libstdc++
type_traits
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1 // C++11 <type_traits> -*- C++ -*-
2 
3 // Copyright (C) 2007-2019 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file include/type_traits
26  * This is a Standard C++ Library header.
27  */
28 
29 #ifndef _GLIBCXX_TYPE_TRAITS
30 #define _GLIBCXX_TYPE_TRAITS 1
31 
32 #pragma GCC system_header
33 
34 #if __cplusplus < 201103L
35 # include <bits/c++0x_warning.h>
36 #else
37 
38 #include <bits/c++config.h>
39 
40 namespace std _GLIBCXX_VISIBILITY(default)
41 {
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
43 
44  /**
45  * @defgroup metaprogramming Metaprogramming
46  * @ingroup utilities
47  *
48  * Template utilities for compile-time introspection and modification,
49  * including type classification traits, type property inspection traits
50  * and type transformation traits.
51  *
52  * @{
53  */
54 
55  /// integral_constant
56  template<typename _Tp, _Tp __v>
58  {
59  static constexpr _Tp value = __v;
60  typedef _Tp value_type;
62  constexpr operator value_type() const noexcept { return value; }
63 #if __cplusplus > 201103L
64 
65 #define __cpp_lib_integral_constant_callable 201304
66 
67  constexpr value_type operator()() const noexcept { return value; }
68 #endif
69  };
70 
71  template<typename _Tp, _Tp __v>
73 
74  /// The type used as a compile-time boolean with true value.
76 
77  /// The type used as a compile-time boolean with false value.
79 
80  template<bool __v>
82 
83 #if __cplusplus > 201402L
84 # define __cpp_lib_bool_constant 201505
85  template<bool __v>
86  using bool_constant = integral_constant<bool, __v>;
87 #endif
88 
89  // Meta programming helper types.
90 
91  template<bool, typename, typename>
92  struct conditional;
93 
94  template <typename _Type>
95  struct __type_identity
96  { using type = _Type; };
97 
98  template<typename _Tp>
99  using __type_identity_t = typename __type_identity<_Tp>::type;
100 
101  template<typename...>
102  struct __or_;
103 
104  template<>
105  struct __or_<>
106  : public false_type
107  { };
108 
109  template<typename _B1>
110  struct __or_<_B1>
111  : public _B1
112  { };
113 
114  template<typename _B1, typename _B2>
115  struct __or_<_B1, _B2>
116  : public conditional<_B1::value, _B1, _B2>::type
117  { };
118 
119  template<typename _B1, typename _B2, typename _B3, typename... _Bn>
120  struct __or_<_B1, _B2, _B3, _Bn...>
121  : public conditional<_B1::value, _B1, __or_<_B2, _B3, _Bn...>>::type
122  { };
123 
124  template<typename...>
125  struct __and_;
126 
127  template<>
128  struct __and_<>
129  : public true_type
130  { };
131 
132  template<typename _B1>
133  struct __and_<_B1>
134  : public _B1
135  { };
136 
137  template<typename _B1, typename _B2>
138  struct __and_<_B1, _B2>
139  : public conditional<_B1::value, _B2, _B1>::type
140  { };
141 
142  template<typename _B1, typename _B2, typename _B3, typename... _Bn>
143  struct __and_<_B1, _B2, _B3, _Bn...>
144  : public conditional<_B1::value, __and_<_B2, _B3, _Bn...>, _B1>::type
145  { };
146 
147  template<typename _Pp>
148  struct __not_
149  : public __bool_constant<!bool(_Pp::value)>
150  { };
151 
152 #if __cplusplus >= 201703L
153 
154  template<typename... _Bn>
155  inline constexpr bool __or_v = __or_<_Bn...>::value;
156  template<typename... _Bn>
157  inline constexpr bool __and_v = __and_<_Bn...>::value;
158 
159 #define __cpp_lib_logical_traits 201510
160 
161  template<typename... _Bn>
162  struct conjunction
163  : __and_<_Bn...>
164  { };
165 
166  template<typename... _Bn>
167  struct disjunction
168  : __or_<_Bn...>
169  { };
170 
171  template<typename _Pp>
172  struct negation
173  : __not_<_Pp>
174  { };
175 
176  template<typename... _Bn>
177  inline constexpr bool conjunction_v = conjunction<_Bn...>::value;
178 
179  template<typename... _Bn>
180  inline constexpr bool disjunction_v = disjunction<_Bn...>::value;
181 
182  template<typename _Pp>
183  inline constexpr bool negation_v = negation<_Pp>::value;
184 
185 #endif // C++17
186 
187  // Forward declarations
188  template<typename>
189  struct is_reference;
190  template<typename>
191  struct is_function;
192  template<typename>
193  struct is_void;
194  template<typename>
195  struct __is_array_unknown_bounds;
196 
197  // Helper functions that return false_type for incomplete classes,
198  // incomplete unions and arrays of known bound from those.
