1// C++11 <type_traits> -*- C++ -*-
2
3// Copyright (C) 2007-2024 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#pragma GCC system_header
33
34#if __cplusplus < 201103L
35# include <bits/c++0x_warning.h>
36#else
37
38#include <bits/c++config.h>
39
40#define __glibcxx_want_bool_constant
41#define __glibcxx_want_bounded_array_traits
42#define __glibcxx_want_has_unique_object_representations
43#define __glibcxx_want_integral_constant_callable
44#define __glibcxx_want_is_aggregate
45#define __glibcxx_want_is_constant_evaluated
46#define __glibcxx_want_is_final
47#define __glibcxx_want_is_invocable
48#define __glibcxx_want_is_layout_compatible
49#define __glibcxx_want_is_nothrow_convertible
50#define __glibcxx_want_is_null_pointer
51#define __glibcxx_want_is_pointer_interconvertible
52#define __glibcxx_want_is_scoped_enum
53#define __glibcxx_want_is_swappable
54#define __glibcxx_want_logical_traits
55#define __glibcxx_want_reference_from_temporary
56#define __glibcxx_want_remove_cvref
57#define __glibcxx_want_result_of_sfinae
58#define __glibcxx_want_transformation_trait_aliases
59#define __glibcxx_want_type_identity
60#define __glibcxx_want_type_trait_variable_templates
61#define __glibcxx_want_unwrap_ref
62#define __glibcxx_want_void_t
63#include <bits/version.h>
64
65namespace std _GLIBCXX_VISIBILITY(default)
66{
67_GLIBCXX_BEGIN_NAMESPACE_VERSION
68
69 template<typename _Tp>
70 class reference_wrapper;
71
72 /**
73 * @defgroup metaprogramming Metaprogramming
74 * @ingroup utilities
75 *
76 * Template utilities for compile-time introspection and modification,
77 * including type classification traits, type property inspection traits
78 * and type transformation traits.
79 *
80 * @since C++11
81 *
82 * @{
83 */
84
85 /// integral_constant
86 template<typename _Tp, _Tp __v>
87 struct integral_constant
88 {
89 static constexpr _Tp value = __v;
90 using value_type = _Tp;
91 using type = integral_constant<_Tp, __v>;
92 constexpr operator value_type() const noexcept { return value; }
93
94#ifdef __cpp_lib_integral_constant_callable // C++ >= 14
95 constexpr value_type operator()() const noexcept { return value; }
96#endif
97 };
98
99#if ! __cpp_inline_variables
100 template<typename _Tp, _Tp __v>
101 constexpr _Tp integral_constant<_Tp, __v>::value;
102#endif
103
104 /// @cond undocumented
105 /// bool_constant for C++11
106 template<bool __v>
107 using __bool_constant = integral_constant<bool, __v>;
108 /// @endcond
109
110 /// The type used as a compile-time boolean with true value.
111 using true_type = __bool_constant<true>;
112
113 /// The type used as a compile-time boolean with false value.
114 using false_type = __bool_constant<false>;
115
116#ifdef __cpp_lib_bool_constant // C++ >= 17
117 /// Alias template for compile-time boolean constant types.
118 /// @since C++17
119 template<bool __v>
120 using bool_constant = __bool_constant<__v>;
121#endif
122
123 // Metaprogramming helper types.
124
125 // Primary template.
126 /// Define a member typedef `type` only if a boolean constant is true.
127 template<bool, typename _Tp = void>
128 struct enable_if
129 { };
130
131 // Partial specialization for true.
132 template<typename _Tp>
133 struct enable_if<true, _Tp>
134 { using type = _Tp; };
135
136 // __enable_if_t (std::enable_if_t for C++11)
137 template<bool _Cond, typename _Tp = void>
138 using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
139
140 template<bool>
141 struct __conditional
142 {
143 template<typename _Tp, typename>
144 using type = _Tp;
145 };
146
147 template<>
148 struct __conditional<false>
149 {
150 template<typename, typename _Up>
151 using type = _Up;
152 };
153
154 // More efficient version of std::conditional_t for internal use (and C++11)
155 template<bool _Cond, typename _If, typename _Else>
156 using __conditional_t
157 = typename __conditional<_Cond>::template type<_If, _Else>;
158
159 /// @cond undocumented
160 template <typename _Type>
161 struct __type_identity
162 { using type = _Type; };
163
164 template<typename _Tp>
165 using __type_identity_t = typename __type_identity<_Tp>::type;
166
167 namespace __detail
168 {
169 // A variadic alias template that resolves to its first argument.
170 template<typename _Tp, typename...>
171 using __first_t = _Tp;
172
173 // These are deliberately not defined.
174 template<typename... _Bn>
175 auto __or_fn(int) -> __first_t<false_type,
176 __enable_if_t<!bool(_Bn::value)>...>;
177
178 template<typename... _Bn>
179 auto __or_fn(...) -> true_type;
180
181 template<typename... _Bn>
182 auto __and_fn(int) -> __first_t<true_type,
183 __enable_if_t<bool(_Bn::value)>...>;
184
185 template<typename... _Bn>
186 auto __and_fn(...) -> false_type;
187 } // namespace detail
188
189 // Like C++17 std::dis/conjunction, but usable in C++11 and resolves
190 // to either true_type or false_type which allows for a more efficient
191 // implementation that avoids recursive class template instantiation.
192 template<typename... _Bn>
193 struct __or_
194 : decltype(__detail::__or_fn<_Bn...>(0))
195 { };
196
197 template<typename... _Bn>
198 struct __and_
199 : decltype(__detail::__and_fn<_Bn...>(0))
200 { };
201
202 template<typename _Pp>
203 struct __not_
204 : __bool_constant<!bool(_Pp::value)>
205 { };
206 /// @endcond
207
208#ifdef __cpp_lib_logical_traits // C++ >= 17
209
210 /// @cond undocumented
211 template<typename... _Bn>
212 inline constexpr bool __or_v = __or_<_Bn...>::value;
213 template<typename... _Bn>
214 inline constexpr bool __and_v = __and_<_Bn...>::value;
215
216 namespace __detail
217 {
218 template<typename /* = void */, typename _B1, typename... _Bn>
219 struct __disjunction_impl
220 { using type = _B1; };
221
222 template<typename _B1, typename _B2, typename... _Bn>
223 struct __disjunction_impl<__enable_if_t<!bool(_B1::value)>, _B1, _B2, _Bn...>
224 { using type = typename __disjunction_impl<void, _B2, _Bn...>::type; };
225
226 template<typename /* = void */, typename _B1, typename... _Bn>
227 struct __conjunction_impl
228 { using type = _B1; };
229
230 template<typename _B1, typename _B2, typename... _Bn>
231 struct __conjunction_impl<__enable_if_t<bool(_B1::value)>, _B1, _B2, _Bn...>
232 { using type = typename __conjunction_impl<void, _B2, _Bn...>::type; };
233 } // namespace __detail
234 /// @endcond
235
236 template<typename... _Bn>
237 struct conjunction
238 : __detail::__conjunction_impl<void, _Bn...>::type
239 { };
240
241 template<>
242 struct conjunction<>
243 : true_type
244 { };
245
246 template<typename... _Bn>
247 struct disjunction
248 : __detail::__disjunction_impl<void, _Bn...>::type
249 { };
250
251 template<>
252 struct disjunction<>
253 : false_type
254 { };
255
256 template<typename _Pp>
257 struct negation
258 : __not_<_Pp>::type
259 { };
260
261 /** @ingroup variable_templates
262 * @{
263 */
264 template<typename... _Bn>
265 inline constexpr bool conjunction_v = conjunction<_Bn...>::value;
266
267 template<typename... _Bn>
268 inline constexpr bool disjunction_v = disjunction<_Bn...>::value;
269
270 template<typename _Pp>
271 inline constexpr bool negation_v = negation<_Pp>::value;
272 /// @}
273
274#endif // __cpp_lib_logical_traits
275
276 // Forward declarations
277 template<typename>
278 struct is_reference;
279 template<typename>
280 struct is_function;
281 template<typename>
282 struct is_void;
283 template<typename>
284 struct remove_cv;
285 template<typename>
286 struct is_const;
287
288 /// @cond undocumented
289 template<typename>
290 struct __is_array_unknown_bounds;
291
292 // Helper functions that return false_type for incomplete classes,
293 // incomplete unions and arrays of known bound from those.
294
295 template <typename _Tp, size_t = sizeof(_Tp)>
296 constexpr true_type __is_complete_or_unbounded(__type_identity<_Tp>)
297 { return {}; }
298
299 template <typename _TypeIdentity,
300 typename _NestedType = typename _TypeIdentity::type>
301 constexpr typename __or_<
302 is_reference<_NestedType>,
303 is_function<_NestedType>,
304 is_void<_NestedType>,
305 __is_array_unknown_bounds<_NestedType>
306 >::type __is_complete_or_unbounded(_TypeIdentity)
307 { return {}; }
308
309 // __remove_cv_t (std::remove_cv_t for C++11).
310 template<typename _Tp>
311 using __remove_cv_t = typename remove_cv<_Tp>::type;
312 /// @endcond
313
314 // Primary type categories.
315
316 /// is_void
317 template<typename _Tp>
318 struct is_void
319 : public false_type { };
320
321 template<>
322 struct is_void<void>
323 : public true_type { };
324
325 template<>
326 struct is_void<const void>
327 : public true_type { };
328
329 template<>
330 struct is_void<volatile void>
331 : public true_type { };
332
333 template<>
334 struct is_void<const volatile void>
335 : public true_type { };
336
337 /// @cond undocumented
338 template<typename>
339 struct __is_integral_helper
340 : public false_type { };
341
342 template<>
343 struct __is_integral_helper<bool>
344 : public true_type { };
345
346 template<>
347 struct __is_integral_helper<char>
348 : public true_type { };
349
350 template<>
351 struct __is_integral_helper<signed char>
352 : public true_type { };
353
354 template<>
355 struct __is_integral_helper<unsigned char>
356 : public true_type { };
357
358 // We want is_integral<wchar_t> to be true (and make_signed/unsigned to work)
359 // even when libc doesn't provide working <wchar.h> and related functions,
360 // so don't check _GLIBCXX_USE_WCHAR_T here.
361 template<>
362 struct __is_integral_helper<wchar_t>
363 : public true_type { };
364
365#ifdef _GLIBCXX_USE_CHAR8_T
366 template<>
367 struct __is_integral_helper<char8_t>
368 : public true_type { };
369#endif
370
371 template<>
372 struct __is_integral_helper<char16_t>
373 : public true_type { };
374
375 template<>
376 struct __is_integral_helper<char32_t>
377 : public true_type { };
378
379 template<>
380 struct __is_integral_helper<short>
381 : public true_type { };
382
383 template<>
384 struct __is_integral_helper<unsigned short>
385 : public true_type { };
386
387 template<>
388 struct __is_integral_helper<int>
389 : public true_type { };
390
391 template<>
392 struct __is_integral_helper<unsigned int>
393 : public true_type { };
394
395 template<>
396 struct __is_integral_helper<long>
397 : public true_type { };
398
399 template<>
400 struct __is_integral_helper<unsigned long>
401 : public true_type { };
402
403 template<>
404 struct __is_integral_helper<long long>
405 : public true_type { };
406
407 template<>
408 struct __is_integral_helper<unsigned long long>
409 : public true_type { };
410
411 // Conditionalizing on __STRICT_ANSI__ here will break any port that
412 // uses one of these types for size_t.
413#if defined(__GLIBCXX_TYPE_INT_N_0)
414 __extension__
415 template<>
416 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_0>
417 : public true_type { };
418
419 __extension__
420 template<>
421 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_0>
422 : public true_type { };
423#endif
424#if defined(__GLIBCXX_TYPE_INT_N_1)
425 __extension__
426 template<>
427 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_1>
428 : public true_type { };
429
430 __extension__
431 template<>
432 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_1>
433 : public true_type { };
434#endif
435#if defined(__GLIBCXX_TYPE_INT_N_2)
436 __extension__
437 template<>
438 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_2>
439 : public true_type { };
440
441 __extension__
442 template<>
443 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_2>
444 : public true_type { };
445#endif
446#if defined(__GLIBCXX_TYPE_INT_N_3)
447 __extension__
448 template<>
449 struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_3>
450 : public true_type { };
451
452 __extension__
453 template<>
454 struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_3>
455 : public true_type { };
456#endif
457 /// @endcond
458
459 /// is_integral
460 template<typename _Tp>
461 struct is_integral
462 : public __is_integral_helper<__remove_cv_t<_Tp>>::type
463 { };
464
465 /// @cond undocumented
466 template<typename>
467 struct __is_floating_point_helper
468 : public false_type { };
469
470 template<>
471 struct __is_floating_point_helper<float>
472 : public true_type { };
473
474 template<>
475 struct __is_floating_point_helper<double>
476 : public true_type { };
477
478 template<>
479 struct __is_floating_point_helper<long double>
480 : public true_type { };
481
482#ifdef __STDCPP_FLOAT16_T__
483 template<>
484 struct __is_floating_point_helper<_Float16>
485 : public true_type { };
486#endif
487
488#ifdef __STDCPP_FLOAT32_T__
489 template<>
490 struct __is_floating_point_helper<_Float32>
491 : public true_type { };
492#endif
493
494#ifdef __STDCPP_FLOAT64_T__
495 template<>
496 struct __is_floating_point_helper<_Float64>
497 : public true_type { };
498#endif
499
500#ifdef __STDCPP_FLOAT128_T__
501 template<>
502 struct __is_floating_point_helper<_Float128>
503 : public true_type { };
504#endif
505
506#ifdef __STDCPP_BFLOAT16_T__
507 template<>
508 struct __is_floating_point_helper<__gnu_cxx::__bfloat16_t>
509 : public true_type { };
510#endif
511
512#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
513 template<>
514 struct __is_floating_point_helper<__float128>
515 : public true_type { };
516#endif
517 /// @endcond
518
519 /// is_floating_point
520 template<typename _Tp>
521 struct is_floating_point
522 : public __is_floating_point_helper<__remove_cv_t<_Tp>>::type
523 { };
524
525 /// is_array
526#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_array)
527 template<typename _Tp>
528 struct is_array
529 : public __bool_constant<__is_array(_Tp)>
530 { };
531#else
532 template<typename>
533 struct is_array
534 : public false_type { };
535
536 template<typename _Tp, std::size_t _Size>
537 struct is_array<_Tp[_Size]>
538 : public true_type { };
539
540 template<typename _Tp>
541 struct is_array<_Tp[]>
542 : public true_type { };
543#endif
544
545 template<typename>
546 struct __is_pointer_helper
547 : public false_type { };
548
549 template<typename _Tp>
550 struct __is_pointer_helper<_Tp*>
551 : public true_type { };
552
553 /// is_pointer
554 template<typename _Tp>
555 struct is_pointer
556 : public __is_pointer_helper<__remove_cv_t<_Tp>>::type
557 { };
558
559 /// is_lvalue_reference
560 template<typename>
561 struct is_lvalue_reference
562 : public false_type { };
563
564 template<typename _Tp>
565 struct is_lvalue_reference<_Tp&>
566 : public true_type { };
567
568 /// is_rvalue_reference
569 template<typename>
570 struct is_rvalue_reference
571 : public false_type { };
572
573 template<typename _Tp>
574 struct is_rvalue_reference<_Tp&&>
575 : public true_type { };
576
577 /// is_member_object_pointer
578#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_object_pointer)
579 template<typename _Tp>
580 struct is_member_object_pointer
581 : public __bool_constant<__is_member_object_pointer(_Tp)>
582 { };
583#else
584 template<typename>
585 struct __is_member_object_pointer_helper
586 : public false_type { };
587
588 template<typename _Tp, typename _Cp>
589 struct __is_member_object_pointer_helper<_Tp _Cp::*>
590 : public __not_<is_function<_Tp>>::type { };
591
592
593 template<typename _Tp>
594 struct is_member_object_pointer
595 : public __is_member_object_pointer_helper<__remove_cv_t<_Tp>>::type
596 { };
597#endif
598
599#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_function_pointer)
600 /// is_member_function_pointer
601 template<typename _Tp>
602 struct is_member_function_pointer
603 : public __bool_constant<__is_member_function_pointer(_Tp)>
604 { };
605#else
606 template<typename>
607 struct __is_member_function_pointer_helper
608 : public false_type { };
609
610 template<typename _Tp, typename _Cp>
611 struct __is_member_function_pointer_helper<_Tp _Cp::*>
612 : public is_function<_Tp>::type { };
613
614 /// is_member_function_pointer
615 template<typename _Tp>
616 struct is_member_function_pointer
617 : public __is_member_function_pointer_helper<__remove_cv_t<_Tp>>::type
618 { };
619#endif
620
621 /// is_enum
622 template<typename _Tp>
623 struct is_enum
624 : public __bool_constant<__is_enum(_Tp)>
625 { };
626
627 /// is_union
628 template<typename _Tp>
629 struct is_union
630 : public __bool_constant<__is_union(_Tp)>
631 { };
632
633 /// is_class
634 template<typename _Tp>
635 struct is_class
636 : public __bool_constant<__is_class(_Tp)>
637 { };
638
639 /// is_function
640#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_function)
641 template<typename _Tp>
642 struct is_function
643 : public __bool_constant<__is_function(_Tp)>
644 { };
645#else
646 template<typename _Tp>
647 struct is_function
648 : public __bool_constant<!is_const<const _Tp>::value> { };
649
650 template<typename _Tp>
651 struct is_function<_Tp&>
652 : public false_type { };
653
654 template<typename _Tp>
655 struct is_function<_Tp&&>
656 : public false_type { };
657#endif
658
659#ifdef __cpp_lib_is_null_pointer // C++ >= 11
660 /// is_null_pointer (LWG 2247).
