xref: /freebsd/contrib/llvm-project/libcxx/include/any (revision b64c5a0ace59af62eff52bfe110a521dc73c937b)
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_ANY
11#define _LIBCPP_ANY
12
13/*
14   any synopsis
15
16namespace std {
17
18  class bad_any_cast : public bad_cast
19  {
20  public:
21    virtual const char* what() const noexcept;
22  };
23
24  class any
25  {
26  public:
27
28    // 6.3.1 any construct/destruct
29    any() noexcept;
30
31    any(const any& other);
32    any(any&& other) noexcept;
33
34    template <class ValueType>
35      any(ValueType&& value);
36
37    ~any();
38
39    // 6.3.2 any assignments
40    any& operator=(const any& rhs);
41    any& operator=(any&& rhs) noexcept;
42
43    template <class ValueType>
44      any& operator=(ValueType&& rhs);
45
46    // 6.3.3 any modifiers
47    template <class ValueType, class... Args>
48      decay_t<ValueType>& emplace(Args&&... args);
49    template <class ValueType, class U, class... Args>
50      decay_t<ValueType>& emplace(initializer_list<U>, Args&&...);
51    void reset() noexcept;
52    void swap(any& rhs) noexcept;
53
54    // 6.3.4 any observers
55    bool has_value() const noexcept;
56    const type_info& type() const noexcept;
57  };
58
59   // 6.4 Non-member functions
60  void swap(any& x, any& y) noexcept;
61
62  template <class T, class ...Args>
63    any make_any(Args&& ...args);
64  template <class T, class U, class ...Args>
65    any make_any(initializer_list<U>, Args&& ...args);
66
67  template<class ValueType>
68    ValueType any_cast(const any& operand);
69  template<class ValueType>
70    ValueType any_cast(any& operand);
71  template<class ValueType>
72    ValueType any_cast(any&& operand);
73
74  template<class ValueType>
75    const ValueType* any_cast(const any* operand) noexcept;
76  template<class ValueType>
77    ValueType* any_cast(any* operand) noexcept;
78
79} // namespace std
80
81*/
82
83#include <__config>
84#include <__memory/allocator.h>
85#include <__memory/allocator_destructor.h>
86#include <__memory/allocator_traits.h>
87#include <__memory/unique_ptr.h>
88#include <__type_traits/add_const.h>
89#include <__type_traits/add_pointer.h>
90#include <__type_traits/aligned_storage.h>
91#include <__type_traits/conditional.h>
92#include <__type_traits/decay.h>
93#include <__type_traits/is_constructible.h>
94#include <__type_traits/is_function.h>
95#include <__type_traits/is_nothrow_constructible.h>
96#include <__type_traits/is_reference.h>
97#include <__type_traits/is_same.h>
98#include <__type_traits/is_void.h>
99#include <__type_traits/remove_cv.h>
100#include <__type_traits/remove_cvref.h>
101#include <__type_traits/remove_reference.h>
102#include <__utility/forward.h>
103#include <__utility/in_place.h>
104#include <__utility/move.h>
105#include <__utility/unreachable.h>
106#include <__verbose_abort>
107#include <initializer_list>
108#include <typeinfo>
109#include <version>
110
111#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
112#  pragma GCC system_header
113#endif
114
115_LIBCPP_PUSH_MACROS
116#include <__undef_macros>
117
118namespace std {
119class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_BAD_ANY_CAST bad_any_cast : public bad_cast {
120public:
121  const char* what() const _NOEXCEPT override;
122};
123} // namespace std
124
125_LIBCPP_BEGIN_NAMESPACE_STD
126
127#if _LIBCPP_STD_VER >= 17
128
129_LIBCPP_NORETURN inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST void __throw_bad_any_cast() {
130#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
131  throw bad_any_cast();
