosen hardening mode. These
// macros are only for internal use -- users should only pick one of the high-level hardening modes described above.
//
// - `_LIBCPP_ASSERT_VALID_INPUT_RANGE` -- checks that ranges (whether expressed as an iterator pair, an iterator and
//   a sentinel, an iterator and a count, or a `std::range`) given as input to library functions are valid:
//   - the sentinel is reachable from the begin iterator;
//   - TODO(hardening): both iterators refer to the same container.
//
// - `_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS` -- checks that any attempts to access a container element, whether through
//   the container object or through an iterator, are valid and do not attempt to go out of bounds or otherwise access
//   a non-existent element. For iterator checks to work, bounded iterators must be enabled in the ABI. Types like
//   `optional` and `function` are considered one-element containers for the purposes of this check.
//
// - `_LIBCPP_ASSERT_NON_NULL` -- checks that the pointer being dereferenced is not null. On most modern platforms zero
//   address does not refer to an actual location in memory, so a null pointer dereference would not compromize the
//   memory security of a program (however, it is still undefined behavior that can result in strange errors due to
//   compiler optimizations).
//
// - `_LIBCPP_ASSERT_NON_OVERLAPPING_RANGES` -- for functions that take several ranges as arguments, checks that the
//   given ranges do not overlap.
//
// - `_LIBCPP_ASSERT_VALID_DEALLOCATION` -- checks that an attempt to deallocate memory is valid (e.g. the given object
//   was allocated by the given allocator). Violating this category typically results in a memory leak.
//
// - `_LIBCPP_ASSERT_VALID_EXTERNAL_API_CALL` -- checks that a call to an external API doesn't fail in
//   an unexpected manner. This includes triggering documented cases of undefined behavior in an external library (like
//   attempting to unlock an unlocked mutex in pthreads). Any API external to the library falls under this category
//   (from system calls to compiler intrinsics). We generally don't expect these failures to compromize memory safety or
//   otherwise create an immediate security issue.
//
// - `_LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR` -- checks any operations that exchange nodes between containers to make sure
//   the containers have compatible allocators.
//
// - `_LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN` -- checks that the given argument is within the domain of valid arguments
//   for the function. Violating this typically produces an incorrect result (e.g. the clamp algorithm returns the
//   original value without clamping it due to incorrect functors) or puts an object into an invalid state (e.g.
//   a string view where only a subset of elements is possible to access). This category is for assertions violating
//   which doesn't cause any immediate issues in the library -- whatever the consequences are, they will happen in the
//   user code.
//
// - `_LIBCPP_ASSERT_PEDANTIC` -- checks prerequisites which are imposed by the Standard, but violating which happens to
//   be benign in our implementation.
//
// - `_LIBCPP_ASSERT_SEMANTIC_REQUIREMENT` -- checks that the given argument satisfies the semantic requirements imposed
//   by the Standard. Typically, there is no simple way to completely prove that a semantic requirement is satisfied;
//   thus, this would often be a heuristic check and it might be quite expensive.
//
// - `_LIBCPP_ASSERT_INTERNAL` -- checks that internal invariants of the library hold. These assertions don't depend on
//   user input.
//
// - `_LIBCPP_ASSERT_UNCATEGORIZED` -- for assertions that haven't been properly classified yet.

// clang-format off
#  define _LIBCPP_HARDENING_MODE_NONE      (1 << 1)
#  define _LIBCPP_HARDENING_MODE_FAST      (1 << 2)
#  define _LIBCPP_HARDENING_MODE_EXTENSIVE (1 << 4) // Deliberately not ordered.
#  define _LIBCPP_HARDENING_MODE_DEBUG     (1 << 3)
// clang-format on

#  ifndef _LIBCPP_HARDENING_MODE

#    ifndef _LIBCPP_HARDENING_MODE_DEFAULT
#      error _LIBCPP_HARDENING_MODE_DEFAULT is not defined. This definition should be set at configuration time in the \
`__config_site` header, please make sure your installation of libc++ is not broken.
#    endif

#    define _LIBCPP_HARDENING_MODE _LIBCPP_HARDENING_MODE_DEFAULT
#  endif

#  if _LIBCPP_HARDENING_MODE != _LIBCPP_HARDENING_MODE_NONE &&                                                         \
      _LIBCPP_HARDENING_MODE != _LIBCPP_HARDENING_MODE_FAST &&                                                         \
      _LIBCPP_HARDENING_MODE != _LIBCPP_HARDENING_MODE_EXTENSIVE &&                                                    \
      _LIBCPP_HARDENING_MODE != _LIBCPP_HARDENING_MODE_DEBUG
#    error _LIBCPP_HARDENING_MODE must be set to one of the following values: \
_LIBCPP_HARDENING_MODE_NONE, \
_LIBCPP_HARDENING_MODE_FAST, \
_LIBCPP_HARDENING_MODE_EXTENSIVE, \
_LIBCPP_HARDENING_MODE_DEBUG
#  endif

// } HARDENING

#  define _LIBCPP_TOSTRING2(x) #x
#  define _LIBCPP_TOSTRING(x) _LIBCPP_TOSTRING2(x)

// NOLINTNEXTLINE(libcpp-cpp-version-check)
#  if __cplusplus < 201103L
#    define _LIBCPP_CXX03_LANG
#  endif

#  ifndef __has_constexpr_builtin
#    define __has_constexpr_builtin(x) 0
#  endif

// This checks wheter a Clang module is built
#  ifndef __building_module
#    define __building_module(...) 0
#  endif

// '__is_identifier' returns '0' if '__x' is a reserved identifier provided by
// the compiler and '1' otherwise.
#  ifndef __is_identifier
#    define __is_identifier(__x) 1
#  endif

#  ifndef __has_declspec_attribute
#    define __has_declspec_attribute(__x) 0
#  endif

#  define __has_keyword(__x) !(__is_identifier(__x))

#  ifndef __has_warning
#    define __has_warning(...) 0
#  endif

#  if !defined(_LIBCPP_COMPILER_CLANG_BASED) && __cplusplus < 201103L
#    error "libc++ only supports C++03 with Clang-based compilers. Please enable C++11"
#  endif

#  if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_NO_VCRUNTIME)
#    define _LIBCPP_ABI_VCRUNTIME
#  endif

#  if __has_feature(experimental_library)
#    ifndef _LIBCPP_ENABLE_EXPERIMENTAL
#      define _LIBCPP_ENABLE_EXPERIMENTAL
#    endif
#  endif