661 template<typename _Tp>
662 struct is_null_pointer
663 : public false_type { };
664
665 template<>
666 struct is_null_pointer<std::nullptr_t>
667 : public true_type { };
668
669 template<>
670 struct is_null_pointer<const std::nullptr_t>
671 : public true_type { };
672
673 template<>
674 struct is_null_pointer<volatile std::nullptr_t>
675 : public true_type { };
676
677 template<>
678 struct is_null_pointer<const volatile std::nullptr_t>
679 : public true_type { };
680
681 /// __is_nullptr_t (deprecated extension).
682 /// @deprecated Non-standard. Use `is_null_pointer` instead.
683 template<typename _Tp>
684 struct __is_nullptr_t
685 : public is_null_pointer<_Tp>
686 { } _GLIBCXX_DEPRECATED_SUGGEST("std::is_null_pointer");
687#endif // __cpp_lib_is_null_pointer
688
689 // Composite type categories.
690
691 /// is_reference
692#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_reference)
693 template<typename _Tp>
694 struct is_reference
695 : public __bool_constant<__is_reference(_Tp)>
696 { };
697#else
698 template<typename _Tp>
699 struct is_reference
700 : public false_type
701 { };
702
703 template<typename _Tp>
704 struct is_reference<_Tp&>
705 : public true_type
706 { };
707
708 template<typename _Tp>
709 struct is_reference<_Tp&&>
710 : public true_type
711 { };
712#endif
713
714 /// is_arithmetic
715 template<typename _Tp>
716 struct is_arithmetic
717 : public __or_<is_integral<_Tp>, is_floating_point<_Tp>>::type
718 { };
719
720 /// is_fundamental
721 template<typename _Tp>
722 struct is_fundamental
723 : public __or_<is_arithmetic<_Tp>, is_void<_Tp>,
724 is_null_pointer<_Tp>>::type
725 { };
726
727 /// is_object
728#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_object)
729 template<typename _Tp>
730 struct is_object
731 : public __bool_constant<__is_object(_Tp)>
732 { };
733#else
734 template<typename _Tp>
735 struct is_object
736 : public __not_<__or_<is_function<_Tp>, is_reference<_Tp>,
737 is_void<_Tp>>>::type
738 { };
739#endif
740
741 template<typename>
742 struct is_member_pointer;
743
744 /// is_scalar
745 template<typename _Tp>
746 struct is_scalar
747 : public __or_<is_arithmetic<_Tp>, is_enum<_Tp>, is_pointer<_Tp>,
748 is_member_pointer<_Tp>, is_null_pointer<_Tp>>::type
749 { };
750
751 /// is_compound
752 template<typename _Tp>
753 struct is_compound
754 : public __bool_constant<!is_fundamental<_Tp>::value> { };
755
756 /// is_member_pointer
757#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
758 template<typename _Tp>
759 struct is_member_pointer
760 : public __bool_constant<__is_member_pointer(_Tp)>
761 { };
762#else
763 /// @cond undocumented
764 template<typename _Tp>
765 struct __is_member_pointer_helper
766 : public false_type { };
767
768 template<typename _Tp, typename _Cp>
769 struct __is_member_pointer_helper<_Tp _Cp::*>
770 : public true_type { };
771 /// @endcond
772
773 template<typename _Tp>
774 struct is_member_pointer
775 : public __is_member_pointer_helper<__remove_cv_t<_Tp>>::type
776 { };
777#endif
778
779 template<typename, typename>
780 struct is_same;
781
782 /// @cond undocumented
783 template<typename _Tp, typename... _Types>
784 using __is_one_of = __or_<is_same<_Tp, _Types>...>;
785
786 // Check if a type is one of the signed integer types.
787 __extension__
788 template<typename _Tp>
789 using __is_signed_integer = __is_one_of<__remove_cv_t<_Tp>,
790 signed char, signed short, signed int, signed long,
791 signed long long
792#if defined(__GLIBCXX_TYPE_INT_N_0)
793 , signed __GLIBCXX_TYPE_INT_N_0
794#endif
795#if defined(__GLIBCXX_TYPE_INT_N_1)
796 , signed __GLIBCXX_TYPE_INT_N_1
797#endif
798#if defined(__GLIBCXX_TYPE_INT_N_2)
799 , signed __GLIBCXX_TYPE_INT_N_2
800#endif
801#if defined(__GLIBCXX_TYPE_INT_N_3)
802 , signed __GLIBCXX_TYPE_INT_N_3
803#endif
804 >;
805
806 // Check if a type is one of the unsigned integer types.
807 __extension__
808 template<typename _Tp>
809 using __is_unsigned_integer = __is_one_of<__remove_cv_t<_Tp>,
810 unsigned char, unsigned short, unsigned int, unsigned long,
811 unsigned long long
812#if defined(__GLIBCXX_TYPE_INT_N_0)
813 , unsigned __GLIBCXX_TYPE_INT_N_0
814#endif
815#if defined(__GLIBCXX_TYPE_INT_N_1)
816 , unsigned __GLIBCXX_TYPE_INT_N_1
817#endif
818#if defined(__GLIBCXX_TYPE_INT_N_2)
819 , unsigned __GLIBCXX_TYPE_INT_N_2
820#endif
821#if defined(__GLIBCXX_TYPE_INT_N_3)
822 , unsigned __GLIBCXX_TYPE_INT_N_3
823#endif
824 >;
825
826 // Check if a type is one of the signed or unsigned integer types.
827 template<typename _Tp>
828 using __is_standard_integer
829 = __or_<__is_signed_integer<_Tp>, __is_unsigned_integer<_Tp>>;
830
831 // __void_t (std::void_t for C++11)
832 template<typename...> using __void_t = void;
833 /// @endcond
834
835 // Type properties.
836
837 /// is_const
838 template<typename>
839 struct is_const
840 : public false_type { };
841
842 template<typename _Tp>
843 struct is_const<_Tp const>
844 : public true_type { };
845
846 /// is_volatile
847 template<typename>
848 struct is_volatile
849 : public false_type { };
850
851 template<typename _Tp>
852 struct is_volatile<_Tp volatile>
853 : public true_type { };
854
855 /// is_trivial
856 template<typename _Tp>
857 struct is_trivial
858 : public __bool_constant<__is_trivial(_Tp)>
859 {
860 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
861 "template argument must be a complete class or an unbounded array");
862 };
863
864 /// is_trivially_copyable
865 template<typename _Tp>
866 struct is_trivially_copyable
867 : public __bool_constant<__is_trivially_copyable(_Tp)>
868 {
869 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
870 "template argument must be a complete class or an unbounded array");
871 };
872
873 /// is_standard_layout
874 template<typename _Tp>
875 struct is_standard_layout
876 : public __bool_constant<__is_standard_layout(_Tp)>
877 {
878 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
879 "template argument must be a complete class or an unbounded array");
880 };
881
882 /** is_pod
883 * @deprecated Deprecated in C++20.
884 * Use `is_standard_layout && is_trivial` instead.
885 */
886 // Could use is_standard_layout && is_trivial instead of the builtin.
887 template<typename _Tp>
888 struct
889 _GLIBCXX20_DEPRECATED_SUGGEST("is_standard_layout && is_trivial")
890 is_pod
891 : public __bool_constant<__is_pod(_Tp)>
892 {
893 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
894 "template argument must be a complete class or an unbounded array");
895 };
896
897 /** is_literal_type
898 * @deprecated Deprecated in C++17, removed in C++20.
899 * The idea of a literal type isn't useful.
900 */
901 template<typename _Tp>
902 struct
903 _GLIBCXX17_DEPRECATED
904 is_literal_type
905 : public __bool_constant<__is_literal_type(_Tp)>
906 {
907 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
908 "template argument must be a complete class or an unbounded array");
909 };
910
911 /// is_empty
912 template<typename _Tp>
913 struct is_empty
914 : public __bool_constant<__is_empty(_Tp)>
915 { };
916
917 /// is_polymorphic
918 template<typename _Tp>
919 struct is_polymorphic
920 : public __bool_constant<__is_polymorphic(_Tp)>
921 { };
922
923#ifdef __cpp_lib_is_final // C++ >= 14
924 /// is_final
925 /// @since C++14
926 template<typename _Tp>
927 struct is_final
928 : public __bool_constant<__is_final(_Tp)>
929 { };
930#endif
931
932 /// is_abstract
933 template<typename _Tp>
934 struct is_abstract
935 : public __bool_constant<__is_abstract(_Tp)>
936 { };
937
938 /// @cond undocumented
939 template<typename _Tp,
940 bool = is_arithmetic<_Tp>::value>
941 struct __is_signed_helper
942 : public false_type { };
943
944 template<typename _Tp>
945 struct __is_signed_helper<_Tp, true>
946 : public __bool_constant<_Tp(-1) < _Tp(0)>
947 { };
948 /// @endcond
949
950 /// is_signed
951 template<typename _Tp>
952 struct is_signed
953 : public __is_signed_helper<_Tp>::type
954 { };
955
956 /// is_unsigned
957 template<typename _Tp>
958 struct is_unsigned
959 : public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>::type
960 { };
961
962 /// @cond undocumented
963 template<typename _Tp, typename _Up = _Tp&&>
964 _Up
965 __declval(int);
966
967 template<typename _Tp>
968 _Tp
969 __declval(long);
970 /// @endcond
971
972 template<typename _Tp>
973 auto declval() noexcept -> decltype(__declval<_Tp>(0));
974
975 template<typename>
976 struct remove_all_extents;
977
978 /// @cond undocumented
979 template<typename _Tp>
980 struct __is_array_known_bounds
981 : public false_type
982 { };
983
984 template<typename _Tp, size_t _Size>
985 struct __is_array_known_bounds<_Tp[_Size]>
986 : public true_type
987 { };
988
989 template<typename _Tp>
990 struct __is_array_unknown_bounds
991 : public false_type
992 { };
993
994 template<typename _Tp>
995 struct __is_array_unknown_bounds<_Tp[]>
996 : public true_type
997 { };
998
999 // Destructible and constructible type properties.
1000
1001 // In N3290 is_destructible does not say anything about function
1002 // types and abstract types, see LWG 2049. This implementation
1003 // describes function types as non-destructible and all complete
1004 // object types as destructible, iff the explicit destructor
1005 // call expression is wellformed.
1006 struct __do_is_destructible_impl
1007 {
1008 template<typename _Tp, typename = decltype(declval<_Tp&>().~_Tp())>
1009 static true_type __test(int);
1010
1011 template<typename>
1012 static false_type __test(...);
1013 };
1014
1015 template<typename _Tp>
1016 struct __is_destructible_impl
1017 : public __do_is_destructible_impl
1018 {
1019 using type = decltype(__test<_Tp>(0));
1020 };
1021
1022 template<typename _Tp,
1023 bool = __or_<is_void<_Tp>,
1024 __is_array_unknown_bounds<_Tp>,
1025 is_function<_Tp>>::value,
1026 bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
1027 struct __is_destructible_safe;
1028
1029 template<typename _Tp>
1030 struct __is_destructible_safe<_Tp, false, false>
1031 : public __is_destructible_impl<typename
1032 remove_all_extents<_Tp>::type>::type
1033 { };
1034
1035 template<typename _Tp>
1036 struct __is_destructible_safe<_Tp, true, false>
1037 : public false_type { };
1038
1039 template<typename _Tp>
1040 struct __is_destructible_safe<_Tp, false, true>
1041 : public true_type { };
1042 /// @endcond
1043
1044 /// is_destructible
1045 template<typename _Tp>
1046 struct is_destructible
1047 : public __is_destructible_safe<_Tp>::type
1048 {
1049 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1050 "template argument must be a complete class or an unbounded array");
1051 };
1052
1053 /// @cond undocumented
1054
1055 // is_nothrow_destructible requires that is_destructible is
1056 // satisfied as well. We realize that by mimicing the
1057 // implementation of is_destructible but refer to noexcept(expr)
1058 // instead of decltype(expr).