132#  else
133  _LIBCPP_VERBOSE_ABORT("bad_any_cast was thrown in -fno-exceptions mode");
134#  endif
135}
136
137// Forward declarations
138class _LIBCPP_TEMPLATE_VIS any;
139
140template <class _ValueType>
141_LIBCPP_HIDE_FROM_ABI add_pointer_t<add_const_t<_ValueType>> any_cast(any const*) _NOEXCEPT;
142
143template <class _ValueType>
144_LIBCPP_HIDE_FROM_ABI add_pointer_t<_ValueType> any_cast(any*) _NOEXCEPT;
145
146namespace __any_imp {
147_LIBCPP_SUPPRESS_DEPRECATED_PUSH
148using _Buffer = aligned_storage_t<3 * sizeof(void*), alignof(void*)>;
149_LIBCPP_SUPPRESS_DEPRECATED_POP
150
151template <class _Tp>
152using _IsSmallObject =
153    integral_constant<bool,
154                      sizeof(_Tp) <= sizeof(_Buffer) && alignof(_Buffer) % alignof(_Tp) == 0 &&
155                          is_nothrow_move_constructible<_Tp>::value >;
156
157enum class _Action { _Destroy, _Copy, _Move, _Get, _TypeInfo };
158
159template <class _Tp>
160struct _SmallHandler;
161template <class _Tp>
162struct _LargeHandler;
163
164template <class _Tp>
165struct _LIBCPP_TEMPLATE_VIS __unique_typeinfo {
166  static constexpr int __id = 0;
167};
168template <class _Tp>
169constexpr int __unique_typeinfo<_Tp>::__id;
170
171template <class _Tp>
172inline _LIBCPP_HIDE_FROM_ABI constexpr const void* __get_fallback_typeid() {
173  return &__unique_typeinfo<remove_cv_t<remove_reference_t<_Tp>>>::__id;
174}
175
176template <class _Tp>
177inline _LIBCPP_HIDE_FROM_ABI bool __compare_typeid(type_info const* __id, const void* __fallback_id) {
178#  if !defined(_LIBCPP_HAS_NO_RTTI)
179  if (__id && *__id == typeid(_Tp))
180    return true;
181#  endif
182  return !__id && __fallback_id == __any_imp::__get_fallback_typeid<_Tp>();
183}
184
185template <class _Tp>
186using _Handler = conditional_t< _IsSmallObject<_Tp>::value, _SmallHandler<_Tp>, _LargeHandler<_Tp>>;
187
188} // namespace __any_imp
189
190class _LIBCPP_TEMPLATE_VIS any {
191public:
192  // construct/destruct
193  _LIBCPP_HIDE_FROM_ABI constexpr any() _NOEXCEPT : __h_(nullptr) {}
194
195  _LIBCPP_HIDE_FROM_ABI any(any const& __other) : __h_(nullptr) {
196    if (__other.__h_)
197      __other.__call(_Action::_Copy, this);
198  }
199
200  _LIBCPP_HIDE_FROM_ABI any(any&& __other) _NOEXCEPT : __h_(nullptr) {
201    if (__other.__h_)
202      __other.__call(_Action::_Move, this);
203  }
204
205  template < class _ValueType,
206             class _Tp = decay_t<_ValueType>,
207             class     = enable_if_t< !is_same<_Tp, any>::value && !__is_inplace_type<_ValueType>::value &&
208                                      is_copy_constructible<_Tp>::value> >
209  _LIBCPP_HIDE_FROM_ABI any(_ValueType&& __value);
210
211  template <class _ValueType,
212            class... _Args,
213            class _Tp = decay_t<_ValueType>,
214            class     = enable_if_t< is_constructible<_Tp, _Args...>::value && is_copy_constructible<_Tp>::value > >
215  _LIBCPP_HIDE_FROM_ABI explicit any(in_place_type_t<_ValueType>, _Args&&... __args);
216
217  template <class _ValueType,
218            class _Up,
219            class... _Args,
220            class _Tp = decay_t<_ValueType>,
221            class     = enable_if_t< is_constructible<_Tp, initializer_list<_Up>&, _Args...>::value &&
222                                     is_copy_constructible<_Tp>::value> >
223  _LIBCPP_HIDE_FROM_ABI explicit any(in_place_type_t<_ValueType>, initializer_list<_Up>, _Args&&... __args);
224
225  _LIBCPP_HIDE_FROM_ABI ~any() { this->reset(); }
226
227  // assignments
228  _LIBCPP_HIDE_FROM_ABI any& operator=(any const& __rhs) {