// Incomplete features get their own specific disabling flags. This makes it
// easier to grep for target specific flags once the feature is complete.
#  if defined(_LIBCPP_ENABLE_EXPERIMENTAL) || defined(_LIBCPP_BUILDING_LIBRARY)
#    define _LIBCPP_HAS_EXPERIMENTAL_LIBRARY 1
#  else
#    define _LIBCPP_HAS_EXPERIMENTAL_LIBRARY 0
#  endif

#  define _LIBCPP_HAS_EXPERIMENTAL_PSTL _LIBCPP_HAS_EXPERIMENTAL_LIBRARY
#  define _LIBCPP_HAS_EXPERIMENTAL_TZDB _LIBCPP_HAS_EXPERIMENTAL_LIBRARY
#  define _LIBCPP_HAS_EXPERIMENTAL_SYNCSTREAM _LIBCPP_HAS_EXPERIMENTAL_LIBRARY

#  if defined(__MVS__)
#    include <features.h> // for __NATIVE_ASCII_F
#  endif

#  if defined(_WIN32)
#    define _LIBCPP_WIN32API
#    define _LIBCPP_SHORT_WCHAR 1
// Both MinGW and native MSVC provide a "MSVC"-like environment
#    define _LIBCPP_MSVCRT_LIKE
// If mingw not explicitly detected, assume using MS C runtime only if
// a MS compatibility version is specified.
#    if defined(_MSC_VER) && !defined(__MINGW32__)
#      define _LIBCPP_MSVCRT // Using Microsoft's C Runtime library
#    endif
#    if (defined(_M_AMD64) || defined(__x86_64__)) || (defined(_M_ARM) || defined(__arm__))
#      define _LIBCPP_HAS_BITSCAN64 1
#    else
#      define _LIBCPP_HAS_BITSCAN64 0
#    endif
#    define _LIBCPP_HAS_OPEN_WITH_WCHAR 1
#  else
#    define _LIBCPP_HAS_OPEN_WITH_WCHAR 0
#    define _LIBCPP_HAS_BITSCAN64 0
#  endif // defined(_WIN32)

#  if defined(_AIX) && !defined(__64BIT__)
// The size of wchar is 2 byte on 32-bit mode on AIX.
#    define _LIBCPP_SHORT_WCHAR 1
#  endif

// Libc++ supports various implementations of std::random_device.
//
// _LIBCPP_USING_DEV_RANDOM
//      Read entropy from the given file, by default `/dev/urandom`.
//      If a token is provided, it is assumed to be the path to a file
//      to read entropy from. This is the default behavior if nothing
//      else is specified. This implementation requires storing state
//      inside `std::random_device`.
//
// _LIBCPP_USING_ARC4_RANDOM
//      Use arc4random(). This allows obtaining random data even when
//      using sandboxing mechanisms. On some platforms like Apple, this
//      is the recommended source of entropy for user-space programs.
//      When this option is used, the token passed to `std::random_device`'s
//      constructor *must* be "/dev/urandom" -- anything else is an error.
//
// _LIBCPP_USING_GETENTROPY
//      Use getentropy().
//      When this option is used, the token passed to `std::random_device`'s
//      constructor *must* be "/dev/urandom" -- anything else is an error.
//
// _LIBCPP_USING_FUCHSIA_CPRNG
//      Use Fuchsia's zx_cprng_draw() system call, which is specified to
//      deliver high-quality entropy and cannot fail.
//      When this option is used, the token passed to `std::random_device`'s
//      constructor *must* be "/dev/urandom" -- anything else is an error.
//
// _LIBCPP_USING_NACL_RANDOM
//      NaCl's sandbox (which PNaCl also runs in) doesn't allow filesystem access,
//      including accesses to the special files under `/dev`. This implementation
//      uses the NaCL syscall `nacl_secure_random_init()` to get entropy.
//      When this option is used, the token passed to `std::random_device`'s
//      constructor *must* be "/dev/urandom" -- anything else is an error.
//
// _LIBCPP_USING_WIN32_RANDOM
//      Use rand_s(), for use on Windows.
//      When this option is used, the token passed to `std::random_device`'s
//      constructor *must* be "/dev/urandom" -- anything else is an error.
#  if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||                     \
      defined(__DragonFly__)
#    define _LIBCPP_USING_ARC4_RANDOM
#  elif defined(__wasi__) || defined(__EMSCRIPTEN__)
#    define _LIBCPP_USING_GETENTROPY
#  elif defined(__Fuchsia__)
#    define _LIBCPP_USING_FUCHSIA_CPRNG
#  elif defined(__native_client__)
#    define _LIBCPP_USING_NACL_RANDOM
#  elif defined(_LIBCPP_WIN32API)
#    define _LIBCPP_USING_WIN32_RANDOM
#  else
#    define _LIBCPP_USING_DEV_RANDOM
#  endif

#  ifndef _LIBCPP_CXX03_LANG

#    define _LIBCPP_ALIGNOF(_Tp) alignof(_Tp)
#    define _ALIGNAS_TYPE(x) alignas(x)
#    define _ALIGNAS(x) alignas(x)
#    define _NOEXCEPT noexcept
#    define _NOEXCEPT_(...) noexcept(__VA_ARGS__)
#    define _LIBCPP_CONSTEXPR constexpr

#  else

#    define _LIBCPP_ALIGNOF(_Tp) _Alignof(_Tp)
#    define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
#    define _ALIGNAS(x) __attribute__((__aligned__(x)))
#    define nullptr __nullptr
#    define _NOEXCEPT throw()
#    define _NOEXCEPT_(...)
#    define static_assert(...) _Static_assert(__VA_ARGS__)
#    define decltype(...) __decltype(__VA_ARGS__)
#    define _LIBCPP_CONSTEXPR

typedef __char16_t char16_t;
typedef __char32_t char32_t;

#  endif

#  define _LIBCPP_PREFERRED_ALIGNOF(_Tp) __alignof(_Tp)

// Objective-C++ features (opt-in)
#  if __has_feature(objc_arc)
#    define _LIBCPP_HAS_OBJC_ARC 1
#  else
#    define _LIBCPP_HAS_OBJC_ARC 0
#  endif

#  if __has_feature(objc_arc_weak)
#    define _LIBCPP_HAS_OBJC_ARC_WEAK 1
#  else
#    define _LIBCPP_HAS_OBJC_ARC_WEAK 0
#  endif

#  if __has_extension(blocks)
#    define _LIBCPP_HAS_EXTENSION_BLOCKS 1
#  else
#    define _LIBCPP_HAS_EXTENSION_BLOCKS 0
#  endif

#  if _LIBCPP_HAS_EXTENSION_BLOCKS && defined(__APPLE__)
#    define _LIBCPP_HAS_BLOCKS_RUNTIME 1
#  else
#    define _LIBCPP_HAS_BLOCKS_RUNTIME 0
#  endif