1059 struct __do_is_nt_destructible_impl
1060 {
1061 template<typename _Tp>
1062 static __bool_constant<noexcept(declval<_Tp&>().~_Tp())>
1063 __test(int);
1064
1065 template<typename>
1066 static false_type __test(...);
1067 };
1068
1069 template<typename _Tp>
1070 struct __is_nt_destructible_impl
1071 : public __do_is_nt_destructible_impl
1072 {
1073 using type = decltype(__test<_Tp>(0));
1074 };
1075
1076 template<typename _Tp,
1077 bool = __or_<is_void<_Tp>,
1078 __is_array_unknown_bounds<_Tp>,
1079 is_function<_Tp>>::value,
1080 bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
1081 struct __is_nt_destructible_safe;
1082
1083 template<typename _Tp>
1084 struct __is_nt_destructible_safe<_Tp, false, false>
1085 : public __is_nt_destructible_impl<typename
1086 remove_all_extents<_Tp>::type>::type
1087 { };
1088
1089 template<typename _Tp>
1090 struct __is_nt_destructible_safe<_Tp, true, false>
1091 : public false_type { };
1092
1093 template<typename _Tp>
1094 struct __is_nt_destructible_safe<_Tp, false, true>
1095 : public true_type { };
1096 /// @endcond
1097
1098 /// is_nothrow_destructible
1099 template<typename _Tp>
1100 struct is_nothrow_destructible
1101 : public __is_nt_destructible_safe<_Tp>::type
1102 {
1103 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1104 "template argument must be a complete class or an unbounded array");
1105 };
1106
1107 /// @cond undocumented
1108 template<typename _Tp, typename... _Args>
1109 using __is_constructible_impl
1110 = __bool_constant<__is_constructible(_Tp, _Args...)>;
1111 /// @endcond
1112
1113 /// is_constructible
1114 template<typename _Tp, typename... _Args>
1115 struct is_constructible
1116 : public __is_constructible_impl<_Tp, _Args...>
1117 {
1118 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1119 "template argument must be a complete class or an unbounded array");
1120 };
1121
1122 /// is_default_constructible
1123 template<typename _Tp>
1124 struct is_default_constructible
1125 : public __is_constructible_impl<_Tp>
1126 {
1127 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1128 "template argument must be a complete class or an unbounded array");
1129 };
1130
1131 /// @cond undocumented
1132 template<typename _Tp, typename = void>
1133 struct __add_lvalue_reference_helper
1134 { using type = _Tp; };
1135
1136 template<typename _Tp>
1137 struct __add_lvalue_reference_helper<_Tp, __void_t<_Tp&>>
1138 { using type = _Tp&; };
1139
1140 template<typename _Tp>
1141 using __add_lval_ref_t = typename __add_lvalue_reference_helper<_Tp>::type;
1142 /// @endcond
1143
1144 /// is_copy_constructible
1145 template<typename _Tp>
1146 struct is_copy_constructible
1147 : public __is_constructible_impl<_Tp, __add_lval_ref_t<const _Tp>>
1148 {
1149 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1150 "template argument must be a complete class or an unbounded array");
1151 };
1152
1153 /// @cond undocumented
1154 template<typename _Tp, typename = void>
1155 struct __add_rvalue_reference_helper
1156 { using type = _Tp; };
1157
1158 template<typename _Tp>
1159 struct __add_rvalue_reference_helper<_Tp, __void_t<_Tp&&>>
1160 { using type = _Tp&&; };
1161
1162 template<typename _Tp>
1163 using __add_rval_ref_t = typename __add_rvalue_reference_helper<_Tp>::type;
1164 /// @endcond
1165
1166 /// is_move_constructible
1167 template<typename _Tp>
1168 struct is_move_constructible
1169 : public __is_constructible_impl<_Tp, __add_rval_ref_t<_Tp>>
1170 {
1171 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1172 "template argument must be a complete class or an unbounded array");
1173 };
1174
1175 /// @cond undocumented
1176 template<typename _Tp, typename... _Args>
1177 using __is_nothrow_constructible_impl
1178 = __bool_constant<__is_nothrow_constructible(_Tp, _Args...)>;
1179 /// @endcond
1180
1181 /// is_nothrow_constructible
1182 template<typename _Tp, typename... _Args>
1183 struct is_nothrow_constructible
1184 : public __is_nothrow_constructible_impl<_Tp, _Args...>
1185 {
1186 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1187 "template argument must be a complete class or an unbounded array");
1188 };
1189
1190 /// is_nothrow_default_constructible
1191 template<typename _Tp>
1192 struct is_nothrow_default_constructible
1193 : public __is_nothrow_constructible_impl<_Tp>
1194 {
1195 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1196 "template argument must be a complete class or an unbounded array");
1197 };
1198
1199 /// is_nothrow_copy_constructible
1200 template<typename _Tp>
1201 struct is_nothrow_copy_constructible
1202 : public __is_nothrow_constructible_impl<_Tp, __add_lval_ref_t<const _Tp>>
1203 {
1204 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1205 "template argument must be a complete class or an unbounded array");
1206 };
1207
1208 /// is_nothrow_move_constructible
1209 template<typename _Tp>
1210 struct is_nothrow_move_constructible
1211 : public __is_nothrow_constructible_impl<_Tp, __add_rval_ref_t<_Tp>>
1212 {
1213 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1214 "template argument must be a complete class or an unbounded array");
1215 };
1216
1217 /// @cond undocumented
1218 template<typename _Tp, typename _Up>
1219 using __is_assignable_impl = __bool_constant<__is_assignable(_Tp, _Up)>;
1220 /// @endcond
1221
1222 /// is_assignable
1223 template<typename _Tp, typename _Up>
1224 struct is_assignable
1225 : public __is_assignable_impl<_Tp, _Up>
1226 {
1227 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1228 "template argument must be a complete class or an unbounded array");
1229 };
1230
1231 /// is_copy_assignable
1232 template<typename _Tp>
1233 struct is_copy_assignable
1234 : public __is_assignable_impl<__add_lval_ref_t<_Tp>,
1235 __add_lval_ref_t<const _Tp>>
1236 {
1237 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1238 "template argument must be a complete class or an unbounded array");
1239 };
1240
1241 /// is_move_assignable
1242 template<typename _Tp>
1243 struct is_move_assignable
1244 : public __is_assignable_impl<__add_lval_ref_t<_Tp>, __add_rval_ref_t<_Tp>>
1245 {
1246 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1247 "template argument must be a complete class or an unbounded array");
1248 };
1249
1250 /// @cond undocumented
1251 template<typename _Tp, typename _Up>
1252 using __is_nothrow_assignable_impl
1253 = __bool_constant<__is_nothrow_assignable(_Tp, _Up)>;
1254 /// @endcond
1255
1256 /// is_nothrow_assignable
1257 template<typename _Tp, typename _Up>
1258 struct is_nothrow_assignable
1259 : public __is_nothrow_assignable_impl<_Tp, _Up>
1260 {
1261 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1262 "template argument must be a complete class or an unbounded array");
1263 };
1264
1265 /// is_nothrow_copy_assignable
1266 template<typename _Tp>
1267 struct is_nothrow_copy_assignable
1268 : public __is_nothrow_assignable_impl<__add_lval_ref_t<_Tp>,
1269 __add_lval_ref_t<const _Tp>>
1270 {
1271 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1272 "template argument must be a complete class or an unbounded array");
1273 };
1274
1275 /// is_nothrow_move_assignable
1276 template<typename _Tp>
1277 struct is_nothrow_move_assignable
1278 : public __is_nothrow_assignable_impl<__add_lval_ref_t<_Tp>,
1279 __add_rval_ref_t<_Tp>>
1280 {
1281 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1282 "template argument must be a complete class or an unbounded array");
1283 };
1284
1285 /// @cond undocumented
1286 template<typename _Tp, typename... _Args>
1287 using __is_trivially_constructible_impl
1288 = __bool_constant<__is_trivially_constructible(_Tp, _Args...)>;
1289 /// @endcond
1290
1291 /// is_trivially_constructible
1292 template<typename _Tp, typename... _Args>
1293 struct is_trivially_constructible
1294 : public __is_trivially_constructible_impl<_Tp, _Args...>
1295 {
1296 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1297 "template argument must be a complete class or an unbounded array");
1298 };
1299
1300 /// is_trivially_default_constructible
1301 template<typename _Tp>
1302 struct is_trivially_default_constructible
1303 : public __is_trivially_constructible_impl<_Tp>
1304 {
1305 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1306 "template argument must be a complete class or an unbounded array");
1307 };
1308
1309#if __cpp_variable_templates && __cpp_concepts
1310 template<typename _Tp>
1311 constexpr bool __is_implicitly_default_constructible_v
1312 = requires (void(&__f)(_Tp)) { __f({}); };
1313
1314 template<typename _Tp>
1315 struct __is_implicitly_default_constructible
1316 : __bool_constant<__is_implicitly_default_constructible_v<_Tp>>
1317 { };
1318#else
1319 struct __do_is_implicitly_default_constructible_impl
1320 {
1321 template <typename _Tp>
1322 static void __helper(const _Tp&);
1323
1324 template <typename _Tp>
1325 static true_type __test(const _Tp&,
1326 decltype(__helper<const _Tp&>({}))* = 0);
1327
1328 static false_type __test(...);
1329 };
1330
1331 template<typename _Tp>
1332 struct __is_implicitly_default_constructible_impl
1333 : public __do_is_implicitly_default_constructible_impl
1334 {
1335 using type = decltype(__test(declval<_Tp>()));
1336 };
1337
1338 template<typename _Tp>
1339 struct __is_implicitly_default_constructible_safe
1340 : public __is_implicitly_default_constructible_impl<_Tp>::type
1341 { };
1342
1343 template <typename _Tp>
1344 struct __is_implicitly_default_constructible
1345 : public __and_<__is_constructible_impl<_Tp>,
1346 __is_implicitly_default_constructible_safe<_Tp>>::type
1347 { };
1348#endif
1349
1350 /// is_trivially_copy_constructible
1351 template<typename _Tp>
1352 struct is_trivially_copy_constructible
1353 : public __is_trivially_constructible_impl<_Tp, __add_lval_ref_t<const _Tp>>
1354 {
1355 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1356 "template argument must be a complete class or an unbounded array");
1357 };
1358
1359 /// is_trivially_move_constructible
1360 template<typename _Tp>
1361 struct is_trivially_move_constructible
1362 : public __is_trivially_constructible_impl<_Tp, __add_rval_ref_t<_Tp>>
1363 {
1364 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1365 "template argument must be a complete class or an unbounded array");
1366 };
1367
1368 /// @cond undocumented
1369 template<typename _Tp, typename _Up>
1370 using __is_trivially_assignable_impl
1371 = __bool_constant<__is_trivially_assignable(_Tp, _Up)>;
1372 /// @endcond
1373
1374 /// is_trivially_assignable
1375 template<typename _Tp, typename _Up>
1376 struct is_trivially_assignable
1377 : public __is_trivially_assignable_impl<_Tp, _Up>
1378 {
1379 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1380 "template argument must be a complete class or an unbounded array");
1381 };
1382
1383 /// is_trivially_copy_assignable
1384 template<typename _Tp>
1385 struct is_trivially_copy_assignable
1386 : public __is_trivially_assignable_impl<__add_lval_ref_t<_Tp>,
1387 __add_lval_ref_t<const _Tp>>
1388 {
1389 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1390 "template argument must be a complete class or an unbounded array");
1391 };
1392
1393 /// is_trivially_move_assignable
1394 template<typename _Tp>
1395 struct is_trivially_move_assignable
1396 : public __is_trivially_assignable_impl<__add_lval_ref_t<_Tp>,
1397 __add_rval_ref_t<_Tp>>
1398 {
1399 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1400 "template argument must be a complete class or an unbounded array");
1401 };
1402
1403 /// is_trivially_destructible
1404 template<typename _Tp>
1405 struct is_trivially_destructible
1406 : public __and_<__is_destructible_safe<_Tp>,
1407 __bool_constant<__has_trivial_destructor(_Tp)>>::type
1408 {
1409 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1410 "template argument must be a complete class or an unbounded array");
1411 };
1412
1413
1414 /// has_virtual_destructor
1415 template<typename _Tp>
1416 struct has_virtual_destructor
1417 : public __bool_constant<__has_virtual_destructor(_Tp)>
1418 {
1419 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1420 "template argument must be a complete class or an unbounded array");
1421 };
1422
1423
1424 // type property queries.
1425
1426 /// alignment_of
1427 template<typename _Tp>
1428 struct alignment_of
1429 : public integral_constant<std::size_t, alignof(_Tp)>
1430 {
1431 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1432 "template argument must be a complete class or an unbounded array");
1433 };
1434
1435 /// rank
1436 template<typename>
1437 struct rank
1438 : public integral_constant<std::size_t, 0> { };
1439
1440 template<typename _Tp, std::size_t _Size>
1441 struct rank<_Tp[_Size]>
1442 : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
1443
1444 template<typename _Tp>
1445 struct rank<_Tp[]>
1446 : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
1447
1448 /// extent
1449 template<typename, unsigned _Uint = 0>
1450 struct extent
1451 : public integral_constant<size_t, 0> { };
1452
1453 template<typename _Tp, size_t _Size>
1454 struct extent<_Tp[_Size], 0>
1455 : public integral_constant<size_t, _Size> { };
1456
1457 template<typename _Tp, unsigned _Uint, size_t _Size>
1458 struct extent<_Tp[_Size], _Uint>
1459 : public extent<_Tp, _Uint - 1>::type { };
1460
1461 template<typename _Tp>
1462 struct extent<_Tp[], 0>
1463 : public integral_constant<size_t, 0> { };
1464
1465 template<typename _Tp, unsigned _Uint>
1466 struct extent<_Tp[], _Uint>
1467 : public extent<_Tp, _Uint - 1>::type { };
1468
1469
1470 // Type relations.
1471
1472 /// is_same
1473#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_same)
1474 template<typename _Tp, typename _Up>
1475 struct is_same
1476 : public __bool_constant<__is_same(_Tp, _Up)>
1477 { };
1478#else
1479 template<typename _Tp, typename _Up>
1480 struct is_same
1481 : public false_type
1482 { };
1483
1484 template<typename _Tp>
1485 struct is_same<_Tp, _Tp>
1486 : public true_type
1487 { };
1488#endif
1489
1490 /// is_base_of
1491 template<typename _Base, typename _Derived>
1492 struct is_base_of
1493 : public __bool_constant<__is_base_of(_Base, _Derived)>
1494 { };
1495
1496#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_convertible)
1497 template<typename _From, typename _To>
1498 struct is_convertible
1499 : public __bool_constant<__is_convertible(_From, _To)>
1500 { };
1501#else
1502 template<typename _From, typename _To,
1503 bool = __or_<is_void<_From>, is_function<_To>,
1504 is_array<_To>>::value>
1505 struct __is_convertible_helper
1506 {
1507 using type = typename is_void<_To>::type;
1508 };
1509
1510#pragma GCC diagnostic push
1511#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
1512 template<typename _From, typename _To>
1513 class __is_convertible_helper<_From, _To, false>
1514 {
1515 template<typename _To1>
1516 static void __test_aux(_To1) noexcept;
1517
1518 template<typename _From1, typename _To1,
1519 typename = decltype(__test_aux<_To1>(std::declval<_From1>()))>
1520 static true_type
1521 __test(int);
1522
1523 template<typename, typename>
1524 static false_type
1525 __test(...);
1526
1527 public:
1528 using type = decltype(__test<_From, _To>(0));
1529 };
1530#pragma GCC diagnostic pop
1531
1532 /// is_convertible
1533 template<typename _From, typename _To>
1534 struct is_convertible
1535 : public __is_convertible_helper<_From, _To>::type
1536 { };
1537#endif
1538
1539 // helper trait for unique_ptr<T[]>, shared_ptr<T[]>, and span<T, N>
1540 template<typename _ToElementType, typename _FromElementType>
1541 using __is_array_convertible
1542 = is_convertible<_FromElementType(*)[], _ToElementType(*)[]>;
1543
1544#ifdef __cpp_lib_is_nothrow_convertible // C++ >= 20
1545
1546#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_convertible)
1547 /// is_nothrow_convertible_v
1548 template<typename _From, typename _To>
1549 inline constexpr bool is_nothrow_convertible_v
1550 = __is_nothrow_convertible(_From, _To);
1551
1552 /// is_nothrow_convertible
1553 template<typename _From, typename _To>
1554 struct is_nothrow_convertible
1555 : public bool_constant<is_nothrow_convertible_v<_From, _To>>
1556 { };
1557#else
1558 template<typename _From, typename _To,
1559 bool = __or_<is_void<_From>, is_function<_To>,
1560 is_array<_To>>::value>
1561 struct __is_nt_convertible_helper
1562 : is_void<_To>
1563 { };
1564
1565#pragma GCC diagnostic push
1566#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
1567 template<typename _From, typename _To>
1568 class __is_nt_convertible_helper<_From, _To, false>
1569 {
1570 template<typename _To1>
1571 static void __test_aux(_To1) noexcept;
1572
1573 template<typename _From1, typename _To1>
1574 static
1575 __bool_constant<noexcept(__test_aux<_To1>(std::declval<_From1>()))>
1576 __test(int);
1577
1578 template<typename, typename>
1579 static false_type
1580 __test(...);
1581
1582 public:
1583 using type = decltype(__test<_From, _To>(0));
1584 };
1585#pragma GCC diagnostic pop
1586
1587 /// is_nothrow_convertible
1588 template<typename _From, typename _To>
1589 struct is_nothrow_convertible
1590 : public __is_nt_convertible_helper<_From, _To>::type
1591 { };
1592
1593 /// is_nothrow_convertible_v
1594 template<typename _From, typename _To>
1595 inline constexpr bool is_nothrow_convertible_v
1596 = is_nothrow_convertible<_From, _To>::value;
1597#endif
1598#endif // __cpp_lib_is_nothrow_convertible
1599
1600#pragma GCC diagnostic push
1601#pragma GCC diagnostic ignored "-Wc++14-extensions" // for variable templates
1602 template<typename _Tp, typename... _Args>
1603 struct __is_nothrow_new_constructible_impl
1604 : __bool_constant<
1605 noexcept(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))
1606 >
1607 { };
1608
1609 template<typename _Tp, typename... _Args>
1610 _GLIBCXX17_INLINE constexpr bool __is_nothrow_new_constructible
1611 = __and_<is_constructible<_Tp, _Args...>,
1612 __is_nothrow_new_constructible_impl<_Tp, _Args...>>::value;
1613#pragma GCC diagnostic pop
1614
1615 // Const-volatile modifications.
1616
1617 /// remove_const
1618 template<typename _Tp>
1619 struct remove_const
1620 { using type = _Tp; };
1621
1622 template<typename _Tp>
1623 struct remove_const<_Tp const>
1624 { using type = _Tp; };
1625
1626 /// remove_volatile
1627 template<typename _Tp>
1628 struct remove_volatile
1629 { using type = _Tp; };
1630
1631 template<typename _Tp>
1632 struct remove_volatile<_Tp volatile>
1633 { using type = _Tp; };
1634
1635 /// remove_cv
1636#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cv)
1637 template<typename _Tp>
1638 struct remove_cv
1639 { using type = __remove_cv(_Tp); };
1640#else
1641 template<typename _Tp>
1642 struct remove_cv
1643 { using type = _Tp; };
1644
1645 template<typename _Tp>
1646 struct remove_cv<const _Tp>
1647 { using type = _Tp; };
1648
1649 template<typename _Tp>
1650 struct remove_cv<volatile _Tp>
1651 { using type = _Tp; };
1652
1653 template<typename _Tp>
1654 struct remove_cv<const volatile _Tp>
1655 { using type = _Tp; };
1656#endif
1657
1658 /// add_const
1659 template<typename _Tp>
1660 struct add_const
1661 { using type = _Tp const; };
1662
1663 /// add_volatile
1664 template<typename _Tp>
1665 struct add_volatile
1666 { using type = _Tp volatile; };
1667
1668 /// add_cv
1669 template<typename _Tp>
1670 struct add_cv
1671 { using type = _Tp const volatile; };
1672
1673#ifdef __cpp_lib_transformation_trait_aliases // C++ >= 14
1674 /// Alias template for remove_const
1675 template<typename _Tp>
1676 using remove_const_t = typename remove_const<_Tp>::type;
1677
1678 /// Alias template for remove_volatile
1679 template<typename _Tp>
1680 using remove_volatile_t = typename remove_volatile<_Tp>::type;
1681
1682 /// Alias template for remove_cv
1683 template<typename _Tp>
1684 using remove_cv_t = typename remove_cv<_Tp>::type;
1685
1686 /// Alias template for add_const
1687 template<typename _Tp>
1688 using add_const_t = typename add_const<_Tp>::type;
1689
1690 /// Alias template for add_volatile
1691 template<typename _Tp>
1692 using add_volatile_t = typename add_volatile<_Tp>::type;
1693
1694 /// Alias template for add_cv
1695 template<typename _Tp>
1696 using add_cv_t = typename add_cv<_Tp>::type;
1697#endif
1698
1699 // Reference transformations.
1700
1701 /// remove_reference
1702#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_reference)
1703 template<typename _Tp>
1704 struct remove_reference
1705 { using type = __remove_reference(_Tp); };
1706#else
1707 template<typename _Tp>
1708 struct remove_reference
1709 { using type = _Tp; };
1710
1711 template<typename _Tp>
1712 struct remove_reference<_Tp&>
1713 { using type = _Tp; };
1714
1715 template<typename _Tp>
1716 struct remove_reference<_Tp&&>
1717 { using type = _Tp; };
1718#endif
1719
1720 /// add_lvalue_reference
1721 template<typename _Tp>
1722 struct add_lvalue_reference
1723 { using type = __add_lval_ref_t<_Tp>; };
1724
1725 /// add_rvalue_reference
1726 template<typename _Tp>
1727 struct add_rvalue_reference
1728 { using type = __add_rval_ref_t<_Tp>; };
1729
1730#if __cplusplus > 201103L
1731 /// Alias template for remove_reference
1732 template<typename _Tp>
1733 using remove_reference_t = typename remove_reference<_Tp>::type;
1734
1735 /// Alias template for add_lvalue_reference
1736 template<typename _Tp>
1737 using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1738
1739 /// Alias template for add_rvalue_reference
1740 template<typename _Tp>
1741 using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1742#endif
1743
1744 // Sign modifications.