229    any(__rhs).swap(*this);
230    return *this;
231  }
232
233  _LIBCPP_HIDE_FROM_ABI any& operator=(any&& __rhs) _NOEXCEPT {
234    any(std::move(__rhs)).swap(*this);
235    return *this;
236  }
237
238  template < class _ValueType,
239             class _Tp = decay_t<_ValueType>,
240             class     = enable_if_t< !is_same<_Tp, any>::value && is_copy_constructible<_Tp>::value> >
241  _LIBCPP_HIDE_FROM_ABI any& operator=(_ValueType&& __rhs);
242
243  template <class _ValueType,
244            class... _Args,
245            class _Tp = decay_t<_ValueType>,
246            class     = enable_if_t< is_constructible<_Tp, _Args...>::value && is_copy_constructible<_Tp>::value> >
247  _LIBCPP_HIDE_FROM_ABI _Tp& emplace(_Args&&...);
248
249  template <class _ValueType,
250            class _Up,
251            class... _Args,
252            class _Tp = decay_t<_ValueType>,
253            class     = enable_if_t< is_constructible<_Tp, initializer_list<_Up>&, _Args...>::value &&
254                                     is_copy_constructible<_Tp>::value> >
255  _LIBCPP_HIDE_FROM_ABI _Tp& emplace(initializer_list<_Up>, _Args&&...);
256
257  // 6.3.3 any modifiers
258  _LIBCPP_HIDE_FROM_ABI void reset() _NOEXCEPT {
259    if (__h_)
260      this->__call(_Action::_Destroy);
261  }
262
263  _LIBCPP_HIDE_FROM_ABI void swap(any& __rhs) _NOEXCEPT;
264
265  // 6.3.4 any observers
266  _LIBCPP_HIDE_FROM_ABI bool has_value() const _NOEXCEPT { return __h_ != nullptr; }
267
268#  if !defined(_LIBCPP_HAS_NO_RTTI)
269  _LIBCPP_HIDE_FROM_ABI const type_info& type() const _NOEXCEPT {
270    if (__h_) {
271      return *static_cast<type_info const*>(this->__call(_Action::_TypeInfo));
272    } else {
273      return typeid(void);
274    }
275  }
276#  endif
277
278private:
279  typedef __any_imp::_Action _Action;
280  using _HandleFuncPtr = void* (*)(_Action, any const*, any*, const type_info*, const void* __fallback_info);
281
282  union _Storage {
283    _LIBCPP_HIDE_FROM_ABI constexpr _Storage() : __ptr(nullptr) {}
284    void* __ptr;
285    __any_imp::_Buffer __buf;
286  };
287
288  _LIBCPP_HIDE_FROM_ABI void*
289  __call(_Action __a, any* __other = nullptr, type_info const* __info = nullptr, const void* __fallback_info = nullptr)
290      const {
291    return __h_(__a, this, __other, __info, __fallback_info);
292  }
293
294  _LIBCPP_HIDE_FROM_ABI void* __call(
295      _Action __a, any* __other = nullptr, type_info const* __info = nullptr, const void* __fallback_info = nullptr) {
296    return __h_(__a, this, __other, __info, __fallback_info);
297  }
298
299  template <class>
300  friend struct __any_imp::_SmallHandler;
301  template <class>
302  friend struct __any_imp::_LargeHandler;
303
304  template <class _ValueType>
305  friend add_pointer_t<add_const_t<_ValueType>> any_cast(any const*) _NOEXCEPT;
306
307  template <class _ValueType>
308  friend add_pointer_t<_ValueType> any_cast(any*) _NOEXCEPT;
309
310  _HandleFuncPtr __h_ = nullptr;
311  _Storage __s_;
312};
313
314namespace __any_imp {
315template <class _Tp>
316struct _LIBCPP_TEMPLATE_VIS _SmallHandler {
317  _LIBCPP_HIDE_FROM_ABI static void*
318  __handle(_Action __act, any const* __this, any* __other, type_info const* __info, const void* __fallback_info) {
319    switch (__act) {
320    case _Action::_Destroy:
321      __destroy(const_cast<any&>(*__this));
322      return nullptr;
323    case _Action::_Copy:
324      __copy(*__this, *__other);
325      return nullptr;
326    case _Action::_Move:
327      __move(const_cast<any&>(*__this), *__other);