#  if __has_feature(address_sanitizer)
#    define _LIBCPP_HAS_ASAN 1
#  else
#    define _LIBCPP_HAS_ASAN 0
#  endif

#  define _LIBCPP_ALWAYS_INLINE __attribute__((__always_inline__))

#  if defined(_LIBCPP_OBJECT_FORMAT_COFF)

#    ifdef _DLL
#      define _LIBCPP_CRT_FUNC __declspec(dllimport)
#    else
#      define _LIBCPP_CRT_FUNC
#    endif

#    if defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) || (defined(__MINGW32__) && !defined(_LIBCPP_BUILDING_LIBRARY))
#      define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
#      define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
#      define _LIBCPP_OVERRIDABLE_FUNC_VIS
#      define _LIBCPP_EXPORTED_FROM_ABI
#    elif defined(_LIBCPP_BUILDING_LIBRARY)
#      if defined(__MINGW32__)
#        define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __declspec(dllexport)
#        define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
#      else
#        define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
#        define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __declspec(dllexport)
#      endif
#      define _LIBCPP_OVERRIDABLE_FUNC_VIS __declspec(dllexport)
#      define _LIBCPP_EXPORTED_FROM_ABI __declspec(dllexport)
#    else
#      define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __declspec(dllimport)
#      define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
#      define _LIBCPP_OVERRIDABLE_FUNC_VIS
#      define _LIBCPP_EXPORTED_FROM_ABI __declspec(dllimport)
#    endif

#    define _LIBCPP_HIDDEN
#    define _LIBCPP_TEMPLATE_DATA_VIS
#    define _LIBCPP_NAMESPACE_VISIBILITY

#  else

#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#      define _LIBCPP_VISIBILITY(vis) __attribute__((__visibility__(vis)))
#    else
#      define _LIBCPP_VISIBILITY(vis)
#    endif

#    define _LIBCPP_HIDDEN _LIBCPP_VISIBILITY("hidden")
#    define _LIBCPP_TEMPLATE_DATA_VIS _LIBCPP_VISIBILITY("default")
#    define _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_VISIBILITY("default")
#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_VISIBILITY("default")
#    define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS

// TODO: Make this a proper customization point or remove the option to override it.
#    ifndef _LIBCPP_OVERRIDABLE_FUNC_VIS
#      define _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_VISIBILITY("default")
#    endif

#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
#      define _LIBCPP_NAMESPACE_VISIBILITY __attribute__((__type_visibility__("default")))
#    elif !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#      define _LIBCPP_NAMESPACE_VISIBILITY __attribute__((__visibility__("default")))
#    else
#      define _LIBCPP_NAMESPACE_VISIBILITY
#    endif

#  endif // defined(_LIBCPP_OBJECT_FORMAT_COFF)

#  if __has_attribute(exclude_from_explicit_instantiation)
#    define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION __attribute__((__exclude_from_explicit_instantiation__))
#  else
// Try to approximate the effect of exclude_from_explicit_instantiation
// (which is that entities are not assumed to be provided by explicit
// template instantiations in the dylib) by always inlining those entities.
#    define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION _LIBCPP_ALWAYS_INLINE
#  endif

#  ifdef _LIBCPP_COMPILER_CLANG_BASED
#    define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("clang diagnostic push")
#    define _LIBCPP_DIAGNOSTIC_POP _Pragma("clang diagnostic pop")
#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(clang diagnostic ignored str))
#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
#  elif defined(_LIBCPP_COMPILER_GCC)
#    define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
#    define _LIBCPP_DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(GCC diagnostic ignored str))
#  else
#    define _LIBCPP_DIAGNOSTIC_PUSH
#    define _LIBCPP_DIAGNOSTIC_POP
#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
#    define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
#  endif

#  if _LIBCPP_HARDENING_MODE == _LIBCPP_HARDENING_MODE_FAST
#    define _LIBCPP_HARDENING_SIG f
#  elif _LIBCPP_HARDENING_MODE == _LIBCPP_HARDENING_MODE_EXTENSIVE
#    define _LIBCPP_HARDENING_SIG s
#  elif _LIBCPP_HARDENING_MODE == _LIBCPP_HARDENING_MODE_DEBUG
#    define _LIBCPP_HARDENING_SIG d
#  else
#    define _LIBCPP_HARDENING_SIG n // "none"
#  endif

#  if !_LIBCPP_HAS_EXCEPTIONS
#    define _LIBCPP_EXCEPTIONS_SIG n
#  else
#    define _LIBCPP_EXCEPTIONS_SIG e
#  endif

#  define _LIBCPP_ODR_SIGNATURE                                                                                        \
    _LIBCPP_CONCAT(_LIBCPP_CONCAT(_LIBCPP_HARDENING_SIG, _LIBCPP_EXCEPTIONS_SIG), _LIBCPP_VERSION)

// This macro marks a symbol as being hidden from libc++'s ABI. This is achieved
// on two levels:
// 1. The symbol is given hidden visibility, which ensures that users won't start exporting
//    symbols from their dynamic library by means of using the libc++ headers. This ensures
//    that those symbols stay private to the dynamic library in which it is defined.
//
// 2. The symbol is given an ABI tag that encodes the ODR-relevant properties of the library.
//    This ensures that no ODR violation can arise from mixing two TUs compiled with different
//    versions or configurations of libc++ (such as exceptions vs no-exceptions). Indeed, if the
//    program contains two definitions of a function, the ODR requires them to be token-by-token
//    equivalent, and the linker is allowed to pick either definition and discard the other one.
//
//    For example, if a program contains a copy of `vector::at()` compiled with exceptions enabled
//    *and* a copy of `vector::at()` compiled with exceptions disabled (by means of having two TUs
//    compiled with different settings), the two definitions are both visible by the linker and they
//    have the same name, but they have a meaningfully different implementation (one throws an exception
//    and the other aborts the program). This violates the ODR and makes the program ill-formed, and in
//    practice what will happen is that the linker will pick one of the definitions at random and will
//    discard the other one. This can quite clearly lead to incorrect program behavior.
//
//    A similar reasoning holds for many other properties that are ODR-affecting. Essentially any
//    property that causes the code of a function to differ from the code in another configuration
//    can be considered ODR-affecting. In practice, we don't encode all such properties in the ABI
//    tag, but we encode the ones that we think are most important: library version, exceptions, and
//    hardening mode.
//
//    Note that historically, solving this problem has been achieved in various ways, including
//    force-inlining all functions or giving internal linkage to all functions. Both these previous
//    solutions suffer from drawbacks that lead notably to code bloat.
//
// Note that we use _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION to ensure that we don't depend
// on _LIBCPP_HIDE_FROM_ABI methods of classes explicitly instantiated in the dynamic library.
//
// Also note that the _LIBCPP_HIDE_FROM_ABI_VIRTUAL macro should be used on virtual functions
// instead of _LIBCPP_HIDE_FROM_ABI. That macro does not use an ABI tag. Indeed, the mangled
// name of a virtual function is part of its ABI, since some architectures like arm64e can sign
// the virtual function pointer in the vtable based on the mangled name of the function. Since
// we use an ABI tag that changes with each released version, the mangled name of the virtual
// function would change, which is incorrect. Note that it doesn't make much sense to change
// the implementation of a virtual function in an ABI-incompatible way in the first place,
// since that would be an ABI break anyway. Hence, the lack of ABI tag should not be noticeable.
//
// The macro can be applied to record and enum types. When the tagged type is nested in
// a record this "parent" record needs to have the macro too. Another use case for applying
// this macro to records and unions is to apply an ABI tag to inline constexpr variables.
// This can be useful for inline variables that are implementation details which are expected
// to change in the future.
//
// TODO: We provide a escape hatch with _LIBCPP_NO_ABI_TAG for folks who want to avoid increasing
//       the length of symbols with an ABI tag. In practice, we should remove the escape hatch and
//       use compression mangling instead, see https://github.com/itanium-cxx-abi/cxx-abi/issues/70.
#  ifndef _LIBCPP_NO_ABI_TAG
#    define _LIBCPP_HIDE_FROM_ABI                                                                                      \
      _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION                                                       \
      __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_ODR_SIGNATURE))))
#  else
#    define _LIBCPP_HIDE_FROM_ABI _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION
#  endif
#  define _LIBCPP_HIDE_FROM_ABI_VIRTUAL _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION

#  ifdef _LIBCPP_BUILDING_LIBRARY
#    if _LIBCPP_ABI_VERSION > 1
#      define _LIBCPP_HIDE_FROM_ABI_AFTER_V1 _LIBCPP_HIDE_FROM_ABI
#    else
#      define _LIBCPP_HIDE_FROM_ABI_AFTER_V1
#    endif
#  else
#    define _LIBCPP_HIDE_FROM_ABI_AFTER_V1 _LIBCPP_HIDE_FROM_ABI
#  endif

// TODO: Remove this workaround once we drop support for Clang 16
#  if __has_warning("-Wc++23-extensions")
#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED_CXX23_EXTENSION _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++23-extensions")
#  else
#    define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED_CXX23_EXTENSION _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++2b-extensions")
#  endif

// Clang modules take a significant compile time hit when pushing and popping diagnostics.
// Since all the headers are marked as system headers in the modulemap, we can simply disable this
// pushing and popping when building with clang modules.
#  if !__has_feature(modules)
#    define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS                                                                         \
      _LIBCPP_DIAGNOSTIC_PUSH                                                                                          \
      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++11-extensions")                                                           \
      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++14-extensions")                                                           \
      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++17-extensions")                                                           \
      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++20-extensions")                                                           \
      _LIBCPP_CLANG_DIAGNOSTIC_IGNORED_CXX23_EXTENSION                                                                 \
      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++14-extensions")                                                             \
      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++17-extensions")                                                             \
      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++20-extensions")                                                             \
      _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++23-extensions")
#    define _LIBCPP_POP_EXTENSION_DIAGNOSTICS _LIBCPP_DIAGNOSTIC_POP
#  else
#    define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS
#    define _LIBCPP_POP_EXTENSION_DIAGNOSTICS
#  endif

// clang-format off

// The unversioned namespace is used when we want to be ABI compatible with other standard libraries in some way. There
// are two main categories where that's the case:
// - Historically, we have made exception types ABI compatible with libstdc++ to allow throwing them between libstdc++
//   and libc++. This is not used anymore for new exception types, since there is no use-case for it anymore.
// - Types and functions which are used by the compiler are in the unversioned namespace, since the compiler has to know
//   their mangling without the appropriate declaration in some cases.
// If it's not clear whether using the unversioned namespace is the correct thing to do, it's not. The versioned
// namespace (_LIBCPP_BEGIN_NAMESPACE_STD) should almost always be used.
#  define _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD                                                                      \
    _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS namespace _LIBCPP_NAMESPACE_VISIBILITY std {

#  define _LIBCPP_END_UNVERSIONED_NAMESPACE_STD } _LIBCPP_POP_EXTENSION_DIAGNOSTICS

#  define _LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD inline namespace _LIBCPP_ABI_NAMESPACE {
#  define _LIBCPP_END_NAMESPACE_STD } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD

// TODO: This should really be in the versioned namespace
#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD namespace experimental {
#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD

#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v1 {
#define _LIBCPP_END_NAMESPACE_LFTS } _LIBCPP_END_NAMESPACE_EXPERIMENTAL

#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v2 {
#define _LIBCPP_END_NAMESPACE_LFTS_V2 } _LIBCPP_END_NAMESPACE_EXPERIMENTAL

#ifdef _LIBCPP_ABI_NO_FILESYSTEM_INLINE_NAMESPACE
#  define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD namespace filesystem {
#  define _LIBCPP_END_NAMESPACE_FILESYSTEM } _LIBCPP_END_NAMESPACE_STD
#else
#  define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD                                               \
                                             inline namespace __fs { namespace filesystem {

#  define _LIBCPP_END_NAMESPACE_FILESYSTEM }} _LIBCPP_END_NAMESPACE_STD
#endif

// clang-format on

#  if __has_attribute(__enable_if__)
#    define _LIBCPP_PREFERRED_OVERLOAD __attribute__((__enable_if__(true, "")))
#  endif

#  if !defined(__SIZEOF_INT128__) || defined(_MSC_VER)
#    define _LIBCPP_HAS_INT128 0
#  else
#    define _LIBCPP_HAS_INT128 1
#  endif

#  ifdef _LIBCPP_CXX03_LANG
#    define _LIBCPP_DECLARE_STRONG_ENUM(x)                                                                             \
      struct _LIBCPP_EXPORTED_FROM_ABI x {                                                                             \
        enum __lx
// clang-format off
#    define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)                                                                      \
      __lx __v_;                                                                                                       \
      _LIBCPP_HIDE_FROM_ABI x(__lx __v) : __v_(__v) {}                                                                 \
      _LIBCPP_HIDE_FROM_ABI explicit x(int __v) : __v_(static_cast<__lx>(__v)) {}                                      \
      _LIBCPP_HIDE_FROM_ABI operator int() const { return __v_; }                                                      \
      };
// clang-format on

#  else // _LIBCPP_CXX03_LANG
#    define _LIBCPP_DECLARE_STRONG_ENUM(x) enum class x
#    define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)
#  endif // _LIBCPP_CXX03_LANG