1745
1746 /// @cond undocumented
1747
1748 // Utility for constructing identically cv-qualified types.
1749 template<typename _Unqualified, bool _IsConst, bool _IsVol>
1750 struct __cv_selector;
1751
1752 template<typename _Unqualified>
1753 struct __cv_selector<_Unqualified, false, false>
1754 { using __type = _Unqualified; };
1755
1756 template<typename _Unqualified>
1757 struct __cv_selector<_Unqualified, false, true>
1758 { using __type = volatile _Unqualified; };
1759
1760 template<typename _Unqualified>
1761 struct __cv_selector<_Unqualified, true, false>
1762 { using __type = const _Unqualified; };
1763
1764 template<typename _Unqualified>
1765 struct __cv_selector<_Unqualified, true, true>
1766 { using __type = const volatile _Unqualified; };
1767
1768 template<typename _Qualified, typename _Unqualified,
1769 bool _IsConst = is_const<_Qualified>::value,
1770 bool _IsVol = is_volatile<_Qualified>::value>
1771 class __match_cv_qualifiers
1772 {
1773 using __match = __cv_selector<_Unqualified, _IsConst, _IsVol>;
1774
1775 public:
1776 using __type = typename __match::__type;
1777 };
1778
1779 // Utility for finding the unsigned versions of signed integral types.
1780 template<typename _Tp>
1781 struct __make_unsigned
1782 { using __type = _Tp; };
1783
1784 template<>
1785 struct __make_unsigned<char>
1786 { using __type = unsigned char; };
1787
1788 template<>
1789 struct __make_unsigned<signed char>
1790 { using __type = unsigned char; };
1791
1792 template<>
1793 struct __make_unsigned<short>
1794 { using __type = unsigned short; };
1795
1796 template<>
1797 struct __make_unsigned<int>
1798 { using __type = unsigned int; };
1799
1800 template<>
1801 struct __make_unsigned<long>
1802 { using __type = unsigned long; };
1803
1804 template<>
1805 struct __make_unsigned<long long>
1806 { using __type = unsigned long long; };
1807
1808#if defined(__GLIBCXX_TYPE_INT_N_0)
1809 __extension__
1810 template<>
1811 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_0>
1812 { using __type = unsigned __GLIBCXX_TYPE_INT_N_0; };
1813#endif
1814#if defined(__GLIBCXX_TYPE_INT_N_1)
1815 __extension__
1816 template<>
1817 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_1>
1818 { using __type = unsigned __GLIBCXX_TYPE_INT_N_1; };
1819#endif
1820#if defined(__GLIBCXX_TYPE_INT_N_2)
1821 __extension__
1822 template<>
1823 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_2>
1824 { using __type = unsigned __GLIBCXX_TYPE_INT_N_2; };
1825#endif
1826#if defined(__GLIBCXX_TYPE_INT_N_3)
1827 __extension__
1828 template<>
1829 struct __make_unsigned<__GLIBCXX_TYPE_INT_N_3>
1830 { using __type = unsigned __GLIBCXX_TYPE_INT_N_3; };
1831#endif
1832
1833 // Select between integral and enum: not possible to be both.
1834 template<typename _Tp,
1835 bool _IsInt = is_integral<_Tp>::value,
1836 bool _IsEnum = __is_enum(_Tp)>
1837 class __make_unsigned_selector;
1838
1839 template<typename _Tp>
1840 class __make_unsigned_selector<_Tp, true, false>
1841 {
1842 using __unsigned_type
1843 = typename __make_unsigned<__remove_cv_t<_Tp>>::__type;
1844
1845 public:
1846 using __type
1847 = typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
1848 };
1849
1850 class __make_unsigned_selector_base
1851 {
1852 protected:
1853 template<typename...> struct _List { };
1854
1855 template<typename _Tp, typename... _Up>
1856 struct _List<_Tp, _Up...> : _List<_Up...>
1857 { static constexpr size_t __size = sizeof(_Tp); };
1858
1859 template<size_t _Sz, typename _Tp, bool = (_Sz <= _Tp::__size)>
1860 struct __select;
1861
1862 template<size_t _Sz, typename _Uint, typename... _UInts>
1863 struct __select<_Sz, _List<_Uint, _UInts...>, true>
1864 { using __type = _Uint; };
1865
1866 template<size_t _Sz, typename _Uint, typename... _UInts>
1867 struct __select<_Sz, _List<_Uint, _UInts...>, false>
1868 : __select<_Sz, _List<_UInts...>>
1869 { };
1870 };
1871
1872 // Choose unsigned integer type with the smallest rank and same size as _Tp
1873 template<typename _Tp>
1874 class __make_unsigned_selector<_Tp, false, true>
1875 : __make_unsigned_selector_base
1876 {
1877 // With -fshort-enums, an enum may be as small as a char.
1878 using _UInts = _List<unsigned char, unsigned short, unsigned int,
1879 unsigned long, unsigned long long>;
1880
1881 using __unsigned_type = typename __select<sizeof(_Tp), _UInts>::__type;
1882
1883 public:
1884 using __type
1885 = typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
1886 };
1887
1888 // wchar_t, char8_t, char16_t and char32_t are integral types but are
1889 // neither signed integer types nor unsigned integer types, so must be
1890 // transformed to the unsigned integer type with the smallest rank.
1891 // Use the partial specialization for enumeration types to do that.
1892 template<>
1893 struct __make_unsigned<wchar_t>
1894 {
1895 using __type
1896 = typename __make_unsigned_selector<wchar_t, false, true>::__type;
1897 };
1898
1899#ifdef _GLIBCXX_USE_CHAR8_T
1900 template<>
1901 struct __make_unsigned<char8_t>
1902 {
1903 using __type
1904 = typename __make_unsigned_selector<char8_t, false, true>::__type;
1905 };
1906#endif
1907
1908 template<>
1909 struct __make_unsigned<char16_t>
1910 {
1911 using __type
1912 = typename __make_unsigned_selector<char16_t, false, true>::__type;
1913 };
1914
1915 template<>
1916 struct __make_unsigned<char32_t>
1917 {
1918 using __type
1919 = typename __make_unsigned_selector<char32_t, false, true>::__type;
1920 };
1921 /// @endcond
1922
1923 // Given an integral/enum type, return the corresponding unsigned
1924 // integer type.
1925 // Primary template.
1926 /// make_unsigned
1927 template<typename _Tp>
1928 struct make_unsigned
1929 { using type = typename __make_unsigned_selector<_Tp>::__type; };
1930
1931 // Integral, but don't define.
1932 template<> struct make_unsigned<bool>;
1933 template<> struct make_unsigned<bool const>;
1934 template<> struct make_unsigned<bool volatile>;
1935 template<> struct make_unsigned<bool const volatile>;
1936
1937 /// @cond undocumented
1938
1939 // Utility for finding the signed versions of unsigned integral types.
1940 template<typename _Tp>
1941 struct __make_signed
1942 { using __type = _Tp; };
1943
1944 template<>
1945 struct __make_signed<char>
1946 { using __type = signed char; };
1947
1948 template<>
1949 struct __make_signed<unsigned char>
1950 { using __type = signed char; };
1951
1952 template<>
1953 struct __make_signed<unsigned short>
1954 { using __type = signed short; };
1955
1956 template<>
1957 struct __make_signed<unsigned int>
1958 { using __type = signed int; };
1959
1960 template<>
1961 struct __make_signed<unsigned long>
1962 { using __type = signed long; };
1963
1964 template<>
1965 struct __make_signed<unsigned long long>
1966 { using __type = signed long long; };
1967
1968#if defined(__GLIBCXX_TYPE_INT_N_0)
1969 __extension__
1970 template<>
1971 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_0>
1972 { using __type = __GLIBCXX_TYPE_INT_N_0; };
1973#endif
1974#if defined(__GLIBCXX_TYPE_INT_N_1)
1975 __extension__
1976 template<>
1977 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_1>
1978 { using __type = __GLIBCXX_TYPE_INT_N_1; };
1979#endif
1980#if defined(__GLIBCXX_TYPE_INT_N_2)
1981 __extension__
1982 template<>
1983 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_2>
1984 { using __type = __GLIBCXX_TYPE_INT_N_2; };
1985#endif
1986#if defined(__GLIBCXX_TYPE_INT_N_3)
1987 __extension__
1988 template<>
1989 struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_3>
1990 { using __type = __GLIBCXX_TYPE_INT_N_3; };
1991#endif
1992
1993 // Select between integral and enum: not possible to be both.
1994 template<typename _Tp,
1995 bool _IsInt = is_integral<_Tp>::value,
1996 bool _IsEnum = __is_enum(_Tp)>
1997 class __make_signed_selector;
1998
1999 template<typename _Tp>
2000 class __make_signed_selector<_Tp, true, false>
2001 {
2002 using __signed_type
2003 = typename __make_signed<__remove_cv_t<_Tp>>::__type;
2004
2005 public:
2006 using __type
2007 = typename __match_cv_qualifiers<_Tp, __signed_type>::__type;
2008 };
2009
2010 // Choose signed integer type with the smallest rank and same size as _Tp
2011 template<typename _Tp>
2012 class __make_signed_selector<_Tp, false, true>
2013 {
2014 using __unsigned_type = typename __make_unsigned_selector<_Tp>::__type;
2015
2016 public:
2017 using __type = typename __make_signed_selector<__unsigned_type>::__type;
2018 };
2019
2020 // wchar_t, char16_t and char32_t are integral types but are neither
2021 // signed integer types nor unsigned integer types, so must be
2022 // transformed to the signed integer type with the smallest rank.
2023 // Use the partial specialization for enumeration types to do that.
2024 template<>
2025 struct __make_signed<wchar_t>
2026 {
2027 using __type
2028 = typename __make_signed_selector<wchar_t, false, true>::__type;
2029 };
2030
2031#if defined(_GLIBCXX_USE_CHAR8_T)
2032 template<>
2033 struct __make_signed<char8_t>
2034 {
2035 using __type
2036 = typename __make_signed_selector<char8_t, false, true>::__type;
2037 };
2038#endif
2039
2040 template<>
2041 struct __make_signed<char16_t>
2042 {
2043 using __type
2044 = typename __make_signed_selector<char16_t, false, true>::__type;
2045 };
2046
2047 template<>
2048 struct __make_signed<char32_t>
2049 {
2050 using __type
2051 = typename __make_signed_selector<char32_t, false, true>::__type;
2052 };
2053 /// @endcond
2054
2055 // Given an integral/enum type, return the corresponding signed
2056 // integer type.
2057 // Primary template.
2058 /// make_signed
2059 template<typename _Tp>
2060 struct make_signed
2061 { using type = typename __make_signed_selector<_Tp>::__type; };
2062
2063 // Integral, but don't define.
2064 template<> struct make_signed<bool>;
2065 template<> struct make_signed<bool const>;
2066 template<> struct make_signed<bool volatile>;
2067 template<> struct make_signed<bool const volatile>;
2068
2069#if __cplusplus > 201103L
2070 /// Alias template for make_signed
2071 template<typename _Tp>
2072 using make_signed_t = typename make_signed<_Tp>::type;
2073
2074 /// Alias template for make_unsigned
2075 template<typename _Tp>
2076 using make_unsigned_t = typename make_unsigned<_Tp>::type;
2077#endif
2078
2079 // Array modifications.
2080
2081 /// remove_extent
2082 template<typename _Tp>
2083 struct remove_extent
2084 { using type = _Tp; };
2085
2086 template<typename _Tp, std::size_t _Size>
2087 struct remove_extent<_Tp[_Size]>
2088 { using type = _Tp; };
2089
2090 template<typename _Tp>
2091 struct remove_extent<_Tp[]>
2092 { using type = _Tp; };
2093
2094 /// remove_all_extents
2095 template<typename _Tp>
2096 struct remove_all_extents
2097 { using type = _Tp; };
2098
2099 template<typename _Tp, std::size_t _Size>
2100 struct remove_all_extents<_Tp[_Size]>
2101 { using type = typename remove_all_extents<_Tp>::type; };
2102
2103 template<typename _Tp>
2104 struct remove_all_extents<_Tp[]>
2105 { using type = typename remove_all_extents<_Tp>::type; };
2106
2107#if __cplusplus > 201103L
2108 /// Alias template for remove_extent
2109 template<typename _Tp>
2110 using remove_extent_t = typename remove_extent<_Tp>::type;
2111
2112 /// Alias template for remove_all_extents
2113 template<typename _Tp>
2114 using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
2115#endif
2116
2117 // Pointer modifications.
2118
2119 /// remove_pointer
2120#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_pointer)
2121 template<typename _Tp>
2122 struct remove_pointer
2123 { using type = __remove_pointer(_Tp); };
2124#else
2125 template<typename _Tp, typename>
2126 struct __remove_pointer_helper
2127 { using type = _Tp; };
2128
2129 template<typename _Tp, typename _Up>
2130 struct __remove_pointer_helper<_Tp, _Up*>
2131 { using type = _Up; };
2132
2133 template<typename _Tp>
2134 struct remove_pointer
2135 : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
2136 { };
2137#endif
2138
2139 template<typename _Tp, typename = void>
2140 struct __add_pointer_helper
2141 { using type = _Tp; };
2142
2143 template<typename _Tp>
2144 struct __add_pointer_helper<_Tp, __void_t<_Tp*>>
2145 { using type = _Tp*; };
2146
2147 /// add_pointer
2148 template<typename _Tp>
2149 struct add_pointer
2150 : public __add_pointer_helper<_Tp>
2151 { };
2152
2153 template<typename _Tp>
2154 struct add_pointer<_Tp&>
2155 { using type = _Tp*; };
2156
2157 template<typename _Tp>
2158 struct add_pointer<_Tp&&>
2159 { using type = _Tp*; };
2160
2161#if __cplusplus > 201103L
2162 /// Alias template for remove_pointer
2163 template<typename _Tp>
2164 using remove_pointer_t = typename remove_pointer<_Tp>::type;
2165
2166 /// Alias template for add_pointer
2167 template<typename _Tp>
2168 using add_pointer_t = typename add_pointer<_Tp>::type;
2169#endif
2170
2171 template<std::size_t _Len>
2172 struct __aligned_storage_msa
2173 {
2174 union __type
2175 {
2176 unsigned char __data[_Len];
2177 struct __attribute__((__aligned__)) { } __align;
2178 };
2179 };
2180
2181 /**
2182 * @brief Alignment type.
2183 *
2184 * The value of _Align is a default-alignment which shall be the
2185 * most stringent alignment requirement for any C++ object type
2186 * whose size is no greater than _Len (3.9). The member typedef
2187 * type shall be a POD type suitable for use as uninitialized
2188 * storage for any object whose size is at most _Len and whose
2189 * alignment is a divisor of _Align.
2190 *
2191 * @deprecated Deprecated in C++23. Uses can be replaced by an
2192 * array std::byte[_Len] declared with alignas(_Align).
2193 */
2194 template<std::size_t _Len, std::size_t _Align =
2195 __alignof__(typename __aligned_storage_msa<_Len>::__type)>
2196 struct
2197 _GLIBCXX23_DEPRECATED
2198 aligned_storage
2199 {
2200 union type
2201 {
2202 unsigned char __data[_Len];
2203 struct __attribute__((__aligned__((_Align)))) { } __align;
2204 };
2205 };
2206
2207 template <typename... _Types>
2208 struct __strictest_alignment
2209 {
2210 static const size_t _S_alignment = 0;
2211 static const size_t _S_size = 0;
2212 };
2213
2214 template <typename _Tp, typename... _Types>
2215 struct __strictest_alignment<_Tp, _Types...>
2216 {
2217 static const size_t _S_alignment =
2218 alignof(_Tp) > __strictest_alignment<_Types...>::_S_alignment
2219 ? alignof(_Tp) : __strictest_alignment<_Types...>::_S_alignment;
2220 static const size_t _S_size =
2221 sizeof(_Tp) > __strictest_alignment<_Types...>::_S_size
2222 ? sizeof(_Tp) : __strictest_alignment<_Types...>::_S_size;
2223 };
2224
2225#pragma GCC diagnostic push
2226#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
2227
2228 /**
2229 * @brief Provide aligned storage for types.
2230 *
2231 * [meta.trans.other]
2232 *
2233 * Provides aligned storage for any of the provided types of at
2234 * least size _Len.
2235 *
2236 * @see aligned_storage
2237 *
2238 * @deprecated Deprecated in C++23.
2239 */
2240 template <size_t _Len, typename... _Types>
2241 struct
2242 _GLIBCXX23_DEPRECATED
2243 aligned_union
2244 {
2245 private:
2246 static_assert(sizeof...(_Types) != 0, "At least one type is required");
2247
2248 using __strictest = __strictest_alignment<_Types...>;
2249 static const size_t _S_len = _Len > __strictest::_S_size
2250 ? _Len : __strictest::_S_size;
2251 public:
2252 /// The value of the strictest alignment of _Types.
2253 static const size_t alignment_value = __strictest::_S_alignment;
2254 /// The storage.
2255 using type = typename aligned_storage<_S_len, alignment_value>::type;
2256 };
2257
2258 template <size_t _Len, typename... _Types>
2259 const size_t aligned_union<_Len, _Types...>::alignment_value;
2260#pragma GCC diagnostic pop
2261
2262 /// @cond undocumented
2263
2264 // Decay trait for arrays and functions, used for perfect forwarding
2265 // in make_pair, make_tuple, etc.
