libcxx/include/__availability

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___AVAILABILITY
  11 #define _LIBCPP___AVAILABILITY
  12
  13 #include <__config>
  14
  15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  16 #  pragma GCC system_header
  17 #endif
  18
  19 // Libc++ is shipped by various vendors. In particular, it is used as a system
  20 // library on macOS, iOS and other Apple platforms. In order for users to be
  21 // able to compile a binary that is intended to be deployed to an older version
  22 // of a platform, Clang provides availability attributes [1]. These attributes
  23 // can be placed on declarations and are used to describe the life cycle of a
  24 // symbol in the library.
  25 //
  26 // The main goal is to ensure a compile-time error if a symbol that hasn't been
  27 // introduced in a previously released library is used in a program that targets
  28 // that previously released library. Normally, this would be a load-time error
  29 // when one tries to launch the program against the older library.
  30 //
  31 // For example, the filesystem library was introduced in the dylib in macOS 10.15.
  32 // If a user compiles on a macOS 10.15 host but targets macOS 10.13 with their
  33 // program, the compiler would normally not complain (because the required
  34 // declarations are in the headers), but the dynamic loader would fail to find
  35 // the symbols when actually trying to launch the program on macOS 10.13. To
  36 // turn this into a compile-time issue instead, declarations are annotated with
  37 // when they were introduced, and the compiler can produce a diagnostic if the
  38 // program references something that isn't available on the deployment target.
  39 //
  40 // This mechanism is general in nature, and any vendor can add their markup to
  41 // the library (see below). Whenever a new feature is added that requires support
  42 // in the shared library, two macros are added below to allow marking the feature
  43 // as unavailable:
  44 // 1. A macro named `_LIBCPP_AVAILABILITY_HAS_NO_<feature>` which must be defined
  45 //    exactly when compiling for a target that doesn't support the feature.
  46 // 2. A macro named `_LIBCPP_AVAILABILITY_<feature>`, which must always be defined
  47 //    and must expand to the proper availability attribute for the platform.
  48 //
  49 // When vendors decide to ship the feature as part of their shared library, they
  50 // can update these macros appropriately for their platform, and the library will
  51 // use those to provide an optimal user experience.
  52 //
  53 // Furthermore, many features in the standard library have corresponding
  54 // feature-test macros. The `_LIBCPP_AVAILABILITY_HAS_NO_<feature>` macros
  55 // are checked by the corresponding feature-test macros generated by
  56 // generate_feature_test_macro_components.py to ensure that the library
  57 // doesn't announce a feature as being implemented if it is unavailable on
  58 // the deployment target.
  59 //
  60 // Note that this mechanism is disabled by default in the "upstream" libc++.
  61 // Availability annotations are only meaningful when shipping libc++ inside
  62 // a platform (i.e. as a system library), and so vendors that want them should
  63 // turn those annotations on at CMake configuration time.
  64 //
  65 // [1]: https://clang.llvm.org/docs/AttributeReference.html#availability
  66
  67
  68 // For backwards compatibility, allow users to define _LIBCPP_DISABLE_AVAILABILITY
  69 // for a while.
  70 #if defined(_LIBCPP_DISABLE_AVAILABILITY)
  71 #   if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
  72 #       define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
  73 #   endif
  74 #endif
  75
  76 // Availability markup is disabled when building the library, or when the compiler
  77 // doesn't support the proper attributes.
  78 #if defined(_LIBCPP_BUILDING_LIBRARY) ||                                        \
  79     defined(_LIBCXXABI_BUILDING_LIBRARY) ||                                     \
  80     !__has_feature(attribute_availability_with_strict) ||                       \
  81     !__has_feature(attribute_availability_in_templates) ||                      \
  82     !__has_extension(pragma_clang_attribute_external_declaration)
  83 #   if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
  84 #       define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
  85 #   endif
  86 #endif
  87
  88 #if defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
  89
  90     // This controls the availability of std::shared_mutex and std::shared_timed_mutex,
  91     // which were added to the dylib later.
