libstdc++: type_traits Source File

libstdc++

type_traits
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1// C++11 <type_traits> -*- C++ -*-
2
3// Copyright (C) 2007-2026 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file include/type_traits
26 * This is a Standard C++ Library header.
27 */
28
29#ifndef _GLIBCXX_TYPE_TRAITS
30#define _GLIBCXX_TYPE_TRAITS 1
31
32#ifdef _GLIBCXX_SYSHDR
33#pragma GCC system_header
34#endif
35
36#if __cplusplus < 201103L
37# include <bits/c++0x_warning.h>
38#else
39
40#include <bits/c++config.h>
41
42#define __glibcxx_want_bool_constant
43#define __glibcxx_want_bounded_array_traits
44#define __glibcxx_want_common_reference
45#define __glibcxx_want_has_unique_object_representations
46#define __glibcxx_want_integral_constant_callable
47#define __glibcxx_want_is_aggregate
48#define __glibcxx_want_is_constant_evaluated
49#define __glibcxx_want_is_final
50#define __glibcxx_want_is_implicit_lifetime
51#define __glibcxx_want_is_invocable
52#define __glibcxx_want_is_layout_compatible
53#define __glibcxx_want_is_nothrow_convertible
54#define __glibcxx_want_is_null_pointer
55#define __glibcxx_want_is_pointer_interconvertible
56#define __glibcxx_want_is_scoped_enum
57#define __glibcxx_want_is_structural
58#define __glibcxx_want_is_swappable
59#define __glibcxx_want_is_virtual_base_of
60#define __glibcxx_want_logical_traits
61#define __glibcxx_want_reference_from_temporary
62#define __glibcxx_want_remove_cvref
63#define __glibcxx_want_result_of_sfinae
64#define __glibcxx_want_transformation_trait_aliases
65#define __glibcxx_want_type_identity
66#define __glibcxx_want_type_trait_variable_templates
67#define __glibcxx_want_unwrap_ref
68#define __glibcxx_want_void_t
69#include <bits/version.h>
70
71extern "C++"
72{
73namespace std _GLIBCXX_VISIBILITY(default)
74{
75_GLIBCXX_BEGIN_NAMESPACE_VERSION
76
77 template<typename _Tp>
78 class reference_wrapper;
79
80 /**
81 * @defgroup metaprogramming Metaprogramming
82 * @ingroup utilities
83 *
84 * Template utilities for compile-time introspection and modification,
85 * including type classification traits, type property inspection traits
86 * and type transformation traits.
87 *
88 * @since C++11
89 *
90 * @{
91 */
92
93 /// integral_constant
94 template<typename _Tp, _Tp __v>
95 struct integral_constant
96 {
97 static constexpr _Tp value = __v;
98 using value_type = _Tp;
99 using type = integral_constant<_Tp, __v>;
100 constexpr operator value_type() const noexcept { return value; }
101
102#ifdef __cpp_lib_integral_constant_callable // C++ >= 14
103 constexpr value_type operator()() const noexcept { return value; }
104#endif
105 };
106
107#if ! __cpp_inline_variables
108 template<typename _Tp, _Tp __v>
109 constexpr _Tp integral_constant<_Tp, __v>::value;
110#endif
111
112 /// @cond undocumented
113 /// bool_constant for C++11
114 template<bool __v>
115 using __bool_constant = integral_constant<bool, __v>;
116 /// @endcond
117
118 /// The type used as a compile-time boolean with true value.
119 using true_type = __bool_constant<true>;
120
121 /// The type used as a compile-time boolean with false value.
122 using false_type = __bool_constant<false>;
123
124#ifdef __cpp_lib_bool_constant // C++ >= 17
125 /// Alias template for compile-time boolean constant types.
126 /// @since C++17
127 template<bool __v>
128 using bool_constant = __bool_constant<__v>;
129#endif
130
131 // Metaprogramming helper types.
132
133 // Primary template.
134 /// Define a member typedef `type` only if a boolean constant is true.
135 template<bool, typename _Tp = void>
136 struct enable_if
137 { };
138
139 // Partial specialization for true.
140 template<typename _Tp>
141 struct enable_if<true, _Tp>
142 { using type = _Tp; };
143
144 // __enable_if_t (std::enable_if_t for C++11)
145 template<bool _Cond, typename _Tp = void>
146 using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
147
148 template<bool>
149 struct __conditional
150 {
151 template<typename _Tp, typename>
152 using type = _Tp;
153 };
154
155 template<>
156 struct __conditional<false>
157 {
158 template<typename, typename _Up>
159 using type = _Up;
160 };
161
162 // More efficient version of std::conditional_t for internal use (and C++11)
163 template<bool _Cond, typename _If, typename _Else>
164 using __conditional_t
165 = typename __conditional<_Cond>::template type<_If, _Else>;
166
167 /// @cond undocumented
168 template <typename _Type>
169 struct __type_identity
170 { using type = _Type; };
171
172 template<typename _Tp>
173 using __type_identity_t = typename __type_identity<_Tp>::type;
174
175 namespace __detail
176 {
177 // A variadic alias template that resolves to its first argument.
178 template<typename _Tp, typename...>
179 using __first_t = _Tp;
180
181 // These are deliberately not defined.
182 template<typename... _Bn>
183 auto __or_fn(int) -> __first_t<false_type,
184 __enable_if_t<!bool(_Bn::value)>...>;
185
186 template<typename... _Bn>
187 auto __or_fn(...) -> true_type;
188
189 template<typename... _Bn>
190 auto __and_fn(int) -> __first_t<true_type,
191 __enable_if_t<bool(_Bn::value)>...>;
192
193 template<typename... _Bn>
194 auto __and_fn(...) -> false_type;
195 } // namespace detail
196
197 // Like C++17 std::dis/conjunction, but usable in C++11 and resolves
198 // to either true_type or false_type which allows for a more efficient
199 // implementation that avoids recursive class template instantiation.
200 template<typename... _Bn>
201 struct __or_
202 : decltype(__detail::__or_fn<_Bn...>(0))
203 { };
204
205 template<typename... _Bn>
206 struct __and_
207 : decltype(__detail::__and_fn<_Bn...>(0))
208 { };
209
210 template<typename _Pp>
211 struct __not_
212 : __bool_constant<!bool(_Pp::value)>
213 { };
214 /// @endcond
215
216#ifdef __cpp_lib_logical_traits // C++ >= 17
217
218 /// @cond undocumented
219 template<typename... _Bn>
220 inline constexpr bool __or_v = __or_<_Bn...>::value;
221 template<typename... _Bn>
222 inline constexpr bool __and_v = __and_<_Bn...>::value;
223
224 namespace __detail
225 {
226 template<typename /* = void */, typename _B1, typename... _Bn>
227 struct __disjunction_impl
228 { using type = _B1; };
229
230 template<typename _B1, typename _B2, typename... _Bn>
231 struct __disjunction_impl<__enable_if_t<!bool(_B1::value)>, _B1, _B2, _Bn...>
232 { using type = typename __disjunction_impl<void, _B2, _Bn...>::type; };
233
234 template<typename /* = void */, typename _B1, typename... _Bn>
235 struct __conjunction_impl
236 { using type = _B1; };
237
238 template<typename _B1, typename _B2, typename... _Bn>
239 struct __conjunction_impl<__enable_if_t<bool(_B1::value)>, _B1, _B2, _Bn...>
240 { using type = typename __conjunction_impl<void, _B2, _Bn...>::type; };
241 } // namespace __detail
242 /// @endcond
243
244 template<typename... _Bn>
245 struct conjunction
246 : __detail::__conjunction_impl<void, _Bn...>::type
247 { };
248
249 template<>
250 struct conjunction<>
251 : true_type
252 { };
253
254 template<typename... _Bn>
255 struct disjunction
256 : __detail::__disjunction_impl<void, _Bn...>::type
257 { };
258
259 template<>
260 struct disjunction<>
261 : false_type
262 { };
263
264 template<typename _Pp>
265 struct negation
266 : __not_<_Pp>::type
267 { };
268
269 /** @ingroup variable_templates
270 * @{
271 */
272 template<typename... _Bn>
273 inline constexpr bool conjunction_v = conjunction<_Bn...>::value;
274
275 template<typename... _Bn>
276 inline constexpr bool disjunction_v = disjunction<_Bn...>::value;
277
278 template<typename _Pp>
279 inline constexpr bool negation_v = negation<_Pp>::value;
280 /// @}
281
282#endif // __cpp_lib_logical_traits
283
284 // Forward declarations
285 template<typename>
286 struct is_object;
287 template<typename>
288 struct remove_cv;
289 template<typename>
290 struct is_const;
291
292 /// @cond undocumented
293 template<typename>
294 struct __is_array_unknown_bounds;
295
296 // An object type which is not an unbounded array.
297 // It might still be an incomplete type, but if this is false_type
298 // then we can be certain it's not a complete object type.
299 template<typename _Tp>
300 using __maybe_complete_object_type
301 = __and_<is_object<_Tp>, __not_<__is_array_unknown_bounds<_Tp>>>;
302
303 // Helper functions that return false_type for incomplete classes,
304 // incomplete unions and arrays of known bound from those.
305
306 // More specialized overload for complete object types (returning true_type).
307 template<typename _Tp,
308 typename = __enable_if_t<__maybe_complete_object_type<_Tp>::value>,
309 size_t = sizeof(_Tp)>
310 constexpr true_type
311 __is_complete_or_unbounded(__type_identity<_Tp>)
312 { return {}; };
313
314 // Less specialized overload for reference and unknown-bound array types
315 // (returning true_type), and incomplete types (returning false_type).
316 template<typename _TypeIdentity,
317 typename _NestedType = typename _TypeIdentity::type>
318 constexpr typename __not_<__maybe_complete_object_type<_NestedType>>::type
319 __is_complete_or_unbounded(_TypeIdentity)
320 { return {}; }
321
322 // __remove_cv_t (std::remove_cv_t for C++11).
323 template<typename _Tp>
324 using __remove_cv_t = typename remove_cv<_Tp>::type;
325 /// @endcond
326
327 // Primary type categories.
328
329 /// is_void
330 template<typename _Tp>
331 struct is_void
332 : public false_type { };
333
334 template<>
335 struct is_void<void>
336 : public true_type { };
337
338 template<>
339 struct is_void<const void>
340 : public true_type { };
341
342 template<>
343 struct is_void<volatile void>
344 : public true_type { };
345
346 template<>
347 struct is_void<const volatile void>
348 : public true_type { };
349
350 /// @cond undocumented
351
352 // Every integral type is either one of the character types, one of the
353 // signed integer types, one of the unsigned integer types, or bool,
354 // or a cv-qualified version of one of those types ([basic.fundamental]).
355 // For now we only need to distinguish the signed/unsigned integer types.
356 enum class _Integer_kind { _None, _Signed, _Unsigned };
357
358 template<typename>
359 struct __is_integral_helper
360 : public false_type
361 { static constexpr auto _S_kind = _Integer_kind::_None; };
362
363 template<>
364 struct __is_integral_helper<bool>
365 : public true_type
366 { static constexpr auto _S_kind = _Integer_kind::_None; };
367
368 template<>
369 struct __is_integral_helper<char>
370 : public true_type
371 { static constexpr auto _S_kind = _Integer_kind::_None; };
372
373 template<>
374 struct __is_integral_helper<signed char>
375 : public true_type
376 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
377
378 template<>
379 struct __is_integral_helper<unsigned char>
380 : public true_type
381 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
382
383 // We want is_integral<wchar_t> to be true (and make_signed/unsigned to work)
384 // even when libc doesn't provide working <wchar.h> and related functions,
385 // so don't check _GLIBCXX_USE_WCHAR_T here.
386 template<>
387 struct __is_integral_helper<wchar_t>
388 : public true_type
389 { static constexpr auto _S_kind = _Integer_kind::_None; };
390
391#ifdef _GLIBCXX_USE_CHAR8_T
392 template<>
393 struct __is_integral_helper<char8_t>
394 : public true_type
395 { static constexpr auto _S_kind = _Integer_kind::_None; };
396#endif
397
398 template<>
399 struct __is_integral_helper<char16_t>
400 : public true_type
401 { static constexpr auto _S_kind = _Integer_kind::_None; };
402
403 template<>
404 struct __is_integral_helper<char32_t>
405 : public true_type
406 { static constexpr auto _S_kind = _Integer_kind::_None; };
407
408 template<>
409 struct __is_integral_helper<short>
410 : public true_type
411 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
412
413 template<>
414 struct __is_integral_helper<unsigned short>
415 : public true_type
416 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
417
418 template<>
419 struct __is_integral_helper<int>
420 : public true_type
421 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
422
423 template<>
424 struct __is_integral_helper<unsigned int>
425 : public true_type
426 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
427
428 template<>
429 struct __is_integral_helper<long>
430 : public true_type
431 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
432
433 template<>
434 struct __is_integral_helper<unsigned long>
435 : public true_type
436 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
437
438 template<>
439 struct __is_integral_helper<long long>
440 : public true_type
441 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
442
443 template<>
444 struct __is_integral_helper<unsigned long long>
445 : public true_type
446 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
447
448 // Conditionalizing on __STRICT_ANSI__ here will break any port that
449 // uses one of these types for size_t.
450#if defined(__GLIBCXX_TYPE_INT_N_0)
451 __extension__
452 template<>
453 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_0>
454 : public true_type
455 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
456
457 __extension__
458 template<>
459 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_0>
460 : public true_type
461 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
462#endif
463#if defined(__GLIBCXX_TYPE_INT_N_1)
464 __extension__
465 template<>
466 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_1>
467 : public true_type
468 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
469
470 __extension__
471 template<>
472 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_1>
473 : public true_type
474 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
475#endif
476#if defined(__GLIBCXX_TYPE_INT_N_2)
477 __extension__
478 template<>
479 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_2>
480 : public true_type
481 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
482
483 __extension__
484 template<>
485 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_2>
486 : public true_type
487 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
488#endif
489#if defined(__GLIBCXX_TYPE_INT_N_3)
490 __extension__
491 template<>
492 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_3>
493 : public true_type
494 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
495
496 __extension__
497 template<>
498 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_3>
499 : public true_type
500 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
501#endif
502
503#if defined __SIZEOF_INT128__ && defined __STRICT_ANSI__
504 __extension__
505 template<>
506 struct __is_integral_helper<__int128>
507 : public true_type
508 { static constexpr auto _S_kind = _Integer_kind::_Signed; };
509
510 __extension__
511 template<>
512 struct __is_integral_helper<unsigned __int128>
513 : public true_type
514 { static constexpr auto _S_kind = _Integer_kind::_Unsigned; };
515#endif
516
517 // Check if a type is one of the signed integer types.
518 template<typename _Tp>
519 using __is_signed_integer
520 = __bool_constant<__is_integral_helper<_Tp>::_S_kind
521 == _Integer_kind::_Signed>;
522
523 // Check if a type is one of the unsigned integer types.
524 template<typename _Tp>
525 using __is_unsigned_integer
526 = __bool_constant<__is_integral_helper<_Tp>::_S_kind
527 == _Integer_kind::_Unsigned>;
528
529 // Check if a type is one of the signed or unsigned integer types.
530 // i.e. an integral type except bool, char, wchar_t, and charN_t.
531 template<typename _Tp>
532 using __is_signed_or_unsigned_integer
533 = __bool_constant<__is_integral_helper<_Tp>::_S_kind
534 != _Integer_kind::_None>;
535
536 /// @endcond
537
538 /// is_integral
539 template<typename _Tp>
540 struct is_integral
541 : public __is_integral_helper<__remove_cv_t<_Tp>>::type
542 { };
543
544 /// @cond undocumented
545 template<typename>
546 struct __is_floating_point_helper
547 : public false_type { };
548
549 template<>
550 struct __is_floating_point_helper<float>
551 : public true_type { };
552
553 template<>
554 struct __is_floating_point_helper<double>
555 : public true_type { };
556
557 template<>
558 struct __is_floating_point_helper<long double>
559 : public true_type { };
560
561#ifdef __STDCPP_FLOAT16_T__
562 template<>
563 struct __is_floating_point_helper<_Float16>
564 : public true_type { };
565#endif
566
567#ifdef __STDCPP_FLOAT32_T__
568 template<>
569 struct __is_floating_point_helper<_Float32>
570 : public true_type { };
571#endif
572
573#ifdef __STDCPP_FLOAT64_T__
574 template<>
575 struct __is_floating_point_helper<_Float64>
576 : public true_type { };
577#endif
578
579#ifdef __STDCPP_FLOAT128_T__
580 template<>
581 struct __is_floating_point_helper<_Float128>
582 : public true_type { };
583#endif
584
585#ifdef __STDCPP_BFLOAT16_T__
586 template<>
587 struct __is_floating_point_helper<__gnu_cxx::__bfloat16_t>
588 : public true_type { };
589#endif
590
591#ifdef _GLIBCXX_USE_FLOAT128
592 template<>
593 struct __is_floating_point_helper<__float128>
594 : public true_type { };
595#endif
596 /// @endcond
597
598 /// is_floating_point
599 template<typename _Tp>
600 struct is_floating_point
601 : public __is_floating_point_helper<__remove_cv_t<_Tp>>::type
602 { };
603
604 /// is_array
605#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_array)
606 template<typename _Tp>
607 struct is_array
608 : public __bool_constant<__is_array(_Tp)>
609 { };
610#else
611 template<typename>
612 struct is_array
613 : public false_type { };
614
615 template<typename _Tp, std::size_t _Size>
616 struct is_array<_Tp[_Size]>
617 : public true_type { };
618
619 template<typename _Tp>
620 struct is_array<_Tp[]>
621 : public true_type { };
622#endif
623
624 /// is_pointer
625#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
626 template<typename _Tp>
627 struct is_pointer
628 : public __bool_constant<__is_pointer(_Tp)>
629 { };
630#else
631 template<typename _Tp>
632 struct is_pointer
633 : public false_type { };
634
635 template<typename _Tp>
636 struct is_pointer<_Tp*>
637 : public true_type { };
638
639 template<typename _Tp>
640 struct is_pointer<_Tp* const>
641 : public true_type { };
642
643 template<typename _Tp>
644 struct is_pointer<_Tp* volatile>
645 : public true_type { };
646
647 template<typename _Tp>
648 struct is_pointer<_Tp* const volatile>
649 : public true_type { };
650#endif
651
652 /// is_lvalue_reference
653 template<typename>
654 struct is_lvalue_reference
655 : public false_type { };
656
657 template<typename _Tp>
658 struct is_lvalue_reference<_Tp&>
659 : public true_type { };
660
661 /// is_rvalue_reference
662 template<typename>
663 struct is_rvalue_reference
664 : public false_type { };
665
666 template<typename _Tp>
667 struct is_rvalue_reference<_Tp&&>
668 : public true_type { };
669
670 /// is_member_object_pointer
671#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_object_pointer)
672 template<typename _Tp>
673 struct is_member_object_pointer
674 : public __bool_constant<__is_member_object_pointer(_Tp)>
675 { };
676#else
677 template<typename _Tp>
678 struct is_function;
679
680 template<typename>
681 struct __is_member_object_pointer_helper
682 : public false_type { };
683
684 template<typename _Tp, typename _Cp>
685 struct __is_member_object_pointer_helper<_Tp _Cp::*>
686 : public __not_<is_function<_Tp>>::type { };
687
688
689 template<typename _Tp>
690 struct is_member_object_pointer
691 : public __is_member_object_pointer_helper<__remove_cv_t<_Tp>>::type
692 { };
693#endif
694
695#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_function_pointer)
696 /// is_member_function_pointer
697 template<typename _Tp>
698 struct is_member_function_pointer
699 : public __bool_constant<__is_member_function_pointer(_Tp)>
700 { };
701#else
702 template<typename _Tp>
703 struct is_function;
704
705 template<typename>
706 struct __is_member_function_pointer_helper
707 : public false_type { };
708
709 template<typename _Tp, typename _Cp>
710 struct __is_member_function_pointer_helper<_Tp _Cp::*>
711 : public is_function<_Tp>::type { };
712
713 /// is_member_function_pointer
714 template<typename _Tp>
715 struct is_member_function_pointer
716 : public __is_member_function_pointer_helper<__remove_cv_t<_Tp>>::type
717 { };
718#endif
719
720 /// is_enum
721 template<typename _Tp>
722 struct is_enum
723 : public __bool_constant<__is_enum(_Tp)>
724 { };
725
726 /// is_union
727 template<typename _Tp>
728 struct is_union
729 : public __bool_constant<__is_union(_Tp)>
730 { };
731
732 /// is_class
733 template<typename _Tp>
734 struct is_class
735 : public __bool_constant<__is_class(_Tp)>
736 { };
737
738 /// is_function
739#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_function)
740 template<typename _Tp>
741 struct is_function
742 : public __bool_constant<__is_function(_Tp)>
743 { };
744#else
745 template<typename _Tp>
746 struct is_function
747 : public __bool_constant<!is_const<const _Tp>::value> { };
748
749 template<typename _Tp>
750 struct is_function<_Tp&>
751 : public false_type { };
752
753 template<typename _Tp>
754 struct is_function<_Tp&&>
755 : public false_type { };
756#endif
757
758#if __cpp_impl_reflection >= 202506L // C++ >= 26
759 /// is_reflection
760 template<typename _Tp>
761 struct is_reflection
762 : public false_type { };
763
764 template<>
765 struct is_reflection<decltype(^^int)>
766 : public true_type { };
767
768 template<>
769 struct is_reflection<const decltype(^^int)>
770 : public true_type { };
771
772 template<>
773 struct is_reflection<volatile decltype(^^int)>
774 : public true_type { };
775
776 template<>
777 struct is_reflection<const volatile decltype(^^int)>
778 : public true_type { };
779#endif
780
781#ifdef __cpp_lib_is_null_pointer // C++ >= 11
782 /// is_null_pointer (LWG 2247).