199 
200  template <typename _T, size_t = sizeof(_T)>
201  constexpr true_type __is_complete_or_unbounded(__type_identity<_T>)
202  { return {}; }
203 
204  template <typename _TypeIdentity,
205  typename _NestedType = typename _TypeIdentity::type>
206  constexpr typename __or_<
207  is_reference<_NestedType>,
208  is_function<_NestedType>,
209  is_void<_NestedType>,
210  __is_array_unknown_bounds<_NestedType>
211  >::type __is_complete_or_unbounded(_TypeIdentity)
212  { return {}; }
213 
214  // For several sfinae-friendly trait implementations we transport both the
215  // result information (as the member type) and the failure information (no
216  // member type). This is very similar to std::enable_if, but we cannot use
217  // them, because we need to derive from them as an implementation detail.
218 
219  template<typename _Tp>
220  struct __success_type
221  { typedef _Tp type; };
222 
223  struct __failure_type
224  { };
225 
226  template<typename>
227  struct remove_cv;
228 
229  // __remove_cv_t (std::remove_cv_t for C++11).
230  template<typename _Tp>
231  using __remove_cv_t = typename remove_cv<_Tp>::type;
232 
233  template<typename>
234  struct is_const;
235 
236  // Primary type categories.
237 
238  template<typename>
239  struct __is_void_helper
240  : public false_type { };
241 
242  template<>
243  struct __is_void_helper<void>
244  : public true_type { };
245 
246  /// is_void
247  template<typename _Tp>
248  struct is_void
249  : public __is_void_helper<__remove_cv_t<_Tp>>::type
250  { };
251 
252  template<typename>
253  struct __is_integral_helper
254  : public false_type { };
255 
256  template<>
257  struct __is_integral_helper<bool>
258  : public true_type { };
259 
260  template<>
261  struct __is_integral_helper<char>
262  : public true_type { };
263 
264  template<>
265  struct __is_integral_helper<signed char>
266  : public true_type { };
267 
268  template<>
269  struct __is_integral_helper<unsigned char>
270  : public true_type { };
271 
272 #ifdef _GLIBCXX_USE_WCHAR_T
273  template<>
274  struct __is_integral_helper<wchar_t>
275  : public true_type { };
276 #endif
277 
278 #ifdef _GLIBCXX_USE_CHAR8_T
279  template<>
280  struct __is_integral_helper<char8_t>
281  : public true_type { };
282 #endif
283 
284  template<>
285  struct __is_integral_helper<char16_t>
286  : public true_type { };
287 
288  template<>
289  struct __is_integral_helper<char32_t>
290  : public true_type { };
291 
292  template<>
293  struct __is_integral_helper<short>
294  : public true_type { };
295 
296  template<>
297  struct __is_integral_helper<unsigned short>
298  : public true_type { };
299 
300  template<>
301  struct __is_integral_helper<int>
302  : public true_type { };
303 
304  template<>
305  struct __is_integral_helper<unsigned int>
306  : public true_type { };
307 
308  template<>
309  struct __is_integral_helper<long>
310  : public true_type { };
311 
312  template<>
313  struct __is_integral_helper<unsigned long>
314  : public true_type { };
315 
316  template<>
317  struct __is_integral_helper<long long>
318  : public true_type { };
319 
320  template<>
321  struct __is_integral_helper<unsigned long long>
322  : public true_type { };
323 
324  // Conditionalizing on __STRICT_ANSI__ here will break any port that
325  // uses one of these types for size_t.