328      return nullptr;
329    case _Action::_Get:
330      return __get(const_cast<any&>(*__this), __info, __fallback_info);
331    case _Action::_TypeInfo:
332      return __type_info();
333    }
334    __libcpp_unreachable();
335  }
336
337  template <class... _Args>
338  _LIBCPP_HIDE_FROM_ABI static _Tp& __create(any& __dest, _Args&&... __args) {
339    typedef allocator<_Tp> _Alloc;
340    typedef allocator_traits<_Alloc> _ATraits;
341    _Alloc __a;
342    _Tp* __ret = static_cast<_Tp*>(static_cast<void*>(&__dest.__s_.__buf));
343    _ATraits::construct(__a, __ret, std::forward<_Args>(__args)...);
344    __dest.__h_ = &_SmallHandler::__handle;
345    return *__ret;
346  }
347
348private:
349  _LIBCPP_HIDE_FROM_ABI static void __destroy(any& __this) {
350    typedef allocator<_Tp> _Alloc;
351    typedef allocator_traits<_Alloc> _ATraits;
352    _Alloc __a;
353    _Tp* __p = static_cast<_Tp*>(static_cast<void*>(&__this.__s_.__buf));
354    _ATraits::destroy(__a, __p);
355    __this.__h_ = nullptr;
356  }
357
358  _LIBCPP_HIDE_FROM_ABI static void __copy(any const& __this, any& __dest) {
359    _SmallHandler::__create(__dest, *static_cast<_Tp const*>(static_cast<void const*>(&__this.__s_.__buf)));
360  }
361
362  _LIBCPP_HIDE_FROM_ABI static void __move(any& __this, any& __dest) {
363    _SmallHandler::__create(__dest, std::move(*static_cast<_Tp*>(static_cast<void*>(&__this.__s_.__buf))));
364    __destroy(__this);
365  }
366
367  _LIBCPP_HIDE_FROM_ABI static void* __get(any& __this, type_info const* __info, const void* __fallback_id) {
368    if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_id))
369      return static_cast<void*>(&__this.__s_.__buf);
370    return nullptr;
371  }
372
373  _LIBCPP_HIDE_FROM_ABI static void* __type_info() {
374#  if !defined(_LIBCPP_HAS_NO_RTTI)
375    return const_cast<void*>(static_cast<void const*>(&typeid(_Tp)));
376#  else
377    return nullptr;
378#  endif
379  }
380};
381
382template <class _Tp>
383struct _LIBCPP_TEMPLATE_VIS _LargeHandler {
384  _LIBCPP_HIDE_FROM_ABI static void*
385  __handle(_Action __act, any const* __this, any* __other, type_info const* __info, void const* __fallback_info) {
386    switch (__act) {
387    case _Action::_Destroy:
388      __destroy(const_cast<any&>(*__this));
389      return nullptr;
390    case _Action::_Copy:
391      __copy(*__this, *__other);
392      return nullptr;
393    case _Action::_Move:
394      __move(const_cast<any&>(*__this), *__other);
395      return nullptr;
396    case _Action::_Get:
397      return __get(const_cast<any&>(*__this), __info, __fallback_info);
398    case _Action::_TypeInfo:
399      return __type_info();
400    }
401    __libcpp_unreachable();
402  }
403
404  template <class... _Args>
405  _LIBCPP_HIDE_FROM_ABI static _Tp& __create(any& __dest, _Args&&... __args) {
406    typedef allocator<_Tp> _Alloc;
407    typedef allocator_traits<_Alloc> _ATraits;
408    typedef __allocator_destructor<_Alloc> _Dp;
409    _Alloc __a;
410    unique_ptr<_Tp, _Dp> __hold(_ATraits::allocate(__a, 1), _Dp(__a, 1));
411    _Tp* __ret = __hold.get();
412    _ATraits::construct(__a, __ret, std::forward<_Args>(__args)...);
413    __dest.__s_.__ptr = __hold.release();
414    __dest.__h_       = &_LargeHandler::__handle;
415    return *__ret;
416  }
417
418private:
419  _LIBCPP_HIDE_FROM_ABI static void __destroy(any& __this) {
420    typedef allocator<_Tp> _Alloc;
421    typedef allocator_traits<_Alloc> _ATraits;
422    _Alloc __a;
423    _Tp* __p = static_cast<_Tp*>(__this.__s_.__ptr);