783 template<typename _Tp>
784 struct is_null_pointer
785 : public false_type { };
786
787 template<>
788 struct is_null_pointer<std::nullptr_t>
789 : public true_type { };
790
791 template<>
792 struct is_null_pointer<const std::nullptr_t>
793 : public true_type { };
794
795 template<>
796 struct is_null_pointer<volatile std::nullptr_t>
797 : public true_type { };
798
799 template<>
800 struct is_null_pointer<const volatile std::nullptr_t>
801 : public true_type { };
802
803 /// __is_nullptr_t (deprecated extension).
804 /// @deprecated Non-standard. Use `is_null_pointer` instead.
805 template<typename _Tp>
806 struct __is_nullptr_t
807 : public is_null_pointer<_Tp>
808 { } _GLIBCXX_DEPRECATED_SUGGEST("std::is_null_pointer");
809#endif // __cpp_lib_is_null_pointer
810
811 // Composite type categories.
812
813 /// is_reference
814#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_reference)
815 template<typename _Tp>
816 struct is_reference
817 : public __bool_constant<__is_reference(_Tp)>
818 { };
819#else
820 template<typename _Tp>
821 struct is_reference
822 : public false_type
823 { };
824
825 template<typename _Tp>
826 struct is_reference<_Tp&>
827 : public true_type
828 { };
829
830 template<typename _Tp>
831 struct is_reference<_Tp&&>
832 : public true_type
833 { };
834#endif
835
836 /// is_arithmetic
837 template<typename _Tp>
838 struct is_arithmetic
839 : public __or_<is_integral<_Tp>, is_floating_point<_Tp>>::type
840 { };
841
842 /// is_fundamental
843 template<typename _Tp>
844 struct is_fundamental
845 : public __or_<is_arithmetic<_Tp>, is_void<_Tp>,
846 is_null_pointer<_Tp>
847#if __cpp_impl_reflection >= 202506L
848 , is_reflection<_Tp>
849#endif
850 >::type
851 { };
852
853 /// is_object
854#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_object)
855 template<typename _Tp>
856 struct is_object
857 : public __bool_constant<__is_object(_Tp)>
858 { };
859#else
860 template<typename _Tp>
861 struct is_object
862 : public __not_<__or_<is_function<_Tp>, is_reference<_Tp>,
863 is_void<_Tp>>>::type
864 { };
865#endif
866
867 template<typename>
868 struct is_member_pointer;
869
870 /// is_scalar
871 template<typename _Tp>
872 struct is_scalar
873 : public __or_<is_arithmetic<_Tp>, is_enum<_Tp>, is_pointer<_Tp>,
874 is_member_pointer<_Tp>, is_null_pointer<_Tp>
875#if __cpp_impl_reflection >= 202506L
876 , is_reflection<_Tp>
877#endif
878 >::type
879 { };
880
881 /// is_compound
882 template<typename _Tp>
883 struct is_compound
884 : public __bool_constant<!is_fundamental<_Tp>::value> { };
885
886 /// is_member_pointer
887#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
888 template<typename _Tp>
889 struct is_member_pointer
890 : public __bool_constant<__is_member_pointer(_Tp)>
891 { };
892#else
893 /// @cond undocumented
894 template<typename _Tp>
895 struct __is_member_pointer_helper
896 : public false_type { };
897
898 template<typename _Tp, typename _Cp>
899 struct __is_member_pointer_helper<_Tp _Cp::*>
900 : public true_type { };
901 /// @endcond
902
903 template<typename _Tp>
904 struct is_member_pointer
905 : public __is_member_pointer_helper<__remove_cv_t<_Tp>>::type
906 { };
907#endif
908
909 template<typename, typename>
910 struct is_same;
911
912 /// @cond undocumented
913 template<typename _Tp, typename... _Types>
914 using __is_one_of = __or_<is_same<_Tp, _Types>...>;
915
916 // __void_t (std::void_t for C++11)
917 template<typename...> using __void_t = void;
918 /// @endcond
919
920 // Type properties.
921
922 /// is_const
923#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
924 template<typename _Tp>
925 struct is_const
926 : public __bool_constant<__is_const(_Tp)>
927 { };
928#else
929 template<typename>
930 struct is_const
931 : public false_type { };
932
933 template<typename _Tp>
934 struct is_const<_Tp const>
935 : public true_type { };
936#endif
937
938 /// is_volatile
939#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_volatile)
940 template<typename _Tp>
941 struct is_volatile
942 : public __bool_constant<__is_volatile(_Tp)>
943 { };
944#else
945 template<typename>
946 struct is_volatile
947 : public false_type { };
948
949 template<typename _Tp>
950 struct is_volatile<_Tp volatile>
951 : public true_type { };
952#endif
953
954 /** is_trivial
955 * @deprecated Deprecated in C++26.
956 * Use a combination of one or more more specialized type traits instead,
957 * such as `is_trivially_default_constructible`,
958 * `is_trivially_copy_constructible`, `is_trivially_copy_assignable`,
959 * etc., depending on the exact check(s) needed.
960 */
961 template<typename _Tp>
962 struct
963 _GLIBCXX26_DEPRECATED_SUGGEST("is_trivially_default_constructible && is_trivially_copyable")
964 is_trivial
965 : public __bool_constant<__is_trivial(_Tp)>
966 {
967 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
968 "template argument must be a complete class or an unbounded array");
969 };
970
971 /// is_trivially_copyable
972 template<typename _Tp>
973 struct is_trivially_copyable
974 : public __bool_constant<__is_trivially_copyable(_Tp)>
975 {
976 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
977 "template argument must be a complete class or an unbounded array");
978 };
979
980 /// is_standard_layout
981 template<typename _Tp>
982 struct is_standard_layout
983 : public __bool_constant<__is_standard_layout(_Tp)>
984 {
985 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
986 "template argument must be a complete class or an unbounded array");
987 };
988
989 /** is_pod
990 * @deprecated Deprecated in C++20.
991 * Use `is_standard_layout && is_trivial` instead.
992 */
993 // Could use is_standard_layout && is_trivial instead of the builtin.
994 template<typename _Tp>
995 struct
996 _GLIBCXX20_DEPRECATED_SUGGEST("is_standard_layout && is_trivial")
997 is_pod
998 : public __bool_constant<__is_pod(_Tp)>
999 {
1000 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1001 "template argument must be a complete class or an unbounded array");
1002 };
1003
1004 /** is_literal_type
1005 * @deprecated Deprecated in C++17, removed in C++20.
1006 * The idea of a literal type isn't useful.
1007 */
1008 template<typename _Tp>
1009 struct
1010 _GLIBCXX17_DEPRECATED
1011 is_literal_type
1012 : public __bool_constant<__is_literal_type(_Tp)>
1013 {
1014 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1015 "template argument must be a complete class or an unbounded array");
1016 };
1017
1018 /// is_empty
1019 template<typename _Tp>
1020 struct is_empty
1021 : public __bool_constant<__is_empty(_Tp)>
1022 { };
1023
1024 /// is_polymorphic
1025 template<typename _Tp>
1026 struct is_polymorphic
1027 : public __bool_constant<__is_polymorphic(_Tp)>
1028 { };
1029
1030#ifdef __cpp_lib_is_final // C++ >= 14
1031 /// is_final
1032 /// @since C++14
1033 template<typename _Tp>
1034 struct is_final
1035 : public __bool_constant<__is_final(_Tp)>
1036 { };
1037#endif
1038
1039 /// is_abstract
1040 template<typename _Tp>
1041 struct is_abstract
1042 : public __bool_constant<__is_abstract(_Tp)>
1043 { };
1044
1045 /// @cond undocumented
1046 template<typename _Tp,
1047 bool = is_arithmetic<_Tp>::value>
1048 struct __is_signed_helper
1049 : public false_type { };
1050
1051 template<typename _Tp>
1052 struct __is_signed_helper<_Tp, true>
1053 : public __bool_constant<_Tp(-1) < _Tp(0)>
1054 { };
1055 /// @endcond
1056
1057 /// is_signed
1058 template<typename _Tp>
1059 struct is_signed
1060 : public __is_signed_helper<_Tp>::type
1061 { };
1062
1063 /// is_unsigned
1064 template<typename _Tp>
1065 struct is_unsigned
1066 : public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>::type
1067 { };
1068
1069 /// @cond undocumented
1070 template<typename _Tp, typename _Up = _Tp&&>
1071 _Up
1072 __declval(int);
1073
1074 template<typename _Tp>
1075 _Tp
1076 __declval(long);
1077 /// @endcond
1078
1079 template<typename _Tp>
1080 auto declval() noexcept -> decltype(__declval<_Tp>(0));
1081
1082 template<typename>
1083 struct remove_all_extents;
1084
1085 /// @cond undocumented
1086 template<typename _Tp>
1087 struct __is_array_known_bounds
1088 : public false_type
1089 { };
1090
1091 template<typename _Tp, size_t _Size>
1092 struct __is_array_known_bounds<_Tp[_Size]>
1093 : public true_type
1094 { };
1095
1096 template<typename _Tp>
1097 struct __is_array_unknown_bounds
1098 : public false_type
1099 { };
1100
1101 template<typename _Tp>
1102 struct __is_array_unknown_bounds<_Tp[]>
1103 : public true_type
1104 { };
1105 /// @endcond
1106
1107 // Destructible and constructible type properties.
1108
1109#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_destructible)
1110 /// is_destructible
1111 template<typename _Tp>
1112 struct is_destructible
1113 : public __bool_constant<__is_destructible(_Tp)>
1114 { };
1115#else
1116 /// @cond undocumented
1117
1118 // In N3290 is_destructible does not say anything about function
1119 // types and abstract types, see LWG 2049. This implementation
1120 // describes function types as non-destructible and all complete
1121 // object types as destructible, iff the explicit destructor
1122 // call expression is wellformed.
1123 struct __do_is_destructible_impl
1124 {
1125 template<typename _Tp, typename = decltype(declval<_Tp&>().~_Tp())>
1126 static true_type __test(int);
1127
1128 template<typename>
1129 static false_type __test(...);
1130 };
1131
1132 template<typename _Tp>
1133 struct __is_destructible_impl
1134 : public __do_is_destructible_impl
1135 {
1136 using type = decltype(__test<_Tp>(0));
1137 };
1138
1139 template<typename _Tp,
1140 bool = __or_<is_void<_Tp>,
1141 __is_array_unknown_bounds<_Tp>,
1142 is_function<_Tp>>::value,
1143 bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
1144 struct __is_destructible_safe;
1145
1146 template<typename _Tp>
1147 struct __is_destructible_safe<_Tp, false, false>
1148 : public __is_destructible_impl<typename
1149 remove_all_extents<_Tp>::type>::type
1150 { };
1151
1152 template<typename _Tp>
1153 struct __is_destructible_safe<_Tp, true, false>
1154 : public false_type { };
1155
1156 template<typename _Tp>
1157 struct __is_destructible_safe<_Tp, false, true>
1158 : public true_type { };
1159 /// @endcond
1160
1161 /// is_destructible
1162 template<typename _Tp>
1163 struct is_destructible
1164 : public __is_destructible_safe<_Tp>::type
1165 {
1166 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1167 "template argument must be a complete class or an unbounded array");
1168 };
1169#endif
1170
1171#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_destructible)
1172 /// is_nothrow_destructible
1173 template<typename _Tp>
1174 struct is_nothrow_destructible
1175 : public __bool_constant<__is_nothrow_destructible(_Tp)>
1176 { };
1177#else
1178 /// @cond undocumented
1179
1180 // is_nothrow_destructible requires that is_destructible is
1181 // satisfied as well. We realize that by mimicing the
1182 // implementation of is_destructible but refer to noexcept(expr)
1183 // instead of decltype(expr).
1184 struct __do_is_nt_destructible_impl
1185 {
1186 template<typename _Tp>
1187 static __bool_constant<noexcept(declval<_Tp&>().~_Tp())>
1188 __test(int);
1189
1190 template<typename>
1191 static false_type __test(...);
1192 };
1193
1194 template<typename _Tp>
1195 struct __is_nt_destructible_impl
1196 : public __do_is_nt_destructible_impl
1197 {
1198 using type = decltype(__test<_Tp>(0));
1199 };
1200
1201 template<typename _Tp,
1202 bool = __or_<is_void<_Tp>,
1203 __is_array_unknown_bounds<_Tp>,
1204 is_function<_Tp>>::value,
1205 bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
1206 struct __is_nt_destructible_safe;
1207
1208 template<typename _Tp>
1209 struct __is_nt_destructible_safe<_Tp, false, false>
1210 : public __is_nt_destructible_impl<typename
1211 remove_all_extents<_Tp>::type>::type
1212 { };
1213
1214 template<typename _Tp>
1215 struct __is_nt_destructible_safe<_Tp, true, false>
1216 : public false_type { };
1217
1218 template<typename _Tp>
1219 struct __is_nt_destructible_safe<_Tp, false, true>
1220 : public true_type { };
1221 /// @endcond
1222
1223 /// is_nothrow_destructible
1224 template<typename _Tp>
1225 struct is_nothrow_destructible
1226 : public __is_nt_destructible_safe<_Tp>::type
1227 {
1228 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1229 "template argument must be a complete class or an unbounded array");
1230 };
1231#endif
1232
1233 /// @cond undocumented
1234 template<typename _Tp, typename... _Args>
1235 using __is_constructible_impl
1236 = __bool_constant<__is_constructible(_Tp, _Args...)>;
1237 /// @endcond
1238
1239 /// is_constructible
1240 template<typename _Tp, typename... _Args>
1241 struct is_constructible
1242 : public __is_constructible_impl<_Tp, _Args...>
1243 {
1244 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1245 "template argument must be a complete class or an unbounded array");
1246 };
1247
1248 /// is_default_constructible
1249 template<typename _Tp>
1250 struct is_default_constructible
1251 : public __is_constructible_impl<_Tp>
1252 {
1253 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1254 "template argument must be a complete class or an unbounded array");
1255 };
1256
1257 /// @cond undocumented
1258#if _GLIBCXX_USE_BUILTIN_TRAIT(__add_lvalue_reference)
1259 template<typename _Tp>
1260 using __add_lval_ref_t = __add_lvalue_reference(_Tp);
1261#else
1262 template<typename _Tp, typename = void>
1263 struct __add_lvalue_reference_helper
1264 { using type = _Tp; };
1265
1266 template<typename _Tp>
1267 struct __add_lvalue_reference_helper<_Tp, __void_t<_Tp&>>
1268 { using type = _Tp&; };
1269
1270 template<typename _Tp>
1271 using __add_lval_ref_t = typename __add_lvalue_reference_helper<_Tp>::type;
1272#endif
1273 /// @endcond
1274
1275 /// is_copy_constructible
1276 template<typename _Tp>
1277 struct is_copy_constructible
1278 : public __is_constructible_impl<_Tp, __add_lval_ref_t<const _Tp>>
1279 {
1280 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1281 "template argument must be a complete class or an unbounded array");
1282 };
1283
1284 /// @cond undocumented
1285#if _GLIBCXX_USE_BUILTIN_TRAIT(__add_rvalue_reference)
1286 template<typename _Tp>
1287 using __add_rval_ref_t = __add_rvalue_reference(_Tp);
1288#else
1289 template<typename _Tp, typename = void>
1290 struct __add_rvalue_reference_helper
1291 { using type = _Tp; };
1292
1293 template<typename _Tp>
1294 struct __add_rvalue_reference_helper<_Tp, __void_t<_Tp&&>>
1295 { using type = _Tp&&; };
1296
1297 template<typename _Tp>
1298 using __add_rval_ref_t = typename __add_rvalue_reference_helper<_Tp>::type;
1299#endif
1300 /// @endcond
1301
1302 /// is_move_constructible
1303 template<typename _Tp>
1304 struct is_move_constructible
1305 : public __is_constructible_impl<_Tp, __add_rval_ref_t<_Tp>>
1306 {
1307 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1308 "template argument must be a complete class or an unbounded array");
1309 };
1310
1311 /// @cond undocumented
1312 template<typename _Tp, typename... _Args>
1313 using __is_nothrow_constructible_impl
1314 = __bool_constant<__is_nothrow_constructible(_Tp, _Args...)>;
1315 /// @endcond
1316
1317 /// is_nothrow_constructible
1318 template<typename _Tp, typename... _Args>
1319 struct is_nothrow_constructible
1320 : public __is_nothrow_constructible_impl<_Tp, _Args...>
1321 {
1322 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1323 "template argument must be a complete class or an unbounded array");
1324 };
1325
1326 /// is_nothrow_default_constructible
1327 template<typename _Tp>
1328 struct is_nothrow_default_constructible
1329 : public __is_nothrow_constructible_impl<_Tp>
1330 {
1331 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1332 "template argument must be a complete class or an unbounded array");
1333 };
1334
1335 /// is_nothrow_copy_constructible
1336 template<typename _Tp>
1337 struct is_nothrow_copy_constructible
1338 : public __is_nothrow_constructible_impl<_Tp, __add_lval_ref_t<const _Tp>>
1339 {
1340 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1341 "template argument must be a complete class or an unbounded array");
1342 };
1343
1344 /// is_nothrow_move_constructible
1345 template<typename _Tp>
1346 struct is_nothrow_move_constructible
1347 : public __is_nothrow_constructible_impl<_Tp, __add_rval_ref_t<_Tp>>
1348 {
1349 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1350 "template argument must be a complete class or an unbounded array");
1351 };
1352
1353 /// @cond undocumented
1354 template<typename _Tp, typename _Up>
1355 using __is_assignable_impl = __bool_constant<__is_assignable(_Tp, _Up)>;
1356 /// @endcond
1357
1358 /// is_assignable
1359 template<typename _Tp, typename _Up>
1360 struct is_assignable
1361 : public __is_assignable_impl<_Tp, _Up>
1362 {
1363 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1364 "template argument must be a complete class or an unbounded array");
1365 };
1366
1367 /// is_copy_assignable
1368 template<typename _Tp>
1369 struct is_copy_assignable
1370 : public __is_assignable_impl<__add_lval_ref_t<_Tp>,
1371 __add_lval_ref_t<const _Tp>>
1372 {
1373 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1374 "template argument must be a complete class or an unbounded array");
1375 };
1376
1377 /// is_move_assignable
1378 template<typename _Tp>
1379 struct is_move_assignable
1380 : public __is_assignable_impl<__add_lval_ref_t<_Tp>, __add_rval_ref_t<_Tp>>
1381 {
1382 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1383 "template argument must be a complete class or an unbounded array");
1384 };
1385
1386 /// @cond undocumented
1387 template<typename _Tp, typename _Up>
1388 using __is_nothrow_assignable_impl
1389 = __bool_constant<__is_nothrow_assignable(_Tp, _Up)>;
1390 /// @endcond
1391
1392 /// is_nothrow_assignable
1393 template<typename _Tp, typename _Up>
1394 struct is_nothrow_assignable
1395 : public __is_nothrow_assignable_impl<_Tp, _Up>
1396 {
1397 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1398 "template argument must be a complete class or an unbounded array");
1399 };
1400
1401 /// is_nothrow_copy_assignable
1402 template<typename _Tp>
1403 struct is_nothrow_copy_assignable
1404 : public __is_nothrow_assignable_impl<__add_lval_ref_t<_Tp>,
1405 __add_lval_ref_t<const _Tp>>
1406 {