326 #if defined(__GLIBCXX_TYPE_INT_N_0)
327  template<>
328  struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_0>
329  : public true_type { };
330 
331  template<>
332  struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_0>
333  : public true_type { };
334 #endif
335 #if defined(__GLIBCXX_TYPE_INT_N_1)
336  template<>
337  struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_1>
338  : public true_type { };
339 
340  template<>
341  struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_1>
342  : public true_type { };
343 #endif
344 #if defined(__GLIBCXX_TYPE_INT_N_2)
345  template<>
346  struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_2>
347  : public true_type { };
348 
349  template<>
350  struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_2>
351  : public true_type { };
352 #endif
353 #if defined(__GLIBCXX_TYPE_INT_N_3)
354  template<>
355  struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_3>
356  : public true_type { };
357 
358  template<>
359  struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_3>
360  : public true_type { };
361 #endif
362 
363  /// is_integral
364  template<typename _Tp>
365  struct is_integral
366  : public __is_integral_helper<__remove_cv_t<_Tp>>::type
367  { };
368 
369  template<typename>
370  struct __is_floating_point_helper
371  : public false_type { };
372 
373  template<>
374  struct __is_floating_point_helper<float>
375  : public true_type { };
376 
377  template<>
378  struct __is_floating_point_helper<double>
379  : public true_type { };
380 
381  template<>
382  struct __is_floating_point_helper<long double>
383  : public true_type { };
384 
385 #if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128) && !defined(__CUDACC__)
386  template<>
387  struct __is_floating_point_helper<__float128>
388  : public true_type { };
389 #endif
390 
391  /// is_floating_point
392  template<typename _Tp>
394  : public __is_floating_point_helper<__remove_cv_t<_Tp>>::type
395  { };
396 
397  /// is_array
398  template<typename>
399  struct is_array
400  : public false_type { };
401 
402  template<typename _Tp, std::size_t _Size>
403  struct is_array<_Tp[_Size]>
404  : public true_type { };
405 
406  template<typename _Tp>
407  struct is_array<_Tp[]>
408  : public true_type { };
409 
410  template<typename>
411  struct __is_pointer_helper
412  : public false_type { };
413 
414  template<typename _Tp>
415  struct __is_pointer_helper<_Tp*>
416  : public true_type { };
417 
418  /// is_pointer
419  template<typename _Tp>
420  struct is_pointer
421  : public __is_pointer_helper<__remove_cv_t<_Tp>>::type
422  { };
423 
424  /// is_lvalue_reference
425  template<typename>
427  : public false_type { };
428 
429  template<typename _Tp>
430  struct is_lvalue_reference<_Tp&>
431  : public true_type { };
432 
433  /// is_rvalue_reference
434  template<typename>
436  : public false_type { };
437 
438  template<typename _Tp>
439  struct is_rvalue_reference<_Tp&&>
440  : public true_type { };
441 
442  template<typename>
443  struct __is_member_object_pointer_helper
444  : public false_type { };
445 
446  template<typename _Tp, typename _Cp>
447  struct __is_member_object_pointer_helper<_Tp _Cp::*>
448  : public __not_<is_function<_Tp>>::type { };
449 
450  /// is_member_object_pointer
451  template<typename _Tp>
453  : public __is_member_object_pointer_helper<__remove_cv_t<_Tp>>::type
454  { };
455 
456  template<typename>
457  struct __is_member_function_pointer_helper
458  : public false_type { };
459 
460  template<typename _Tp, typename _Cp>
461  struct __is_member_function_pointer_helper<_Tp _Cp::*>
462  : public is_function<_Tp>::type { };
463 
464  /// is_member_function_pointer
465  template<typename _Tp>
467  : public __is_member_function_pointer_helper<__remove_cv_t<_Tp>>::type
468  { };
469 
470  /// is_enum
471  template<typename _Tp>
472  struct is_enum
473  : public integral_constant<bool, __is_enum(_Tp)>
474  { };
475 
476  /// is_union
477  template<typename _Tp>
478  struct is_union
479  : public integral_constant<bool, __is_union(_Tp)>
480  { };
481 
482  /// is_class
483  template<typename _Tp>
484  struct is_class
485  : public integral_constant<bool, __is_class(_Tp)>
486  { };
487 
488  /// is_function
489  template<typename _Tp>
490  struct is_function
491  : public __bool_constant<!is_const<const _Tp>::value> { };
492 
493  template<typename _Tp>
494  struct is_function<_Tp&>
495  : public false_type { };
496 
497  template<typename _Tp>
498  struct is_function<_Tp&&>
499  : public false_type { };
500 
501 #define __cpp_lib_is_null_pointer 201309
502 
503  template<typename>
504  struct __is_null_pointer_helper
505  : public false_type { };
506 
507  template<>
508  struct __is_null_pointer_helper<std::nullptr_t>
509  : public true_type { };
510 
511  /// is_null_pointer (LWG 2247).
512  template<typename _Tp>
514  : public __is_null_pointer_helper<__remove_cv_t<_Tp>>::type
515  { };
516 
517  /// __is_nullptr_t (deprecated extension).