  92 // #   define _LIBCPP_AVAILABILITY_HAS_NO_SHARED_MUTEX
  93 #   define _LIBCPP_AVAILABILITY_SHARED_MUTEX
  94
  95     // These macros control the availability of std::bad_optional_access and
  96     // other exception types. These were put in the shared library to prevent
  97     // code bloat from every user program defining the vtable for these exception
  98     // types.
  99     //
 100     // Note that when exceptions are disabled, the methods that normally throw
 101     // these exceptions can be used even on older deployment targets, but those
 102     // methods will abort instead of throwing.
 103 // #   define _LIBCPP_AVAILABILITY_HAS_NO_BAD_OPTIONAL_ACCESS
 104 #   define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
 105
 106 // #   define _LIBCPP_AVAILABILITY_HAS_NO_BAD_VARIANT_ACCESS
 107 #   define _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS
 108
 109 // #   define _LIBCPP_AVAILABILITY_HAS_NO_BAD_ANY_CAST
 110 #   define _LIBCPP_AVAILABILITY_BAD_ANY_CAST
 111
 112     // This controls the availability of std::uncaught_exceptions().
 113 // #   define _LIBCPP_AVAILABILITY_HAS_NO_UNCAUGHT_EXCEPTIONS
 114 #   define _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS
 115
 116     // This controls the availability of the sized version of ::operator delete,
 117     // ::operator delete[], and their align_val_t variants, which were all added
 118     // in C++17, and hence not present in early dylibs.
 119 // #   define _LIBCPP_AVAILABILITY_HAS_NO_SIZED_NEW_DELETE
 120 #   define _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE
 121
 122     // This controls the availability of the std::future_error exception.
 123     //
 124     // Note that when exceptions are disabled, the methods that normally throw
 125     // std::future_error can be used even on older deployment targets, but those
 126     // methods will abort instead of throwing.
 127 // #   define _LIBCPP_AVAILABILITY_HAS_NO_FUTURE_ERROR
 128 #   define _LIBCPP_AVAILABILITY_FUTURE_ERROR
 129
 130     // This controls the availability of std::type_info's vtable.
 131     // I can't imagine how using std::type_info can work at all if
 132     // this isn't supported.
 133 // #   define _LIBCPP_AVAILABILITY_HAS_NO_TYPEINFO_VTABLE
 134 #   define _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
 135
 136     // This controls the availability of std::locale::category members
 137     // (e.g. std::locale::collate), which are defined in the dylib.
 138 // #   define _LIBCPP_AVAILABILITY_HAS_NO_LOCALE_CATEGORY
 139 #   define _LIBCPP_AVAILABILITY_LOCALE_CATEGORY
 140
 141     // This controls the availability of atomic operations on std::shared_ptr
 142     // (e.g. `std::atomic_store(std::shared_ptr)`), which require a shared
 143     // lock table located in the dylib.
 144 // #   define _LIBCPP_AVAILABILITY_HAS_NO_ATOMIC_SHARED_PTR
 145 #   define _LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
 146
 147     // These macros control the availability of all parts of <filesystem> that
 148     // depend on something in the dylib.
 149 // #   define _LIBCPP_AVAILABILITY_HAS_NO_FILESYSTEM_LIBRARY
 150 #   define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY
 151 #   define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_PUSH
 152 #   define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_POP
 153
 154     // This controls the availability of floating-point std::to_chars functions.
 155     // These overloads were added later than the integer overloads.
 156 // #   define _LIBCPP_AVAILABILITY_HAS_NO_TO_CHARS_FLOATING_POINT
 157 #   define _LIBCPP_AVAILABILITY_TO_CHARS_FLOATING_POINT
 158
 159     // This controls the availability of the C++20 synchronization library,
 160     // which requires shared library support for various operations
 161     // (see libcxx/src/atomic.cpp). This includes <barier>, <latch>,
 162     // <semaphore>, and notification functions on std::atomic.
 163 // #   define _LIBCPP_AVAILABILITY_HAS_NO_SYNC
 164 #   define _LIBCPP_AVAILABILITY_SYNC
 165
 166     // This controls whether the library claims to provide a default verbose
 167     // termination function, and consequently whether the headers will try
 168     // to use it when the mechanism isn't overriden at compile-time.