1407 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1408 "template argument must be a complete class or an unbounded array");
1409 };
1410
1411 /// is_nothrow_move_assignable
1412 template<typename _Tp>
1413 struct is_nothrow_move_assignable
1414 : public __is_nothrow_assignable_impl<__add_lval_ref_t<_Tp>,
1415 __add_rval_ref_t<_Tp>>
1416 {
1417 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1418 "template argument must be a complete class or an unbounded array");
1419 };
1420
1421 /// @cond undocumented
1422 template<typename _Tp, typename... _Args>
1423 using __is_trivially_constructible_impl
1424 = __bool_constant<__is_trivially_constructible(_Tp, _Args...)>;
1425 /// @endcond
1426
1427 /// is_trivially_constructible
1428 template<typename _Tp, typename... _Args>
1429 struct is_trivially_constructible
1430 : public __is_trivially_constructible_impl<_Tp, _Args...>
1431 {
1432 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1433 "template argument must be a complete class or an unbounded array");
1434 };
1435
1436 /// is_trivially_default_constructible
1437 template<typename _Tp>
1438 struct is_trivially_default_constructible
1439 : public __is_trivially_constructible_impl<_Tp>
1440 {
1441 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1442 "template argument must be a complete class or an unbounded array");
1443 };
1444
1445#if __cpp_variable_templates && __cpp_concepts
1446 template<typename _Tp>
1447 constexpr bool __is_implicitly_default_constructible_v
1448 = requires (void(&__f)(_Tp)) { __f({}); };
1449
1450 template<typename _Tp>
1451 struct __is_implicitly_default_constructible
1452 : __bool_constant<__is_implicitly_default_constructible_v<_Tp>>
1453 { };
1454#else
1455 struct __do_is_implicitly_default_constructible_impl
1456 {
1457 template <typename _Tp>
1458 static void __helper(const _Tp&);
1459
1460 template <typename _Tp>
1461 static true_type __test(const _Tp&,
1462 decltype(__helper<const _Tp&>({}))* = 0);
1463
1464 static false_type __test(...);
1465 };
1466
1467 template<typename _Tp>
1468 struct __is_implicitly_default_constructible_impl
1469 : public __do_is_implicitly_default_constructible_impl
1470 {
1471 using type = decltype(__test(declval<_Tp>()));
1472 };
1473
1474 template<typename _Tp>
1475 struct __is_implicitly_default_constructible_safe
1476 : public __is_implicitly_default_constructible_impl<_Tp>::type
1477 { };
1478
1479 template <typename _Tp>
1480 struct __is_implicitly_default_constructible
1481 : public __and_<__is_constructible_impl<_Tp>,
1482 __is_implicitly_default_constructible_safe<_Tp>>::type
1483 { };
1484#endif
1485
1486 /// is_trivially_copy_constructible
1487 template<typename _Tp>
1488 struct is_trivially_copy_constructible
1489 : public __is_trivially_constructible_impl<_Tp, __add_lval_ref_t<const _Tp>>
1490 {
1491 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1492 "template argument must be a complete class or an unbounded array");
1493 };
1494
1495 /// is_trivially_move_constructible
1496 template<typename _Tp>
1497 struct is_trivially_move_constructible
1498 : public __is_trivially_constructible_impl<_Tp, __add_rval_ref_t<_Tp>>
1499 {
1500 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1501 "template argument must be a complete class or an unbounded array");
1502 };
1503
1504 /// @cond undocumented
1505 template<typename _Tp, typename _Up>
1506 using __is_trivially_assignable_impl
1507 = __bool_constant<__is_trivially_assignable(_Tp, _Up)>;
1508 /// @endcond
1509
1510 /// is_trivially_assignable
1511 template<typename _Tp, typename _Up>
1512 struct is_trivially_assignable
1513 : public __is_trivially_assignable_impl<_Tp, _Up>
1514 {
1515 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1516 "template argument must be a complete class or an unbounded array");
1517 };
1518
1519 /// is_trivially_copy_assignable
1520 template<typename _Tp>
1521 struct is_trivially_copy_assignable
1522 : public __is_trivially_assignable_impl<__add_lval_ref_t<_Tp>,
1523 __add_lval_ref_t<const _Tp>>
1524 {
1525 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1526 "template argument must be a complete class or an unbounded array");
1527 };
1528
1529 /// is_trivially_move_assignable
1530 template<typename _Tp>
1531 struct is_trivially_move_assignable
1532 : public __is_trivially_assignable_impl<__add_lval_ref_t<_Tp>,
1533 __add_rval_ref_t<_Tp>>
1534 {
1535 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1536 "template argument must be a complete class or an unbounded array");
1537 };
1538
1539#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_trivially_destructible)
1540 /// is_trivially_destructible
1541 template<typename _Tp>
1542 struct is_trivially_destructible
1543 : public __bool_constant<__is_trivially_destructible(_Tp)>
1544 { };
1545#else
1546 /// is_trivially_destructible
1547 template<typename _Tp>
1548 struct is_trivially_destructible
1549 : public __and_<__is_destructible_safe<_Tp>,
1550 __bool_constant<__has_trivial_destructor(_Tp)>>::type
1551 {
1552 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1553 "template argument must be a complete class or an unbounded array");
1554 };
1555#endif
1556
1557 /// has_virtual_destructor
1558 template<typename _Tp>
1559 struct has_virtual_destructor
1560 : public __bool_constant<__has_virtual_destructor(_Tp)>
1561 {
1562 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1563 "template argument must be a complete class or an unbounded array");
1564 };
1565
1566
1567 // type property queries.
1568
1569 /// alignment_of
1570 template<typename _Tp>
1571 struct alignment_of
1572 : public integral_constant<std::size_t, alignof(_Tp)>
1573 {
1574 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1575 "template argument must be a complete class or an unbounded array");
1576 };
1577
1578 /// rank
1579#if _GLIBCXX_USE_BUILTIN_TRAIT(__array_rank) \
1580 && (!defined(__clang__) || __clang_major__ >= 20) // PR118559
1581 template<typename _Tp>
1582 struct rank
1583 : public integral_constant<std::size_t, __array_rank(_Tp)> { };
1584#else
1585 template<typename>
1586 struct rank
1587 : public integral_constant<std::size_t, 0> { };
1588
1589 template<typename _Tp, std::size_t _Size>
1590 struct rank<_Tp[_Size]>
1591 : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
1592
1593 template<typename _Tp>
1594 struct rank<_Tp[]>
1595 : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
1596#endif
1597
1598 /// extent
1599 template<typename, unsigned _Uint = 0>
1600 struct extent
1601 : public integral_constant<size_t, 0> { };
1602
1603 template<typename _Tp, size_t _Size>
1604 struct extent<_Tp[_Size], 0>
1605 : public integral_constant<size_t, _Size> { };
1606
1607 template<typename _Tp, unsigned _Uint, size_t _Size>
1608 struct extent<_Tp[_Size], _Uint>
1609 : public extent<_Tp, _Uint - 1>::type { };
1610
1611 template<typename _Tp>
1612 struct extent<_Tp[], 0>
1613 : public integral_constant<size_t, 0> { };
1614
1615 template<typename _Tp, unsigned _Uint>
1616 struct extent<_Tp[], _Uint>
1617 : public extent<_Tp, _Uint - 1>::type { };
1618
1619
1620 // Type relations.
1621
1622 /// is_same
1623#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_same)
1624 template<typename _Tp, typename _Up>
1625 struct is_same
1626 : public __bool_constant<__is_same(_Tp, _Up)>
1627 { };
1628#else
1629 template<typename _Tp, typename _Up>
1630 struct is_same
1631 : public false_type
1632 { };
1633
1634 template<typename _Tp>
1635 struct is_same<_Tp, _Tp>
1636 : public true_type
1637 { };
1638#endif
1639
1640 /// is_base_of
1641 template<typename _Base, typename _Derived>
1642 struct is_base_of
1643 : public __bool_constant<__is_base_of(_Base, _Derived)>
1644 { };
1645
1646#ifdef __cpp_lib_is_virtual_base_of // C++ >= 26
1647 /// is_virtual_base_of
1648 /// @since C++26
1649 template<typename _Base, typename _Derived>
1650 struct is_virtual_base_of
1651 : public bool_constant<__builtin_is_virtual_base_of(_Base, _Derived)>
1652 { };
1653#endif
1654
1655#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_convertible)
1656 template<typename _From, typename _To>
1657 struct is_convertible
1658 : public __bool_constant<__is_convertible(_From, _To)>
1659 { };
1660#else
1661 template<typename _From, typename _To,
1662 bool = __or_<is_void<_From>, is_function<_To>,
1663 is_array<_To>>::value>
1664 struct __is_convertible_helper
1665 {
1666 using type = typename is_void<_To>::type;
1667 };
1668
1669#pragma GCC diagnostic push
1670#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
1671 template<typename _From, typename _To>
1672 class __is_convertible_helper<_From, _To, false>
1673 {
1674 template<typename _To1>
1675 static void __test_aux(_To1) noexcept;
1676
1677 template<typename _From1, typename _To1,
1678 typename = decltype(__test_aux<_To1>(std::declval<_From1>()))>
1679 static true_type
1680 __test(int);
1681
1682 template<typename, typename>
1683 static false_type
1684 __test(...);
1685
1686 public:
1687 using type = decltype(__test<_From, _To>(0));
1688 };
1689#pragma GCC diagnostic pop
1690
1691 /// is_convertible
1692 template<typename _From, typename _To>
1693 struct is_convertible
1694 : public __is_convertible_helper<_From, _To>::type
1695 { };
1696#endif
1697
1698 // helper trait for unique_ptr<T[]>, shared_ptr<T[]>, and span<T, N>
1699 template<typename _ToElementType, typename _FromElementType>
1700 using __is_array_convertible
1701 = is_convertible<_FromElementType(*)[], _ToElementType(*)[]>;
1702
1703#ifdef __cpp_lib_is_nothrow_convertible // C++ >= 20
1704
1705#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_convertible)
1706 /// is_nothrow_convertible_v
1707 template<typename _From, typename _To>
1708 inline constexpr bool is_nothrow_convertible_v
1709 = __is_nothrow_convertible(_From, _To);
1710
1711 /// is_nothrow_convertible
1712 template<typename _From, typename _To>
1713 struct is_nothrow_convertible
1714 : public bool_constant<is_nothrow_convertible_v<_From, _To>>
1715 { };
1716#else
1717 template<typename _From, typename _To,
1718 bool = __or_<is_void<_From>, is_function<_To>,
1719 is_array<_To>>::value>
1720 struct __is_nt_convertible_helper
1721 : is_void<_To>
1722 { };
1723
1724#pragma GCC diagnostic push
1725#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
1726 template<typename _From, typename _To>
1727 class __is_nt_convertible_helper<_From, _To, false>
1728 {
1729 template<typename _To1>
1730 static void __test_aux(_To1) noexcept;
1731
1732 template<typename _From1, typename _To1>
1733 static
1734 __bool_constant<noexcept(__test_aux<_To1>(std::declval<_From1>()))>
1735 __test(int);
1736
1737 template<typename, typename>
1738 static false_type
1739 __test(...);
1740
1741 public:
1742 using type = decltype(__test<_From, _To>(0));
1743 };
1744#pragma GCC diagnostic pop
1745
1746 /// is_nothrow_convertible
1747 template<typename _From, typename _To>
1748 struct is_nothrow_convertible
1749 : public __is_nt_convertible_helper<_From, _To>::type
1750 { };
1751
1752 /// is_nothrow_convertible_v
1753 template<typename _From, typename _To>
1754 inline constexpr bool is_nothrow_convertible_v
1755 = is_nothrow_convertible<_From, _To>::value;
1756#endif
1757#endif // __cpp_lib_is_nothrow_convertible
1758
1759#pragma GCC diagnostic push
1760#pragma GCC diagnostic ignored "-Wc++14-extensions" // for variable templates
1761 template<typename _Tp, typename... _Args>
1762 struct __is_nothrow_new_constructible_impl
1763 : __bool_constant<
1764 noexcept(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))
1765 >
1766 { };
1767
1768 template<typename _Tp, typename... _Args>
1769 _GLIBCXX17_INLINE constexpr bool __is_nothrow_new_constructible
1770 = __and_<is_constructible<_Tp, _Args...>,
1771 __is_nothrow_new_constructible_impl<_Tp, _Args...>>::value;
1772#pragma GCC diagnostic pop
1773
1774 // Const-volatile modifications.
1775
1776 /// remove_const
1777 template<typename _Tp>
1778 struct remove_const
1779 { using type = _Tp; };
1780
1781 template<typename _Tp>
1782 struct remove_const<_Tp const>
1783 { using type = _Tp; };
1784
1785 /// remove_volatile
1786 template<typename _Tp>
1787 struct remove_volatile
1788 { using type = _Tp; };
1789
1790 template<typename _Tp>
1791 struct remove_volatile<_Tp volatile>
1792 { using type = _Tp; };
1793
1794 /// remove_cv
1795#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cv)
1796 template<typename _Tp>
1797 struct remove_cv
1798 { using type = __remove_cv(_Tp); };
1799#else
1800 template<typename _Tp>
1801 struct remove_cv
1802 { using type = _Tp; };
1803
1804 template<typename _Tp>
1805 struct remove_cv<const _Tp>
1806 { using type = _Tp; };
1807
1808 template<typename _Tp>
1809 struct remove_cv<volatile _Tp>
1810 { using type = _Tp; };
1811
1812 template<typename _Tp>
1813 struct remove_cv<const volatile _Tp>
1814 { using type = _Tp; };
1815#endif
1816
1817 /// add_const
1818 template<typename _Tp>
1819 struct add_const
1820 { using type = _Tp const; };
1821
1822 /// add_volatile
1823 template<typename _Tp>
1824 struct add_volatile
1825 { using type = _Tp volatile; };
1826
1827 /// add_cv
1828 template<typename _Tp>
1829 struct add_cv
1830 { using type = _Tp const volatile; };
1831
1832#ifdef __cpp_lib_transformation_trait_aliases // C++ >= 14
1833 /// Alias template for remove_const
1834 template<typename _Tp>
1835 using remove_const_t = typename remove_const<_Tp>::type;
1836
1837 /// Alias template for remove_volatile
1838 template<typename _Tp>
1839 using remove_volatile_t = typename remove_volatile<_Tp>::type;
1840
1841 /// Alias template for remove_cv
1842 template<typename _Tp>
1843 using remove_cv_t = typename remove_cv<_Tp>::type;
1844
1845 /// Alias template for add_const
1846 template<typename _Tp>
1847 using add_const_t = typename add_const<_Tp>::type;
1848
1849 /// Alias template for add_volatile
1850 template<typename _Tp>
1851 using add_volatile_t = typename add_volatile<_Tp>::type;
1852
1853 /// Alias template for add_cv
1854 template<typename _Tp>
1855 using add_cv_t = typename add_cv<_Tp>::type;
1856#endif
1857
1858 // Reference transformations.
1859
1860 /// remove_reference
1861#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_reference)
1862 template<typename _Tp>
1863 struct remove_reference
1864 { using type = __remove_reference(_Tp); };
1865#else
1866 template<typename _Tp>
1867 struct remove_reference
1868 { using type = _Tp; };
1869
1870 template<typename _Tp>
1871 struct remove_reference<_Tp&>
1872 { using type = _Tp; };
1873
1874 template<typename _Tp>
1875 struct remove_reference<_Tp&&>
1876 { using type = _Tp; };
1877#endif
1878
1879 /// add_lvalue_reference
1880 template<typename _Tp>
1881 struct add_lvalue_reference
1882 { using type = __add_lval_ref_t<_Tp>; };
1883
1884 /// add_rvalue_reference
1885 template<typename _Tp>
1886 struct add_rvalue_reference
1887 { using type = __add_rval_ref_t<_Tp>; };
1888
1889#if __cplusplus > 201103L
1890 /// Alias template for remove_reference
1891 template<typename _Tp>
1892 using remove_reference_t = typename remove_reference<_Tp>::type;
1893
1894 /// Alias template for add_lvalue_reference
1895 template<typename _Tp>
1896 using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1897
1898 /// Alias template for add_rvalue_reference
1899 template<typename _Tp>
1900 using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1901#endif
1902
1903 // Sign modifications.
1904
1905 /// @cond undocumented
1906
1907 // Utility for constructing identically cv-qualified types.
1908 template<typename _Unqualified, bool _IsConst, bool _IsVol>
1909 struct __cv_selector;
1910
1911 template<typename _Unqualified>
1912 struct __cv_selector<_Unqualified, false, false>
1913 { using __type = _Unqualified; };
1914
1915 template<typename _Unqualified>
1916 struct __cv_selector<_Unqualified, false, true>
1917 { using __type = volatile _Unqualified; };
1918
1919 template<typename _Unqualified>
1920 struct __cv_selector<_Unqualified, true, false>
1921 { using __type = const _Unqualified; };
1922
1923 template<typename _Unqualified>
1924 struct __cv_selector<_Unqualified, true, true>
1925 { using __type = const volatile _Unqualified; };
1926
1927 template<typename _Qualified, typename _Unqualified,
1928 bool _IsConst = is_const<_Qualified>::value,
1929 bool _IsVol = is_volatile<_Qualified>::value>
1930 class __match_cv_qualifiers
1931 {
1932 using __match = __cv_selector<_Unqualified, _IsConst, _IsVol>;
1933
1934 public:
1935 using __type = typename __match::__type;
1936 };
1937
1938 // Utility for finding the unsigned versions of signed integral types.
1939 template<typename _Tp>
1940 struct __make_unsigned
1941 { using __type = _Tp; };
1942
1943 template<>
1944 struct __make_unsigned<char>
1945 { using __type = unsigned char; };
1946
1947 template<>
1948 struct __make_unsigned<signed char>
1949 { using __type = unsigned char; };
1950
1951 template<>
1952 struct __make_unsigned<short>
1953 { using __type = unsigned short; };
1954
1955 template<>
1956 struct __make_unsigned<int>
1957 { using __type = unsigned int; };
1958
1959 template<>
1960 struct __make_unsigned<long>
1961 { using __type = unsigned long; };
1962
1963 template<>
1964 struct __make_unsigned<long long>
1965 { using __type = unsigned long long; };
1966
1967#if defined(__GLIBCXX_TYPE_INT_N_0)
1968 __extension__
1969 template<>
1970 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_0>
1971 { using __type = unsigned __GLIBCXX_TYPE_INT_N_0; };
1972#endif
1973#if defined(__GLIBCXX_TYPE_INT_N_1)
1974 __extension__
1975 template<>
1976 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_1>
1977 { using __type = unsigned __GLIBCXX_TYPE_INT_N_1; };
1978#endif
1979#if defined(__GLIBCXX_TYPE_INT_N_2)
1980 __extension__
1981 template<>
1982 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_2>
1983 { using __type = unsigned __GLIBCXX_TYPE_INT_N_2; };
1984#endif
1985#if defined(__GLIBCXX_TYPE_INT_N_3)
1986 __extension__
1987 template<>
1988 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_3>
1989 { using __type = unsigned __GLIBCXX_TYPE_INT_N_3; };
1990#endif
1991#if defined __SIZEOF_INT128__ && defined __STRICT_ANSI__
1992 __extension__
1993 template<>
1994 struct __make_unsigned<__int128>
1995 { using __type = unsigned __int128; };
1996#endif
1997
1998 // Select between integral and enum: not possible to be both.