518  template<typename _Tp>
520  : public is_null_pointer<_Tp>
521  { } _GLIBCXX_DEPRECATED;
522 
523  // Composite type categories.
524 
525  /// is_reference
526  template<typename _Tp>
527  struct is_reference
528  : public __or_<is_lvalue_reference<_Tp>,
529  is_rvalue_reference<_Tp>>::type
530  { };
531 
532  /// is_arithmetic
533  template<typename _Tp>
535  : public __or_<is_integral<_Tp>, is_floating_point<_Tp>>::type
536  { };
537 
538  /// is_fundamental
539  template<typename _Tp>
541  : public __or_<is_arithmetic<_Tp>, is_void<_Tp>,
542  is_null_pointer<_Tp>>::type
543  { };
544 
545  /// is_object
546  template<typename _Tp>
547  struct is_object
548  : public __not_<__or_<is_function<_Tp>, is_reference<_Tp>,
549  is_void<_Tp>>>::type
550  { };
551 
552  template<typename>
554 
555  /// is_scalar
556  template<typename _Tp>
557  struct is_scalar
558  : public __or_<is_arithmetic<_Tp>, is_enum<_Tp>, is_pointer<_Tp>,
559  is_member_pointer<_Tp>, is_null_pointer<_Tp>>::type
560  { };
561 
562  /// is_compound
563  template<typename _Tp>
564  struct is_compound
565  : public __not_<is_fundamental<_Tp>>::type { };
566 
567  template<typename _Tp>
568  struct __is_member_pointer_helper
569  : public false_type { };
570 
571  template<typename _Tp, typename _Cp>
572  struct __is_member_pointer_helper<_Tp _Cp::*>
573  : public true_type { };
574 
575  /// is_member_pointer
576  template<typename _Tp>
577  struct is_member_pointer
578  : public __is_member_pointer_helper<__remove_cv_t<_Tp>>::type
579  { };
580 
581  template<typename, typename>
582  struct is_same;
583 
584  template<typename _Tp, typename... _Types>
585  using __is_one_of = __or_<is_same<_Tp, _Types>...>;
586 
587  // Check if a type is one of the signed integer types.
588  template<typename _Tp>
589  using __is_signed_integer = __is_one_of<__remove_cv_t<_Tp>,
590  signed char, signed short, signed int, signed long,
591  signed long long
592 #if defined(__GLIBCXX_TYPE_INT_N_0)
593  , signed __GLIBCXX_TYPE_INT_N_0
594 #endif
595 #if defined(__GLIBCXX_TYPE_INT_N_1)
596  , signed __GLIBCXX_TYPE_INT_N_1
597 #endif
598 #if defined(__GLIBCXX_TYPE_INT_N_2)
599  , signed __GLIBCXX_TYPE_INT_N_2
600 #endif
601 #if defined(__GLIBCXX_TYPE_INT_N_3)
602  , signed __GLIBCXX_TYPE_INT_N_3
603 #endif
604  >;
605 
606  // Check if a type is one of the unsigned integer types.
607  template<typename _Tp>
608  using __is_unsigned_integer = __is_one_of<__remove_cv_t<_Tp>,
609  unsigned char, unsigned short, unsigned int, unsigned long,
610  unsigned long long
611 #if defined(__GLIBCXX_TYPE_INT_N_0)
612  , unsigned __GLIBCXX_TYPE_INT_N_0
613 #endif
614 #if defined(__GLIBCXX_TYPE_INT_N_1)
615  , unsigned __GLIBCXX_TYPE_INT_N_1
616 #endif
617 #if defined(__GLIBCXX_TYPE_INT_N_2)
618  , unsigned __GLIBCXX_TYPE_INT_N_2
619 #endif
620 #if defined(__GLIBCXX_TYPE_INT_N_3)
621  , unsigned __GLIBCXX_TYPE_INT_N_3
622 #endif
623  >;
624 
625 
626  // __void_t (std::void_t for C++11)
627  template<typename...> using __void_t = void;
628 
629  // Utility to detect referenceable types ([defns.referenceable]).
630 
631  template<typename _Tp, typename = void>
632  struct __is_referenceable
633  : public false_type
634  { };
635 
636  template<typename _Tp>
637  struct __is_referenceable<_Tp, __void_t<_Tp&>>
638  : public true_type
639  { };
640 
641  // Type properties.