 169 // #   define _LIBCPP_AVAILABILITY_HAS_NO_VERBOSE_ABORT
 170 #   define _LIBCPP_AVAILABILITY_VERBOSE_ABORT
 171
 172     // This controls the availability of the C++17 std::pmr library,
 173     // which is implemented in large part in the built library.
 174 // #   define _LIBCPP_AVAILABILITY_HAS_NO_PMR
 175 #   define _LIBCPP_AVAILABILITY_PMR
 176
 177     // This controls the availability of the C++20 time zone database.
 178     // The parser code is built in the library.
 179 // #   define _LIBCPP_AVAILABILITY_HAS_NO_TZDB
 180 #   define _LIBCPP_AVAILABILITY_TZDB
 181
 182 // Enable additional explicit instantiations of iostreams components. This
 183 // reduces the number of weak definitions generated in programs that use
 184 // iostreams by providing a single strong definition in the shared library.
 185 //
 186 // TODO: Enable additional explicit instantiations on GCC once it supports exclude_from_explicit_instantiation,
 187 //       or once libc++ doesn't use the attribute anymore.
 188 // TODO: Enable them on Windows once https://llvm.org/PR41018 has been fixed.
 189 #if defined(_LIBCPP_COMPILER_GCC) || defined(_WIN32)
 190 #  define _LIBCPP_AVAILABILITY_HAS_NO_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1
 191 #endif
 192
 193 #elif defined(__APPLE__)
 194
 195     // shared_mutex and shared_timed_mutex
 196 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200) ||    \
 197         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 100000) || \
 198         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 100000) ||         \
 199         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 30000)
 200 #       define _LIBCPP_AVAILABILITY_HAS_NO_SHARED_MUTEX
 201 #   endif
 202 #   define _LIBCPP_AVAILABILITY_SHARED_MUTEX                                    \
 203         __attribute__((availability(macos,strict,introduced=10.12)))            \
 204         __attribute__((availability(ios,strict,introduced=10.0)))               \
 205         __attribute__((availability(tvos,strict,introduced=10.0)))              \
 206         __attribute__((availability(watchos,strict,introduced=3.0)))
 207
 208         // bad_optional_access, bad_variant_access and bad_any_cast
 209         // Note: bad_optional_access & friends were not introduced in the matching
 210         // macOS and iOS versions, so the version mismatch between macOS and others
 211         // is intended.
 212 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101300) ||    \
 213         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 120000) || \
 214         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 120000) ||         \
 215         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 50000)
 216 #       define _LIBCPP_AVAILABILITY_HAS_NO_BAD_OPTIONAL_ACCESS
 217 #       define _LIBCPP_AVAILABILITY_HAS_NO_BAD_VARIANT_ACCESS
 218 #       define _LIBCPP_AVAILABILITY_HAS_NO_BAD_ANY_CAST
 219 #   endif
 220 #   define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS                             \
 221         __attribute__((availability(macos,strict,introduced=10.13)))            \
 222         __attribute__((availability(ios,strict,introduced=12.0)))               \
 223         __attribute__((availability(tvos,strict,introduced=12.0)))              \
 224         __attribute__((availability(watchos,strict,introduced=5.0)))
 225 #   define _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS                              \
 226         _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
 227 #   define _LIBCPP_AVAILABILITY_BAD_ANY_CAST                                    \
 228         _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
 229
 230     // uncaught_exceptions
 231 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200) ||    \
 232         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 100000) || \
 233         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 100000) ||         \
 234         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 30000)
 235 #       define _LIBCPP_AVAILABILITY_HAS_NO_UNCAUGHT_EXCEPTIONS
 236 #   endif
 237 #   define _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS                             \
 238         __attribute__((availability(macos,strict,introduced=10.12)))            \
 239         __attribute__((availability(ios,strict,introduced=10.0)))               \
 240         __attribute__((availability(tvos,strict,introduced=10.0)))              \
 241         __attribute__((availability(watchos,strict,introduced=3.0)))
 242
 243     // sized operator new and sized operator delete
 244 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200) ||    \
 245         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 100000) || \
 246         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 100000) ||         \