1999 template<typename _Tp,
2000 bool _IsInt = is_integral<_Tp>::value,
2001 bool _IsEnum = __is_enum(_Tp)>
2002 class __make_unsigned_selector;
2003
2004 template<typename _Tp>
2005 class __make_unsigned_selector<_Tp, true, false>
2006 {
2007 using __unsigned_type
2008 = typename __make_unsigned<__remove_cv_t<_Tp>>::__type;
2009
2010 public:
2011 using __type
2012 = typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
2013 };
2014
2015 class __make_unsigned_selector_base
2016 {
2017 protected:
2018 template<typename...> struct _List { };
2019
2020 template<typename _Tp, typename... _Up>
2021 struct _List<_Tp, _Up...> : _List<_Up...>
2022 { static constexpr size_t __size = sizeof(_Tp); };
2023
2024 template<size_t _Sz, typename _Tp, bool = (_Sz <= _Tp::__size)>
2025 struct __select;
2026
2027 template<size_t _Sz, typename _Uint, typename... _UInts>
2028 struct __select<_Sz, _List<_Uint, _UInts...>, true>
2029 { using __type = _Uint; };
2030
2031 template<size_t _Sz, typename _Uint, typename... _UInts>
2032 struct __select<_Sz, _List<_Uint, _UInts...>, false>
2033 : __select<_Sz, _List<_UInts...>>
2034 { };
2035 };
2036
2037 // Choose unsigned integer type with the smallest rank and same size as _Tp
2038 template<typename _Tp>
2039 class __make_unsigned_selector<_Tp, false, true>
2040 : __make_unsigned_selector_base
2041 {
2042 // With -fshort-enums, an enum may be as small as a char.
2043 __extension__
2044 using _UInts = _List<unsigned char, unsigned short, unsigned int,
2045 unsigned long, unsigned long long
2046#ifdef __SIZEOF_INT128__
2047 , unsigned __int128
2048#endif
2049 >;
2050
2051 using __unsigned_type = typename __select<sizeof(_Tp), _UInts>::__type;
2052
2053 public:
2054 using __type
2055 = typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
2056 };
2057
2058 // wchar_t, char8_t, char16_t and char32_t are integral types but are
2059 // neither signed integer types nor unsigned integer types, so must be
2060 // transformed to the unsigned integer type with the smallest rank.
2061 // Use the partial specialization for enumeration types to do that.
2062 template<>
2063 struct __make_unsigned<wchar_t>
2064 {
2065 using __type
2066 = typename __make_unsigned_selector<wchar_t, false, true>::__type;
2067 };
2068
2069#ifdef _GLIBCXX_USE_CHAR8_T
2070 template<>
2071 struct __make_unsigned<char8_t>
2072 {
2073 using __type
2074 = typename __make_unsigned_selector<char8_t, false, true>::__type;
2075 };
2076#endif
2077
2078 template<>
2079 struct __make_unsigned<char16_t>
2080 {
2081 using __type
2082 = typename __make_unsigned_selector<char16_t, false, true>::__type;
2083 };
2084
2085 template<>
2086 struct __make_unsigned<char32_t>
2087 {
2088 using __type
2089 = typename __make_unsigned_selector<char32_t, false, true>::__type;
2090 };
2091 /// @endcond
2092
2093 // Given an integral/enum type, return the corresponding unsigned
2094 // integer type.
2095 // Primary template.
2096 /// make_unsigned
2097 template<typename _Tp>
2098 struct make_unsigned
2099 { using type = typename __make_unsigned_selector<_Tp>::__type; };
2100
2101 // Integral, but don't define.
2102 template<> struct make_unsigned<bool>;
2103 template<> struct make_unsigned<bool const>;
2104 template<> struct make_unsigned<bool volatile>;
2105 template<> struct make_unsigned<bool const volatile>;
2106
2107 /// @cond undocumented
2108
2109 // Utility for finding the signed versions of unsigned integral types.
2110 template<typename _Tp>
2111 struct __make_signed
2112 { using __type = _Tp; };
2113
2114 template<>
2115 struct __make_signed<char>
2116 { using __type = signed char; };
2117
2118 template<>
2119 struct __make_signed<unsigned char>
2120 { using __type = signed char; };
2121
2122 template<>
2123 struct __make_signed<unsigned short>
2124 { using __type = signed short; };
2125
2126 template<>
2127 struct __make_signed<unsigned int>
2128 { using __type = signed int; };
2129
2130 template<>
2131 struct __make_signed<unsigned long>
2132 { using __type = signed long; };
2133
2134 template<>
2135 struct __make_signed<unsigned long long>
2136 { using __type = signed long long; };
2137
2138#if defined(__GLIBCXX_TYPE_INT_N_0)
2139 __extension__
2140 template<>
2141 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_0>
2142 { using __type = __GLIBCXX_TYPE_INT_N_0; };
2143#endif
2144#if defined(__GLIBCXX_TYPE_INT_N_1)
2145 __extension__
2146 template<>
2147 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_1>
2148 { using __type = __GLIBCXX_TYPE_INT_N_1; };
2149#endif
2150#if defined(__GLIBCXX_TYPE_INT_N_2)
2151 __extension__
2152 template<>
2153 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_2>
2154 { using __type = __GLIBCXX_TYPE_INT_N_2; };
2155#endif
2156#if defined(__GLIBCXX_TYPE_INT_N_3)
2157 __extension__
2158 template<>
2159 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_3>
2160 { using __type = __GLIBCXX_TYPE_INT_N_3; };
2161#endif
2162#if defined __SIZEOF_INT128__ && defined __STRICT_ANSI__
2163 __extension__
2164 template<>
2165 struct __make_signed<unsigned __int128>
2166 { using __type = __int128; };
2167#endif
2168
2169 // Select between integral and enum: not possible to be both.
2170 template<typename _Tp,
2171 bool _IsInt = is_integral<_Tp>::value,
2172 bool _IsEnum = __is_enum(_Tp)>
2173 class __make_signed_selector;
2174
2175 template<typename _Tp>
2176 class __make_signed_selector<_Tp, true, false>
2177 {
2178 using __signed_type
2179 = typename __make_signed<__remove_cv_t<_Tp>>::__type;
2180
2181 public:
2182 using __type
2183 = typename __match_cv_qualifiers<_Tp, __signed_type>::__type;
2184 };
2185
2186 // Choose signed integer type with the smallest rank and same size as _Tp
2187 template<typename _Tp>
2188 class __make_signed_selector<_Tp, false, true>
2189 {
2190 using __unsigned_type = typename __make_unsigned_selector<_Tp>::__type;
2191
2192 public:
2193 using __type = typename __make_signed_selector<__unsigned_type>::__type;
2194 };
2195
2196 // wchar_t, char16_t and char32_t are integral types but are neither
2197 // signed integer types nor unsigned integer types, so must be
2198 // transformed to the signed integer type with the smallest rank.
2199 // Use the partial specialization for enumeration types to do that.
2200 template<>
2201 struct __make_signed<wchar_t>
2202 {
2203 using __type
2204 = typename __make_signed_selector<wchar_t, false, true>::__type;
2205 };
2206
2207#if defined(_GLIBCXX_USE_CHAR8_T)
2208 template<>
2209 struct __make_signed<char8_t>
2210 {
2211 using __type
2212 = typename __make_signed_selector<char8_t, false, true>::__type;
2213 };
2214#endif
2215
2216 template<>
2217 struct __make_signed<char16_t>
2218 {
2219 using __type
2220 = typename __make_signed_selector<char16_t, false, true>::__type;
2221 };
2222
2223 template<>
2224 struct __make_signed<char32_t>
2225 {
2226 using __type
2227 = typename __make_signed_selector<char32_t, false, true>::__type;
2228 };
2229 /// @endcond
2230
2231 // Given an integral/enum type, return the corresponding signed
2232 // integer type.
2233 // Primary template.
2234 /// make_signed
2235 template<typename _Tp>
2236 struct make_signed
2237 { using type = typename __make_signed_selector<_Tp>::__type; };
2238
2239 // Integral, but don't define.
2240 template<> struct make_signed<bool>;
2241 template<> struct make_signed<bool const>;
2242 template<> struct make_signed<bool volatile>;
2243 template<> struct make_signed<bool const volatile>;
2244
2245#if __cplusplus > 201103L
2246 /// Alias template for make_signed
2247 template<typename _Tp>
2248 using make_signed_t = typename make_signed<_Tp>::type;
2249
2250 /// Alias template for make_unsigned
2251 template<typename _Tp>
2252 using make_unsigned_t = typename make_unsigned<_Tp>::type;
2253#endif
2254
2255 // Array modifications.
2256
2257 /// remove_extent
2258#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_extent)
2259 template<typename _Tp>
2260 struct remove_extent
2261 { using type = __remove_extent(_Tp); };
2262#else
2263 template<typename _Tp>
2264 struct remove_extent
2265 { using type = _Tp; };
2266
2267 template<typename _Tp, std::size_t _Size>
2268 struct remove_extent<_Tp[_Size]>
2269 { using type = _Tp; };
2270
2271 template<typename _Tp>
2272 struct remove_extent<_Tp[]>
2273 { using type = _Tp; };
2274#endif
2275
2276 /// remove_all_extents
2277#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_all_extents)
2278 template<typename _Tp>
2279 struct remove_all_extents
2280 { using type = __remove_all_extents(_Tp); };
2281#else
2282 template<typename _Tp>
2283 struct remove_all_extents
2284 { using type = _Tp; };
2285
2286 template<typename _Tp, std::size_t _Size>
2287 struct remove_all_extents<_Tp[_Size]>
2288 { using type = typename remove_all_extents<_Tp>::type; };
2289
2290 template<typename _Tp>
2291 struct remove_all_extents<_Tp[]>
2292 { using type = typename remove_all_extents<_Tp>::type; };
2293#endif
2294
2295#if __cplusplus > 201103L
2296 /// Alias template for remove_extent
2297 template<typename _Tp>
2298 using remove_extent_t = typename remove_extent<_Tp>::type;
2299
2300 /// Alias template for remove_all_extents
2301 template<typename _Tp>
2302 using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
2303#endif
2304
2305 // Pointer modifications.
2306
2307 /// remove_pointer
2308#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_pointer)
2309 template<typename _Tp>
2310 struct remove_pointer
2311 { using type = __remove_pointer(_Tp); };
2312#else
2313 template<typename _Tp, typename>
2314 struct __remove_pointer_helper
2315 { using type = _Tp; };
2316
2317 template<typename _Tp, typename _Up>
2318 struct __remove_pointer_helper<_Tp, _Up*>
2319 { using type = _Up; };
2320
2321 template<typename _Tp>
2322 struct remove_pointer
2323 : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
2324 { };
2325#endif
2326
2327 /// add_pointer
2328#if _GLIBCXX_USE_BUILTIN_TRAIT(__add_pointer)
2329 template<typename _Tp>
2330 struct add_pointer
2331 { using type = __add_pointer(_Tp); };
2332#else
2333 template<typename _Tp, typename = void>
2334 struct __add_pointer_helper
2335 { using type = _Tp; };
2336
2337 template<typename _Tp>
2338 struct __add_pointer_helper<_Tp, __void_t<_Tp*>>
2339 { using type = _Tp*; };
2340
2341 template<typename _Tp>
2342 struct add_pointer
2343 : public __add_pointer_helper<_Tp>
2344 { };
2345
2346 template<typename _Tp>
2347 struct add_pointer<_Tp&>
2348 { using type = _Tp*; };
2349
2350 template<typename _Tp>
2351 struct add_pointer<_Tp&&>
2352 { using type = _Tp*; };
2353#endif
2354
2355#if __cplusplus > 201103L
2356 /// Alias template for remove_pointer
2357 template<typename _Tp>
2358 using remove_pointer_t = typename remove_pointer<_Tp>::type;
2359
2360 /// Alias template for add_pointer
2361 template<typename _Tp>
2362 using add_pointer_t = typename add_pointer<_Tp>::type;
2363#endif
2364
2365 /// @cond undocumented
2366
2367 // Aligned to maximum fundamental alignment
2368 struct __attribute__((__aligned__)) __aligned_storage_max_align_t
2369 { };
2370
2371 constexpr size_t
2372 __aligned_storage_default_alignment([[__maybe_unused__]] size_t __len)
2373 {
2374#if _GLIBCXX_INLINE_VERSION
2375 using _Max_align
2376 = integral_constant<size_t, alignof(__aligned_storage_max_align_t)>;
2377
2378 return __len > (_Max_align::value / 2)
2379 ? _Max_align::value
2380# if _GLIBCXX_USE_BUILTIN_TRAIT(__builtin_clzg)
2381 : 1 << (__SIZE_WIDTH__ - __builtin_clzg(__len - 1u));
2382# else
2383 : 1 << (__LLONG_WIDTH__ - __builtin_clzll(__len - 1ull));
2384# endif
2385#else
2386 // Returning a fixed value is incorrect, but kept for ABI compatibility.
2387 // XXX GLIBCXX_ABI Deprecated
2388 return alignof(__aligned_storage_max_align_t);
2389#endif
2390 }
2391 /// @endcond
2392
2393 /**
2394 * @brief Aligned storage
2395 *
2396 * The member typedef `type` is be a POD type suitable for use as
2397 * uninitialized storage for any object whose size is at most `_Len`
2398 * and whose alignment is a divisor of `_Align`.
2399 *
2400 * It is important to use the nested `type` as uninitialized storage,
2401 * not the `std::aligned_storage` type itself which is an empty class
2402 * with 1-byte alignment. So this is correct:
2403 *
2404 * `typename std::aligned_storage<sizeof(X), alignof(X)>::type m_xobj;`
2405 *
2406 * This is wrong:
2407 *
2408 * `std::aligned_storage<sizeof(X), alignof(X)> m_xobj;`
2409 *
2410 * In C++14 and later `std::aligned_storage_t<sizeof(X), alignof(X)>`
2411 * can be used to refer to the `type` member typedef.
2412 *
2413 * The default value of _Align is supposed to be the most stringent
2414 * fundamental alignment requirement for any C++ object type whose size
2415 * is no greater than `_Len` (see [basic.align] in the C++ standard).
2416 *
2417 * @bug In this implementation the default value for _Align is always the
2418 * maximum fundamental alignment, i.e. `alignof(max_align_t)`, which is
2419 * incorrect. It should be an alignment value no greater than `_Len`.
2420 *
2421 * @deprecated Deprecated in C++23. Uses can be replaced by an
2422 * array `std::byte[_Len]` declared with `alignas(_Align)`.
2423 */
2424 template<size_t _Len,
2425 size_t _Align = __aligned_storage_default_alignment(_Len)>
2426 struct
2427 _GLIBCXX23_DEPRECATED
2428 aligned_storage
2429 {
2430 struct type
2431 {
2432 alignas(_Align) unsigned char __data[_Len];
2433 };
2434 };
2435
2436 template <typename... _Types>
2437 struct __strictest_alignment
2438 {
2439 static const size_t _S_alignment = 0;
2440 static const size_t _S_size = 0;
2441 };
2442
2443 template <typename _Tp, typename... _Types>
2444 struct __strictest_alignment<_Tp, _Types...>
2445 {
2446 static const size_t _S_alignment =
2447 alignof(_Tp) > __strictest_alignment<_Types...>::_S_alignment
2448 ? alignof(_Tp) : __strictest_alignment<_Types...>::_S_alignment;
2449 static const size_t _S_size =
2450 sizeof(_Tp) > __strictest_alignment<_Types...>::_S_size
2451 ? sizeof(_Tp) : __strictest_alignment<_Types...>::_S_size;
2452 };
2453
2454#pragma GCC diagnostic push
2455#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
2456
2457 /**
2458 * @brief Provide aligned storage for types.
2459 *
2460 * [meta.trans.other]
2461 *
2462 * Provides aligned storage for any of the provided types of at
2463 * least size _Len.
2464 *
2465 * @see aligned_storage
2466 *
2467 * @deprecated Deprecated in C++23.
2468 */
2469 template <size_t _Len, typename... _Types>
2470 struct
2471 _GLIBCXX23_DEPRECATED
2472 aligned_union
2473 {
2474 private:
2475 static_assert(sizeof...(_Types) != 0, "At least one type is required");
2476
2477 using __strictest = __strictest_alignment<_Types...>;
2478 static const size_t _S_len = _Len > __strictest::_S_size
2479 ? _Len : __strictest::_S_size;
2480 public:
2481 /// The value of the strictest alignment of _Types.
2482 static const size_t alignment_value = __strictest::_S_alignment;
2483 /// The storage.
2484 using type = typename aligned_storage<_S_len, alignment_value>::type;
2485 };
2486
2487 template <size_t _Len, typename... _Types>
2488 const size_t aligned_union<_Len, _Types...>::alignment_value;
2489#pragma GCC diagnostic pop
2490
2491 // Decay trait for arrays and functions, used for perfect forwarding
2492 // in make_pair, make_tuple, etc.
2493#if _GLIBCXX_USE_BUILTIN_TRAIT(__decay)
2494 template<typename _Tp>
2495 struct decay
2496 { using type = __decay(_Tp); };
2497#else
2498 /// @cond undocumented
2499
2500 template<typename _Up>
2501 struct __decay_selector
2502 : __conditional_t<is_const<const _Up>::value, // false for functions
2503 remove_cv<_Up>, // N.B. DR 705.
2504 add_pointer<_Up>> // function decays to pointer
2505 { };
2506
2507 template<typename _Up, size_t _Nm>
2508 struct __decay_selector<_Up[_Nm]>
2509 { using type = _Up*; };
2510
2511 template<typename _Up>
2512 struct __decay_selector<_Up[]>
2513 { using type = _Up*; };
2514
2515 /// @endcond
2516
2517 /// decay
2518 template<typename _Tp>
2519 struct decay
2520 { using type = typename __decay_selector<_Tp>::type; };
2521
2522 template<typename _Tp>
2523 struct decay<_Tp&>
2524 { using type = typename __decay_selector<_Tp>::type; };
2525
2526 template<typename _Tp>
2527 struct decay<_Tp&&>
2528 { using type = typename __decay_selector<_Tp>::type; };
2529#endif
2530
2531 /// @cond undocumented
2532
2533 // Helper which adds a reference to a type when given a reference_wrapper
2534 template<typename _Tp>
2535 struct __strip_reference_wrapper
2536 {
2537 using __type = _Tp;
2538 };
2539
2540 template<typename _Tp>
2541 struct __strip_reference_wrapper<reference_wrapper<_Tp> >
2542 {
2543 using __type = _Tp&;
2544 };
2545
2546 // __decay_t (std::decay_t for C++11).
2547 template<typename _Tp>
2548 using __decay_t = typename decay<_Tp>::type;
2549
2550 template<typename _Tp>
2551 using __decay_and_strip = __strip_reference_wrapper<__decay_t<_Tp>>;
2552 /// @endcond
2553
2554 /// @cond undocumented
2555
2556 // Helper for SFINAE constraints
2557 template<typename... _Cond>
2558 using _Require = __enable_if_t<__and_<_Cond...>::value>;
2559
2560 // __remove_cvref_t (std::remove_cvref_t for C++11).
2561 template<typename _Tp>
2562 using __remove_cvref_t
2563 = typename remove_cv<typename remove_reference<_Tp>::type>::type;
2564 /// @endcond
2565
2566 // Primary template.
2567 /// Define a member typedef @c type to one of two argument types.
2568 template<bool _Cond, typename _Iftrue, typename _Iffalse>
2569 struct conditional
2570 { using type = _Iftrue; };
2571
2572 // Partial specialization for false.
2573 template<typename _Iftrue, typename _Iffalse>
2574 struct conditional<false, _Iftrue, _Iffalse>
2575 { using type = _Iffalse; };
2576
2577 /// common_type
2578 template<typename... _Tp>
2579 struct common_type;
2580
2581 // Sfinae-friendly common_type implementation:
2582
2583 /// @cond undocumented
2584
2585 // For several sfinae-friendly trait implementations we transport both the
2586 // result information (as the member type) and the failure information (no
2587 // member type). This is very similar to std::enable_if, but we cannot use
2588 // that, because we need to derive from them as an implementation detail.
2589
2590 template<typename _Tp>
2591 struct __success_type
2592 { using type = _Tp; };
2593
2594 struct __failure_type
2595 { };
2596
2597 struct __do_common_type_impl
2598 {
2599 template<typename _Tp, typename _Up>
2600 using __cond_t
2601 = decltype(true ? std::declval<_Tp>() : std::declval<_Up>());
2602
2603 // if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
2604 // denotes a valid type, let C denote that type.