#  ifdef __FreeBSD__
#    define _DECLARE_C99_LDBL_MATH 1
#  endif

// If we are getting operator new from the MSVC CRT, then allocation overloads
// for align_val_t were added in 19.12, aka VS 2017 version 15.3.
#  if defined(_LIBCPP_MSVCRT) && defined(_MSC_VER) && _MSC_VER < 1912
#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 0
#  elif defined(_LIBCPP_ABI_VCRUNTIME) && !defined(__cpp_aligned_new)
// We're deferring to Microsoft's STL to provide aligned new et al. We don't
// have it unless the language feature test macro is defined.
#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 0
#  elif defined(__MVS__)
#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 0
#  else
#    define _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION 1
#  endif

#  if !_LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION || (!defined(__cpp_aligned_new) || __cpp_aligned_new < 201606)
#    define _LIBCPP_HAS_ALIGNED_ALLOCATION 0
#  else
#    define _LIBCPP_HAS_ALIGNED_ALLOCATION 1
#  endif

// It is not yet possible to use aligned_alloc() on all Apple platforms since
// 10.15 was the first version to ship an implementation of aligned_alloc().
#  if defined(__APPLE__)
#    if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) &&                                                     \
         __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101500) ||                                                    \
        (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) &&                                                    \
         __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 130000) ||                                                   \
        (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) &&                                                     \
         __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 60000) ||                                                     \
        (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 130000)
#      define _LIBCPP_HAS_C11_ALIGNED_ALLOC 0
#    else
#      define _LIBCPP_HAS_C11_ALIGNED_ALLOC 1
#    endif
#  elif defined(__ANDROID__) && __ANDROID_API__ < 28
// Android only provides aligned_alloc when targeting API 28 or higher.
#    define _LIBCPP_HAS_C11_ALIGNED_ALLOC 0
#  else
#    define _LIBCPP_HAS_C11_ALIGNED_ALLOC 1
#  endif

#  if defined(__APPLE__) || defined(__FreeBSD__)
#    define _LIBCPP_HAS_DEFAULTRUNELOCALE
#  endif

#  if defined(__APPLE__) || defined(__FreeBSD__)
#    define _LIBCPP_WCTYPE_IS_MASK
#  endif

#  if _LIBCPP_STD_VER <= 17 || !defined(__cpp_char8_t)
#    define _LIBCPP_HAS_CHAR8_T 0
#  else
#    define _LIBCPP_HAS_CHAR8_T 1
#  endif

// Deprecation macros.
//
// Deprecations warnings are always enabled, except when users explicitly opt-out
// by defining _LIBCPP_DISABLE_DEPRECATION_WARNINGS.
#  if !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
#    if __has_attribute(__deprecated__)
#      define _LIBCPP_DEPRECATED __attribute__((__deprecated__))
#      define _LIBCPP_DEPRECATED_(m) __attribute__((__deprecated__(m)))
#    elif _LIBCPP_STD_VER >= 14
#      define _LIBCPP_DEPRECATED [[deprecated]]
#      define _LIBCPP_DEPRECATED_(m) [[deprecated(m)]]
#    else
#      define _LIBCPP_DEPRECATED
#      define _LIBCPP_DEPRECATED_(m)
#    endif
#  else
#    define _LIBCPP_DEPRECATED
#    define _LIBCPP_DEPRECATED_(m)
#  endif

#  if !defined(_LIBCPP_CXX03_LANG)
#    define _LIBCPP_DEPRECATED_IN_CXX11 _LIBCPP_DEPRECATED
#  else
#    define _LIBCPP_DEPRECATED_IN_CXX11
#  endif

#  if _LIBCPP_STD_VER >= 14
#    define _LIBCPP_DEPRECATED_IN_CXX14 _LIBCPP_DEPRECATED
#  else
#    define _LIBCPP_DEPRECATED_IN_CXX14
#  endif

#  if _LIBCPP_STD_VER >= 17
#    define _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_DEPRECATED
#  else
#    define _LIBCPP_DEPRECATED_IN_CXX17
#  endif

#  if _LIBCPP_STD_VER >= 20
#    define _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_DEPRECATED
#  else
#    define _LIBCPP_DEPRECATED_IN_CXX20
#  endif

#  if _LIBCPP_STD_VER >= 23
#    define _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_DEPRECATED
#  else
#    define _LIBCPP_DEPRECATED_IN_CXX23
#  endif

#  if _LIBCPP_STD_VER >= 26
#    define _LIBCPP_DEPRECATED_IN_CXX26 _LIBCPP_DEPRECATED
#    define _LIBCPP_DEPRECATED_IN_CXX26_(m) _LIBCPP_DEPRECATED_(m)
#  else
#    define _LIBCPP_DEPRECATED_IN_CXX26
#    define _LIBCPP_DEPRECATED_IN_CXX26_(m)
#  endif

#  if _LIBCPP_HAS_CHAR8_T
#    define _LIBCPP_DEPRECATED_WITH_CHAR8_T _LIBCPP_DEPRECATED
#  else
#    define _LIBCPP_DEPRECATED_WITH_CHAR8_T
#  endif

// Macros to enter and leave a state where deprecation warnings are suppressed.
#  if defined(_LIBCPP_COMPILER_CLANG_BASED) || defined(_LIBCPP_COMPILER_GCC)
#    define _LIBCPP_SUPPRESS_DEPRECATED_PUSH                                                                           \
      _Pragma("GCC diagnostic push") _Pragma("GCC diagnostic ignored \"-Wdeprecated\"")                                \
          _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
#    define _LIBCPP_SUPPRESS_DEPRECATED_POP _Pragma("GCC diagnostic pop")
#  else
#    define _LIBCPP_SUPPRESS_DEPRECATED_PUSH
#    define _LIBCPP_SUPPRESS_DEPRECATED_POP
#  endif

#  if _LIBCPP_STD_VER <= 11
#    define _LIBCPP_EXPLICIT_SINCE_CXX14
#  else
#    define _LIBCPP_EXPLICIT_SINCE_CXX14 explicit
#  endif

#  if _LIBCPP_STD_VER >= 23
#    define _LIBCPP_EXPLICIT_SINCE_CXX23 explicit
#  else
#    define _LIBCPP_EXPLICIT_SINCE_CXX23
#  endif

#  if _LIBCPP_STD_VER >= 14
#    define _LIBCPP_CONSTEXPR_SINCE_CXX14 constexpr
#  else
#    define _LIBCPP_CONSTEXPR_SINCE_CXX14
#  endif