2266 template<typename _Up>
2267 struct __decay_selector
2268 : __conditional_t<is_const<const _Up>::value, // false for functions
2269 remove_cv<_Up>, // N.B. DR 705.
2270 add_pointer<_Up>> // function decays to pointer
2271 { };
2272
2273 template<typename _Up, size_t _Nm>
2274 struct __decay_selector<_Up[_Nm]>
2275 { using type = _Up*; };
2276
2277 template<typename _Up>
2278 struct __decay_selector<_Up[]>
2279 { using type = _Up*; };
2280
2281 /// @endcond
2282
2283 /// decay
2284 template<typename _Tp>
2285 struct decay
2286 { using type = typename __decay_selector<_Tp>::type; };
2287
2288 template<typename _Tp>
2289 struct decay<_Tp&>
2290 { using type = typename __decay_selector<_Tp>::type; };
2291
2292 template<typename _Tp>
2293 struct decay<_Tp&&>
2294 { using type = typename __decay_selector<_Tp>::type; };
2295
2296 /// @cond undocumented
2297
2298 // Helper which adds a reference to a type when given a reference_wrapper
2299 template<typename _Tp>
2300 struct __strip_reference_wrapper
2301 {
2302 using __type = _Tp;
2303 };
2304
2305 template<typename _Tp>
2306 struct __strip_reference_wrapper<reference_wrapper<_Tp> >
2307 {
2308 using __type = _Tp&;
2309 };
2310
2311 // __decay_t (std::decay_t for C++11).
2312 template<typename _Tp>
2313 using __decay_t = typename decay<_Tp>::type;
2314
2315 template<typename _Tp>
2316 using __decay_and_strip = __strip_reference_wrapper<__decay_t<_Tp>>;
2317 /// @endcond
2318
2319 /// @cond undocumented
2320
2321 // Helper for SFINAE constraints
2322 template<typename... _Cond>
2323 using _Require = __enable_if_t<__and_<_Cond...>::value>;
2324
2325 // __remove_cvref_t (std::remove_cvref_t for C++11).
2326 template<typename _Tp>
2327 using __remove_cvref_t
2328 = typename remove_cv<typename remove_reference<_Tp>::type>::type;
2329 /// @endcond
2330
2331 // Primary template.
2332 /// Define a member typedef @c type to one of two argument types.
2333 template<bool _Cond, typename _Iftrue, typename _Iffalse>
2334 struct conditional
2335 { using type = _Iftrue; };
2336
2337 // Partial specialization for false.
2338 template<typename _Iftrue, typename _Iffalse>
2339 struct conditional<false, _Iftrue, _Iffalse>
2340 { using type = _Iffalse; };
2341
2342 /// common_type
2343 template<typename... _Tp>
2344 struct common_type;
2345
2346 // Sfinae-friendly common_type implementation:
2347
2348 /// @cond undocumented
2349
2350 // For several sfinae-friendly trait implementations we transport both the
2351 // result information (as the member type) and the failure information (no
2352 // member type). This is very similar to std::enable_if, but we cannot use
2353 // that, because we need to derive from them as an implementation detail.
2354
2355 template<typename _Tp>
2356 struct __success_type
2357 { using type = _Tp; };
2358
2359 struct __failure_type
2360 { };
2361
2362 struct __do_common_type_impl
2363 {
2364 template<typename _Tp, typename _Up>
2365 using __cond_t
2366 = decltype(true ? std::declval<_Tp>() : std::declval<_Up>());
2367
2368 // if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
2369 // denotes a valid type, let C denote that type.
2370 template<typename _Tp, typename _Up>
2371 static __success_type<__decay_t<__cond_t<_Tp, _Up>>>
2372 _S_test(int);
2373
2374#if __cplusplus > 201703L
2375 // Otherwise, if COND-RES(CREF(D1), CREF(D2)) denotes a type,
2376 // let C denote the type decay_t<COND-RES(CREF(D1), CREF(D2))>.
2377 template<typename _Tp, typename _Up>
2378 static __success_type<__remove_cvref_t<__cond_t<const _Tp&, const _Up&>>>
2379 _S_test_2(int);
2380#endif
2381
2382 template<typename, typename>
2383 static __failure_type
2384 _S_test_2(...);
2385
2386 template<typename _Tp, typename _Up>
2387 static decltype(_S_test_2<_Tp, _Up>(0))
2388 _S_test(...);
2389 };
2390
2391 // If sizeof...(T) is zero, there shall be no member type.
2392 template<>
2393 struct common_type<>
2394 { };
2395
2396 // If sizeof...(T) is one, the same type, if any, as common_type_t<T0, T0>.
2397 template<typename _Tp0>
2398 struct common_type<_Tp0>
2399 : public common_type<_Tp0, _Tp0>
2400 { };
2401
2402 // If sizeof...(T) is two, ...
2403 template<typename _Tp1, typename _Tp2,
2404 typename _Dp1 = __decay_t<_Tp1>, typename _Dp2 = __decay_t<_Tp2>>
2405 struct __common_type_impl
2406 {
2407 // If is_same_v<T1, D1> is false or is_same_v<T2, D2> is false,
2408 // let C denote the same type, if any, as common_type_t<D1, D2>.
2409 using type = common_type<_Dp1, _Dp2>;
2410 };
2411
2412 template<typename _Tp1, typename _Tp2>
2413 struct __common_type_impl<_Tp1, _Tp2, _Tp1, _Tp2>
2414 : private __do_common_type_impl
2415 {
2416 // Otherwise, if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
2417 // denotes a valid type, let C denote that type.
2418 using type = decltype(_S_test<_Tp1, _Tp2>(0));
2419 };
2420
2421 // If sizeof...(T) is two, ...
2422 template<typename _Tp1, typename _Tp2>
2423 struct common_type<_Tp1, _Tp2>
2424 : public __common_type_impl<_Tp1, _Tp2>::type
2425 { };
2426
2427 template<typename...>
2428 struct __common_type_pack
2429 { };
2430
2431 template<typename, typename, typename = void>
2432 struct __common_type_fold;
2433
2434 // If sizeof...(T) is greater than two, ...
2435 template<typename _Tp1, typename _Tp2, typename... _Rp>
2436 struct common_type<_Tp1, _Tp2, _Rp...>
2437 : public __common_type_fold<common_type<_Tp1, _Tp2>,
2438 __common_type_pack<_Rp...>>
2439 { };
2440
2441 // Let C denote the same type, if any, as common_type_t<T1, T2>.
2442 // If there is such a type C, type shall denote the same type, if any,
2443 // as common_type_t<C, R...>.
2444 template<typename _CTp, typename... _Rp>
2445 struct __common_type_fold<_CTp, __common_type_pack<_Rp...>,
2446 __void_t<typename _CTp::type>>
2447 : public common_type<typename _CTp::type, _Rp...>
2448 { };
2449
2450 // Otherwise, there shall be no member type.
2451 template<typename _CTp, typename _Rp>
2452 struct __common_type_fold<_CTp, _Rp, void>
2453 { };
2454
2455 template<typename _Tp, bool = __is_enum(_Tp)>
2456 struct __underlying_type_impl
2457 {
2458 using type = __underlying_type(_Tp);
2459 };
2460
2461 template<typename _Tp>
2462 struct __underlying_type_impl<_Tp, false>
2463 { };
2464 /// @endcond
2465
2466 /// The underlying type of an enum.
2467 template<typename _Tp>
2468 struct underlying_type
2469 : public __underlying_type_impl<_Tp>
2470 { };
2471
2472 /// @cond undocumented
2473 template<typename _Tp>
2474 struct __declval_protector
2475 {
2476 static const bool __stop = false;
2477 };
2478 /// @endcond
2479
2480 /** Utility to simplify expressions used in unevaluated operands
2481 * @since C++11
2482 * @ingroup utilities
2483 */
2484 template<typename _Tp>
2485 auto declval() noexcept -> decltype(__declval<_Tp>(0))
2486 {
2487 static_assert(__declval_protector<_Tp>::__stop,
2488 "declval() must not be used!");
2489 return __declval<_Tp>(0);
2490 }
2491
2492 /// result_of
2493 template<typename _Signature>
2494 struct result_of;
2495
2496 // Sfinae-friendly result_of implementation:
2497
2498 /// @cond undocumented
2499 struct __invoke_memfun_ref { };
2500 struct __invoke_memfun_deref { };
2501 struct __invoke_memobj_ref { };
2502 struct __invoke_memobj_deref { };
2503 struct __invoke_other { };
2504
2505 // Associate a tag type with a specialization of __success_type.
2506 template<typename _Tp, typename _Tag>
2507 struct __result_of_success : __success_type<_Tp>
2508 { using __invoke_type = _Tag; };
2509
2510 // [func.require] paragraph 1 bullet 1:
2511 struct __result_of_memfun_ref_impl
2512 {
2513 template<typename _Fp, typename _Tp1, typename... _Args>
2514 static __result_of_success<decltype(
2515 (std::declval<_Tp1>().*std::declval<_Fp>())(std::declval<_Args>()...)
2516 ), __invoke_memfun_ref> _S_test(int);
2517
2518 template<typename...>
2519 static __failure_type _S_test(...);
2520 };
2521
2522 template<typename _MemPtr, typename _Arg, typename... _Args>
2523 struct __result_of_memfun_ref
2524 : private __result_of_memfun_ref_impl
2525 {
2526 using type = decltype(_S_test<_MemPtr, _Arg, _Args...>(0));
2527 };
2528
2529 // [func.require] paragraph 1 bullet 2:
2530 struct __result_of_memfun_deref_impl
2531 {
2532 template<typename _Fp, typename _Tp1, typename... _Args>
2533 static __result_of_success<decltype(
2534 ((*std::declval<_Tp1>()).*std::declval<_Fp>())(std::declval<_Args>()...)
2535 ), __invoke_memfun_deref> _S_test(int);
2536
2537 template<typename...>
2538 static __failure_type _S_test(...);
2539 };
2540
2541 template<typename _MemPtr, typename _Arg, typename... _Args>
2542 struct __result_of_memfun_deref
2543 : private __result_of_memfun_deref_impl
2544 {
2545 using type = decltype(_S_test<_MemPtr, _Arg, _Args...>(0));
2546 };
2547
2548 // [func.require] paragraph 1 bullet 3:
2549 struct __result_of_memobj_ref_impl
2550 {
2551 template<typename _Fp, typename _Tp1>
2552 static __result_of_success<decltype(
2553 std::declval<_Tp1>().*std::declval<_Fp>()
2554 ), __invoke_memobj_ref> _S_test(int);
2555
2556 template<typename, typename>
2557 static __failure_type _S_test(...);
2558 };
2559
2560 template<typename _MemPtr, typename _Arg>
2561 struct __result_of_memobj_ref
2562 : private __result_of_memobj_ref_impl
2563 {
2564 using type = decltype(_S_test<_MemPtr, _Arg>(0));
2565 };
2566
2567 // [func.require] paragraph 1 bullet 4:
2568 struct __result_of_memobj_deref_impl
2569 {
2570 template<typename _Fp, typename _Tp1>
2571 static __result_of_success<decltype(
2572 (*std::declval<_Tp1>()).*std::declval<_Fp>()
2573 ), __invoke_memobj_deref> _S_test(int);
2574
2575 template<typename, typename>
2576 static __failure_type _S_test(...);
2577 };
2578
2579 template<typename _MemPtr, typename _Arg>
2580 struct __result_of_memobj_deref
2581 : private __result_of_memobj_deref_impl
2582 {
2583 using type = decltype(_S_test<_MemPtr, _Arg>(0));
2584 };
2585
2586 template<typename _MemPtr, typename _Arg>
2587 struct __result_of_memobj;
2588
2589 template<typename _Res, typename _Class, typename _Arg>
2590 struct __result_of_memobj<_Res _Class::*, _Arg>
2591 {
2592 using _Argval = __remove_cvref_t<_Arg>;
2593 using _MemPtr = _Res _Class::*;
2594 using type = typename __conditional_t<__or_<is_same<_Argval, _Class>,
2595 is_base_of<_Class, _Argval>>::value,
2596 __result_of_memobj_ref<_MemPtr, _Arg>,
2597 __result_of_memobj_deref<_MemPtr, _Arg>
2598 >::type;
2599 };
2600
2601 template<typename _MemPtr, typename _Arg, typename... _Args>
2602 struct __result_of_memfun;
2603
2604 template<typename _Res, typename _Class, typename _Arg, typename... _Args>
2605 struct __result_of_memfun<_Res _Class::*, _Arg, _Args...>
2606 {
2607 using _Argval = typename remove_reference<_Arg>::type;
2608 using _MemPtr = _Res _Class::*;
2609 using type = typename __conditional_t<is_base_of<_Class, _Argval>::value,
2610 __result_of_memfun_ref<_MemPtr, _Arg, _Args...>,
2611 __result_of_memfun_deref<_MemPtr, _Arg, _Args...>
2612 >::type;
2613 };
2614
2615 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2616 // 2219. INVOKE-ing a pointer to member with a reference_wrapper
2617 // as the object expression
2618
2619 // Used by result_of, invoke etc. to unwrap a reference_wrapper.
2620 template<typename _Tp, typename _Up = __remove_cvref_t<_Tp>>
2621 struct __inv_unwrap
2622 {
2623 using type = _Tp;
2624 };
2625
2626 template<typename _Tp, typename _Up>
2627 struct __inv_unwrap<_Tp, reference_wrapper<_Up>>
2628 {
2629 using type = _Up&;
2630 };
2631
2632 template<bool, bool, typename _Functor, typename... _ArgTypes>
2633 struct __result_of_impl
2634 {
2635 using type = __failure_type;
2636 };
2637
2638 template<typename _MemPtr, typename _Arg>
2639 struct __result_of_impl<true, false, _MemPtr, _Arg>
2640 : public __result_of_memobj<__decay_t<_MemPtr>,
2641 typename __inv_unwrap<_Arg>::type>
2642 { };
2643
2644 template<typename _MemPtr, typename _Arg, typename... _Args>
2645 struct __result_of_impl<false, true, _MemPtr, _Arg, _Args...>
2646 : public __result_of_memfun<__decay_t<_MemPtr>,
2647 typename __inv_unwrap<_Arg>::type, _Args...>
2648 { };
2649
2650 // [func.require] paragraph 1 bullet 5:
2651 struct __result_of_other_impl
2652 {
2653 template<typename _Fn, typename... _Args>
2654 static __result_of_success<decltype(
2655 std::declval<_Fn>()(std::declval<_Args>()...)
2656 ), __invoke_other> _S_test(int);
2657
2658 template<typename...>
2659 static __failure_type _S_test(...);
2660 };
2661
2662 template<typename _Functor, typename... _ArgTypes>
2663 struct __result_of_impl<false, false, _Functor, _ArgTypes...>
2664 : private __result_of_other_impl
2665 {
2666 using type = decltype(_S_test<_Functor, _ArgTypes...>(0));
2667 };
2668
2669 // __invoke_result (std::invoke_result for C++11)
2670 template<typename _Functor, typename... _ArgTypes>
2671 struct __invoke_result
2672 : public __result_of_impl<
2673 is_member_object_pointer<
2674 typename remove_reference<_Functor>::type
2675 >::value,
2676 is_member_function_pointer<
2677 typename remove_reference<_Functor>::type
2678 >::value,
2679 _Functor, _ArgTypes...
2680 >::type
2681 { };
2682
2683 // __invoke_result_t (std::invoke_result_t for C++11)
2684 template<typename _Fn, typename... _Args>
2685 using __invoke_result_t = typename __invoke_result<_Fn, _Args...>::type;
2686 /// @endcond
2687
2688 template<typename _Functor, typename... _ArgTypes>
2689 struct result_of<_Functor(_ArgTypes...)>
2690 : public __invoke_result<_Functor, _ArgTypes...>
2691 { } _GLIBCXX17_DEPRECATED_SUGGEST("std::invoke_result");
2692
2693#if __cplusplus >= 201402L
2694#pragma GCC diagnostic push
2695#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
2696 /// Alias template for aligned_storage
2697 template<size_t _Len, size_t _Align =
2698 __alignof__(typename __aligned_storage_msa<_Len>::__type)>
2699 using aligned_storage_t _GLIBCXX23_DEPRECATED = typename aligned_storage<_Len, _Align>::type;
2700
2701 template <size_t _Len, typename... _Types>
2702 using aligned_union_t _GLIBCXX23_DEPRECATED = typename aligned_union<_Len, _Types...>::type;
2703#pragma GCC diagnostic pop
2704
2705 /// Alias template for decay
2706 template<typename _Tp>
2707 using decay_t = typename decay<_Tp>::type;
2708
2709 /// Alias template for enable_if
2710 template<bool _Cond, typename _Tp = void>
2711 using enable_if_t = typename enable_if<_Cond, _Tp>::type;
2712
2713 /// Alias template for conditional
2714 template<bool _Cond, typename _Iftrue, typename _Iffalse>
2715 using conditional_t = typename conditional<_Cond, _Iftrue, _Iffalse>::type;
2716
2717 /// Alias template for common_type
2718 template<typename... _Tp>
2719 using common_type_t = typename common_type<_Tp...>::type;
2720
2721 /// Alias template for underlying_type
2722 template<typename _Tp>
2723 using underlying_type_t = typename underlying_type<_Tp>::type;
2724
2725 /// Alias template for result_of
2726 template<typename _Tp>
2727 using result_of_t = typename result_of<_Tp>::type;
2728#endif // C++14
2729
2730#ifdef __cpp_lib_void_t // C++ >= 17 || GNU++ >= 11
2731 /// A metafunction that always yields void, used for detecting valid types.