2605 template<typename _Tp, typename _Up>
2606 static __success_type<__decay_t<__cond_t<_Tp, _Up>>>
2607 _S_test(int);
2608
2609#if __cplusplus > 201703L
2610 // Otherwise, if COND-RES(CREF(D1), CREF(D2)) denotes a type,
2611 // let C denote the type decay_t<COND-RES(CREF(D1), CREF(D2))>.
2612 template<typename _Tp, typename _Up>
2613 static __success_type<__remove_cvref_t<__cond_t<const _Tp&, const _Up&>>>
2614 _S_test_2(int);
2615#endif
2616
2617 template<typename, typename>
2618 static __failure_type
2619 _S_test_2(...);
2620
2621 template<typename _Tp, typename _Up>
2622 static decltype(_S_test_2<_Tp, _Up>(0))
2623 _S_test(...);
2624 };
2625
2626 // If sizeof...(T) is zero, there shall be no member type.
2627 template<>
2628 struct common_type<>
2629 { };
2630
2631 // If sizeof...(T) is one, the same type, if any, as common_type_t<T0, T0>.
2632 template<typename _Tp0>
2633 struct common_type<_Tp0>
2634 : public common_type<_Tp0, _Tp0>
2635 { };
2636
2637 // If sizeof...(T) is two, ...
2638 template<typename _Tp1, typename _Tp2,
2639 typename _Dp1 = __decay_t<_Tp1>, typename _Dp2 = __decay_t<_Tp2>>
2640 struct __common_type_impl
2641 {
2642 // If is_same_v<T1, D1> is false or is_same_v<T2, D2> is false,
2643 // let C denote the same type, if any, as common_type_t<D1, D2>.
2644 using type = common_type<_Dp1, _Dp2>;
2645 };
2646
2647 template<typename _Tp1, typename _Tp2>
2648 struct __common_type_impl<_Tp1, _Tp2, _Tp1, _Tp2>
2649 : private __do_common_type_impl
2650 {
2651 // Otherwise, if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
2652 // denotes a valid type, let C denote that type.
2653 using type = decltype(_S_test<_Tp1, _Tp2>(0));
2654 };
2655
2656 // If sizeof...(T) is two, ...
2657 template<typename _Tp1, typename _Tp2>
2658 struct common_type<_Tp1, _Tp2>
2659 : public __common_type_impl<_Tp1, _Tp2>::type
2660 { };
2661
2662 template<typename...>
2663 struct __common_type_pack
2664 { };
2665
2666 template<typename, typename, typename = void>
2667 struct __common_type_fold;
2668
2669 // If sizeof...(T) is greater than two, ...
2670 template<typename _Tp1, typename _Tp2, typename... _Rp>
2671 struct common_type<_Tp1, _Tp2, _Rp...>
2672 : public __common_type_fold<common_type<_Tp1, _Tp2>,
2673 __common_type_pack<_Rp...>>
2674 { };
2675
2676 // Let C denote the same type, if any, as common_type_t<T1, T2>.
2677 // If there is such a type C, type shall denote the same type, if any,
2678 // as common_type_t<C, R...>.
2679 template<typename _CTp, typename... _Rp>
2680 struct __common_type_fold<_CTp, __common_type_pack<_Rp...>,
2681 __void_t<typename _CTp::type>>
2682 : public common_type<typename _CTp::type, _Rp...>
2683 { };
2684
2685 // Otherwise, there shall be no member type.
2686 template<typename _CTp, typename _Rp>
2687 struct __common_type_fold<_CTp, _Rp, void>
2688 { };
2689
2690 template<typename _Tp, bool = __is_enum(_Tp)>
2691 struct __underlying_type_impl
2692 {
2693 using type = __underlying_type(_Tp);
2694 };
2695
2696 template<typename _Tp>
2697 struct __underlying_type_impl<_Tp, false>
2698 { };
2699 /// @endcond
2700
2701 /// The underlying type of an enum.
2702 template<typename _Tp>
2703 struct underlying_type
2704 : public __underlying_type_impl<_Tp>
2705 { };
2706
2707 /// @cond undocumented
2708 template<typename _Tp>
2709 struct __declval_protector
2710 {
2711 static const bool __stop = false;
2712 };
2713 /// @endcond
2714
2715 /** Utility to simplify expressions used in unevaluated operands
2716 * @since C++11
2717 * @ingroup utilities
2718 */
2719 template<typename _Tp>
2720 auto declval() noexcept -> decltype(__declval<_Tp>(0))
2721 {
2722 static_assert(__declval_protector<_Tp>::__stop,
2723 "declval() must not be used!");
2724 return __declval<_Tp>(0);
2725 }
2726
2727 /// result_of
2728 template<typename _Signature>
2729 struct result_of;
2730
2731 // Sfinae-friendly result_of implementation:
2732
2733 /// @cond undocumented
2734 struct __invoke_memfun_ref { };
2735 struct __invoke_memfun_deref { };
2736 struct __invoke_memobj_ref { };
2737 struct __invoke_memobj_deref { };
2738 struct __invoke_other { };
2739
2740 // Associate a tag type with a specialization of __success_type.
2741 template<typename _Tp, typename _Tag>
2742 struct __result_of_success : __success_type<_Tp>
2743 { using __invoke_type = _Tag; };
2744
2745 // [func.require] paragraph 1 bullet 1:
2746 struct __result_of_memfun_ref_impl
2747 {
2748 template<typename _Fp, typename _Tp1, typename... _Args>
2749 static __result_of_success<decltype(
2750 (std::declval<_Tp1>().*std::declval<_Fp>())(std::declval<_Args>()...)
2751 ), __invoke_memfun_ref> _S_test(int);
2752
2753 template<typename...>
2754 static __failure_type _S_test(...);
2755 };
2756
2757 template<typename _MemPtr, typename _Arg, typename... _Args>
2758 struct __result_of_memfun_ref
2759 : private __result_of_memfun_ref_impl
2760 {
2761 using type = decltype(_S_test<_MemPtr, _Arg, _Args...>(0));
2762 };
2763
2764 // [func.require] paragraph 1 bullet 2:
2765 struct __result_of_memfun_deref_impl
2766 {
2767 template<typename _Fp, typename _Tp1, typename... _Args>
2768 static __result_of_success<decltype(
2769 ((*std::declval<_Tp1>()).*std::declval<_Fp>())(std::declval<_Args>()...)
2770 ), __invoke_memfun_deref> _S_test(int);
2771
2772 template<typename...>
2773 static __failure_type _S_test(...);
2774 };
2775
2776 template<typename _MemPtr, typename _Arg, typename... _Args>
2777 struct __result_of_memfun_deref
2778 : private __result_of_memfun_deref_impl
2779 {
2780 using type = decltype(_S_test<_MemPtr, _Arg, _Args...>(0));
2781 };
2782
2783 // [func.require] paragraph 1 bullet 3:
2784 struct __result_of_memobj_ref_impl
2785 {
2786 template<typename _Fp, typename _Tp1>
2787 static __result_of_success<decltype(
2788 std::declval<_Tp1>().*std::declval<_Fp>()
2789 ), __invoke_memobj_ref> _S_test(int);
2790
2791 template<typename, typename>
2792 static __failure_type _S_test(...);
2793 };
2794
2795 template<typename _MemPtr, typename _Arg>
2796 struct __result_of_memobj_ref
2797 : private __result_of_memobj_ref_impl
2798 {
2799 using type = decltype(_S_test<_MemPtr, _Arg>(0));
2800 };
2801
2802 // [func.require] paragraph 1 bullet 4:
2803 struct __result_of_memobj_deref_impl
2804 {
2805 template<typename _Fp, typename _Tp1>
2806 static __result_of_success<decltype(
2807 (*std::declval<_Tp1>()).*std::declval<_Fp>()
2808 ), __invoke_memobj_deref> _S_test(int);
2809
2810 template<typename, typename>
2811 static __failure_type _S_test(...);
2812 };
2813
2814 template<typename _MemPtr, typename _Arg>
2815 struct __result_of_memobj_deref
2816 : private __result_of_memobj_deref_impl
2817 {
2818 using type = decltype(_S_test<_MemPtr, _Arg>(0));
2819 };
2820
2821 template<typename _MemPtr, typename _Arg>
2822 struct __result_of_memobj;
2823
2824 template<typename _Res, typename _Class, typename _Arg>
2825 struct __result_of_memobj<_Res _Class::*, _Arg>
2826 {
2827 using _Argval = __remove_cvref_t<_Arg>;
2828 using _MemPtr = _Res _Class::*;
2829 using type = typename __conditional_t<__or_<is_same<_Argval, _Class>,
2830 is_base_of<_Class, _Argval>>::value,
2831 __result_of_memobj_ref<_MemPtr, _Arg>,
2832 __result_of_memobj_deref<_MemPtr, _Arg>
2833 >::type;
2834 };
2835
2836 template<typename _MemPtr, typename _Arg, typename... _Args>
2837 struct __result_of_memfun;
2838
2839 template<typename _Res, typename _Class, typename _Arg, typename... _Args>
2840 struct __result_of_memfun<_Res _Class::*, _Arg, _Args...>
2841 {
2842 using _Argval = typename remove_reference<_Arg>::type;
2843 using _MemPtr = _Res _Class::*;
2844 using type = typename __conditional_t<is_base_of<_Class, _Argval>::value,
2845 __result_of_memfun_ref<_MemPtr, _Arg, _Args...>,
2846 __result_of_memfun_deref<_MemPtr, _Arg, _Args...>
2847 >::type;
2848 };
2849
2850 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2851 // 2219. INVOKE-ing a pointer to member with a reference_wrapper
2852 // as the object expression
2853
2854 // Used by result_of, invoke etc. to unwrap a reference_wrapper.
2855 template<typename _Tp, typename _Up = __remove_cvref_t<_Tp>>
2856 struct __inv_unwrap
2857 {
2858 using type = _Tp;
2859 };
2860
2861 template<typename _Tp, typename _Up>
2862 struct __inv_unwrap<_Tp, reference_wrapper<_Up>>
2863 {
2864 using type = _Up&;
2865 };
2866
2867 template<bool, bool, typename _Functor, typename... _ArgTypes>
2868 struct __result_of_impl
2869 {
2870 using type = __failure_type;
2871 };
2872
2873 template<typename _MemPtr, typename _Arg>
2874 struct __result_of_impl<true, false, _MemPtr, _Arg>
2875 : public __result_of_memobj<__decay_t<_MemPtr>,
2876 typename __inv_unwrap<_Arg>::type>
2877 { };
2878
2879 template<typename _MemPtr, typename _Arg, typename... _Args>
2880 struct __result_of_impl<false, true, _MemPtr, _Arg, _Args...>
2881 : public __result_of_memfun<__decay_t<_MemPtr>,
2882 typename __inv_unwrap<_Arg>::type, _Args...>
2883 { };
2884
2885 // [func.require] paragraph 1 bullet 5:
2886 struct __result_of_other_impl
2887 {
2888 template<typename _Fn, typename... _Args>
2889 static __result_of_success<decltype(
2890 std::declval<_Fn>()(std::declval<_Args>()...)
2891 ), __invoke_other> _S_test(int);
2892
2893 template<typename...>
2894 static __failure_type _S_test(...);
2895 };
2896
2897 template<typename _Functor, typename... _ArgTypes>
2898 struct __result_of_impl<false, false, _Functor, _ArgTypes...>
2899 : private __result_of_other_impl
2900 {
2901 using type = decltype(_S_test<_Functor, _ArgTypes...>(0));
2902 };
2903
2904 // __invoke_result (std::invoke_result for C++11)
2905 template<typename _Functor, typename... _ArgTypes>
2906 struct __invoke_result
2907 : public __result_of_impl<
2908 is_member_object_pointer<
2909 typename remove_reference<_Functor>::type
2910 >::value,
2911 is_member_function_pointer<
2912 typename remove_reference<_Functor>::type
2913 >::value,
2914 _Functor, _ArgTypes...
2915 >::type
2916 { };
2917
2918 // __invoke_result_t (std::invoke_result_t for C++11)
2919 template<typename _Fn, typename... _Args>
2920 using __invoke_result_t = typename __invoke_result<_Fn, _Args...>::type;
2921 /// @endcond
2922
2923 template<typename _Functor, typename... _ArgTypes>
2924 struct result_of<_Functor(_ArgTypes...)>
2925 : public __invoke_result<_Functor, _ArgTypes...>
2926 { } _GLIBCXX17_DEPRECATED_SUGGEST("std::invoke_result");
2927
2928#if __cplusplus >= 201402L
2929#pragma GCC diagnostic push
2930#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
2931 /// Alias template for aligned_storage
2932 template<size_t _Len,
2933 size_t _Align = __aligned_storage_default_alignment(_Len)>
2934 using aligned_storage_t _GLIBCXX23_DEPRECATED = typename aligned_storage<_Len, _Align>::type;
2935
2936 template <size_t _Len, typename... _Types>
2937 using aligned_union_t _GLIBCXX23_DEPRECATED = typename aligned_union<_Len, _Types...>::type;
2938#pragma GCC diagnostic pop
2939
2940 /// Alias template for decay
2941 template<typename _Tp>
2942 using decay_t = typename decay<_Tp>::type;
2943
2944 /// Alias template for enable_if
2945 template<bool _Cond, typename _Tp = void>
2946 using enable_if_t = typename enable_if<_Cond, _Tp>::type;
2947
2948 /// Alias template for conditional
2949 template<bool _Cond, typename _Iftrue, typename _Iffalse>
2950 using conditional_t = typename conditional<_Cond, _Iftrue, _Iffalse>::type;
2951
2952 /// Alias template for common_type
2953 template<typename... _Tp>
2954 using common_type_t = typename common_type<_Tp...>::type;
2955
2956 /// Alias template for underlying_type
2957 template<typename _Tp>
2958 using underlying_type_t = typename underlying_type<_Tp>::type;
2959
2960 /// Alias template for result_of
2961 template<typename _Tp>
2962 using result_of_t = typename result_of<_Tp>::type;
2963#endif // C++14
2964
2965#ifdef __cpp_lib_void_t // C++ >= 17 || GNU++ >= 11
2966 /// A metafunction that always yields void, used for detecting valid types.
2967 template<typename...> using void_t = void;
2968#endif
2969
2970 /// @cond undocumented
2971
2972 // Detection idiom.
2973 // Detect whether _Op<_Args...> is a valid type, use default _Def if not.
2974
2975#if __cpp_concepts
2976 // Implementation of the detection idiom (negative case).
2977 template<typename _Def, template<typename...> class _Op, typename... _Args>
2978 struct __detected_or
2979 {
2980 using type = _Def;
2981 using __is_detected = false_type;
2982 };
2983
2984 // Implementation of the detection idiom (positive case).
2985 template<typename _Def, template<typename...> class _Op, typename... _Args>
2986 requires requires { typename _Op<_Args...>; }
2987 struct __detected_or<_Def, _Op, _Args...>
2988 {
2989 using type = _Op<_Args...>;
2990 using __is_detected = true_type;
2991 };
2992#else
2993 /// Implementation of the detection idiom (negative case).
2994 template<typename _Default, typename _AlwaysVoid,
2995 template<typename...> class _Op, typename... _Args>
2996 struct __detector
2997 {
2998 using type = _Default;
2999 using __is_detected = false_type;
3000 };
3001
3002 /// Implementation of the detection idiom (positive case).
3003 template<typename _Default, template<typename...> class _Op,
3004 typename... _Args>
3005 struct __detector<_Default, __void_t<_Op<_Args...>>, _Op, _Args...>
3006 {
3007 using type = _Op<_Args...>;
3008 using __is_detected = true_type;
3009 };
3010
3011 template<typename _Default, template<typename...> class _Op,
3012 typename... _Args>
3013 using __detected_or = __detector<_Default, void, _Op, _Args...>;
3014#endif // __cpp_concepts
3015
3016 // _Op<_Args...> if that is a valid type, otherwise _Default.
3017 template<typename _Default, template<typename...> class _Op,
3018 typename... _Args>
3019 using __detected_or_t
3020 = typename __detected_or<_Default, _Op, _Args...>::type;
3021
3022 /**
3023 * Use SFINAE to determine if the type _Tp has a publicly-accessible
3024 * member type _NTYPE.
3025 */
3026#define _GLIBCXX_HAS_NESTED_TYPE(_NTYPE) \
3027 template<typename _Tp, typename = __void_t<>> \
3028 struct __has_##_NTYPE \
3029 : false_type \
3030 { }; \
3031 template<typename _Tp> \
3032 struct __has_##_NTYPE<_Tp, __void_t<typename _Tp::_NTYPE>> \
3033 : true_type \
3034 { };
3035
3036 template <typename _Tp>
3037 struct __is_swappable;
3038
3039 template <typename _Tp>
3040 struct __is_nothrow_swappable;
3041
3042 template<typename>
3043 struct __is_tuple_like_impl : false_type
3044 { };
3045
3046 // Internal type trait that allows us to sfinae-protect tuple_cat.