 247         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 30000)
 248 #       define _LIBCPP_AVAILABILITY_HAS_NO_SIZED_NEW_DELETE
 249 #   endif
 250 #   define _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE                                \
 251         __attribute__((availability(macos,strict,introduced=10.12)))            \
 252         __attribute__((availability(ios,strict,introduced=10.0)))               \
 253         __attribute__((availability(tvos,strict,introduced=10.0)))              \
 254         __attribute__((availability(watchos,strict,introduced=3.0)))
 255
 256     // future_error
 257 #   if (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 60000)
 258 #       define _LIBCPP_AVAILABILITY_HAS_NO_FUTURE_ERROR
 259 #   endif
 260 #   define _LIBCPP_AVAILABILITY_FUTURE_ERROR                                    \
 261         __attribute__((availability(ios,strict,introduced=6.0)))
 262
 263     // type_info's vtable
 264 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 100900) ||    \
 265         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 70000)
 266 #       define _LIBCPP_AVAILABILITY_HAS_NO_TYPEINFO_VTABLE
 267 #   endif
 268 #   define _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE                                 \
 269         __attribute__((availability(macos,strict,introduced=10.9)))             \
 270         __attribute__((availability(ios,strict,introduced=7.0)))
 271
 272     // locale::category
 273 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 100900) ||    \
 274         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 70000)
 275 #       define _LIBCPP_AVAILABILITY_HAS_NO_LOCALE_CATEGORY
 276 #   endif
 277 #   define _LIBCPP_AVAILABILITY_LOCALE_CATEGORY                                 \
 278         __attribute__((availability(macos,strict,introduced=10.9)))             \
 279         __attribute__((availability(ios,strict,introduced=7.0)))
 280
 281     // atomic operations on shared_ptr
 282 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 100900) ||    \
 283         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 70000)
 284 #       define _LIBCPP_AVAILABILITY_HAS_NO_ATOMIC_SHARED_PTR
 285 #   endif
 286 #   define _LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR                               \
 287         __attribute__((availability(macos,strict,introduced=10.9)))             \
 288         __attribute__((availability(ios,strict,introduced=7.0)))
 289
 290     // <filesystem>
 291 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101500) ||    \
 292         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 130000) || \
 293         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 130000) ||         \
 294         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 60000)
 295 #       define _LIBCPP_AVAILABILITY_HAS_NO_FILESYSTEM_LIBRARY
 296 #   endif
 297 #   define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY                              \
 298         __attribute__((availability(macos,strict,introduced=10.15)))            \
 299         __attribute__((availability(ios,strict,introduced=13.0)))               \
 300         __attribute__((availability(tvos,strict,introduced=13.0)))              \
 301         __attribute__((availability(watchos,strict,introduced=6.0)))
 302 #   define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_PUSH                                 \
 303         _Pragma("clang attribute push(__attribute__((availability(macos,strict,introduced=10.15))), apply_to=any(function,record))") \
 304         _Pragma("clang attribute push(__attribute__((availability(ios,strict,introduced=13.0))), apply_to=any(function,record))")    \
 305         _Pragma("clang attribute push(__attribute__((availability(tvos,strict,introduced=13.0))), apply_to=any(function,record))")   \
 306         _Pragma("clang attribute push(__attribute__((availability(watchos,strict,introduced=6.0))), apply_to=any(function,record))")
 307 #   define _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY_POP                                  \
 308         _Pragma("clang attribute pop")                                          \
 309         _Pragma("clang attribute pop")                                          \
 310         _Pragma("clang attribute pop")                                          \
 311         _Pragma("clang attribute pop")
 312
 313     // std::to_chars(floating-point)
 314 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 130300) ||    \
 315         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 160300) || \
 316         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 160300) ||         \
 317         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 90300)
 318 #       define _LIBCPP_AVAILABILITY_HAS_NO_TO_CHARS_FLOATING_POINT