2732 template<typename...> using void_t = void;
2733#endif
2734
2735 /// @cond undocumented
2736
2737 // Detection idiom.
2738 // Detect whether _Op<_Args...> is a valid type, use default _Def if not.
2739
2740#if __cpp_concepts
2741 // Implementation of the detection idiom (negative case).
2742 template<typename _Def, template<typename...> class _Op, typename... _Args>
2743 struct __detected_or
2744 {
2745 using type = _Def;
2746 using __is_detected = false_type;
2747 };
2748
2749 // Implementation of the detection idiom (positive case).
2750 template<typename _Def, template<typename...> class _Op, typename... _Args>
2751 requires requires { typename _Op<_Args...>; }
2752 struct __detected_or<_Def, _Op, _Args...>
2753 {
2754 using type = _Op<_Args...>;
2755 using __is_detected = true_type;
2756 };
2757#else
2758 /// Implementation of the detection idiom (negative case).
2759 template<typename _Default, typename _AlwaysVoid,
2760 template<typename...> class _Op, typename... _Args>
2761 struct __detector
2762 {
2763 using type = _Default;
2764 using __is_detected = false_type;
2765 };
2766
2767 /// Implementation of the detection idiom (positive case).
2768 template<typename _Default, template<typename...> class _Op,
2769 typename... _Args>
2770 struct __detector<_Default, __void_t<_Op<_Args...>>, _Op, _Args...>
2771 {
2772 using type = _Op<_Args...>;
2773 using __is_detected = true_type;
2774 };
2775
2776 template<typename _Default, template<typename...> class _Op,
2777 typename... _Args>
2778 using __detected_or = __detector<_Default, void, _Op, _Args...>;
2779#endif // __cpp_concepts
2780
2781 // _Op<_Args...> if that is a valid type, otherwise _Default.
2782 template<typename _Default, template<typename...> class _Op,
2783 typename... _Args>
2784 using __detected_or_t
2785 = typename __detected_or<_Default, _Op, _Args...>::type;
2786
2787 /**
2788 * Use SFINAE to determine if the type _Tp has a publicly-accessible
2789 * member type _NTYPE.
2790 */
2791#define _GLIBCXX_HAS_NESTED_TYPE(_NTYPE) \
2792 template<typename _Tp, typename = __void_t<>> \
2793 struct __has_##_NTYPE \
2794 : false_type \
2795 { }; \
2796 template<typename _Tp> \
2797 struct __has_##_NTYPE<_Tp, __void_t<typename _Tp::_NTYPE>> \
2798 : true_type \
2799 { };
2800
2801 template <typename _Tp>
2802 struct __is_swappable;
2803
2804 template <typename _Tp>
2805 struct __is_nothrow_swappable;
2806
2807 template<typename>
2808 struct __is_tuple_like_impl : false_type
2809 { };
2810
2811 // Internal type trait that allows us to sfinae-protect tuple_cat.
2812 template<typename _Tp>
2813 struct __is_tuple_like
2814 : public __is_tuple_like_impl<__remove_cvref_t<_Tp>>::type
2815 { };
2816 /// @endcond
2817
2818 template<typename _Tp>
2819 _GLIBCXX20_CONSTEXPR
2820 inline
2821 _Require<__not_<__is_tuple_like<_Tp>>,
2822 is_move_constructible<_Tp>,
2823 is_move_assignable<_Tp>>
2824 swap(_Tp&, _Tp&)
2825 noexcept(__and_<is_nothrow_move_constructible<_Tp>,
2826 is_nothrow_move_assignable<_Tp>>::value);
2827
2828 template<typename _Tp, size_t _Nm>
2829 _GLIBCXX20_CONSTEXPR
2830 inline
2831 __enable_if_t<__is_swappable<_Tp>::value>
2832 swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
2833 noexcept(__is_nothrow_swappable<_Tp>::value);
2834
2835 /// @cond undocumented
2836 namespace __swappable_details {
2837 using std::swap;
2838
2839 struct __do_is_swappable_impl
2840 {
2841 template<typename _Tp, typename
2842 = decltype(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))>
2843 static true_type __test(int);
2844
2845 template<typename>
2846 static false_type __test(...);
2847 };
2848
2849 struct __do_is_nothrow_swappable_impl
2850 {
2851 template<typename _Tp>
2852 static __bool_constant<
2853 noexcept(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))
2854 > __test(int);
2855
2856 template<typename>
2857 static false_type __test(...);
2858 };
2859
2860 } // namespace __swappable_details
2861
2862 template<typename _Tp>
2863 struct __is_swappable_impl
2864 : public __swappable_details::__do_is_swappable_impl
2865 {
2866 using type = decltype(__test<_Tp>(0));
2867 };
2868
2869 template<typename _Tp>
2870 struct __is_nothrow_swappable_impl
2871 : public __swappable_details::__do_is_nothrow_swappable_impl
2872 {
2873 using type = decltype(__test<_Tp>(0));
2874 };
2875
2876 template<typename _Tp>
2877 struct __is_swappable
2878 : public __is_swappable_impl<_Tp>::type
2879 { };
2880
2881 template<typename _Tp>
2882 struct __is_nothrow_swappable
2883 : public __is_nothrow_swappable_impl<_Tp>::type
2884 { };
2885 /// @endcond
2886
2887#ifdef __cpp_lib_is_swappable // C++ >= 17 || GNU++ >= 11
2888 /// Metafunctions used for detecting swappable types: p0185r1
2889
2890 /// is_swappable
2891 template<typename _Tp>
2892 struct is_swappable
2893 : public __is_swappable_impl<_Tp>::type
2894 {
2895 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
2896 "template argument must be a complete class or an unbounded array");
2897 };
2898
2899 /// is_nothrow_swappable
2900 template<typename _Tp>
2901 struct is_nothrow_swappable
2902 : public __is_nothrow_swappable_impl<_Tp>::type
2903 {
2904 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
2905 "template argument must be a complete class or an unbounded array");
2906 };
2907
2908#if __cplusplus >= 201402L
2909 /// is_swappable_v
2910 template<typename _Tp>
2911 _GLIBCXX17_INLINE constexpr bool is_swappable_v =
2912 is_swappable<_Tp>::value;
2913
2914 /// is_nothrow_swappable_v
2915 template<typename _Tp>
2916 _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_v =
2917 is_nothrow_swappable<_Tp>::value;
2918#endif // __cplusplus >= 201402L
2919
2920 /// @cond undocumented
2921 namespace __swappable_with_details {
2922 using std::swap;
2923
2924 struct __do_is_swappable_with_impl
2925 {
2926 template<typename _Tp, typename _Up, typename
2927 = decltype(swap(std::declval<_Tp>(), std::declval<_Up>())),
2928 typename
2929 = decltype(swap(std::declval<_Up>(), std::declval<_Tp>()))>
2930 static true_type __test(int);
2931
2932 template<typename, typename>
2933 static false_type __test(...);
2934 };
2935
2936 struct __do_is_nothrow_swappable_with_impl
2937 {
2938 template<typename _Tp, typename _Up>
2939 static __bool_constant<
2940 noexcept(swap(std::declval<_Tp>(), std::declval<_Up>()))
2941 &&
2942 noexcept(swap(std::declval<_Up>(), std::declval<_Tp>()))
2943 > __test(int);
2944
2945 template<typename, typename>
2946 static false_type __test(...);
2947 };
2948
2949 } // namespace __swappable_with_details
2950
2951 template<typename _Tp, typename _Up>
2952 struct __is_swappable_with_impl
2953 : public __swappable_with_details::__do_is_swappable_with_impl
2954 {
2955 using type = decltype(__test<_Tp, _Up>(0));
2956 };
2957
2958 // Optimization for the homogenous lvalue case, not required:
2959 template<typename _Tp>
2960 struct __is_swappable_with_impl<_Tp&, _Tp&>
2961 : public __swappable_details::__do_is_swappable_impl
2962 {
2963 using type = decltype(__test<_Tp&>(0));
2964 };
2965
2966 template<typename _Tp, typename _Up>
2967 struct __is_nothrow_swappable_with_impl
2968 : public __swappable_with_details::__do_is_nothrow_swappable_with_impl
2969 {
2970 using type = decltype(__test<_Tp, _Up>(0));
2971 };
2972
2973 // Optimization for the homogenous lvalue case, not required:
2974 template<typename _Tp>
2975 struct __is_nothrow_swappable_with_impl<_Tp&, _Tp&>
2976 : public __swappable_details::__do_is_nothrow_swappable_impl
2977 {
2978 using type = decltype(__test<_Tp&>(0));
2979 };
2980 /// @endcond
2981
2982 /// is_swappable_with
2983 template<typename _Tp, typename _Up>
2984 struct is_swappable_with
2985 : public __is_swappable_with_impl<_Tp, _Up>::type
2986 {
2987 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
2988 "first template argument must be a complete class or an unbounded array");
2989 static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
2990 "second template argument must be a complete class or an unbounded array");
2991 };
2992
2993 /// is_nothrow_swappable_with
2994 template<typename _Tp, typename _Up>
2995 struct is_nothrow_swappable_with
2996 : public __is_nothrow_swappable_with_impl<_Tp, _Up>::type
2997 {
2998 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
2999 "first template argument must be a complete class or an unbounded array");
3000 static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
3001 "second template argument must be a complete class or an unbounded array");
3002 };
3003
3004#if __cplusplus >= 201402L
3005 /// is_swappable_with_v
3006 template<typename _Tp, typename _Up>
3007 _GLIBCXX17_INLINE constexpr bool is_swappable_with_v =
3008 is_swappable_with<_Tp, _Up>::value;
3009
3010 /// is_nothrow_swappable_with_v
3011 template<typename _Tp, typename _Up>
3012 _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_with_v =
3013 is_nothrow_swappable_with<_Tp, _Up>::value;
3014#endif // __cplusplus >= 201402L
3015
3016#endif // __cpp_lib_is_swappable
3017
3018 /// @cond undocumented
3019
3020 // __is_invocable (std::is_invocable for C++11)
3021
3022 // The primary template is used for invalid INVOKE expressions.
3023 template<typename _Result, typename _Ret,
3024 bool = is_void<_Ret>::value, typename = void>
3025 struct __is_invocable_impl
3026 : false_type
3027 {
3028 using __nothrow_conv = false_type; // For is_nothrow_invocable_r
3029 };
3030
3031 // Used for valid INVOKE and INVOKE<void> expressions.
3032 template<typename _Result, typename _Ret>
3033 struct __is_invocable_impl<_Result, _Ret,
3034 /* is_void<_Ret> = */ true,
3035 __void_t<typename _Result::type>>
3036 : true_type
3037 {
3038 using __nothrow_conv = true_type; // For is_nothrow_invocable_r
3039 };
3040
3041#pragma GCC diagnostic push
3042#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
3043 // Used for INVOKE<R> expressions to check the implicit conversion to R.
3044 template<typename _Result, typename _Ret>
3045 struct __is_invocable_impl<_Result, _Ret,
3046 /* is_void<_Ret> = */ false,
3047 __void_t<typename _Result::type>>
3048 {
3049 private:
3050 // The type of the INVOKE expression.
3051 using _Res_t = typename _Result::type;
3052
3053 // Unlike declval, this doesn't add_rvalue_reference, so it respects
3054 // guaranteed copy elision.
3055 static _Res_t _S_get() noexcept;
3056
3057 // Used to check if _Res_t can implicitly convert to _Tp.
3058 template<typename _Tp>
3059 static void _S_conv(__type_identity_t<_Tp>) noexcept;
3060
3061 // This overload is viable if INVOKE(f, args...) can convert to _Tp.
3062 template<typename _Tp,
3063 bool _Nothrow = noexcept(_S_conv<_Tp>(_S_get())),
3064 typename = decltype(_S_conv<_Tp>(_S_get())),
3065#if __has_builtin(__reference_converts_from_temporary)
3066 bool _Dangle = __reference_converts_from_temporary(_Tp, _Res_t)
3067#else
3068 bool _Dangle = false
3069#endif
3070 >
3071 static __bool_constant<_Nothrow && !_Dangle>
3072 _S_test(int);
3073
3074 template<typename _Tp, bool = false>
3075 static false_type
3076 _S_test(...);
3077
3078 public:
3079 // For is_invocable_r
3080 using type = decltype(_S_test<_Ret, /* Nothrow = */ true>(1));
3081
3082 // For is_nothrow_invocable_r
3083 using __nothrow_conv = decltype(_S_test<_Ret>(1));
3084 };
3085#pragma GCC diagnostic pop
3086
3087 template<typename _Fn, typename... _ArgTypes>
3088 struct __is_invocable
3089 : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
3090 { };
3091
3092 template<typename _Fn, typename _Tp, typename... _Args>
3093 constexpr bool __call_is_nt(__invoke_memfun_ref)
3094 {
3095 using _Up = typename __inv_unwrap<_Tp>::type;
3096 return noexcept((std::declval<_Up>().*std::declval<_Fn>())(
3097 std::declval<_Args>()...));
3098 }
3099
3100 template<typename _Fn, typename _Tp, typename... _Args>
3101 constexpr bool __call_is_nt(__invoke_memfun_deref)
3102 {
3103 return noexcept(((*std::declval<_Tp>()).*std::declval<_Fn>())(
3104 std::declval<_Args>()...));
3105 }
3106
3107 template<typename _Fn, typename _Tp>
3108 constexpr bool __call_is_nt(__invoke_memobj_ref)
3109 {
3110 using _Up = typename __inv_unwrap<_Tp>::type;
3111 return noexcept(std::declval<_Up>().*std::declval<_Fn>());
3112 }
3113
3114 template<typename _Fn, typename _Tp>
3115 constexpr bool __call_is_nt(__invoke_memobj_deref)
3116 {
3117 return noexcept((*std::declval<_Tp>()).*std::declval<_Fn>());
3118 }
3119
3120 template<typename _Fn, typename... _Args>
3121 constexpr bool __call_is_nt(__invoke_other)
3122 {
3123 return noexcept(std::declval<_Fn>()(std::declval<_Args>()...));
3124 }
3125
3126 template<typename _Result, typename _Fn, typename... _Args>
3127 struct __call_is_nothrow
3128 : __bool_constant<
3129 std::__call_is_nt<_Fn, _Args...>(typename _Result::__invoke_type{})
3130 >
3131 { };
3132
3133 template<typename _Fn, typename... _Args>
3134 using __call_is_nothrow_
3135 = __call_is_nothrow<__invoke_result<_Fn, _Args...>, _Fn, _Args...>;
3136
3137 // __is_nothrow_invocable (std::is_nothrow_invocable for C++11)
3138 template<typename _Fn, typename... _Args>
3139 struct __is_nothrow_invocable
3140 : __and_<__is_invocable<_Fn, _Args...>,
3141 __call_is_nothrow_<_Fn, _Args...>>::type
3142 { };
3143
3144#pragma GCC diagnostic push
3145#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
3146 struct __nonesuchbase {};
3147 struct __nonesuch : private __nonesuchbase {
3148 ~__nonesuch() = delete;
3149 __nonesuch(__nonesuch const&) = delete;
3150 void operator=(__nonesuch const&) = delete;
3151 };
3152#pragma GCC diagnostic pop
3153 /// @endcond
3154
3155#ifdef __cpp_lib_is_invocable // C++ >= 17
3156 /// std::invoke_result
3157 template<typename _Functor, typename... _ArgTypes>
3158 struct invoke_result
3159 : public __invoke_result<_Functor, _ArgTypes...>
3160 {
3161 static_assert(std::__is_complete_or_unbounded(__type_identity<_Functor>{}),
3162 "_Functor must be a complete class or an unbounded array");
3163 static_assert((std::__is_complete_or_unbounded(
3164 __type_identity<_ArgTypes>{}) && ...),
3165 "each argument type must be a complete class or an unbounded array");
3166 };
3167
3168 /// std::invoke_result_t
3169 template<typename _Fn, typename... _Args>
3170 using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
3171
3172 /// std::is_invocable
3173 template<typename _Fn, typename... _ArgTypes>
3174 struct is_invocable
3175 : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
3176 {
3177 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3178 "_Fn must be a complete class or an unbounded array");
3179 static_assert((std::__is_complete_or_unbounded(
3180 __type_identity<_ArgTypes>{}) && ...),
3181 "each argument type must be a complete class or an unbounded array");
3182 };
3183
3184 /// std::is_invocable_r
3185 template<typename _Ret, typename _Fn, typename... _ArgTypes>
3186 struct is_invocable_r
3187 : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>::type
3188 {
3189 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3190 "_Fn must be a complete class or an unbounded array");
3191 static_assert((std::__is_complete_or_unbounded(
3192 __type_identity<_ArgTypes>{}) && ...),
3193 "each argument type must be a complete class or an unbounded array");
3194 static_assert(std::__is_complete_or_unbounded(__type_identity<_Ret>{}),
3195 "_Ret must be a complete class or an unbounded array");
3196 };
3197
3198 /// std::is_nothrow_invocable
3199 template<typename _Fn, typename... _ArgTypes>
3200 struct is_nothrow_invocable
3201 : __and_<__is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>,
3202 __call_is_nothrow_<_Fn, _ArgTypes...>>::type
3203 {
3204 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3205 "_Fn must be a complete class or an unbounded array");
3206 static_assert((std::__is_complete_or_unbounded(
3207 __type_identity<_ArgTypes>{}) && ...),
3208 "each argument type must be a complete class or an unbounded array");
3209 };
3210
3211 /// @cond undocumented
3212 // This checks that the INVOKE<R> expression is well-formed and that the
3213 // conversion to R does not throw. It does *not* check whether the INVOKE
3214 // expression itself can throw. That is done by __call_is_nothrow_ instead.