3047 template<typename _Tp>
3048 struct __is_tuple_like
3049 : public __is_tuple_like_impl<__remove_cvref_t<_Tp>>::type
3050 { };
3051 /// @endcond
3052
3053 template<typename _Tp>
3054 _GLIBCXX20_CONSTEXPR
3055 inline
3056 _Require<__not_<__is_tuple_like<_Tp>>,
3057 is_move_constructible<_Tp>,
3058 is_move_assignable<_Tp>>
3059 swap(_Tp&, _Tp&)
3060 noexcept(__and_<is_nothrow_move_constructible<_Tp>,
3061 is_nothrow_move_assignable<_Tp>>::value);
3062
3063 template<typename _Tp, size_t _Nm>
3064 _GLIBCXX20_CONSTEXPR
3065 inline
3066 __enable_if_t<__is_swappable<_Tp>::value>
3067 swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
3068 noexcept(__is_nothrow_swappable<_Tp>::value);
3069
3070 /// @cond undocumented
3071 namespace __swappable_details {
3072 using std::swap;
3073
3074 struct __do_is_swappable_impl
3075 {
3076 template<typename _Tp, typename
3077 = decltype(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))>
3078 static true_type __test(int);
3079
3080 template<typename>
3081 static false_type __test(...);
3082 };
3083
3084 struct __do_is_nothrow_swappable_impl
3085 {
3086 template<typename _Tp>
3087 static __bool_constant<
3088 noexcept(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))
3089 > __test(int);
3090
3091 template<typename>
3092 static false_type __test(...);
3093 };
3094
3095 } // namespace __swappable_details
3096
3097 template<typename _Tp>
3098 struct __is_swappable_impl
3099 : public __swappable_details::__do_is_swappable_impl
3100 {
3101 using type = decltype(__test<_Tp>(0));
3102 };
3103
3104 template<typename _Tp>
3105 struct __is_nothrow_swappable_impl
3106 : public __swappable_details::__do_is_nothrow_swappable_impl
3107 {
3108 using type = decltype(__test<_Tp>(0));
3109 };
3110
3111 template<typename _Tp>
3112 struct __is_swappable
3113 : public __is_swappable_impl<_Tp>::type
3114 { };
3115
3116 template<typename _Tp>
3117 struct __is_nothrow_swappable
3118 : public __is_nothrow_swappable_impl<_Tp>::type
3119 { };
3120 /// @endcond
3121
3122#ifdef __cpp_lib_is_swappable // C++ >= 17 || GNU++ >= 11
3123 /// Metafunctions used for detecting swappable types: p0185r1
3124
3125 /// is_swappable
3126 template<typename _Tp>
3127 struct is_swappable
3128 : public __is_swappable_impl<_Tp>::type
3129 {
3130 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
3131 "template argument must be a complete class or an unbounded array");
3132 };
3133
3134 /// is_nothrow_swappable
3135 template<typename _Tp>
3136 struct is_nothrow_swappable
3137 : public __is_nothrow_swappable_impl<_Tp>::type
3138 {
3139 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
3140 "template argument must be a complete class or an unbounded array");
3141 };
3142
3143#if __cplusplus >= 201402L
3144 /// is_swappable_v
3145 template<typename _Tp>
3146 _GLIBCXX17_INLINE constexpr bool is_swappable_v =
3147 is_swappable<_Tp>::value;
3148
3149 /// is_nothrow_swappable_v
3150 template<typename _Tp>
3151 _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_v =
3152 is_nothrow_swappable<_Tp>::value;
3153#endif // __cplusplus >= 201402L
3154
3155 /// @cond undocumented
3156 namespace __swappable_with_details {
3157 using std::swap;
3158
3159 struct __do_is_swappable_with_impl
3160 {
3161 template<typename _Tp, typename _Up, typename
3162 = decltype(swap(std::declval<_Tp>(), std::declval<_Up>())),
3163 typename
3164 = decltype(swap(std::declval<_Up>(), std::declval<_Tp>()))>
3165 static true_type __test(int);
3166
3167 template<typename, typename>
3168 static false_type __test(...);
3169 };
3170
3171 struct __do_is_nothrow_swappable_with_impl
3172 {
3173 template<typename _Tp, typename _Up>
3174 static __bool_constant<
3175 noexcept(swap(std::declval<_Tp>(), std::declval<_Up>()))
3176 &&
3177 noexcept(swap(std::declval<_Up>(), std::declval<_Tp>()))
3178 > __test(int);
3179
3180 template<typename, typename>
3181 static false_type __test(...);
3182 };
3183
3184 } // namespace __swappable_with_details
3185
3186 template<typename _Tp, typename _Up>
3187 struct __is_swappable_with_impl
3188 : public __swappable_with_details::__do_is_swappable_with_impl
3189 {
3190 using type = decltype(__test<_Tp, _Up>(0));
3191 };
3192
3193 // Optimization for the homogenous lvalue case, not required:
3194 template<typename _Tp>
3195 struct __is_swappable_with_impl<_Tp&, _Tp&>
3196 : public __swappable_details::__do_is_swappable_impl
3197 {
3198 using type = decltype(__test<_Tp&>(0));
3199 };
3200
3201 template<typename _Tp, typename _Up>
3202 struct __is_nothrow_swappable_with_impl
3203 : public __swappable_with_details::__do_is_nothrow_swappable_with_impl
3204 {
3205 using type = decltype(__test<_Tp, _Up>(0));
3206 };
3207
3208 // Optimization for the homogenous lvalue case, not required:
3209 template<typename _Tp>
3210 struct __is_nothrow_swappable_with_impl<_Tp&, _Tp&>
3211 : public __swappable_details::__do_is_nothrow_swappable_impl
3212 {
3213 using type = decltype(__test<_Tp&>(0));
3214 };
3215 /// @endcond
3216
3217 /// is_swappable_with
3218 template<typename _Tp, typename _Up>
3219 struct is_swappable_with
3220 : public __is_swappable_with_impl<_Tp, _Up>::type
3221 {
3222 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
3223 "first template argument must be a complete class or an unbounded array");
3224 static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
3225 "second template argument must be a complete class or an unbounded array");
3226 };
3227
3228 /// is_nothrow_swappable_with
3229 template<typename _Tp, typename _Up>
3230 struct is_nothrow_swappable_with
3231 : public __is_nothrow_swappable_with_impl<_Tp, _Up>::type
3232 {
3233 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
3234 "first template argument must be a complete class or an unbounded array");
3235 static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
3236 "second template argument must be a complete class or an unbounded array");
3237 };
3238
3239#if __cplusplus >= 201402L
3240 /// is_swappable_with_v
3241 template<typename _Tp, typename _Up>
3242 _GLIBCXX17_INLINE constexpr bool is_swappable_with_v =
3243 is_swappable_with<_Tp, _Up>::value;
3244
3245 /// is_nothrow_swappable_with_v
3246 template<typename _Tp, typename _Up>
3247 _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_with_v =
3248 is_nothrow_swappable_with<_Tp, _Up>::value;
3249#endif // __cplusplus >= 201402L
3250
3251#endif // __cpp_lib_is_swappable
3252
3253 /// @cond undocumented
3254
3255 // __is_invocable (std::is_invocable for C++11)
3256
3257 // The primary template is used for invalid INVOKE expressions.
3258 template<typename _Result, typename _Ret,
3259 bool = is_void<_Ret>::value, typename = void>
3260 struct __is_invocable_impl
3261 : false_type
3262 {
3263 using __nothrow_conv = false_type; // For is_nothrow_invocable_r
3264 };
3265
3266 // Used for valid INVOKE and INVOKE<void> expressions.
3267 template<typename _Result, typename _Ret>
3268 struct __is_invocable_impl<_Result, _Ret,
3269 /* is_void<_Ret> = */ true,
3270 __void_t<typename _Result::type>>
3271 : true_type
3272 {
3273 using __nothrow_conv = true_type; // For is_nothrow_invocable_r
3274 };
3275
3276#pragma GCC diagnostic push
3277#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
3278 // Used for INVOKE<R> expressions to check the implicit conversion to R.
3279 template<typename _Result, typename _Ret>
3280 struct __is_invocable_impl<_Result, _Ret,
3281 /* is_void<_Ret> = */ false,
3282 __void_t<typename _Result::type>>
3283 {
3284 private:
3285 // The type of the INVOKE expression.
3286 using _Res_t = typename _Result::type;
3287
3288 // Unlike declval, this doesn't add_rvalue_reference, so it respects
3289 // guaranteed copy elision.
3290 static _Res_t _S_get() noexcept;
3291
3292 // Used to check if _Res_t can implicitly convert to _Tp.
3293 template<typename _Tp>
3294 static void _S_conv(__type_identity_t<_Tp>) noexcept;
3295
3296 // This overload is viable if INVOKE(f, args...) can convert to _Tp.
3297 template<typename _Tp,
3298 bool _Nothrow = noexcept(_S_conv<_Tp>(_S_get())),
3299 typename = decltype(_S_conv<_Tp>(_S_get())),
3300#if __has_builtin(__reference_converts_from_temporary)
3301 bool _Dangle = __reference_converts_from_temporary(_Tp, _Res_t)
3302#else
3303 bool _Dangle = false
3304#endif
3305 >
3306 static __bool_constant<_Nothrow && !_Dangle>
3307 _S_test(int);
3308
3309 template<typename _Tp, bool = false>
3310 static false_type
3311 _S_test(...);
3312
3313 public:
3314 // For is_invocable_r
3315 using type = decltype(_S_test<_Ret, /* Nothrow = */ true>(1));
3316
3317 // For is_nothrow_invocable_r
3318 using __nothrow_conv = decltype(_S_test<_Ret>(1));
3319 };
3320#pragma GCC diagnostic pop
3321
3322 template<typename _Fn, typename... _ArgTypes>
3323 struct __is_invocable
3324#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_invocable)
3325 : __bool_constant<__is_invocable(_Fn, _ArgTypes...)>
3326#else
3327 : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
3328#endif
3329 { };
3330
3331 template<typename _Fn, typename _Tp, typename... _Args>
3332 constexpr bool __call_is_nt(__invoke_memfun_ref)
3333 {
3334 using _Up = typename __inv_unwrap<_Tp>::type;
3335 return noexcept((std::declval<_Up>().*std::declval<_Fn>())(
3336 std::declval<_Args>()...));
3337 }
3338
3339 template<typename _Fn, typename _Tp, typename... _Args>
3340 constexpr bool __call_is_nt(__invoke_memfun_deref)
3341 {
3342 return noexcept(((*std::declval<_Tp>()).*std::declval<_Fn>())(
3343 std::declval<_Args>()...));
3344 }
3345
3346 template<typename _Fn, typename _Tp>
3347 constexpr bool __call_is_nt(__invoke_memobj_ref)
3348 {
3349 using _Up = typename __inv_unwrap<_Tp>::type;
3350 return noexcept(std::declval<_Up>().*std::declval<_Fn>());
3351 }
3352
3353 template<typename _Fn, typename _Tp>
3354 constexpr bool __call_is_nt(__invoke_memobj_deref)
3355 {
3356 return noexcept((*std::declval<_Tp>()).*std::declval<_Fn>());
3357 }
3358
3359 template<typename _Fn, typename... _Args>
3360 constexpr bool __call_is_nt(__invoke_other)
3361 {
3362 return noexcept(std::declval<_Fn>()(std::declval<_Args>()...));
3363 }
3364
3365 template<typename _Result, typename _Fn, typename... _Args>
3366 struct __call_is_nothrow
3367 : __bool_constant<
3368 std::__call_is_nt<_Fn, _Args...>(typename _Result::__invoke_type{})
3369 >
3370 { };
3371
3372 template<typename _Fn, typename... _Args>
3373 using __call_is_nothrow_
3374 = __call_is_nothrow<__invoke_result<_Fn, _Args...>, _Fn, _Args...>;
3375
3376 // __is_nothrow_invocable (std::is_nothrow_invocable for C++11)
3377 template<typename _Fn, typename... _Args>
3378 struct __is_nothrow_invocable
3379#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_invocable)
3380 : __bool_constant<__is_nothrow_invocable(_Fn, _Args...)>
3381#else
3382 : __and_<__is_invocable<_Fn, _Args...>,
3383 __call_is_nothrow_<_Fn, _Args...>>::type
3384#endif
3385 { };
3386
3387#pragma GCC diagnostic push
3388#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
3389 struct __nonesuchbase {};
3390 struct __nonesuch : private __nonesuchbase {
3391 ~__nonesuch() = delete;
3392 __nonesuch(__nonesuch const&) = delete;
3393 void operator=(__nonesuch const&) = delete;
3394 };
3395#pragma GCC diagnostic pop
3396 /// @endcond
3397
3398#ifdef __cpp_lib_is_invocable // C++ >= 17
3399 /// std::invoke_result
3400 template<typename _Functor, typename... _ArgTypes>
3401 struct invoke_result
3402 : public __invoke_result<_Functor, _ArgTypes...>
3403 {
3404 static_assert(std::__is_complete_or_unbounded(__type_identity<_Functor>{}),
3405 "_Functor must be a complete class or an unbounded array");
3406 static_assert((std::__is_complete_or_unbounded(
3407 __type_identity<_ArgTypes>{}) && ...),
3408 "each argument type must be a complete class or an unbounded array");
3409 };
3410
3411 /// std::invoke_result_t
3412 template<typename _Fn, typename... _Args>
3413 using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
3414
3415 /// std::is_invocable
3416 template<typename _Fn, typename... _ArgTypes>
3417 struct is_invocable
3418#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_invocable)
3419 : public __bool_constant<__is_invocable(_Fn, _ArgTypes...)>
3420#else
3421 : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
3422#endif
3423 {
3424 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3425 "_Fn must be a complete class or an unbounded array");
3426 static_assert((std::__is_complete_or_unbounded(
3427 __type_identity<_ArgTypes>{}) && ...),
3428 "each argument type must be a complete class or an unbounded array");
3429 };
3430
3431 /// std::is_invocable_r
3432 template<typename _Ret, typename _Fn, typename... _ArgTypes>
3433 struct is_invocable_r
3434 : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>::type
3435 {
3436 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3437 "_Fn must be a complete class or an unbounded array");
3438 static_assert((std::__is_complete_or_unbounded(
3439 __type_identity<_ArgTypes>{}) && ...),
3440 "each argument type must be a complete class or an unbounded array");
3441 static_assert(std::__is_complete_or_unbounded(__type_identity<_Ret>{}),
3442 "_Ret must be a complete class or an unbounded array");
3443 };
3444
3445 /// std::is_nothrow_invocable
3446 template<typename _Fn, typename... _ArgTypes>
3447 struct is_nothrow_invocable
3448#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_invocable)
3449 : public __bool_constant<__is_nothrow_invocable(_Fn, _ArgTypes...)>
3450#else
3451 : __and_<__is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>,
3452 __call_is_nothrow_<_Fn, _ArgTypes...>>::type
3453#endif
3454 {
3455 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3456 "_Fn must be a complete class or an unbounded array");
3457 static_assert((std::__is_complete_or_unbounded(
3458 __type_identity<_ArgTypes>{}) && ...),
3459 "each argument type must be a complete class or an unbounded array");
3460 };
3461
3462 /// @cond undocumented
3463 // This checks that the INVOKE<R> expression is well-formed and that the
3464 // conversion to R does not throw. It does *not* check whether the INVOKE
3465 // expression itself can throw. That is done by __call_is_nothrow_ instead.
3466 template<typename _Result, typename _Ret>
3467 using __is_nt_invocable_impl
3468 = typename __is_invocable_impl<_Result, _Ret>::__nothrow_conv;
3469 /// @endcond
3470
3471 /// std::is_nothrow_invocable_r
3472 template<typename _Ret, typename _Fn, typename... _ArgTypes>
3473 struct is_nothrow_invocable_r
3474 : __and_<__is_nt_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>,
3475 __call_is_nothrow_<_Fn, _ArgTypes...>>::type
3476 {
3477 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3478 "_Fn must be a complete class or an unbounded array");
3479 static_assert((std::__is_complete_or_unbounded(
3480 __type_identity<_ArgTypes>{}) && ...),
3481 "each argument type must be a complete class or an unbounded array");
3482 static_assert(std::__is_complete_or_unbounded(__type_identity<_Ret>{}),
3483 "_Ret must be a complete class or an unbounded array");
3484 };
3485#endif // __cpp_lib_is_invocable
3486
3487#if __cpp_lib_type_trait_variable_templates // C++ >= 17
3488 /**
3489 * @defgroup variable_templates Variable templates for type traits
3490 * @ingroup metaprogramming
3491 *
3492 * Each variable `is_xxx_v<T>` is a boolean constant with the same value
3493 * as the `value` member of the corresponding type trait `is_xxx<T>`.
3494 *
3495 * @since C++17 unless noted otherwise.
3496 */
3497
3498 /**
3499 * @{
3500 * @ingroup variable_templates
3501 */
3502template <typename _Tp>
3503 inline constexpr bool is_void_v = is_void<_Tp>::value;
3504template <typename _Tp>
3505 inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
3506template <typename _Tp>
3507 inline constexpr bool is_integral_v = is_integral<_Tp>::value;
3508template <typename _Tp>
3509 inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
3510
3511#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_array)
3512template <typename _Tp>
3513 inline constexpr bool is_array_v = __is_array(_Tp);
3514#else
3515template <typename _Tp>
3516 inline constexpr bool is_array_v = false;
3517template <typename _Tp>
3518 inline constexpr bool is_array_v<_Tp[]> = true;
3519template <typename _Tp, size_t _Num>
3520 inline constexpr bool is_array_v<_Tp[_Num]> = true;
3521#endif
3522
3523#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
3524template <typename _Tp>
3525 inline constexpr bool is_pointer_v = __is_pointer(_Tp);
3526#else
3527template <typename _Tp>
3528 inline constexpr bool is_pointer_v = false;
3529template <typename _Tp>
3530 inline constexpr bool is_pointer_v<_Tp*> = true;
3531template <typename _Tp>
3532 inline constexpr bool is_pointer_v<_Tp* const> = true;
3533template <typename _Tp>
3534 inline constexpr bool is_pointer_v<_Tp* volatile> = true;
3535template <typename _Tp>
3536 inline constexpr bool is_pointer_v<_Tp* const volatile> = true;
3537#endif
3538
3539template <typename _Tp>
3540 inline constexpr bool is_lvalue_reference_v = false;
3541template <typename _Tp>
3542 inline constexpr bool is_lvalue_reference_v<_Tp&> = true;
3543template <typename _Tp>
3544 inline constexpr bool is_rvalue_reference_v = false;
3545template <typename _Tp>
3546 inline constexpr bool is_rvalue_reference_v<_Tp&&> = true;
3547
3548#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_object_pointer)
3549template <typename _Tp>
3550 inline constexpr bool is_member_object_pointer_v =
3551 __is_member_object_pointer(_Tp);
3552#else
3553template <typename _Tp>
3554 inline constexpr bool is_member_object_pointer_v =
3555 is_member_object_pointer<_Tp>::value;
3556#endif
3557
3558#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_function_pointer)
3559template <typename _Tp>
3560 inline constexpr bool is_member_function_pointer_v =
3561 __is_member_function_pointer(_Tp);
3562#else
3563template <typename _Tp>
3564 inline constexpr bool is_member_function_pointer_v =
3565 is_member_function_pointer<_Tp>::value;
3566#endif
3567
3568#if __cpp_impl_reflection >= 202506L // C++ >= 26
3569template <typename _Tp>
3570 inline constexpr bool is_reflection_v = false;
3571template <>
3572 inline constexpr bool is_reflection_v<decltype(^^int)> = true;
3573template <>
3574 inline constexpr bool is_reflection_v<const decltype(^^int)> = true;
3575template <>
3576 inline constexpr bool is_reflection_v<volatile decltype(^^int)> = true;
3577template <>
3578 inline constexpr bool is_reflection_v<const volatile decltype(^^int)> = true;
3579#endif
3580
3581template <typename _Tp>
3582 inline constexpr bool is_enum_v = __is_enum(_Tp);
3583template <typename _Tp>
3584 inline constexpr bool is_union_v = __is_union(_Tp);
3585template <typename _Tp>
3586 inline constexpr bool is_class_v = __is_class(_Tp);
3587// is_function_v is defined below, after is_const_v.