#  if _LIBCPP_STD_VER >= 17
#    define _LIBCPP_CONSTEXPR_SINCE_CXX17 constexpr
#  else
#    define _LIBCPP_CONSTEXPR_SINCE_CXX17
#  endif

#  if _LIBCPP_STD_VER >= 20
#    define _LIBCPP_CONSTEXPR_SINCE_CXX20 constexpr
#  else
#    define _LIBCPP_CONSTEXPR_SINCE_CXX20
#  endif

#  if _LIBCPP_STD_VER >= 23
#    define _LIBCPP_CONSTEXPR_SINCE_CXX23 constexpr
#  else
#    define _LIBCPP_CONSTEXPR_SINCE_CXX23
#  endif

#  if _LIBCPP_STD_VER >= 26
#    define _LIBCPP_CONSTEXPR_SINCE_CXX26 constexpr
#  else
#    define _LIBCPP_CONSTEXPR_SINCE_CXX26
#  endif

#  ifndef _LIBCPP_WEAK
#    define _LIBCPP_WEAK __attribute__((__weak__))
#  endif

// Thread API
// clang-format off
#  if _LIBCPP_HAS_THREADS &&                                                                                           \
      !_LIBCPP_HAS_THREAD_API_PTHREAD &&                                                                               \
      !_LIBCPP_HAS_THREAD_API_WIN32 &&                                                                                 \
      !_LIBCPP_HAS_THREAD_API_EXTERNAL

#    if defined(__FreeBSD__) ||                                                                                        \
        defined(__wasi__) ||                                                                                           \
        defined(__NetBSD__) ||                                                                                         \
        defined(__OpenBSD__) ||                                                                                        \
        defined(__NuttX__) ||                                                                                          \
        defined(__linux__) ||                                                                                          \
        defined(__GNU__) ||                                                                                            \
        defined(__APPLE__) ||                                                                                          \
        defined(__MVS__) ||                                                                                            \
        defined(_AIX) ||                                                                                               \
        defined(__EMSCRIPTEN__)
// clang-format on
#      undef _LIBCPP_HAS_THREAD_API_PTHREAD
#      define _LIBCPP_HAS_THREAD_API_PTHREAD 1
#    elif defined(__Fuchsia__)
// TODO(44575): Switch to C11 thread API when possible.
#      undef _LIBCPP_HAS_THREAD_API_PTHREAD
#      define _LIBCPP_HAS_THREAD_API_PTHREAD 1
#    elif defined(_LIBCPP_WIN32API)
#      undef _LIBCPP_HAS_THREAD_API_WIN32
#      define _LIBCPP_HAS_THREAD_API_WIN32 1
#    else
#      error "No thread API"
#    endif // _LIBCPP_HAS_THREAD_API
#  endif   // _LIBCPP_HAS_THREADS

#  if _LIBCPP_HAS_THREAD_API_PTHREAD
#    if defined(__ANDROID__) && __ANDROID_API__ >= 30
#      define _LIBCPP_HAS_COND_CLOCKWAIT 1
#    elif defined(_LIBCPP_GLIBC_PREREQ)
#      if _LIBCPP_GLIBC_PREREQ(2, 30)
#        define _LIBCPP_HAS_COND_CLOCKWAIT 1
#      else
#        define _LIBCPP_HAS_COND_CLOCKWAIT 0
#      endif
#    else
#      define _LIBCPP_HAS_COND_CLOCKWAIT 0
#    endif
#  else
#    define _LIBCPP_HAS_COND_CLOCKWAIT 0
#  endif

#  if !_LIBCPP_HAS_THREADS && _LIBCPP_HAS_THREAD_API_PTHREAD
#    error _LIBCPP_HAS_THREAD_API_PTHREAD may only be true when _LIBCPP_HAS_THREADS is true.
#  endif

#  if !_LIBCPP_HAS_THREADS && _LIBCPP_HAS_THREAD_API_EXTERNAL
#    error _LIBCPP_HAS_THREAD_API_EXTERNAL may only be true when _LIBCPP_HAS_THREADS is true.
#  endif

#  if !_LIBCPP_HAS_MONOTONIC_CLOCK && _LIBCPP_HAS_THREADS
#    error _LIBCPP_HAS_MONOTONIC_CLOCK may only be false when _LIBCPP_HAS_THREADS is false.
#  endif

#  if _LIBCPP_HAS_THREADS && !defined(__STDCPP_THREADS__)
#    define __STDCPP_THREADS__ 1
#  endif

// The glibc and Bionic implementation of pthreads implements
// pthread_mutex_destroy as nop for regular mutexes. Additionally, Win32
// mutexes have no destroy mechanism.
//
// This optimization can't be performed on Apple platforms, where
// pthread_mutex_destroy can allow the kernel to release resources.
// See https://llvm.org/D64298 for details.
//
// TODO(EricWF): Enable this optimization on Bionic after speaking to their
//               respective stakeholders.
// clang-format off
#  if (_LIBCPP_HAS_THREAD_API_PTHREAD && defined(__GLIBC__)) ||                                                        \
      (_LIBCPP_HAS_THREAD_API_C11 && defined(__Fuchsia__)) ||                                                          \
       _LIBCPP_HAS_THREAD_API_WIN32
// clang-format on
#    define _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION 1
#  else
#    define _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION 0
#  endif

// Destroying a condvar is a nop on Windows.
//
// This optimization can't be performed on Apple platforms, where
// pthread_cond_destroy can allow the kernel to release resources.
// See https://llvm.org/D64298 for details.
//
// TODO(EricWF): This is potentially true for some pthread implementations
// as well.
#  if (_LIBCPP_HAS_THREAD_API_C11 && defined(__Fuchsia__)) || _LIBCPP_HAS_THREAD_API_WIN32
#    define _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION 1
#  else
#    define _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION 0
#  endif

#  if defined(__BIONIC__) || defined(__NuttX__) || defined(__Fuchsia__) || defined(__wasi__) ||                        \
      _LIBCPP_HAS_MUSL_LIBC || defined(__OpenBSD__) || defined(__LLVM_LIBC__)
#    define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
#  endif

#  if __has_feature(cxx_atomic) || __has_extension(c_atomic) || __has_keyword(_Atomic)
#    define _LIBCPP_HAS_C_ATOMIC_IMP 1
#    define _LIBCPP_HAS_GCC_ATOMIC_IMP 0
#    define _LIBCPP_HAS_EXTERNAL_ATOMIC_IMP 0
#  elif defined(_LIBCPP_COMPILER_GCC)
#    define _LIBCPP_HAS_C_ATOMIC_IMP 0
#    define _LIBCPP_HAS_GCC_ATOMIC_IMP 1
#    define _LIBCPP_HAS_EXTERNAL_ATOMIC_IMP 0
#  endif