424    _ATraits::destroy(__a, __p);
425    _ATraits::deallocate(__a, __p, 1);
426    __this.__h_ = nullptr;
427  }
428
429  _LIBCPP_HIDE_FROM_ABI static void __copy(any const& __this, any& __dest) {
430    _LargeHandler::__create(__dest, *static_cast<_Tp const*>(__this.__s_.__ptr));
431  }
432
433  _LIBCPP_HIDE_FROM_ABI static void __move(any& __this, any& __dest) {
434    __dest.__s_.__ptr = __this.__s_.__ptr;
435    __dest.__h_       = &_LargeHandler::__handle;
436    __this.__h_       = nullptr;
437  }
438
439  _LIBCPP_HIDE_FROM_ABI static void* __get(any& __this, type_info const* __info, void const* __fallback_info) {
440    if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_info))
441      return static_cast<void*>(__this.__s_.__ptr);
442    return nullptr;
443  }
444
445  _LIBCPP_HIDE_FROM_ABI static void* __type_info() {
446#  if !defined(_LIBCPP_HAS_NO_RTTI)
447    return const_cast<void*>(static_cast<void const*>(&typeid(_Tp)));
448#  else
449    return nullptr;
450#  endif
451  }
452};
453
454} // namespace __any_imp
455
456template <class _ValueType, class _Tp, class>
457any::any(_ValueType&& __v) : __h_(nullptr) {
458  __any_imp::_Handler<_Tp>::__create(*this, std::forward<_ValueType>(__v));
459}
460
461template <class _ValueType, class... _Args, class _Tp, class>
462any::any(in_place_type_t<_ValueType>, _Args&&... __args) {
463  __any_imp::_Handler<_Tp>::__create(*this, std::forward<_Args>(__args)...);
464}
465
466template <class _ValueType, class _Up, class... _Args, class _Tp, class>
467any::any(in_place_type_t<_ValueType>, initializer_list<_Up> __il, _Args&&... __args) {
468  __any_imp::_Handler<_Tp>::__create(*this, __il, std::forward<_Args>(__args)...);
469}
470
471template <class _ValueType, class, class>
472inline _LIBCPP_HIDE_FROM_ABI any& any::operator=(_ValueType&& __v) {
473  any(std::forward<_ValueType>(__v)).swap(*this);
474  return *this;
475}
476
477template <class _ValueType, class... _Args, class _Tp, class>
478inline _LIBCPP_HIDE_FROM_ABI _Tp& any::emplace(_Args&&... __args) {
479  reset();
480  return __any_imp::_Handler<_Tp>::__create(*this, std::forward<_Args>(__args)...);
481}
482
483template <class _ValueType, class _Up, class... _Args, class _Tp, class>
484inline _LIBCPP_HIDE_FROM_ABI _Tp& any::emplace(initializer_list<_Up> __il, _Args&&... __args) {
485  reset();
486  return __any_imp::_Handler<_Tp>::__create(*this, __il, std::forward<_Args>(__args)...);
487}
488
489inline _LIBCPP_HIDE_FROM_ABI void any::swap(any& __rhs) _NOEXCEPT {
490  if (this == &__rhs)
491    return;
492  if (__h_ && __rhs.__h_) {
493    any __tmp;
494    __rhs.__call(_Action::_Move, &__tmp);
495    this->__call(_Action::_Move, &__rhs);
496    __tmp.__call(_Action::_Move, this);
497  } else if (__h_) {
498    this->__call(_Action::_Move, &__rhs);
499  } else if (__rhs.__h_) {
500    __rhs.__call(_Action::_Move, this);
501  }
502}
503
504// 6.4 Non-member functions
505
506inline _LIBCPP_HIDE_FROM_ABI void swap(any& __lhs, any& __rhs) _NOEXCEPT { __lhs.swap(__rhs); }
507
508template <class _Tp, class... _Args>
509inline _LIBCPP_HIDE_FROM_ABI any make_any(_Args&&... __args) {
510  return any(in_place_type<_Tp>, std::forward<_Args>(__args)...);
511}
512
513template <class _Tp, class _Up, class... _Args>
514inline _LIBCPP_HIDE_FROM_ABI any make_any(initializer_list<_Up> __il, _Args&&... __args) {
515  return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...);
516}
517
518template <class _ValueType>
519inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST _ValueType any_cast(any const& __v) {