642 
643  /// is_const
644  template<typename>
645  struct is_const
646  : public false_type { };
647 
648  template<typename _Tp>
649  struct is_const<_Tp const>
650  : public true_type { };
651 
652  /// is_volatile
653  template<typename>
654  struct is_volatile
655  : public false_type { };
656 
657  template<typename _Tp>
658  struct is_volatile<_Tp volatile>
659  : public true_type { };
660 
661  /// is_trivial
662  template<typename _Tp>
663  struct is_trivial
664  : public integral_constant<bool, __is_trivial(_Tp)>
665  {
666  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
667  "template argument must be a complete class or an unbounded array");
668  };
669 
670  // is_trivially_copyable
671  template<typename _Tp>
672  struct is_trivially_copyable
673  : public integral_constant<bool, __is_trivially_copyable(_Tp)>
674  {
675  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
676  "template argument must be a complete class or an unbounded array");
677  };
678 
679  /// is_standard_layout
680  template<typename _Tp>
682  : public integral_constant<bool, __is_standard_layout(_Tp)>
683  {
684  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
685  "template argument must be a complete class or an unbounded array");
686  };
687 
688  /// is_pod
689  // Could use is_standard_layout && is_trivial instead of the builtin.
690  template<typename _Tp>
691  struct is_pod
692  : public integral_constant<bool, __is_pod(_Tp)>
693  {
694  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
695  "template argument must be a complete class or an unbounded array");
696  };
697 
698  /// is_literal_type
699  template<typename _Tp>
701  : public integral_constant<bool, __is_literal_type(_Tp)>
702  {
703  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
704  "template argument must be a complete class or an unbounded array");
705  };
706 
707  /// is_empty
708  template<typename _Tp>
709  struct is_empty
710  : public integral_constant<bool, __is_empty(_Tp)>
711  { };
712 
713  /// is_polymorphic
714  template<typename _Tp>
716  : public integral_constant<bool, __is_polymorphic(_Tp)>
717  { };
718 
719 #if __cplusplus >= 201402L
720 #define __cpp_lib_is_final 201402L
721  /// is_final
722  template<typename _Tp>
723  struct is_final
724  : public integral_constant<bool, __is_final(_Tp)>
725  { };
726 #endif
727 
728  /// is_abstract
729  template<typename _Tp>
730  struct is_abstract
731  : public integral_constant<bool, __is_abstract(_Tp)>
732  { };
733 
734  template<typename _Tp,
736  struct __is_signed_helper
737  : public false_type { };
738 
739  template<typename _Tp>
740  struct __is_signed_helper<_Tp, true>
741  : public integral_constant<bool, _Tp(-1) < _Tp(0)>
742  { };
743 
744  /// is_signed
745  template<typename _Tp>
746  struct is_signed
747  : public __is_signed_helper<_Tp>::type
748  { };
749 
750  /// is_unsigned
751  template<typename _Tp>
752  struct is_unsigned
753  : public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>
754  { };
755 
756 
757  // Destructible and constructible type properties.
758 
759  /**
760  * @brief Utility to simplify expressions used in unevaluated operands
761  * @ingroup utilities
762  */
763 
764  template<typename _Tp, typename _Up = _Tp&&>
765  _Up
766  __declval(int);
767 
768  template<typename _Tp>
769  _Tp
770  __declval(long);
771 
772  template<typename _Tp>
773  auto declval() noexcept -> decltype(__declval<_Tp>(0));
774 
775  template<typename, unsigned = 0>
776  struct extent;
777 
778  template<typename>
780 
781  template<typename _Tp>
782  struct __is_array_known_bounds
783  : public integral_constant<bool, (extent<_Tp>::value > 0)>
784  { };
785 
786  template<typename _Tp>
787  struct __is_array_unknown_bounds
788  : public __and_<is_array<_Tp>, __not_<extent<_Tp>>>
789  { };
790 
791  // In N3290 is_destructible does not say anything about function
792  // types and abstract types, see LWG 2049. This implementation
793  // describes function types as non-destructible and all complete
794  // object types as destructible, iff the explicit destructor
795  // call expression is wellformed.