#  if !_LIBCPP_HAS_C_ATOMIC_IMP && !_LIBCPP_HAS_GCC_ATOMIC_IMP && !_LIBCPP_HAS_EXTERNAL_ATOMIC_IMP
#    define _LIBCPP_HAS_ATOMIC_HEADER 0
#  else
#    define _LIBCPP_HAS_ATOMIC_HEADER 1
#    ifndef _LIBCPP_ATOMIC_FLAG_TYPE
#      define _LIBCPP_ATOMIC_FLAG_TYPE bool
#    endif
#  endif

#  if defined(__FreeBSD__) && defined(__clang__) && __has_attribute(__no_thread_safety_analysis__)
#    define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS __attribute__((__no_thread_safety_analysis__))
#  else
#    define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
#  endif

// Work around the attribute handling in clang.  When both __declspec and
// __attribute__ are present, the processing goes awry preventing the definition
// of the types. In MinGW mode, __declspec evaluates to __attribute__, and thus
// combining the two does work.
#  if defined(_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS) && defined(__clang__) &&                                       \
      __has_attribute(acquire_capability) && !defined(_MSC_VER)
#    define _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS 1
#  else
#    define _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS 0
#  endif

#  if _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
#    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x) __attribute__((x))
#  else
#    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x)
#  endif

#  if _LIBCPP_STD_VER >= 20
#    define _LIBCPP_CONSTINIT constinit
#  elif __has_attribute(__require_constant_initialization__)
#    define _LIBCPP_CONSTINIT __attribute__((__require_constant_initialization__))
#  else
#    define _LIBCPP_CONSTINIT
#  endif

#  if defined(__CUDACC__) || defined(__CUDA_ARCH__) || defined(__CUDA_LIBDEVICE__)
// The CUDA SDK contains an unfortunate definition for the __noinline__ macro,
// which breaks the regular __attribute__((__noinline__)) syntax. Therefore,
// when compiling for CUDA we use the non-underscored version of the noinline
// attribute.
//
// This is a temporary workaround and we still expect the CUDA SDK team to solve
// this issue properly in the SDK headers.
//
// See https://github.com/llvm/llvm-project/pull/73838 for more details.
#    define _LIBCPP_NOINLINE __attribute__((noinline))
#  elif __has_attribute(__noinline__)
#    define _LIBCPP_NOINLINE __attribute__((__noinline__))
#  else
#    define _LIBCPP_NOINLINE
#  endif

// We often repeat things just for handling wide characters in the library.
// When wide characters are disabled, it can be useful to have a quick way of
// disabling it without having to resort to #if-#endif, which has a larger
// impact on readability.
#  if !_LIBCPP_HAS_WIDE_CHARACTERS
#    define _LIBCPP_IF_WIDE_CHARACTERS(...)
#  else
#    define _LIBCPP_IF_WIDE_CHARACTERS(...) __VA_ARGS__
#  endif

// clang-format off
#  define _LIBCPP_PUSH_MACROS _Pragma("push_macro(\"min\")") _Pragma("push_macro(\"max\")") _Pragma("push_macro(\"refresh\")") _Pragma("push_macro(\"move\")") _Pragma("push_macro(\"erase\")")
#  define _LIBCPP_POP_MACROS _Pragma("pop_macro(\"min\")") _Pragma("pop_macro(\"max\")") _Pragma("pop_macro(\"refresh\")") _Pragma("pop_macro(\"move\")") _Pragma("pop_macro(\"erase\")")
// clang-format on

#  ifndef _LIBCPP_NO_AUTO_LINK
#    if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
#      if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
#        pragma comment(lib, "c++.lib")
#      else
#        pragma comment(lib, "libc++.lib")
#      endif
#    endif // defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
#  endif   // _LIBCPP_NO_AUTO_LINK

// Configures the fopen close-on-exec mode character, if any. This string will
// be appended to any mode string used by fstream for fopen/fdopen.
//
// Not all platforms support this, but it helps avoid fd-leaks on platforms that
// do.
#  if defined(__BIONIC__)
#    define _LIBCPP_FOPEN_CLOEXEC_MODE "e"
#  else
#    define _LIBCPP_FOPEN_CLOEXEC_MODE
#  endif

#  if __has_cpp_attribute(msvc::no_unique_address)
// MSVC implements [[no_unique_address]] as a silent no-op currently.
// (If/when MSVC breaks its C++ ABI, it will be changed to work as intended.)
// However, MSVC implements [[msvc::no_unique_address]] which does what
// [[no_unique_address]] is supposed to do, in general.
#    define _LIBCPP_NO_UNIQUE_ADDRESS [[msvc::no_unique_address]]
#  else
#    define _LIBCPP_NO_UNIQUE_ADDRESS [[__no_unique_address__]]
#  endif

// c8rtomb() and mbrtoc8() were added in C++20 and C23. Support for these
// functions is gradually being added to existing C libraries. The conditions
// below check for known C library versions and conditions under which these
// functions are declared by the C library.
//
// GNU libc 2.36 and newer declare c8rtomb() and mbrtoc8() in C++ modes if
// __cpp_char8_t is defined or if C2X extensions are enabled. Determining
// the latter depends on internal GNU libc details that are not appropriate
// to depend on here, so any declarations present when __cpp_char8_t is not
// defined are ignored.
#  if defined(_LIBCPP_GLIBC_PREREQ)
#    if _LIBCPP_GLIBC_PREREQ(2, 36) && defined(__cpp_char8_t)
#      define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
#    else
#      define _LIBCPP_HAS_C8RTOMB_MBRTOC8 0
#    endif
#  else
#    define _LIBCPP_HAS_C8RTOMB_MBRTOC8 0
#  endif

// There are a handful of public standard library types that are intended to
// support CTAD but don't need any explicit deduction guides to do so. This
// macro is used to mark them as such, which suppresses the
// '-Wctad-maybe-unsupported' compiler warning when CTAD is used in user code
// with these classes.
#  if _LIBCPP_STD_VER >= 17
#    ifdef _LIBCPP_COMPILER_CLANG_BASED
#      define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(_ClassName)                                                              \
        template <class... _Tag>                                                                                       \
        [[maybe_unused]] _ClassName(typename _Tag::__allow_ctad...)->_ClassName<_Tag...>
#    else
#      define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(ClassName)                                                               \
        template <class... _Tag>                                                                                       \
        ClassName(typename _Tag::__allow_ctad...)->ClassName<_Tag...>
#    endif
#  else
#    define _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(_ClassName) static_assert(true, "")
#  endif

// TODO(LLVM 22): Remove the workaround
#  if defined(__OBJC__) && (!defined(_LIBCPP_CLANG_VER) || _LIBCPP_CLANG_VER < 2001)
#    define _LIBCPP_WORKAROUND_OBJCXX_COMPILER_INTRINSICS
#  endif