3215 template<typename _Result, typename _Ret>
3216 using __is_nt_invocable_impl
3217 = typename __is_invocable_impl<_Result, _Ret>::__nothrow_conv;
3218 /// @endcond
3219
3220 /// std::is_nothrow_invocable_r
3221 template<typename _Ret, typename _Fn, typename... _ArgTypes>
3222 struct is_nothrow_invocable_r
3223 : __and_<__is_nt_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>,
3224 __call_is_nothrow_<_Fn, _ArgTypes...>>::type
3225 {
3226 static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
3227 "_Fn must be a complete class or an unbounded array");
3228 static_assert((std::__is_complete_or_unbounded(
3229 __type_identity<_ArgTypes>{}) && ...),
3230 "each argument type must be a complete class or an unbounded array");
3231 static_assert(std::__is_complete_or_unbounded(__type_identity<_Ret>{}),
3232 "_Ret must be a complete class or an unbounded array");
3233 };
3234#endif // __cpp_lib_is_invocable
3235
3236#if __cpp_lib_type_trait_variable_templates // C++ >= 17
3237 /**
3238 * @defgroup variable_templates Variable templates for type traits
3239 * @ingroup metaprogramming
3240 *
3241 * Each variable `is_xxx_v<T>` is a boolean constant with the same value
3242 * as the `value` member of the corresponding type trait `is_xxx<T>`.
3243 *
3244 * @since C++17 unless noted otherwise.
3245 */
3246
3247 /**
3248 * @{
3249 * @ingroup variable_templates
3250 */
3251template <typename _Tp>
3252 inline constexpr bool is_void_v = is_void<_Tp>::value;
3253template <typename _Tp>
3254 inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
3255template <typename _Tp>
3256 inline constexpr bool is_integral_v = is_integral<_Tp>::value;
3257template <typename _Tp>
3258 inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
3259
3260#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_array)
3261template <typename _Tp>
3262 inline constexpr bool is_array_v = __is_array(_Tp);
3263#else
3264template <typename _Tp>
3265 inline constexpr bool is_array_v = false;
3266template <typename _Tp>
3267 inline constexpr bool is_array_v<_Tp[]> = true;
3268template <typename _Tp, size_t _Num>
3269 inline constexpr bool is_array_v<_Tp[_Num]> = true;
3270#endif
3271
3272template <typename _Tp>
3273 inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
3274template <typename _Tp>
3275 inline constexpr bool is_lvalue_reference_v = false;
3276template <typename _Tp>
3277 inline constexpr bool is_lvalue_reference_v<_Tp&> = true;
3278template <typename _Tp>
3279 inline constexpr bool is_rvalue_reference_v = false;
3280template <typename _Tp>
3281 inline constexpr bool is_rvalue_reference_v<_Tp&&> = true;
3282
3283#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_object_pointer)
3284template <typename _Tp>
3285 inline constexpr bool is_member_object_pointer_v =
3286 __is_member_object_pointer(_Tp);
3287#else
3288template <typename _Tp>
3289 inline constexpr bool is_member_object_pointer_v =
3290 is_member_object_pointer<_Tp>::value;
3291#endif
3292
3293#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_function_pointer)
3294template <typename _Tp>
3295 inline constexpr bool is_member_function_pointer_v =
3296 __is_member_function_pointer(_Tp);
3297#else
3298template <typename _Tp>
3299 inline constexpr bool is_member_function_pointer_v =
3300 is_member_function_pointer<_Tp>::value;
3301#endif
3302
3303template <typename _Tp>
3304 inline constexpr bool is_enum_v = __is_enum(_Tp);
3305template <typename _Tp>
3306 inline constexpr bool is_union_v = __is_union(_Tp);
3307template <typename _Tp>
3308 inline constexpr bool is_class_v = __is_class(_Tp);
3309// is_function_v is defined below, after is_const_v.
3310
3311#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_reference)
3312template <typename _Tp>
3313 inline constexpr bool is_reference_v = __is_reference(_Tp);
3314#else
3315template <typename _Tp>
3316 inline constexpr bool is_reference_v = false;
3317template <typename _Tp>
3318 inline constexpr bool is_reference_v<_Tp&> = true;
3319template <typename _Tp>
3320 inline constexpr bool is_reference_v<_Tp&&> = true;
3321#endif
3322
3323template <typename _Tp>
3324 inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
3325template <typename _Tp>
3326 inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
3327
3328#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_object)
3329template <typename _Tp>
3330 inline constexpr bool is_object_v = __is_object(_Tp);
3331#else
3332template <typename _Tp>
3333 inline constexpr bool is_object_v = is_object<_Tp>::value;
3334#endif
3335
3336template <typename _Tp>
3337 inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
3338template <typename _Tp>
3339 inline constexpr bool is_compound_v = !is_fundamental_v<_Tp>;
3340
3341#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
3342template <typename _Tp>
3343 inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
3344#else
3345template <typename _Tp>
3346 inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
3347#endif
3348
3349template <typename _Tp>
3350 inline constexpr bool is_const_v = false;
3351template <typename _Tp>
3352 inline constexpr bool is_const_v<const _Tp> = true;
3353
3354#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_function)
3355template <typename _Tp>
3356 inline constexpr bool is_function_v = __is_function(_Tp);
3357#else
3358template <typename _Tp>
3359 inline constexpr bool is_function_v = !is_const_v<const _Tp>;
3360template <typename _Tp>
3361 inline constexpr bool is_function_v<_Tp&> = false;
3362template <typename _Tp>
3363 inline constexpr bool is_function_v<_Tp&&> = false;
3364#endif
3365
3366template <typename _Tp>
3367 inline constexpr bool is_volatile_v = false;
3368template <typename _Tp>
3369 inline constexpr bool is_volatile_v<volatile _Tp> = true;
3370
3371template <typename _Tp>
3372 inline constexpr bool is_trivial_v = __is_trivial(_Tp);
3373template <typename _Tp>
3374 inline constexpr bool is_trivially_copyable_v = __is_trivially_copyable(_Tp);
3375template <typename _Tp>
3376 inline constexpr bool is_standard_layout_v = __is_standard_layout(_Tp);
3377template <typename _Tp>
3378 _GLIBCXX20_DEPRECATED_SUGGEST("is_standard_layout_v && is_trivial_v")
3379 inline constexpr bool is_pod_v = __is_pod(_Tp);
3380template <typename _Tp>
3381 _GLIBCXX17_DEPRECATED
3382 inline constexpr bool is_literal_type_v = __is_literal_type(_Tp);
3383template <typename _Tp>
3384 inline constexpr bool is_empty_v = __is_empty(_Tp);
3385template <typename _Tp>
3386 inline constexpr bool is_polymorphic_v = __is_polymorphic(_Tp);
3387template <typename _Tp>
3388 inline constexpr bool is_abstract_v = __is_abstract(_Tp);
3389template <typename _Tp>
3390 inline constexpr bool is_final_v = __is_final(_Tp);
3391
3392template <typename _Tp>
3393 inline constexpr bool is_signed_v = is_signed<_Tp>::value;
3394template <typename _Tp>
3395 inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
3396
3397template <typename _Tp, typename... _Args>
3398 inline constexpr bool is_constructible_v = __is_constructible(_Tp, _Args...);
3399template <typename _Tp>
3400 inline constexpr bool is_default_constructible_v = __is_constructible(_Tp);
3401template <typename _Tp>
3402 inline constexpr bool is_copy_constructible_v
3403 = __is_constructible(_Tp, __add_lval_ref_t<const _Tp>);
3404template <typename _Tp>
3405 inline constexpr bool is_move_constructible_v
3406 = __is_constructible(_Tp, __add_rval_ref_t<_Tp>);
3407
3408template <typename _Tp, typename _Up>
3409 inline constexpr bool is_assignable_v = __is_assignable(_Tp, _Up);
3410template <typename _Tp>
3411 inline constexpr bool is_copy_assignable_v
3412 = __is_assignable(__add_lval_ref_t<_Tp>, __add_lval_ref_t<const _Tp>);
3413template <typename _Tp>
3414 inline constexpr bool is_move_assignable_v
3415 = __is_assignable(__add_lval_ref_t<_Tp>, __add_rval_ref_t<_Tp>);
3416
3417template <typename _Tp>
3418 inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
3419
3420template <typename _Tp, typename... _Args>
3421 inline constexpr bool is_trivially_constructible_v
3422 = __is_trivially_constructible(_Tp, _Args...);
3423template <typename _Tp>
3424 inline constexpr bool is_trivially_default_constructible_v
3425 = __is_trivially_constructible(_Tp);
3426template <typename _Tp>
3427 inline constexpr bool is_trivially_copy_constructible_v
3428 = __is_trivially_constructible(_Tp, __add_lval_ref_t<const _Tp>);
3429template <typename _Tp>
3430 inline constexpr bool is_trivially_move_constructible_v
3431 = __is_trivially_constructible(_Tp, __add_rval_ref_t<_Tp>);
3432
3433template <typename _Tp, typename _Up>
3434 inline constexpr bool is_trivially_assignable_v
3435 = __is_trivially_assignable(_Tp, _Up);
3436template <typename _Tp>
3437 inline constexpr bool is_trivially_copy_assignable_v
3438 = __is_trivially_assignable(__add_lval_ref_t<_Tp>,
3439 __add_lval_ref_t<const _Tp>);
3440template <typename _Tp>
3441 inline constexpr bool is_trivially_move_assignable_v
3442 = __is_trivially_assignable(__add_lval_ref_t<_Tp>,
3443 __add_rval_ref_t<_Tp>);
3444
3445#if __cpp_concepts
3446template <typename _Tp>
3447 inline constexpr bool is_trivially_destructible_v = false;
3448
3449template <typename _Tp>
3450 requires (!is_reference_v<_Tp>) && requires (_Tp& __t) { __t.~_Tp(); }
3451 inline constexpr bool is_trivially_destructible_v<_Tp>
3452 = __has_trivial_destructor(_Tp);
3453template <typename _Tp>
3454 inline constexpr bool is_trivially_destructible_v<_Tp&> = true;
3455template <typename _Tp>
3456 inline constexpr bool is_trivially_destructible_v<_Tp&&> = true;
3457template <typename _Tp, size_t _Nm>
3458 inline constexpr bool is_trivially_destructible_v<_Tp[_Nm]>
3459 = is_trivially_destructible_v<_Tp>;
3460#else
3461template <typename _Tp>
3462 inline constexpr bool is_trivially_destructible_v =
3463 is_trivially_destructible<_Tp>::value;
3464#endif
3465
3466template <typename _Tp, typename... _Args>
3467 inline constexpr bool is_nothrow_constructible_v
3468 = __is_nothrow_constructible(_Tp, _Args...);
3469template <typename _Tp>
3470 inline constexpr bool is_nothrow_default_constructible_v
3471 = __is_nothrow_constructible(_Tp);
3472template <typename _Tp>
3473 inline constexpr bool is_nothrow_copy_constructible_v
3474 = __is_nothrow_constructible(_Tp, __add_lval_ref_t<const _Tp>);
3475template <typename _Tp>
3476 inline constexpr bool is_nothrow_move_constructible_v
3477 = __is_nothrow_constructible(_Tp, __add_rval_ref_t<_Tp>);
3478
3479template <typename _Tp, typename _Up>
3480 inline constexpr bool is_nothrow_assignable_v
3481 = __is_nothrow_assignable(_Tp, _Up);
3482template <typename _Tp>
3483 inline constexpr bool is_nothrow_copy_assignable_v
3484 = __is_nothrow_assignable(__add_lval_ref_t<_Tp>,
3485 __add_lval_ref_t<const _Tp>);
3486template <typename _Tp>
3487 inline constexpr bool is_nothrow_move_assignable_v
3488 = __is_nothrow_assignable(__add_lval_ref_t<_Tp>, __add_rval_ref_t<_Tp>);
3489
3490template <typename _Tp>
3491 inline constexpr bool is_nothrow_destructible_v =
3492 is_nothrow_destructible<_Tp>::value;
3493
3494template <typename _Tp>
3495 inline constexpr bool has_virtual_destructor_v
3496 = __has_virtual_destructor(_Tp);
3497
3498template <typename _Tp>
3499 inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
3500
3501template <typename _Tp>
3502 inline constexpr size_t rank_v = 0;
3503template <typename _Tp, size_t _Size>
3504 inline constexpr size_t rank_v<_Tp[_Size]> = 1 + rank_v<_Tp>;
3505template <typename _Tp>
3506 inline constexpr size_t rank_v<_Tp[]> = 1 + rank_v<_Tp>;
3507
3508template <typename _Tp, unsigned _Idx = 0>
3509 inline constexpr size_t extent_v = 0;
3510template <typename _Tp, size_t _Size>
3511 inline constexpr size_t extent_v<_Tp[_Size], 0> = _Size;
3512template <typename _Tp, unsigned _Idx, size_t _Size>
3513 inline constexpr size_t extent_v<_Tp[_Size], _Idx> = extent_v<_Tp, _Idx - 1>;
3514template <typename _Tp>
3515 inline constexpr size_t extent_v<_Tp[], 0> = 0;
3516template <typename _Tp, unsigned _Idx>
3517 inline constexpr size_t extent_v<_Tp[], _Idx> = extent_v<_Tp, _Idx - 1>;
3518
3519#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_same)
3520template <typename _Tp, typename _Up>
3521 inline constexpr bool is_same_v = __is_same(_Tp, _Up);
3522#else
3523template <typename _Tp, typename _Up>
3524 inline constexpr bool is_same_v = false;
3525template <typename _Tp>
3526 inline constexpr bool is_same_v<_Tp, _Tp> = true;
3527#endif
3528template <typename _Base, typename _Derived>
3529 inline constexpr bool is_base_of_v = __is_base_of(_Base, _Derived);
3530#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_convertible)
3531template <typename _From, typename _To>
3532 inline constexpr bool is_convertible_v = __is_convertible(_From, _To);
3533#else
3534template <typename _From, typename _To>
3535 inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
3536#endif
3537template<typename _Fn, typename... _Args>
3538 inline constexpr bool is_invocable_v = is_invocable<_Fn, _Args...>::value;
3539template<typename _Fn, typename... _Args>
3540 inline constexpr bool is_nothrow_invocable_v
3541 = is_nothrow_invocable<_Fn, _Args...>::value;
3542template<typename _Ret, typename _Fn, typename... _Args>
3543 inline constexpr bool is_invocable_r_v
3544 = is_invocable_r<_Ret, _Fn, _Args...>::value;
3545template<typename _Ret, typename _Fn, typename... _Args>
3546 inline constexpr bool is_nothrow_invocable_r_v
3547 = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
3548/// @}
3549#endif // __cpp_lib_type_trait_variable_templates
3550
3551#ifdef __cpp_lib_has_unique_object_representations // C++ >= 17 && HAS_UNIQ_OBJ_REP
3552 /// has_unique_object_representations
3553 /// @since C++17
3554 template<typename _Tp>
3555 struct has_unique_object_representations
3556 : bool_constant<__has_unique_object_representations(
3557 remove_cv_t<remove_all_extents_t<_Tp>>
3558 )>
3559 {
3560 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
3561 "template argument must be a complete class or an unbounded array");
3562 };
3563
3564# if __cpp_lib_type_trait_variable_templates // C++ >= 17
3565 /// @ingroup variable_templates
3566 template<typename _Tp>
3567 inline constexpr bool has_unique_object_representations_v
3568 = has_unique_object_representations<_Tp>::value;
3569# endif
3570#endif
3571
3572#ifdef __cpp_lib_is_aggregate // C++ >= 17 && builtin_is_aggregate
3573 /// is_aggregate - true if the type is an aggregate.
3574 /// @since C++17
3575 template<typename _Tp>
3576 struct is_aggregate
3577 : bool_constant<__is_aggregate(remove_cv_t<_Tp>)>
3578 { };
3579
3580# if __cpp_lib_type_trait_variable_templates // C++ >= 17
3581 /** is_aggregate_v - true if the type is an aggregate.
3582 * @ingroup variable_templates
3583 * @since C++17
3584 */
3585 template<typename _Tp>
3586 inline constexpr bool is_aggregate_v = __is_aggregate(remove_cv_t<_Tp>);
3587# endif
3588#endif
3589
3590 /** * Remove references and cv-qualifiers.
3591 * @since C++20
3592 * @{
3593 */
3594#ifdef __cpp_lib_remove_cvref // C++ >= 20
3595# if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cvref)
3596 template<typename _Tp>
3597 struct remove_cvref
3598 { using type = __remove_cvref(_Tp); };
3599# else
3600 template<typename _Tp>
3601 struct remove_cvref
3602 { using type = typename remove_cv<_Tp>::type; };
3603
3604 template<typename _Tp>
3605 struct remove_cvref<_Tp&>
3606 { using type = typename remove_cv<_Tp>::type; };
3607
3608 template<typename _Tp>
3609 struct remove_cvref<_Tp&&>
3610 { using type = typename remove_cv<_Tp>::type; };
3611# endif
3612
3613 template<typename _Tp>
3614 using remove_cvref_t = typename remove_cvref<_Tp>::type;
3615 /// @}
3616#endif // __cpp_lib_remove_cvref
3617
3618#ifdef __cpp_lib_type_identity // C++ >= 20
3619 /** * Identity metafunction.