520  using _RawValueType = __remove_cvref_t<_ValueType>;
521  static_assert(is_constructible<_ValueType, _RawValueType const&>::value,
522                "ValueType is required to be a const lvalue reference "
523                "or a CopyConstructible type");
524  auto __tmp = std::any_cast<add_const_t<_RawValueType>>(&__v);
525  if (__tmp == nullptr)
526    __throw_bad_any_cast();
527  return static_cast<_ValueType>(*__tmp);
528}
529
530template <class _ValueType>
531inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST _ValueType any_cast(any& __v) {
532  using _RawValueType = __remove_cvref_t<_ValueType>;
533  static_assert(is_constructible<_ValueType, _RawValueType&>::value,
534                "ValueType is required to be an lvalue reference "
535                "or a CopyConstructible type");
536  auto __tmp = std::any_cast<_RawValueType>(&__v);
537  if (__tmp == nullptr)
538    __throw_bad_any_cast();
539  return static_cast<_ValueType>(*__tmp);
540}
541
542template <class _ValueType>
543inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST _ValueType any_cast(any&& __v) {
544  using _RawValueType = __remove_cvref_t<_ValueType>;
545  static_assert(is_constructible<_ValueType, _RawValueType>::value,
546                "ValueType is required to be an rvalue reference "
547                "or a CopyConstructible type");
548  auto __tmp = std::any_cast<_RawValueType>(&__v);
549  if (__tmp == nullptr)
550    __throw_bad_any_cast();
551  return static_cast<_ValueType>(std::move(*__tmp));
552}
553
554template <class _ValueType>
555inline _LIBCPP_HIDE_FROM_ABI add_pointer_t<add_const_t<_ValueType>> any_cast(any const* __any) _NOEXCEPT {
556  static_assert(!is_void_v<_ValueType>, "_ValueType may not be void.");
557  static_assert(!is_reference<_ValueType>::value, "_ValueType may not be a reference.");
558  return std::any_cast<_ValueType>(const_cast<any*>(__any));
559}
560
561template <class _RetType>
562inline _LIBCPP_HIDE_FROM_ABI _RetType __pointer_or_func_cast(void* __p, /*IsFunction*/ false_type) noexcept {
563  return static_cast<_RetType>(__p);
564}
565
566template <class _RetType>
567inline _LIBCPP_HIDE_FROM_ABI _RetType __pointer_or_func_cast(void*, /*IsFunction*/ true_type) noexcept {
568  return nullptr;
569}
570
571template <class _ValueType>
572_LIBCPP_HIDE_FROM_ABI add_pointer_t<_ValueType> any_cast(any* __any) _NOEXCEPT {
573  using __any_imp::_Action;
574  static_assert(!is_void_v<_ValueType>, "_ValueType may not be void.");
575  static_assert(!is_reference<_ValueType>::value, "_ValueType may not be a reference.");
576  typedef add_pointer_t<_ValueType> _ReturnType;
577  if (__any && __any->__h_) {
578    void* __p = __any->__call(
579        _Action::_Get,
580        nullptr,
581#  if !defined(_LIBCPP_HAS_NO_RTTI)
582        &typeid(_ValueType),
583#  else
584        nullptr,
585#  endif
586        __any_imp::__get_fallback_typeid<_ValueType>());
587    return std::__pointer_or_func_cast<_ReturnType>(__p, is_function<_ValueType>{});
588  }
589  return nullptr;
590}
591
592#endif // _LIBCPP_STD_VER >= 17
593
594_LIBCPP_END_NAMESPACE_STD
595
596_LIBCPP_POP_MACROS
597
598#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 17
599#  include <chrono>
600#endif
601
602#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
603#  include <atomic>
604#  include <concepts>
605#  include <cstdlib>
606#  include <iosfwd>
607#  include <iterator>
608#  include <memory>
609#  include <stdexcept>
610#  include <type_traits>
611#  include <variant>
612#endif
613
614#endif // _LIBCPP_ANY
615