 319 #   endif
 320 #   define _LIBCPP_AVAILABILITY_TO_CHARS_FLOATING_POINT                         \
 321         __attribute__((availability(macos,strict,introduced=13.3)))             \
 322         __attribute__((availability(ios,strict,introduced=16.3)))               \
 323         __attribute__((availability(tvos,strict,introduced=16.3)))              \
 324         __attribute__((availability(watchos,strict,introduced=9.3)))
 325
 326     // c++20 synchronization library
 327 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 110000) ||    \
 328         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 140000) || \
 329         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 140000) ||         \
 330         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 70000)
 331 #       define _LIBCPP_AVAILABILITY_HAS_NO_SYNC
 332 #   endif
 333 #   define _LIBCPP_AVAILABILITY_SYNC                                            \
 334         __attribute__((availability(macos,strict,introduced=11.0)))             \
 335         __attribute__((availability(ios,strict,introduced=14.0)))               \
 336         __attribute__((availability(tvos,strict,introduced=14.0)))              \
 337         __attribute__((availability(watchos,strict,introduced=7.0)))
 338
 339     // __libcpp_verbose_abort
 340 #   if 1 // TODO: Update once this is released
 341 #       define _LIBCPP_AVAILABILITY_HAS_NO_VERBOSE_ABORT
 342 #   endif
 343 #   define _LIBCPP_AVAILABILITY_VERBOSE_ABORT                                   \
 344         __attribute__((unavailable))
 345
 346     // std::pmr
 347 #   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 140000) ||    \
 348         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 170000) || \
 349         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 170000) ||         \
 350         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 100000)
 351 #       define _LIBCPP_AVAILABILITY_HAS_NO_PMR
 352 #   endif
 353 // TODO: Enable std::pmr markup once https://github.com/llvm/llvm-project/issues/40340 has been fixed
 354 //       Until then, it is possible for folks to try to use `std::pmr` when back-deploying to targets that don't support
 355 //       it and it'll be a load-time error, but we don't have a good alternative because the library won't compile if we
 356 //       use availability annotations until that bug has been fixed.
 357 #  if 0
 358 #    define _LIBCPP_AVAILABILITY_PMR                                                                                   \
 359       __attribute__((availability(macos, strict, introduced = 14.0)))                                                  \
 360       __attribute__((availability(ios, strict, introduced = 17.0)))                                                    \
 361       __attribute__((availability(tvos, strict, introduced = 17.0)))                                                   \
 362       __attribute__((availability(watchos, strict, introduced = 10.0)))
 363 #  else
 364 #    define _LIBCPP_AVAILABILITY_PMR
 365 #  endif
 366
 367 #  define _LIBCPP_AVAILABILITY_HAS_NO_TZDB
 368 #  define _LIBCPP_AVAILABILITY_TZDB __attribute__((unavailable))
 369
 370 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 120000)   || \
 371       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 150000) || \
 372       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 150000)         || \
 373       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 80000)
 374 #    define _LIBCPP_AVAILABILITY_HAS_NO_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1
 375 #  endif
 376 #else
 377
 378 // ...New vendors can add availability markup here...
 379
 380 #   error "It looks like you're trying to enable vendor availability markup, but you haven't defined the corresponding macros yet!"
 381
 382 #endif
 383
 384 // Define availability attributes that depend on _LIBCPP_HAS_NO_EXCEPTIONS.
 385 // Those are defined in terms of the availability attributes above, and
 386 // should not be vendor-specific.
 387 #if defined(_LIBCPP_HAS_NO_EXCEPTIONS)
 388 #   define _LIBCPP_AVAILABILITY_FUTURE
 389 #   define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
 390 #   define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
 391 #   define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
 392 #else
 393 #   define _LIBCPP_AVAILABILITY_FUTURE                    _LIBCPP_AVAILABILITY_FUTURE_ERROR
 394 #   define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST        _LIBCPP_AVAILABILITY_BAD_ANY_CAST
 395 #   define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
 396 #   define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS  _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS
 397 #endif
 398
 399 #endif // _LIBCPP___AVAILABILITY