796  struct __do_is_destructible_impl
797  {
798  template<typename _Tp, typename = decltype(declval<_Tp&>().~_Tp())>
799  static true_type __test(int);
800 
801  template<typename>
802  static false_type __test(...);
803  };
804 
805  template<typename _Tp>
806  struct __is_destructible_impl
807  : public __do_is_destructible_impl
808  {
809  typedef decltype(__test<_Tp>(0)) type;
810  };
811 
812  template<typename _Tp,
813  bool = __or_<is_void<_Tp>,
814  __is_array_unknown_bounds<_Tp>,
815  is_function<_Tp>>::value,
816  bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
817  struct __is_destructible_safe;
818 
819  template<typename _Tp>
820  struct __is_destructible_safe<_Tp, false, false>
821  : public __is_destructible_impl<typename
822  remove_all_extents<_Tp>::type>::type
823  { };
824 
825  template<typename _Tp>
826  struct __is_destructible_safe<_Tp, true, false>
827  : public false_type { };
828 
829  template<typename _Tp>
830  struct __is_destructible_safe<_Tp, false, true>
831  : public true_type { };
832 
833  /// is_destructible
834  template<typename _Tp>
836  : public __is_destructible_safe<_Tp>::type
837  {
838  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
839  "template argument must be a complete class or an unbounded array");
840  };
841 
842  // is_nothrow_destructible requires that is_destructible is
843  // satisfied as well. We realize that by mimicing the
844  // implementation of is_destructible but refer to noexcept(expr)
845  // instead of decltype(expr).
846  struct __do_is_nt_destructible_impl
847  {
848  template<typename _Tp>
850  __test(int);
851 
852  template<typename>
853  static false_type __test(...);
854  };
855 
856  template<typename _Tp>
857  struct __is_nt_destructible_impl
858  : public __do_is_nt_destructible_impl
859  {
860  typedef decltype(__test<_Tp>(0)) type;
861  };
862 
863  template<typename _Tp,
864  bool = __or_<is_void<_Tp>,
865  __is_array_unknown_bounds<_Tp>,
866  is_function<_Tp>>::value,
867  bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
868  struct __is_nt_destructible_safe;
869 
870  template<typename _Tp>
871  struct __is_nt_destructible_safe<_Tp, false, false>
872  : public __is_nt_destructible_impl<typename
873  remove_all_extents<_Tp>::type>::type
874  { };
875 
876  template<typename _Tp>
877  struct __is_nt_destructible_safe<_Tp, true, false>
878  : public false_type { };
879 
880  template<typename _Tp>
881  struct __is_nt_destructible_safe<_Tp, false, true>
882  : public true_type { };
883 
884  /// is_nothrow_destructible
885  template<typename _Tp>
887  : public __is_nt_destructible_safe<_Tp>::type
888  {
889  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
890  "template argument must be a complete class or an unbounded array");
891  };
892 
893  template<typename _Tp, typename... _Args>
894  struct __is_constructible_impl
895  : public __bool_constant<__is_constructible(_Tp, _Args...)>
896  { };
897 
898  /// is_constructible
899  template<typename _Tp, typename... _Args>
901  : public __is_constructible_impl<_Tp, _Args...>
902  {
903  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
904  "template argument must be a complete class or an unbounded array");
905  };
906 
907  /// is_default_constructible
908  template<typename _Tp>
910  : public __is_constructible_impl<_Tp>::type
911  {
912  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
913  "template argument must be a complete class or an unbounded array");
914  };
915 
916  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
917  struct __is_copy_constructible_impl;
918 
919  template<typename _Tp>
920  struct __is_copy_constructible_impl<_Tp, false>
921  : public false_type { };
922 
923  template<typename _Tp>
924  struct __is_copy_constructible_impl<_Tp, true>
925  : public __is_constructible_impl<_Tp, const _Tp&>
926  { };
927 
928  /// is_copy_constructible
929  template<typename _Tp>
931  : public __is_copy_constructible_impl<_Tp>
932  {
933  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
934  "template argument must be a complete class or an unbounded array");
935  };
936 
937  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
938  struct __is_move_constructible_impl;
939 
940  template<typename _Tp>
941  struct __is_move_constructible_impl<_Tp, false>
942  : public false_type { };
943 
944  template<typename _Tp>
945  struct __is_move_constructible_impl<_Tp, true>
946  : public __is_constructible_impl<_Tp, _Tp&&>
947  { };
948 
949  /// is_move_constructible
950  template<typename _Tp>
952  : public __is_move_constructible_impl<_Tp>
953  {