3588
3589#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_reference)
3590template <typename _Tp>
3591 inline constexpr bool is_reference_v = __is_reference(_Tp);
3592#else
3593template <typename _Tp>
3594 inline constexpr bool is_reference_v = false;
3595template <typename _Tp>
3596 inline constexpr bool is_reference_v<_Tp&> = true;
3597template <typename _Tp>
3598 inline constexpr bool is_reference_v<_Tp&&> = true;
3599#endif
3600
3601template <typename _Tp>
3602 inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
3603template <typename _Tp>
3604 inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
3605
3606#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_object)
3607template <typename _Tp>
3608 inline constexpr bool is_object_v = __is_object(_Tp);
3609#else
3610template <typename _Tp>
3611 inline constexpr bool is_object_v = is_object<_Tp>::value;
3612#endif
3613
3614template <typename _Tp>
3615 inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
3616template <typename _Tp>
3617 inline constexpr bool is_compound_v = !is_fundamental_v<_Tp>;
3618
3619#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
3620template <typename _Tp>
3621 inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
3622#else
3623template <typename _Tp>
3624 inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
3625#endif
3626
3627#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
3628template <typename _Tp>
3629 inline constexpr bool is_const_v = __is_const(_Tp);
3630#else
3631template <typename _Tp>
3632 inline constexpr bool is_const_v = false;
3633template <typename _Tp>
3634 inline constexpr bool is_const_v<const _Tp> = true;
3635#endif
3636
3637#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_function)
3638template <typename _Tp>
3639 inline constexpr bool is_function_v = __is_function(_Tp);
3640#else
3641template <typename _Tp>
3642 inline constexpr bool is_function_v = !is_const_v<const _Tp>;
3643template <typename _Tp>
3644 inline constexpr bool is_function_v<_Tp&> = false;
3645template <typename _Tp>
3646 inline constexpr bool is_function_v<_Tp&&> = false;
3647#endif
3648
3649#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_volatile)
3650template <typename _Tp>
3651 inline constexpr bool is_volatile_v = __is_volatile(_Tp);
3652#else
3653template <typename _Tp>
3654 inline constexpr bool is_volatile_v = false;
3655template <typename _Tp>
3656 inline constexpr bool is_volatile_v<volatile _Tp> = true;
3657#endif
3658
3659template <typename _Tp>
3660 _GLIBCXX26_DEPRECATED_SUGGEST("is_trivially_default_constructible_v && is_trivially_copyable_v")
3661 inline constexpr bool is_trivial_v = __is_trivial(_Tp);
3662template <typename _Tp>
3663 inline constexpr bool is_trivially_copyable_v = __is_trivially_copyable(_Tp);
3664template <typename _Tp>
3665 inline constexpr bool is_standard_layout_v = __is_standard_layout(_Tp);
3666template <typename _Tp>
3667 _GLIBCXX20_DEPRECATED_SUGGEST("is_standard_layout_v && is_trivial_v")
3668 inline constexpr bool is_pod_v = __is_pod(_Tp);
3669template <typename _Tp>
3670 _GLIBCXX17_DEPRECATED
3671 inline constexpr bool is_literal_type_v = __is_literal_type(_Tp);
3672template <typename _Tp>
3673 inline constexpr bool is_empty_v = __is_empty(_Tp);
3674template <typename _Tp>
3675 inline constexpr bool is_polymorphic_v = __is_polymorphic(_Tp);
3676template <typename _Tp>
3677 inline constexpr bool is_abstract_v = __is_abstract(_Tp);
3678template <typename _Tp>
3679 inline constexpr bool is_final_v = __is_final(_Tp);
3680
3681template <typename _Tp>
3682 inline constexpr bool is_signed_v = is_signed<_Tp>::value;
3683template <typename _Tp>
3684 inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
3685
3686template <typename _Tp, typename... _Args>
3687 inline constexpr bool is_constructible_v = __is_constructible(_Tp, _Args...);
3688template <typename _Tp>
3689 inline constexpr bool is_default_constructible_v = __is_constructible(_Tp);
3690template <typename _Tp>
3691 inline constexpr bool is_copy_constructible_v
3692 = __is_constructible(_Tp, __add_lval_ref_t<const _Tp>);
3693template <typename _Tp>
3694 inline constexpr bool is_move_constructible_v
3695 = __is_constructible(_Tp, __add_rval_ref_t<_Tp>);
3696
3697template <typename _Tp, typename _Up>
3698 inline constexpr bool is_assignable_v = __is_assignable(_Tp, _Up);
3699template <typename _Tp>
3700 inline constexpr bool is_copy_assignable_v
3701 = __is_assignable(__add_lval_ref_t<_Tp>, __add_lval_ref_t<const _Tp>);
3702template <typename _Tp>
3703 inline constexpr bool is_move_assignable_v
3704 = __is_assignable(__add_lval_ref_t<_Tp>, __add_rval_ref_t<_Tp>);
3705
3706#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_destructible)
3707template <typename _Tp>
3708 inline constexpr bool is_destructible_v = __is_destructible(_Tp);
3709#else
3710template <typename _Tp>
3711 inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
3712#endif
3713
3714template <typename _Tp, typename... _Args>
3715 inline constexpr bool is_trivially_constructible_v
3716 = __is_trivially_constructible(_Tp, _Args...);
3717template <typename _Tp>
3718 inline constexpr bool is_trivially_default_constructible_v
3719 = __is_trivially_constructible(_Tp);
3720template <typename _Tp>
3721 inline constexpr bool is_trivially_copy_constructible_v
3722 = __is_trivially_constructible(_Tp, __add_lval_ref_t<const _Tp>);
3723template <typename _Tp>
3724 inline constexpr bool is_trivially_move_constructible_v
3725 = __is_trivially_constructible(_Tp, __add_rval_ref_t<_Tp>);
3726
3727template <typename _Tp, typename _Up>
3728 inline constexpr bool is_trivially_assignable_v
3729 = __is_trivially_assignable(_Tp, _Up);
3730template <typename _Tp>
3731 inline constexpr bool is_trivially_copy_assignable_v
3732 = __is_trivially_assignable(__add_lval_ref_t<_Tp>,
3733 __add_lval_ref_t<const _Tp>);
3734template <typename _Tp>
3735 inline constexpr bool is_trivially_move_assignable_v
3736 = __is_trivially_assignable(__add_lval_ref_t<_Tp>,
3737 __add_rval_ref_t<_Tp>);
3738
3739#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_trivially_destructible)
3740template <typename _Tp>
3741 inline constexpr bool is_trivially_destructible_v
3742 = __is_trivially_destructible(_Tp);
3743#elif __cpp_concepts
3744template <typename _Tp>
3745 inline constexpr bool is_trivially_destructible_v = false;
3746
3747template <typename _Tp>
3748 requires (!is_reference_v<_Tp>) && requires (_Tp& __t) { __t.~_Tp(); }
3749 inline constexpr bool is_trivially_destructible_v<_Tp>
3750 = __has_trivial_destructor(_Tp);
3751template <typename _Tp>
3752 inline constexpr bool is_trivially_destructible_v<_Tp&> = true;
3753template <typename _Tp>
3754 inline constexpr bool is_trivially_destructible_v<_Tp&&> = true;
3755template <typename _Tp, size_t _Nm>
3756 inline constexpr bool is_trivially_destructible_v<_Tp[_Nm]>
3757 = is_trivially_destructible_v<_Tp>;
3758#else
3759template <typename _Tp>
3760 inline constexpr bool is_trivially_destructible_v =
3761 is_trivially_destructible<_Tp>::value;
3762#endif
3763
3764template <typename _Tp, typename... _Args>
3765 inline constexpr bool is_nothrow_constructible_v
3766 = __is_nothrow_constructible(_Tp, _Args...);
3767template <typename _Tp>
3768 inline constexpr bool is_nothrow_default_constructible_v
3769 = __is_nothrow_constructible(_Tp);
3770template <typename _Tp>
3771 inline constexpr bool is_nothrow_copy_constructible_v
3772 = __is_nothrow_constructible(_Tp, __add_lval_ref_t<const _Tp>);
3773template <typename _Tp>
3774 inline constexpr bool is_nothrow_move_constructible_v
3775 = __is_nothrow_constructible(_Tp, __add_rval_ref_t<_Tp>);
3776
3777template <typename _Tp, typename _Up>
3778 inline constexpr bool is_nothrow_assignable_v
3779 = __is_nothrow_assignable(_Tp, _Up);
3780template <typename _Tp>
3781 inline constexpr bool is_nothrow_copy_assignable_v
3782 = __is_nothrow_assignable(__add_lval_ref_t<_Tp>,
3783 __add_lval_ref_t<const _Tp>);
3784template <typename _Tp>
3785 inline constexpr bool is_nothrow_move_assignable_v
3786 = __is_nothrow_assignable(__add_lval_ref_t<_Tp>, __add_rval_ref_t<_Tp>);
3787
3788#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_destructible)
3789template <typename _Tp>
3790 inline constexpr bool is_nothrow_destructible_v
3791 = __is_nothrow_destructible(_Tp);
3792#else
3793template <typename _Tp>
3794 inline constexpr bool is_nothrow_destructible_v =
3795 is_nothrow_destructible<_Tp>::value;
3796#endif
3797
3798template <typename _Tp>
3799 inline constexpr bool has_virtual_destructor_v
3800 = __has_virtual_destructor(_Tp);
3801
3802template <typename _Tp>
3803 inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
3804
3805#if _GLIBCXX_USE_BUILTIN_TRAIT(__array_rank) \
3806 && (!defined(__clang__) || __clang_major__ >= 20) // PR118559
3807template <typename _Tp>
3808 inline constexpr size_t rank_v = __array_rank(_Tp);
3809#else
3810template <typename _Tp>
3811 inline constexpr size_t rank_v = 0;
3812template <typename _Tp, size_t _Size>
3813 inline constexpr size_t rank_v<_Tp[_Size]> = 1 + rank_v<_Tp>;
3814template <typename _Tp>
3815 inline constexpr size_t rank_v<_Tp[]> = 1 + rank_v<_Tp>;
3816#endif
3817
3818template <typename _Tp, unsigned _Idx = 0>
3819 inline constexpr size_t extent_v = 0;
3820template <typename _Tp, size_t _Size>
3821 inline constexpr size_t extent_v<_Tp[_Size], 0> = _Size;
3822template <typename _Tp, unsigned _Idx, size_t _Size>
3823 inline constexpr size_t extent_v<_Tp[_Size], _Idx> = extent_v<_Tp, _Idx - 1>;
3824template <typename _Tp>
3825 inline constexpr size_t extent_v<_Tp[], 0> = 0;
3826template <typename _Tp, unsigned _Idx>
3827 inline constexpr size_t extent_v<_Tp[], _Idx> = extent_v<_Tp, _Idx - 1>;
3828
3829#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_same)
3830template <typename _Tp, typename _Up>
3831 inline constexpr bool is_same_v = __is_same(_Tp, _Up);
3832#else
3833template <typename _Tp, typename _Up>
3834 inline constexpr bool is_same_v = false;
3835template <typename _Tp>
3836 inline constexpr bool is_same_v<_Tp, _Tp> = true;
3837#endif
3838template <typename _Base, typename _Derived>
3839 inline constexpr bool is_base_of_v = __is_base_of(_Base, _Derived);
3840#ifdef __cpp_lib_is_virtual_base_of // C++ >= 26
3841template <typename _Base, typename _Derived>
3842 inline constexpr bool is_virtual_base_of_v = __builtin_is_virtual_base_of(_Base, _Derived);
3843#endif
3844#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_convertible)
3845template <typename _From, typename _To>
3846 inline constexpr bool is_convertible_v = __is_convertible(_From, _To);
3847#else
3848template <typename _From, typename _To>
3849 inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
3850#endif
3851template<typename _Fn, typename... _Args>
3852 inline constexpr bool is_invocable_v
3853#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_invocable)
3854 = __is_invocable(_Fn, _Args...);
3855#else
3856 = is_invocable<_Fn, _Args...>::value;
3857#endif
3858template<typename _Fn, typename... _Args>
3859 inline constexpr bool is_nothrow_invocable_v
3860#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_invocable)
3861 = __is_nothrow_invocable(_Fn, _Args...);
3862#else
3863 = is_nothrow_invocable<_Fn, _Args...>::value;
3864#endif
3865template<typename _Ret, typename _Fn, typename... _Args>
3866 inline constexpr bool is_invocable_r_v
3867 = is_invocable_r<_Ret, _Fn, _Args...>::value;
3868template<typename _Ret, typename _Fn, typename... _Args>
3869 inline constexpr bool is_nothrow_invocable_r_v
3870 = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
3871/// @}
3872#endif // __cpp_lib_type_trait_variable_templates
3873
3874#ifdef __cpp_lib_has_unique_object_representations // C++ >= 17 && HAS_UNIQ_OBJ_REP
3875 /// has_unique_object_representations
3876 /// @since C++17
3877 template<typename _Tp>
3878 struct has_unique_object_representations
3879 : bool_constant<__has_unique_object_representations(
3880 remove_cv_t<remove_all_extents_t<_Tp>>
3881 )>
3882 {
3883 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
3884 "template argument must be a complete class or an unbounded array");
3885 };
3886
3887# if __cpp_lib_type_trait_variable_templates // C++ >= 17
3888 /// @ingroup variable_templates
3889 template<typename _Tp>
3890 inline constexpr bool has_unique_object_representations_v
3891 = has_unique_object_representations<_Tp>::value;
3892# endif
3893#endif
3894
3895#ifdef __cpp_lib_is_aggregate // C++ >= 17 && builtin_is_aggregate
3896 /// is_aggregate - true if the type is an aggregate.
3897 /// @since C++17
3898 template<typename _Tp>
3899 struct is_aggregate
3900 : bool_constant<__is_aggregate(remove_cv_t<_Tp>)>
3901 { };
3902
3903# if __cpp_lib_type_trait_variable_templates // C++ >= 17
3904 /** is_aggregate_v - true if the type is an aggregate.
3905 * @ingroup variable_templates
3906 * @since C++17
3907 */
3908 template<typename _Tp>
3909 inline constexpr bool is_aggregate_v = __is_aggregate(remove_cv_t<_Tp>);
3910# endif
3911#endif
3912
3913#if __cpp_lib_is_structural >= 202603L // C++ >= 26
3914 /// is_structural - true if the type is a structural type.
3915 /// @since C++26
3916 template<typename _Tp>
3917 struct is_structural
3918 : bool_constant<__builtin_is_structural(_Tp)>
3919 { };
3920
3921 /** is_structural_v - true if the type is a structural only type.
3922 * @ingroup variable_templates
3923 * @since C++26
3924 */
3925 template<typename _Tp>
3926 inline constexpr bool is_structural_v
3927 = __builtin_is_structural(_Tp);
3928#endif
3929
3930 /** * Remove references and cv-qualifiers.
3931 * @since C++20
3932 * @{
3933 */
3934#ifdef __cpp_lib_remove_cvref // C++ >= 20
3935# if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cvref)
3936 template<typename _Tp>
3937 struct remove_cvref
3938 { using type = __remove_cvref(_Tp); };
3939# else
3940 template<typename _Tp>
3941 struct remove_cvref
3942 { using type = typename remove_cv<_Tp>::type; };
3943
3944 template<typename _Tp>
3945 struct remove_cvref<_Tp&>
3946 { using type = typename remove_cv<_Tp>::type; };
3947
3948 template<typename _Tp>
3949 struct remove_cvref<_Tp&&>
3950 { using type = typename remove_cv<_Tp>::type; };
3951# endif
3952
3953 template<typename _Tp>
3954 using remove_cvref_t = typename remove_cvref<_Tp>::type;
3955 /// @}
3956#endif // __cpp_lib_remove_cvref
3957
3958#ifdef __cpp_lib_type_identity // C++ >= 20
3959 /** * Identity metafunction.
3960 * @since C++20
3961 * @{
3962 */
3963 template<typename _Tp>
3964 struct type_identity { using type = _Tp; };
3965
3966 template<typename _Tp>
3967 using type_identity_t = typename type_identity<_Tp>::type;
3968 /// @}
3969#endif
3970
3971#ifdef __cpp_lib_unwrap_ref // C++ >= 20
3972 /** Unwrap a reference_wrapper
3973 * @since C++20
3974 * @{
3975 */
3976 template<typename _Tp>
3977 struct unwrap_reference { using type = _Tp; };
3978
3979 template<typename _Tp>
3980 struct unwrap_reference<reference_wrapper<_Tp>> { using type = _Tp&; };
3981
3982 template<typename _Tp>
3983 using unwrap_reference_t = typename unwrap_reference<_Tp>::type;
3984 /// @}
3985
3986 /** Decay type and if it's a reference_wrapper, unwrap it
3987 * @since C++20
3988 * @{
3989 */
3990 template<typename _Tp>
3991 struct unwrap_ref_decay { using type = unwrap_reference_t<decay_t<_Tp>>; };
3992
3993 template<typename _Tp>
3994 using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;
3995 /// @}
3996#endif // __cpp_lib_unwrap_ref
3997
3998#ifdef __cpp_lib_bounded_array_traits // C++ >= 20
3999 /// True for a type that is an array of known bound.
4000 /// @ingroup variable_templates
4001 /// @since C++20
4002# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_bounded_array)
4003 template<typename _Tp>
4004 inline constexpr bool is_bounded_array_v = __is_bounded_array(_Tp);
4005# else
4006 template<typename _Tp>
4007 inline constexpr bool is_bounded_array_v = false;
4008
4009 template<typename _Tp, size_t _Size>
4010 inline constexpr bool is_bounded_array_v<_Tp[_Size]> = true;
4011# endif
4012
4013 /// True for a type that is an array of unknown bound.
4014 /// @ingroup variable_templates
4015 /// @since C++20
4016# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_unbounded_array)
4017 template<typename _Tp>
4018 inline constexpr bool is_unbounded_array_v = __is_unbounded_array(_Tp);
4019# else
4020 template<typename _Tp>
4021 inline constexpr bool is_unbounded_array_v = false;
4022
4023 template<typename _Tp>
4024 inline constexpr bool is_unbounded_array_v<_Tp[]> = true;
4025# endif
4026
4027 /// True for a type that is an array of known bound.
4028 /// @since C++20
4029 template<typename _Tp>
4030 struct is_bounded_array
4031 : public bool_constant<is_bounded_array_v<_Tp>>
4032 { };
4033
4034 /// True for a type that is an array of unknown bound.
4035 /// @since C++20
4036 template<typename _Tp>
4037 struct is_unbounded_array
4038 : public bool_constant<is_unbounded_array_v<_Tp>>
4039 { };
4040#endif // __cpp_lib_bounded_array_traits
4041
4042#if __has_builtin(__is_layout_compatible) && __cplusplus >= 202002L
4043
4044 /// @since C++20
4045 template<typename _Tp, typename _Up>
4046 struct is_layout_compatible
4047 : bool_constant<__is_layout_compatible(_Tp, _Up)>
4048 { };
4049
4050 /// @ingroup variable_templates
4051 /// @since C++20
4052 template<typename _Tp, typename _Up>
4053 constexpr bool is_layout_compatible_v
4054 = __is_layout_compatible(_Tp, _Up);
4055
4056#if __has_builtin(__builtin_is_corresponding_member)
4057# ifndef __cpp_lib_is_layout_compatible
4058# error "libstdc++ bug: is_corresponding_member and is_layout_compatible are provided but their FTM is not set"
4059# endif
4060
4061 /// @since C++20
4062 template<typename _S1, typename _S2, typename _M1, typename _M2>
4063 constexpr bool
4064 is_corresponding_member(_M1 _S1::*__m1, _M2 _S2::*__m2) noexcept
4065 { return __builtin_is_corresponding_member(__m1, __m2); }
4066#endif
4067#endif
4068
4069#if __has_builtin(__is_pointer_interconvertible_base_of) \
4070 && __cplusplus >= 202002L
4071 /// True if `_Derived` is standard-layout and has a base class of type `_Base`
4072 /// @since C++20
4073 template<typename _Base, typename _Derived>
4074 struct is_pointer_interconvertible_base_of
4075 : bool_constant<__is_pointer_interconvertible_base_of(_Base, _Derived)>
4076 { };
4077
4078 /// @ingroup variable_templates
4079 /// @since C++20
4080 template<typename _Base, typename _Derived>
4081 constexpr bool is_pointer_interconvertible_base_of_v
4082 = __is_pointer_interconvertible_base_of(_Base, _Derived);
4083
4084#if __has_builtin(__builtin_is_pointer_interconvertible_with_class)
4085# ifndef __cpp_lib_is_pointer_interconvertible
4086# error "libstdc++ bug: is_pointer_interconvertible available but FTM is not set"
4087# endif
4088
4089 /// True if `__mp` points to the first member of a standard-layout type
4090 /// @returns true if `s.*__mp` is pointer-interconvertible with `s`
4091 /// @since C++20
4092 template<typename _Tp, typename _Mem>
4093 constexpr bool
4094 is_pointer_interconvertible_with_class(_Mem _Tp::*__mp) noexcept
4095 { return __builtin_is_pointer_interconvertible_with_class(__mp); }
4096#endif
4097#endif
4098
4099#ifdef __cpp_lib_is_scoped_enum // C++ >= 23
4100 /// True if the type is a scoped enumeration type.
4101 /// @since C++23
4102
4103# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_scoped_enum)
4104 template<typename _Tp>
4105 struct is_scoped_enum
4106 : bool_constant<__is_scoped_enum(_Tp)>
4107 { };
4108# else
4109 template<typename _Tp>
4110 struct is_scoped_enum
4111 : false_type
4112 { };
4113
4114 template<typename _Tp>
4115 requires __is_enum(_Tp)
4116 && requires(remove_cv_t<_Tp> __t) { __t = __t; } // fails if incomplete
4117 struct is_scoped_enum<_Tp>
4118 : bool_constant<!requires(_Tp __t, void(*__f)(int)) { __f(__t); }>
4119 { };
4120# endif
4121
4122 /// @ingroup variable_templates
4123 /// @since C++23
4124# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_scoped_enum)
4125 template<typename _Tp>
4126 inline constexpr bool is_scoped_enum_v = __is_scoped_enum(_Tp);
4127# else
4128 template<typename _Tp>
4129 inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
4130# endif
4131#endif
4132
4133#ifdef __cpp_lib_is_implicit_lifetime // C++ >= 23
4134 /// True if the type is an implicit-lifetime type.
4135 /// @since C++23
4136
4137 template<typename _Tp>
4138 struct is_implicit_lifetime
4139 : bool_constant<__builtin_is_implicit_lifetime(_Tp)>
4140 { };
4141
4142 /// @ingroup variable_templates
4143 /// @since C++23
4144 template<typename _Tp>
4145 inline constexpr bool is_implicit_lifetime_v
4146 = __builtin_is_implicit_lifetime(_Tp);
4147#endif
4148
4149#ifdef __cpp_lib_reference_from_temporary // C++ >= 23 && ref_{converts,constructs}_from_temp
4150 /// True if _Tp is a reference type, a _Up value can be bound to _Tp in
4151 /// direct-initialization, and a temporary object would be bound to
4152 /// the reference, false otherwise.