3620 * @since C++20
3621 * @{
3622 */
3623 template<typename _Tp>
3624 struct type_identity { using type = _Tp; };
3625
3626 template<typename _Tp>
3627 using type_identity_t = typename type_identity<_Tp>::type;
3628 /// @}
3629#endif
3630
3631#ifdef __cpp_lib_unwrap_ref // C++ >= 20
3632 /** Unwrap a reference_wrapper
3633 * @since C++20
3634 * @{
3635 */
3636 template<typename _Tp>
3637 struct unwrap_reference { using type = _Tp; };
3638
3639 template<typename _Tp>
3640 struct unwrap_reference<reference_wrapper<_Tp>> { using type = _Tp&; };
3641
3642 template<typename _Tp>
3643 using unwrap_reference_t = typename unwrap_reference<_Tp>::type;
3644 /// @}
3645
3646 /** Decay type and if it's a reference_wrapper, unwrap it
3647 * @since C++20
3648 * @{
3649 */
3650 template<typename _Tp>
3651 struct unwrap_ref_decay { using type = unwrap_reference_t<decay_t<_Tp>>; };
3652
3653 template<typename _Tp>
3654 using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;
3655 /// @}
3656#endif // __cpp_lib_unwrap_ref
3657
3658#ifdef __cpp_lib_bounded_array_traits // C++ >= 20
3659 /// True for a type that is an array of known bound.
3660 /// @ingroup variable_templates
3661 /// @since C++20
3662# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_bounded_array)
3663 template<typename _Tp>
3664 inline constexpr bool is_bounded_array_v = __is_bounded_array(_Tp);
3665# else
3666 template<typename _Tp>
3667 inline constexpr bool is_bounded_array_v = false;
3668
3669 template<typename _Tp, size_t _Size>
3670 inline constexpr bool is_bounded_array_v<_Tp[_Size]> = true;
3671# endif
3672
3673 /// True for a type that is an array of unknown bound.
3674 /// @ingroup variable_templates
3675 /// @since C++20
3676 template<typename _Tp>
3677 inline constexpr bool is_unbounded_array_v = false;
3678
3679 template<typename _Tp>
3680 inline constexpr bool is_unbounded_array_v<_Tp[]> = true;
3681
3682 /// True for a type that is an array of known bound.
3683 /// @since C++20
3684 template<typename _Tp>
3685 struct is_bounded_array
3686 : public bool_constant<is_bounded_array_v<_Tp>>
3687 { };
3688
3689 /// True for a type that is an array of unknown bound.
3690 /// @since C++20
3691 template<typename _Tp>
3692 struct is_unbounded_array
3693 : public bool_constant<is_unbounded_array_v<_Tp>>
3694 { };
3695#endif // __cpp_lib_bounded_array_traits
3696
3697#if __has_builtin(__is_layout_compatible) && __cplusplus >= 202002L
3698
3699 /// @since C++20
3700 template<typename _Tp, typename _Up>
3701 struct is_layout_compatible
3702 : bool_constant<__is_layout_compatible(_Tp, _Up)>
3703 { };
3704
3705 /// @ingroup variable_templates
3706 /// @since C++20
3707 template<typename _Tp, typename _Up>
3708 constexpr bool is_layout_compatible_v
3709 = __is_layout_compatible(_Tp, _Up);
3710
3711#if __has_builtin(__builtin_is_corresponding_member)
3712# ifndef __cpp_lib_is_layout_compatible
3713# error "libstdc++ bug: is_corresponding_member and is_layout_compatible are provided but their FTM is not set"
3714# endif
3715
3716 /// @since C++20
3717 template<typename _S1, typename _S2, typename _M1, typename _M2>
3718 constexpr bool
3719 is_corresponding_member(_M1 _S1::*__m1, _M2 _S2::*__m2) noexcept
3720 { return __builtin_is_corresponding_member(__m1, __m2); }
3721#endif
3722#endif
3723
3724#if __has_builtin(__is_pointer_interconvertible_base_of) \
3725 && __cplusplus >= 202002L
3726 /// True if `_Derived` is standard-layout and has a base class of type `_Base`
3727 /// @since C++20
3728 template<typename _Base, typename _Derived>
3729 struct is_pointer_interconvertible_base_of
3730 : bool_constant<__is_pointer_interconvertible_base_of(_Base, _Derived)>
3731 { };
3732
3733 /// @ingroup variable_templates
3734 /// @since C++20
3735 template<typename _Base, typename _Derived>
3736 constexpr bool is_pointer_interconvertible_base_of_v
3737 = __is_pointer_interconvertible_base_of(_Base, _Derived);
3738
3739#if __has_builtin(__builtin_is_pointer_interconvertible_with_class)
3740# ifndef __cpp_lib_is_pointer_interconvertible
3741# error "libstdc++ bug: is_pointer_interconvertible available but FTM is not set"
3742# endif
3743
3744 /// True if `__mp` points to the first member of a standard-layout type
3745 /// @returns true if `s.*__mp` is pointer-interconvertible with `s`
3746 /// @since C++20
3747 template<typename _Tp, typename _Mem>
3748 constexpr bool
3749 is_pointer_interconvertible_with_class(_Mem _Tp::*__mp) noexcept
3750 { return __builtin_is_pointer_interconvertible_with_class(__mp); }
3751#endif
3752#endif
3753
3754#ifdef __cpp_lib_is_scoped_enum // C++ >= 23
3755 /// True if the type is a scoped enumeration type.
3756 /// @since C++23
3757
3758# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_scoped_enum)
3759 template<typename _Tp>
3760 struct is_scoped_enum
3761 : bool_constant<__is_scoped_enum(_Tp)>
3762 { };
3763# else
3764 template<typename _Tp>
3765 struct is_scoped_enum
3766 : false_type
3767 { };
3768
3769 template<typename _Tp>
3770 requires __is_enum(_Tp)
3771 && requires(remove_cv_t<_Tp> __t) { __t = __t; } // fails if incomplete
3772 struct is_scoped_enum<_Tp>
3773 : bool_constant<!requires(_Tp __t, void(*__f)(int)) { __f(__t); }>
3774 { };
3775# endif
3776
3777 /// @ingroup variable_templates
3778 /// @since C++23
3779# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_scoped_enum)
3780 template<typename _Tp>
3781 inline constexpr bool is_scoped_enum_v = __is_scoped_enum(_Tp);
3782# else
3783 template<typename _Tp>
3784 inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
3785# endif
3786#endif
3787
3788#ifdef __cpp_lib_reference_from_temporary // C++ >= 23 && ref_{converts,constructs}_from_temp
3789 /// True if _Tp is a reference type, a _Up value can be bound to _Tp in
3790 /// direct-initialization, and a temporary object would be bound to
3791 /// the reference, false otherwise.
3792 /// @since C++23
3793 template<typename _Tp, typename _Up>
3794 struct reference_constructs_from_temporary
3795 : public bool_constant<__reference_constructs_from_temporary(_Tp, _Up)>
3796 {
3797 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{})
3798 && std::__is_complete_or_unbounded(__type_identity<_Up>{}),
3799 "template argument must be a complete class or an unbounded array");
3800 };
3801
3802 /// True if _Tp is a reference type, a _Up value can be bound to _Tp in
3803 /// copy-initialization, and a temporary object would be bound to
3804 /// the reference, false otherwise.
3805 /// @since C++23
3806 template<typename _Tp, typename _Up>
3807 struct reference_converts_from_temporary
3808 : public bool_constant<__reference_converts_from_temporary(_Tp, _Up)>
3809 {
3810 static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{})
3811 && std::__is_complete_or_unbounded(__type_identity<_Up>{}),
3812 "template argument must be a complete class or an unbounded array");
3813 };
3814
3815 /// @ingroup variable_templates
3816 /// @since C++23
3817 template<typename _Tp, typename _Up>
3818 inline constexpr bool reference_constructs_from_temporary_v
3819 = reference_constructs_from_temporary<_Tp, _Up>::value;
3820
3821 /// @ingroup variable_templates
3822 /// @since C++23
3823 template<typename _Tp, typename _Up>
3824 inline constexpr bool reference_converts_from_temporary_v
3825 = reference_converts_from_temporary<_Tp, _Up>::value;
3826#endif // __cpp_lib_reference_from_temporary
3827
3828#ifdef __cpp_lib_is_constant_evaluated // C++ >= 20 && HAVE_IS_CONST_EVAL
3829 /// Returns true only when called during constant evaluation.
3830 /// @since C++20
3831 constexpr inline bool
3832 is_constant_evaluated() noexcept
3833 {
3834#if __cpp_if_consteval >= 202106L
3835 if consteval { return true; } else { return false; }
3836#else
3837 return __builtin_is_constant_evaluated();
3838#endif
3839 }
3840#endif
3841
3842#if __cplusplus >= 202002L
3843 /// @cond undocumented
3844 template<typename _From, typename _To>
3845 using __copy_cv = typename __match_cv_qualifiers<_From, _To>::__type;
3846
3847 template<typename _Xp, typename _Yp>
3848 using __cond_res
3849 = decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
3850
3851 template<typename _Ap, typename _Bp, typename = void>
3852 struct __common_ref_impl
3853 { };
3854
3855 // [meta.trans.other], COMMON-REF(A, B)
3856 template<typename _Ap, typename _Bp>
3857 using __common_ref = typename __common_ref_impl<_Ap, _Bp>::type;
3858
3859 // COND-RES(COPYCV(X, Y) &, COPYCV(Y, X) &)
3860 template<typename _Xp, typename _Yp>
3861 using __condres_cvref
3862 = __cond_res<__copy_cv<_Xp, _Yp>&, __copy_cv<_Yp, _Xp>&>;
3863
3864 // If A and B are both lvalue reference types, ...
3865 template<typename _Xp, typename _Yp>
3866 struct __common_ref_impl<_Xp&, _Yp&, __void_t<__condres_cvref<_Xp, _Yp>>>
3867 : enable_if<is_reference_v<__condres_cvref<_Xp, _Yp>>,
3868 __condres_cvref<_Xp, _Yp>>
3869 { };
3870
3871 // let C be remove_reference_t<COMMON-REF(X&, Y&)>&&
3872 template<typename _Xp, typename _Yp>
3873 using __common_ref_C = remove_reference_t<__common_ref<_Xp&, _Yp&>>&&;
3874
3875 // If A and B are both rvalue reference types, ...
3876 template<typename _Xp, typename _Yp>
3877 struct __common_ref_impl<_Xp&&, _Yp&&,
3878 _Require<is_convertible<_Xp&&, __common_ref_C<_Xp, _Yp>>,
3879 is_convertible<_Yp&&, __common_ref_C<_Xp, _Yp>>>>
3880 { using type = __common_ref_C<_Xp, _Yp>; };
3881
3882 // let D be COMMON-REF(const X&, Y&)
3883 template<typename _Xp, typename _Yp>
3884 using __common_ref_D = __common_ref<const _Xp&, _Yp&>;
3885
3886 // If A is an rvalue reference and B is an lvalue reference, ...
3887 template<typename _Xp, typename _Yp>
3888 struct __common_ref_impl<_Xp&&, _Yp&,
3889 _Require<is_convertible<_Xp&&, __common_ref_D<_Xp, _Yp>>>>
3890 { using type = __common_ref_D<_Xp, _Yp>; };
3891
3892 // If A is an lvalue reference and B is an rvalue reference, ...
3893 template<typename _Xp, typename _Yp>
3894 struct __common_ref_impl<_Xp&, _Yp&&>
3895 : __common_ref_impl<_Yp&&, _Xp&>
3896 { };
3897 /// @endcond
3898
3899 template<typename _Tp, typename _Up,
3900 template<typename> class _TQual, template<typename> class _UQual>
3901 struct basic_common_reference
3902 { };
3903
3904 /// @cond undocumented
3905 template<typename _Tp>
3906 struct __xref
3907 { template<typename _Up> using __type = __copy_cv<_Tp, _Up>; };
3908
3909 template<typename _Tp>
3910 struct __xref<_Tp&>
3911 { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&; };
3912
3913 template<typename _Tp>
3914 struct __xref<_Tp&&>
3915 { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&&; };
3916
3917 template<typename _Tp1, typename _Tp2>
3918 using __basic_common_ref
3919 = typename basic_common_reference<remove_cvref_t<_Tp1>,
3920 remove_cvref_t<_Tp2>,
3921 __xref<_Tp1>::template __type,
3922 __xref<_Tp2>::template __type>::type;
3923 /// @endcond
3924
3925 template<typename... _Tp>
3926 struct common_reference;
3927
3928 template<typename... _Tp>
3929 using common_reference_t = typename common_reference<_Tp...>::type;
3930
3931 // If sizeof...(T) is zero, there shall be no member type.
3932 template<>
3933 struct common_reference<>
3934 { };
3935
3936 // If sizeof...(T) is one ...
3937 template<typename _Tp0>
3938 struct common_reference<_Tp0>
3939 { using type = _Tp0; };
3940
3941 /// @cond undocumented
3942 template<typename _Tp1, typename _Tp2, int _Bullet = 1, typename = void>
3943 struct __common_reference_impl
3944 : __common_reference_impl<_Tp1, _Tp2, _Bullet + 1>
3945 { };
3946
3947 // If sizeof...(T) is two ...
3948 template<typename _Tp1, typename _Tp2>
3949 struct common_reference<_Tp1, _Tp2>
3950 : __common_reference_impl<_Tp1, _Tp2>
3951 { };
3952
3953 // If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, ...
3954 template<typename _Tp1, typename _Tp2>
3955 struct __common_reference_impl<_Tp1&, _Tp2&, 1,
3956 void_t<__common_ref<_Tp1&, _Tp2&>>>
3957 { using type = __common_ref<_Tp1&, _Tp2&>; };
3958
3959 template<typename _Tp1, typename _Tp2>
3960 struct __common_reference_impl<_Tp1&&, _Tp2&&, 1,
3961 void_t<__common_ref<_Tp1&&, _Tp2&&>>>
3962 { using type = __common_ref<_Tp1&&, _Tp2&&>; };
3963
3964 template<typename _Tp1, typename _Tp2>
3965 struct __common_reference_impl<_Tp1&, _Tp2&&, 1,
3966 void_t<__common_ref<_Tp1&, _Tp2&&>>>
3967 { using type = __common_ref<_Tp1&, _Tp2&&>; };
3968
3969 template<typename _Tp1, typename _Tp2>
3970 struct __common_reference_impl<_Tp1&&, _Tp2&, 1,
3971 void_t<__common_ref<_Tp1&&, _Tp2&>>>
3972 { using type = __common_ref<_Tp1&&, _Tp2&>; };
3973
3974 // Otherwise, if basic_common_reference<...>::type is well-formed, ...
3975 template<typename _Tp1, typename _Tp2>
3976 struct __common_reference_impl<_Tp1, _Tp2, 2,
3977 void_t<__basic_common_ref<_Tp1, _Tp2>>>
3978 { using type = __basic_common_ref<_Tp1, _Tp2>; };
3979
3980 // Otherwise, if COND-RES(T1, T2) is well-formed, ...
3981 template<typename _Tp1, typename _Tp2>
3982 struct __common_reference_impl<_Tp1, _Tp2, 3,
3983 void_t<__cond_res<_Tp1, _Tp2>>>
3984 { using type = __cond_res<_Tp1, _Tp2>; };
3985
3986 // Otherwise, if common_type_t<T1, T2> is well-formed, ...
3987 template<typename _Tp1, typename _Tp2>
3988 struct __common_reference_impl<_Tp1, _Tp2, 4,
3989 void_t<common_type_t<_Tp1, _Tp2>>>
3990 { using type = common_type_t<_Tp1, _Tp2>; };
3991
3992 // Otherwise, there shall be no member type.
3993 template<typename _Tp1, typename _Tp2>
3994 struct __common_reference_impl<_Tp1, _Tp2, 5, void>
3995 { };
3996
3997 // Otherwise, if sizeof...(T) is greater than two, ...
3998 template<typename _Tp1, typename _Tp2, typename... _Rest>
3999 struct common_reference<_Tp1, _Tp2, _Rest...>
4000 : __common_type_fold<common_reference<_Tp1, _Tp2>,
4001 __common_type_pack<_Rest...>>
4002 { };
4003
4004 // Reuse __common_type_fold for common_reference<T1, T2, Rest...>
4005 template<typename _Tp1, typename _Tp2, typename... _Rest>
4006 struct __common_type_fold<common_reference<_Tp1, _Tp2>,
4007 __common_type_pack<_Rest...>,
4008 void_t<common_reference_t<_Tp1, _Tp2>>>
4009 : public common_reference<common_reference_t<_Tp1, _Tp2>, _Rest...>
4010 { };
4011 /// @endcond
4012
4013#endif // C++2a
4014
4015 /// @} group metaprogramming
4016
4017_GLIBCXX_END_NAMESPACE_VERSION
4018} // namespace std
4019
4020#endif // C++11
4021
4022#endif // _GLIBCXX_TYPE_TRAITS
4023