954  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
955  "template argument must be a complete class or an unbounded array");
956  };
957 
958  template<typename _Tp>
959  struct __is_nt_default_constructible_atom
960  : public integral_constant<bool, noexcept(_Tp())>
961  { };
962 
963  template<typename _Tp, bool = is_array<_Tp>::value>
964  struct __is_nt_default_constructible_impl;
965 
966  template<typename _Tp>
967  struct __is_nt_default_constructible_impl<_Tp, true>
968  : public __and_<__is_array_known_bounds<_Tp>,
969  __is_nt_default_constructible_atom<typename
970  remove_all_extents<_Tp>::type>>
971  { };
972 
973  template<typename _Tp>
974  struct __is_nt_default_constructible_impl<_Tp, false>
975  : public __is_nt_default_constructible_atom<_Tp>
976  { };
977 
978  template<typename _Tp>
979  using __is_nothrow_default_constructible_impl
980  = __and_<__is_constructible_impl<_Tp>,
981  __is_nt_default_constructible_impl<_Tp>>;
982 
983  /// is_nothrow_default_constructible
984  template<typename _Tp>
986  : public __is_nothrow_default_constructible_impl<_Tp>::type
987  {
988  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
989  "template argument must be a complete class or an unbounded array");
990  };
991 
992  template<typename _Tp, typename... _Args>
993  struct __is_nt_constructible_impl
994  : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
995  { };
996 
997  template<typename _Tp, typename _Arg>
998  struct __is_nt_constructible_impl<_Tp, _Arg>
999  : public integral_constant<bool,
1000  noexcept(static_cast<_Tp>(declval<_Arg>()))>
1001  { };
1002 
1003  template<typename _Tp>
1004  struct __is_nt_constructible_impl<_Tp>
1005  : public __is_nothrow_default_constructible_impl<_Tp>
1006  { };
1007 
1008  template<typename _Tp, typename... _Args>
1009  struct __is_nothrow_constructible_impl
1010  : public __and_<__is_constructible_impl<_Tp, _Args...>,
1011  __is_nt_constructible_impl<_Tp, _Args...>>
1012  { };
1013 
1014  /// is_nothrow_constructible
1015  template<typename _Tp, typename... _Args>
1017  : public __is_nothrow_constructible_impl<_Tp, _Args...>::type
1018  {
1019  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1020  "template argument must be a complete class or an unbounded array");
1021  };
1022 
1023  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1024  struct __is_nothrow_copy_constructible_impl;
1025 
1026  template<typename _Tp>
1027  struct __is_nothrow_copy_constructible_impl<_Tp, false>
1028  : public false_type { };
1029 
1030  template<typename _Tp>
1031  struct __is_nothrow_copy_constructible_impl<_Tp, true>
1032  : public __is_nothrow_constructible_impl<_Tp, const _Tp&>
1033  { };
1034 
1035  /// is_nothrow_copy_constructible
1036  template<typename _Tp>
1038  : public __is_nothrow_copy_constructible_impl<_Tp>::type
1039  {
1040  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1041  "template argument must be a complete class or an unbounded array");
1042  };
1043 
1044  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1045  struct __is_nothrow_move_constructible_impl;
1046 
1047  template<typename _Tp>
1048  struct __is_nothrow_move_constructible_impl<_Tp, false>
1049  : public false_type { };
1050 
1051  template<typename _Tp>
1052  struct __is_nothrow_move_constructible_impl<_Tp, true>
1053  : public __is_nothrow_constructible_impl<_Tp, _Tp&&>
1054  { };
1055 
1056  /// is_nothrow_move_constructible
1057  template<typename _Tp>
1059  : public __is_nothrow_move_constructible_impl<_Tp>::type
1060  {
1061  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1062  "template argument must be a complete class or an unbounded array");
1063  };
1064 
1065  /// is_assignable
1066  template<typename _Tp, typename _Up>
1068  : public __bool_constant<__is_assignable(_Tp, _Up)>
1069  {
1070  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1071  "template argument must be a complete class or an unbounded array");
1072  };
1073 
1074  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1075  struct __is_copy_assignable_impl;
1076 
1077  template<typename _Tp>
1078  struct __is_copy_assignable_impl<_Tp, false>
1079  : public false_type { };
1080 
1081  template<typename _Tp>
1082  struct __is_copy_assignable_impl<_Tp, true>
1083  : public __bool_constant<__is_assignable(_Tp&, const _Tp&)>
1084  { };
1085 
1086  /// is_copy_assignable
1087  template<typename _Tp>
1089  : public __is_copy_assignable_impl<_Tp>::type
1090  {
1091  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1092  "template argument must be a complete class or an unbounded array");
1093  };
1094 