#  define _PSTL_PRAGMA(x) _Pragma(#x)

// Enable SIMD for compilers that support OpenMP 4.0
#  if (defined(_OPENMP) && _OPENMP >= 201307)

#    define _PSTL_UDR_PRESENT
#    define _PSTL_PRAGMA_SIMD _PSTL_PRAGMA(omp simd)
#    define _PSTL_PRAGMA_DECLARE_SIMD _PSTL_PRAGMA(omp declare simd)
#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM) _PSTL_PRAGMA(omp simd reduction(PRM))
#    define _PSTL_PRAGMA_SIMD_SCAN(PRM) _PSTL_PRAGMA(omp simd reduction(inscan, PRM))
#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan inclusive(PRM))
#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan exclusive(PRM))

// Declaration of reduction functor, where
// NAME - the name of the functor
// OP - type of the callable object with the reduction operation
// omp_in - refers to the local partial result
// omp_out - refers to the final value of the combiner operator
// omp_priv - refers to the private copy of the initial value
// omp_orig - refers to the original variable to be reduced
#    define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)                                                                   \
      _PSTL_PRAGMA(omp declare reduction(NAME:OP : omp_out(omp_in)) initializer(omp_priv = omp_orig))

#  elif defined(_LIBCPP_COMPILER_CLANG_BASED)

#    define _PSTL_PRAGMA_SIMD _Pragma("clang loop vectorize(enable) interleave(enable)")
#    define _PSTL_PRAGMA_DECLARE_SIMD
#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM) _Pragma("clang loop vectorize(enable) interleave(enable)")
#    define _PSTL_PRAGMA_SIMD_SCAN(PRM) _Pragma("clang loop vectorize(enable) interleave(enable)")
#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM)
#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM)
#    define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)

#  else // (defined(_OPENMP) && _OPENMP >= 201307)

#    define _PSTL_PRAGMA_SIMD
#    define _PSTL_PRAGMA_DECLARE_SIMD
#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM)
#    define _PSTL_PRAGMA_SIMD_SCAN(PRM)
#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM)
#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM)
#    define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)

#  endif // (defined(_OPENMP) && _OPENMP >= 201307)

#  define _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED

// Optional attributes - these are useful for a better QoI, but not required to be available

#  define _LIBCPP_NOALIAS __attribute__((__malloc__))
#  define _LIBCPP_NODEBUG [[__gnu__::__nodebug__]]
#  define _LIBCPP_NO_SANITIZE(...) __attribute__((__no_sanitize__(__VA_ARGS__)))
#  define _LIBCPP_INIT_PRIORITY_MAX __attribute__((__init_priority__(100)))
#  define _LIBCPP_ATTRIBUTE_FORMAT(archetype, format_string_index, first_format_arg_index)                             \
    __attribute__((__format__(archetype, format_string_index, first_format_arg_index)))
#  define _LIBCPP_PACKED __attribute__((__packed__))

#  if __has_attribute(__no_sanitize__) && !defined(_LIBCPP_COMPILER_GCC)
#    define _LIBCPP_NO_CFI __attribute__((__no_sanitize__("cfi")))
#  else
#    define _LIBCPP_NO_CFI
#  endif

#  if __has_attribute(__using_if_exists__)
#    define _LIBCPP_USING_IF_EXISTS __attribute__((__using_if_exists__))
#  else
#    define _LIBCPP_USING_IF_EXISTS
#  endif

#  if __has_cpp_attribute(_Clang::__no_destroy__)
#    define _LIBCPP_NO_DESTROY [[_Clang::__no_destroy__]]
#  else
#    define _LIBCPP_NO_DESTROY
#  endif

#  if __has_attribute(__diagnose_if__)
#    define _LIBCPP_DIAGNOSE_WARNING(...) __attribute__((__diagnose_if__(__VA_ARGS__, "warning")))
#  else
#    define _LIBCPP_DIAGNOSE_WARNING(...)
#  endif

#  if __has_cpp_attribute(_Clang::__lifetimebound__)
#    define _LIBCPP_LIFETIMEBOUND [[_Clang::__lifetimebound__]]
#  else
#    define _LIBCPP_LIFETIMEBOUND
#  endif

#  if __has_cpp_attribute(_Clang::__noescape__)
#    define _LIBCPP_NOESCAPE [[_Clang::__noescape__]]
#  else
#    define _LIBCPP_NOESCAPE
#  endif

#  if __has_cpp_attribute(_Clang::__no_specializations__)
#    define _LIBCPP_NO_SPECIALIZATIONS                                                                                 \
      [[_Clang::__no_specializations__("Users are not allowed to specialize this standard library entity")]]
#  else
#    define _LIBCPP_NO_SPECIALIZATIONS
#  endif

#  if __has_cpp_attribute(_Clang::__standalone_debug__)
#    define _LIBCPP_STANDALONE_DEBUG [[_Clang::__standalone_debug__]]
#  else
#    define _LIBCPP_STANDALONE_DEBUG
#  endif

#  if __has_cpp_attribute(_Clang::__preferred_name__)
#    define _LIBCPP_PREFERRED_NAME(x) [[_Clang::__preferred_name__(x)]]
#  else
#    define _LIBCPP_PREFERRED_NAME(x)
#  endif

#  if defined(_LIBCPP_ABI_MICROSOFT) && __has_declspec_attribute(empty_bases)
#    define _LIBCPP_DECLSPEC_EMPTY_BASES __declspec(empty_bases)
#  else
#    define _LIBCPP_DECLSPEC_EMPTY_BASES
#  endif

// Allow for build-time disabling of unsigned integer sanitization
#  if __has_attribute(no_sanitize) && !defined(_LIBCPP_COMPILER_GCC)
#    define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK __attribute__((__no_sanitize__("unsigned-integer-overflow")))
#  else
#    define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
#  endif

#  if __has_feature(nullability)
#    define _LIBCPP_DIAGNOSE_NULLPTR _Nonnull
#  else
#    define _LIBCPP_DIAGNOSE_NULLPTR
#  endif

// TODO(LLVM 22): Remove this macro once LLVM19 support ends. __cpp_explicit_this_parameter has been set in LLVM20.
// Clang-18 has support for deducing this, but it does not set the FTM.
#  if defined(__cpp_explicit_this_parameter) || (defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1800)
#    define _LIBCPP_HAS_EXPLICIT_THIS_PARAMETER 1
#  else
#    define _LIBCPP_HAS_EXPLICIT_THIS_PARAMETER 0
#  endif

#endif // __cplusplus

#endif // _LIBCPP___CONFIG