libstdc++: type_traits Source File

libstdc++

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