4153 /// @since C++23
4154 template<typename _Tp, typename _Up>
4155 struct reference_constructs_from_temporary
4156 : public bool_constant<__reference_constructs_from_temporary(_Tp, _Up)>
4157 {
4158 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{})
4159 && std::__is_complete_or_unbounded(__type_identity<_Up>{}),
4160 "template argument must be a complete class or an unbounded array");
4161 };
4162
4163 /// True if _Tp is a reference type, a _Up value can be bound to _Tp in
4164 /// copy-initialization, and a temporary object would be bound to
4165 /// the reference, false otherwise.
4166 /// @since C++23
4167 template<typename _Tp, typename _Up>
4168 struct reference_converts_from_temporary
4169 : public bool_constant<__reference_converts_from_temporary(_Tp, _Up)>
4170 {
4171 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{})
4172 && std::__is_complete_or_unbounded(__type_identity<_Up>{}),
4173 "template argument must be a complete class or an unbounded array");
4174 };
4175
4176 /// @ingroup variable_templates
4177 /// @since C++23
4178 template<typename _Tp, typename _Up>
4179 inline constexpr bool reference_constructs_from_temporary_v
4180 = reference_constructs_from_temporary<_Tp, _Up>::value;
4181
4182 /// @ingroup variable_templates
4183 /// @since C++23
4184 template<typename _Tp, typename _Up>
4185 inline constexpr bool reference_converts_from_temporary_v
4186 = reference_converts_from_temporary<_Tp, _Up>::value;
4187#endif // __cpp_lib_reference_from_temporary
4188
4189#ifdef __cpp_lib_is_constant_evaluated // C++ >= 20 && HAVE_IS_CONST_EVAL
4190 /// Returns true only when called during constant evaluation.
4191 /// @since C++20
4192 [[__gnu__::__always_inline__]]
4193 constexpr bool
4194 is_constant_evaluated() noexcept
4195 {
4196#if __cpp_if_consteval >= 202106L
4197 if consteval { return true; } else { return false; }
4198#else
4199 return __builtin_is_constant_evaluated();
4200#endif
4201 }
4202#endif
4203
4204#if __cplusplus >= 202002L
4205 /// @cond undocumented
4206 template<typename _From, typename _To>
4207 using __copy_cv = typename __match_cv_qualifiers<_From, _To>::__type;
4208
4209 template<typename _Xp, typename _Yp>
4210 using __cond_res
4211 = decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
4212
4213 template<typename _Ap, typename _Bp, typename = void>
4214 struct __common_ref_impl
4215 { };
4216
4217 // [meta.trans.other], COMMON-REF(A, B)
4218 template<typename _Ap, typename _Bp>
4219 using __common_ref = typename __common_ref_impl<_Ap, _Bp>::type;
4220
4221 // COND-RES(COPYCV(X, Y) &, COPYCV(Y, X) &)
4222 template<typename _Xp, typename _Yp>
4223 using __condres_cvref
4224 = __cond_res<__copy_cv<_Xp, _Yp>&, __copy_cv<_Yp, _Xp>&>;
4225
4226 // If A and B are both lvalue reference types, ...
4227 template<typename _Xp, typename _Yp>
4228 struct __common_ref_impl<_Xp&, _Yp&, __void_t<__condres_cvref<_Xp, _Yp>>>
4229 : enable_if<is_reference_v<__condres_cvref<_Xp, _Yp>>,
4230 __condres_cvref<_Xp, _Yp>>
4231 { };
4232
4233 // let C be remove_reference_t<COMMON-REF(X&, Y&)>&&
4234 template<typename _Xp, typename _Yp>
4235 using __common_ref_C = remove_reference_t<__common_ref<_Xp&, _Yp&>>&&;
4236
4237 // If A and B are both rvalue reference types, ...
4238 template<typename _Xp, typename _Yp>
4239 struct __common_ref_impl<_Xp&&, _Yp&&,
4240 _Require<is_convertible<_Xp&&, __common_ref_C<_Xp, _Yp>>,
4241 is_convertible<_Yp&&, __common_ref_C<_Xp, _Yp>>>>
4242 { using type = __common_ref_C<_Xp, _Yp>; };
4243
4244 // let D be COMMON-REF(const X&, Y&)
4245 template<typename _Xp, typename _Yp>
4246 using __common_ref_D = __common_ref<const _Xp&, _Yp&>;
4247
4248 // If A is an rvalue reference and B is an lvalue reference, ...
4249 template<typename _Xp, typename _Yp>
4250 struct __common_ref_impl<_Xp&&, _Yp&,
4251 _Require<is_convertible<_Xp&&, __common_ref_D<_Xp, _Yp>>>>
4252 { using type = __common_ref_D<_Xp, _Yp>; };
4253
4254 // If A is an lvalue reference and B is an rvalue reference, ...
4255 template<typename _Xp, typename _Yp>
4256 struct __common_ref_impl<_Xp&, _Yp&&>
4257 : __common_ref_impl<_Yp&&, _Xp&>
4258 { };
4259 /// @endcond
4260
4261 template<typename _Tp, typename _Up,
4262 template<typename> class _TQual, template<typename> class _UQual>
4263 struct basic_common_reference
4264 { };
4265
4266 /// @cond undocumented
4267 template<typename _Tp>
4268 struct __xref
4269 { template<typename _Up> using __type = __copy_cv<_Tp, _Up>; };
4270
4271 template<typename _Tp>
4272 struct __xref<_Tp&>
4273 { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&; };
4274
4275 template<typename _Tp>
4276 struct __xref<_Tp&&>
4277 { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&&; };
4278
4279 template<typename _Tp1, typename _Tp2>
4280 using __basic_common_ref
4281 = typename basic_common_reference<remove_cvref_t<_Tp1>,
4282 remove_cvref_t<_Tp2>,
4283 __xref<_Tp1>::template __type,
4284 __xref<_Tp2>::template __type>::type;
4285 /// @endcond
4286
4287 template<typename... _Tp>
4288 struct common_reference;
4289
4290 template<typename... _Tp>
4291 using common_reference_t = typename common_reference<_Tp...>::type;
4292
4293 // If sizeof...(T) is zero, there shall be no member type.
4294 template<>
4295 struct common_reference<>
4296 { };
4297
4298 // If sizeof...(T) is one ...
4299 template<typename _Tp0>
4300 struct common_reference<_Tp0>
4301 { using type = _Tp0; };
4302
4303 /// @cond undocumented
4304 template<typename _Tp1, typename _Tp2, int _Bullet = 1>
4305 struct __common_reference_impl
4306 : __common_reference_impl<_Tp1, _Tp2, _Bullet + 1>
4307 { };
4308
4309 // If sizeof...(T) is two ...
4310 template<typename _Tp1, typename _Tp2>
4311 struct common_reference<_Tp1, _Tp2>
4312 : __common_reference_impl<_Tp1, _Tp2>
4313 { };
4314
4315 // If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, ...
4316 template<typename _Tp1, typename _Tp2>
4317 requires is_reference_v<_Tp1> && is_reference_v<_Tp2>
4318 && requires { typename __common_ref<_Tp1, _Tp2>; }
4319#if __cpp_lib_common_reference // C++ >= 20
4320 && is_convertible_v<add_pointer_t<_Tp1>,
4321 add_pointer_t<__common_ref<_Tp1, _Tp2>>>
4322 && is_convertible_v<add_pointer_t<_Tp2>,
4323 add_pointer_t<__common_ref<_Tp1, _Tp2>>>
4324#endif
4325 struct __common_reference_impl<_Tp1, _Tp2, 1>
4326 { using type = __common_ref<_Tp1, _Tp2>; };
4327
4328 // Otherwise, if basic_common_reference<...>::type is well-formed, ...
4329 template<typename _Tp1, typename _Tp2>
4330 requires requires { typename __basic_common_ref<_Tp1, _Tp2>; }
4331 struct __common_reference_impl<_Tp1, _Tp2, 2>
4332 { using type = __basic_common_ref<_Tp1, _Tp2>; };
4333
4334 // Otherwise, if COND-RES(T1, T2) is well-formed, ...
4335 template<typename _Tp1, typename _Tp2>
4336 requires requires { typename __cond_res<_Tp1, _Tp2>; }
4337 struct __common_reference_impl<_Tp1, _Tp2, 3>
4338 { using type = __cond_res<_Tp1, _Tp2>; };
4339
4340 // Otherwise, if common_type_t<T1, T2> is well-formed, ...
4341 template<typename _Tp1, typename _Tp2>
4342 requires requires { typename common_type_t<_Tp1, _Tp2>; }
4343 struct __common_reference_impl<_Tp1, _Tp2, 4>
4344 { using type = common_type_t<_Tp1, _Tp2>; };
4345
4346 // Otherwise, there shall be no member type.
4347 template<typename _Tp1, typename _Tp2>
4348 struct __common_reference_impl<_Tp1, _Tp2, 5>
4349 { };
4350
4351 // Otherwise, if sizeof...(T) is greater than two, ...
4352 template<typename _Tp1, typename _Tp2, typename... _Rest>
4353 struct common_reference<_Tp1, _Tp2, _Rest...>
4354 : __common_type_fold<common_reference<_Tp1, _Tp2>,
4355 __common_type_pack<_Rest...>>
4356 { };
4357
4358 // Reuse __common_type_fold for common_reference<T1, T2, Rest...>
4359 template<typename _Tp1, typename _Tp2, typename... _Rest>
4360 struct __common_type_fold<common_reference<_Tp1, _Tp2>,
4361 __common_type_pack<_Rest...>,
4362 void_t<common_reference_t<_Tp1, _Tp2>>>
4363 : public common_reference<common_reference_t<_Tp1, _Tp2>, _Rest...>
4364 { };
4365 /// @endcond
4366
4367#endif // C++20
4368
4369#if __cplusplus >= 201103L
4370 // Stores a tuple of indices. Used by tuple and pair, and by bind() to
4371 // extract the elements in a tuple.
4372 template<size_t... _Indexes> struct _Index_tuple { };
4373
4374 // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
4375 template<size_t _Num>
4376 struct _Build_index_tuple
4377 {
4378#if __has_builtin(__make_integer_seq)
4379 template<typename, size_t... _Indices>
4380 using _IdxTuple = _Index_tuple<_Indices...>;
4381
4382 // Clang defines __make_integer_seq for this purpose.
4383 using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
4384#else
4385 // For GCC and other compilers, use __integer_pack instead.
4386 using __type = _Index_tuple<__integer_pack(_Num)...>;
4387#endif
4388 };
4389#endif // C++11
4390
4391 /// @} group metaprogramming
4392
4393_GLIBCXX_END_NAMESPACE_VERSION
4394} // namespace std
4395} // extern "C++"
4396
4397#endif // C++11
4398
4399#endif // _GLIBCXX_TYPE_TRAITS
c++0x_warning.h
version.h
c++config.h
std::true_type
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition type_traits:119
std::aligned_union::alignment_value
static const size_t alignment_value
The value of the strictest alignment of _Types.
Definition type_traits:2480
std::is_corresponding_member
constexpr bool is_corresponding_member(_M1 _S1::*__m1, _M2 _S2::*__m2) noexcept
Definition type_traits:4062
std::common_reference_t
typename common_reference< _Tp... >::type common_reference_t
Definition type_traits:4289
std::result_of_t
typename result_of< _Tp >::type result_of_t
Alias template for result_of.
Definition type_traits:2960
std::aligned_union::type
typename aligned_storage< _S_len, alignment_value >::type type
The storage.
Definition type_traits:2482
std::remove_extent_t
typename remove_extent< _Tp >::type remove_extent_t
Alias template for remove_extent.
Definition type_traits:2296
std::conditional_t
typename conditional< _Cond, _Iftrue, _Iffalse >::type conditional_t
Alias template for conditional.
Definition type_traits:2948
std::underlying_type_t
typename underlying_type< _Tp >::type underlying_type_t
Alias template for underlying_type.
Definition type_traits:2956
std::make_signed_t
typename make_signed< _Tp >::type make_signed_t
Alias template for make_signed.
Definition type_traits:2246
std::add_lvalue_reference_t
typename add_lvalue_reference< _Tp >::type add_lvalue_reference_t
Alias template for add_lvalue_reference.
Definition type_traits:1894
std::aligned_storage_t
typename aligned_storage< _Len, _Align >::type aligned_storage_t
Alias template for aligned_storage.
Definition type_traits:2932
std::remove_reference_t
typename remove_reference< _Tp >::type remove_reference_t
Alias template for remove_reference.
Definition type_traits:1890
std::common_type_t
typename common_type< _Tp... >::type common_type_t
Alias template for common_type.
Definition type_traits:2952
std::add_pointer_t
typename add_pointer< _Tp >::type add_pointer_t
Alias template for add_pointer.
Definition type_traits:2360
std::make_unsigned_t
typename make_unsigned< _Tp >::type make_unsigned_t
Alias template for make_unsigned.
Definition type_traits:2250
std::is_pointer_interconvertible_with_class
constexpr bool is_pointer_interconvertible_with_class(_Mem _Tp::*__mp) noexcept
True if __mp points to the first member of a standard-layout type.
Definition type_traits:4092
std::enable_if_t
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Definition type_traits:2944
std::remove_all_extents_t
typename remove_all_extents< _Tp >::type remove_all_extents_t
Alias template for remove_all_extents.
Definition type_traits:2300
std::remove_pointer_t
typename remove_pointer< _Tp >::type remove_pointer_t
Alias template for remove_pointer.
Definition type_traits:2356
std::add_rvalue_reference_t
typename add_rvalue_reference< _Tp >::type add_rvalue_reference_t
Alias template for add_rvalue_reference.
Definition type_traits:1898
std::false_type
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:122
std::is_layout_compatible_v
constexpr bool is_layout_compatible_v
Definition type_traits:4052
std::is_pointer_interconvertible_base_of_v
constexpr bool is_pointer_interconvertible_base_of_v
Definition type_traits:4080
std::decay_t
typename decay< _Tp >::type decay_t
Alias template for decay.
Definition type_traits:2940
std::declval
auto declval() noexcept -> decltype(__declval< _Tp >(0))
Definition type_traits:2718
std::experimental::fundamentals_v2::void_t
void void_t
A metafunction that always yields void, used for detecting valid types.
Definition experimental/type_traits:262
std
ISO C++ entities toplevel namespace is std.
std::__detail
Implementation details not part of the namespace std interface.
std::reference_wrapper
Primary class template for reference_wrapper.
Definition refwrap.h:316
std::integral_constant
integral_constant
Definition type_traits:96
std::enable_if
Define a member typedef type only if a boolean constant is true.
Definition type_traits:137
std::is_object
is_object
Definition type_traits:857
std::remove_cv
remove_cv
Definition type_traits:1796
std::is_const
is_const
Definition type_traits:926
std::is_void
is_void
Definition type_traits:331
std::is_integral
is_integral
Definition type_traits:541
std::is_floating_point
is_floating_point
Definition type_traits:601
std::is_array
is_array
Definition type_traits:608
std::is_pointer
is_pointer
Definition type_traits:628
std::is_lvalue_reference
is_lvalue_reference
Definition type_traits:654
std::is_rvalue_reference
is_rvalue_reference
Definition type_traits:663
std::is_member_object_pointer
is_member_object_pointer
Definition type_traits:674
std::is_member_function_pointer
is_member_function_pointer
Definition type_traits:699
std::is_enum
is_enum
Definition type_traits:723
std::is_union
is_union
Definition type_traits:729
std::is_class
is_class
Definition type_traits:735
std::is_function
is_function
Definition type_traits:742
std::is_reference
is_reference
Definition type_traits:817
std::is_arithmetic
is_arithmetic
Definition type_traits:839
std::is_fundamental
is_fundamental
Definition type_traits:850
std::is_member_pointer
is_member_pointer
Definition type_traits:890
std::is_scalar
is_scalar
Definition type_traits:878
std::is_compound
is_compound
Definition type_traits:883
std::is_same
is_same
Definition type_traits:1626
std::is_volatile
is_volatile
Definition type_traits:942
std::is_trivial
Definition type_traits:965
std::is_trivially_copyable
is_trivially_copyable
Definition type_traits:974
std::is_standard_layout
is_standard_layout
Definition type_traits:983
std::is_pod
Definition type_traits:998
std::is_literal_type
Definition type_traits:1012
std::is_empty
is_empty
Definition type_traits:1021
std::is_polymorphic
is_polymorphic
Definition type_traits:1027
std::is_abstract
is_abstract
Definition type_traits:1042
std::is_signed
is_signed
Definition type_traits:1060
std::is_unsigned
is_unsigned
Definition type_traits:1066
std::remove_all_extents
remove_all_extents
Definition type_traits:2278
std::is_destructible
is_destructible
Definition type_traits:1113
std::is_nothrow_destructible
is_nothrow_destructible
Definition type_traits:1175
std::is_constructible
is_constructible
Definition type_traits:1242
std::is_default_constructible
is_default_constructible
Definition type_traits:1251
std::is_copy_constructible
is_copy_constructible
Definition type_traits:1278
std::is_move_constructible
is_move_constructible
Definition type_traits:1305
std::is_nothrow_constructible
is_nothrow_constructible
Definition type_traits:1320
std::is_nothrow_default_constructible
is_nothrow_default_constructible
Definition type_traits:1329
std::is_nothrow_copy_constructible
is_nothrow_copy_constructible
Definition type_traits:1338
std::is_nothrow_move_constructible
is_nothrow_move_constructible
Definition type_traits:1347
std::is_assignable
is_assignable
Definition type_traits:1361
std::is_copy_assignable
is_copy_assignable
Definition type_traits:1371
std::is_move_assignable
is_move_assignable
Definition type_traits:1380
std::is_nothrow_assignable
is_nothrow_assignable
Definition type_traits:1395
std::is_nothrow_copy_assignable
is_nothrow_copy_assignable
Definition type_traits:1405
std::is_nothrow_move_assignable
is_nothrow_move_assignable
Definition type_traits:1415
std::is_trivially_constructible
is_trivially_constructible
Definition type_traits:1430
std::is_trivially_default_constructible
is_trivially_default_constructible
Definition type_traits:1439
std::is_trivially_copy_constructible
is_trivially_copy_constructible
Definition type_traits:1489
std::is_trivially_move_constructible
is_trivially_move_constructible
Definition type_traits:1498
std::is_trivially_assignable
is_trivially_assignable
Definition type_traits:1513
std::is_trivially_copy_assignable
is_trivially_copy_assignable
Definition type_traits:1523
std::is_trivially_move_assignable
is_trivially_move_assignable
Definition type_traits:1533
std::is_trivially_destructible
is_trivially_destructible
Definition type_traits:1543
std::has_virtual_destructor
has_virtual_destructor
Definition type_traits:1560
std::alignment_of
alignment_of
Definition type_traits:1572
std::rank
rank
Definition type_traits:1582
std::extent
extent
Definition type_traits:1600
std::is_base_of
is_base_of
Definition type_traits:1643
std::remove_const
remove_const
Definition type_traits:1777
std::remove_volatile
remove_volatile
Definition type_traits:1786
std::add_const
add_const
Definition type_traits:1818
std::add_volatile
add_volatile
Definition type_traits:1823
std::add_cv
add_cv
Definition type_traits:1828
std::remove_reference
remove_reference
Definition type_traits:1862
std::add_lvalue_reference
add_lvalue_reference
Definition type_traits:1880
std::add_rvalue_reference
add_rvalue_reference
Definition type_traits:1885
std::make_unsigned
make_unsigned
Definition type_traits:2097
std::make_signed
make_signed
Definition type_traits:2235
std::remove_extent
remove_extent
Definition type_traits:2259
std::remove_pointer
remove_pointer
Definition type_traits:2309
std::add_pointer
add_pointer
Definition type_traits:2329
std::aligned_storage
Aligned storage.
Definition type_traits:2427
std::aligned_union
Provide aligned storage for types.
Definition type_traits:2471
std::conditional
Define a member typedef type to one of two argument types.
Definition type_traits:2568
std::common_type
common_type
Definition type_traits:2577
std::underlying_type
The underlying type of an enum.
Definition type_traits:2703
std::result_of
result_of
Definition type_traits:2727
std::is_layout_compatible
Definition type_traits:4046
std::is_pointer_interconvertible_base_of
True if _Derived is standard-layout and has a base class of type _Base.
Definition type_traits:4074