1095  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1096  struct __is_move_assignable_impl;
1097 
1098  template<typename _Tp>
1099  struct __is_move_assignable_impl<_Tp, false>
1100  : public false_type { };
1101 
1102  template<typename _Tp>
1103  struct __is_move_assignable_impl<_Tp, true>
1104  : public __bool_constant<__is_assignable(_Tp&, _Tp&&)>
1105  { };
1106 
1107  /// is_move_assignable
1108  template<typename _Tp>
1110  : public __is_move_assignable_impl<_Tp>::type
1111  {
1112  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1113  "template argument must be a complete class or an unbounded array");
1114  };
1115 
1116  template<typename _Tp, typename _Up>
1117  struct __is_nt_assignable_impl
1118  : public integral_constant<bool, noexcept(declval<_Tp>() = declval<_Up>())>
1119  { };
1120 
1121  template<typename _Tp, typename _Up>
1122  struct __is_nothrow_assignable_impl
1123  : public __and_<__bool_constant<__is_assignable(_Tp, _Up)>,
1124  __is_nt_assignable_impl<_Tp, _Up>>
1125  { };
1126 
1127  /// is_nothrow_assignable
1128  template<typename _Tp, typename _Up>
1130  : public __is_nothrow_assignable_impl<_Tp, _Up>
1131  {
1132  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1133  "template argument must be a complete class or an unbounded array");
1134  };
1135 
1136  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1137  struct __is_nt_copy_assignable_impl;
1138 
1139  template<typename _Tp>
1140  struct __is_nt_copy_assignable_impl<_Tp, false>
1141  : public false_type { };
1142 
1143  template<typename _Tp>
1144  struct __is_nt_copy_assignable_impl<_Tp, true>
1145  : public __is_nothrow_assignable_impl<_Tp&, const _Tp&>
1146  { };
1147 
1148  /// is_nothrow_copy_assignable
1149  template<typename _Tp>
1151  : public __is_nt_copy_assignable_impl<_Tp>
1152  {
1153  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1154  "template argument must be a complete class or an unbounded array");
1155  };
1156 
1157  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1158  struct __is_nt_move_assignable_impl;
1159 
1160  template<typename _Tp>
1161  struct __is_nt_move_assignable_impl<_Tp, false>
1162  : public false_type { };
1163 
1164  template<typename _Tp>
1165  struct __is_nt_move_assignable_impl<_Tp, true>
1166  : public __is_nothrow_assignable_impl<_Tp&, _Tp&&>
1167  { };
1168 
1169  /// is_nothrow_move_assignable
1170  template<typename _Tp>
1172  : public __is_nt_move_assignable_impl<_Tp>
1173  {
1174  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1175  "template argument must be a complete class or an unbounded array");
1176  };
1177 
1178  /// is_trivially_constructible
1179  template<typename _Tp, typename... _Args>
1181  : public __bool_constant<__is_trivially_constructible(_Tp, _Args...)>
1182  {
1183  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1184  "template argument must be a complete class or an unbounded array");
1185  };
1186 
1187  /// is_trivially_default_constructible
1188  template<typename _Tp>
1190  : public __bool_constant<__is_trivially_constructible(_Tp)>
1191  {
1192  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1193  "template argument must be a complete class or an unbounded array");
1194  };
1195 
1196  struct __do_is_implicitly_default_constructible_impl
1197  {
1198  template <typename _Tp>
1199  static void __helper(const _Tp&);
1200 
1201  template <typename _Tp>
1202  static true_type __test(const _Tp&,
1203  decltype(__helper<const _Tp&>({}))* = 0);
1204 
1205  static false_type __test(...);
1206  };
1207 
1208  template<typename _Tp>
1209  struct __is_implicitly_default_constructible_impl
1210  : public __do_is_implicitly_default_constructible_impl
1211  {
1212  typedef decltype(__test(declval<_Tp>())) type;
1213  };
1214 
1215  template<typename _Tp>
1216  struct __is_implicitly_default_constructible_safe
1217  : public __is_implicitly_default_constructible_impl<_Tp>::type
1218  { };
1219 
1220  template <typename _Tp>
1221  struct __is_implicitly_default_constructible
1222  : public __and_<__is_constructible_impl<_Tp>,
1223  __is_implicitly_default_constructible_safe<_Tp>>
1224  { };
1225 
1226  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1227  struct __is_trivially_copy_constructible_impl;
1228 
1229  template<typename _Tp>
1230  struct __is_trivially_copy_constructible_impl<_Tp, false>
1231  : public false_type { };
1232 
1233  template<typename _Tp>
1234  struct __is_trivially_copy_constructible_impl<_Tp, true>
1235  : public __and_<__is_copy_constructible_impl<_Tp>,
1236  integral_constant<bool,
1237  __is_trivially_constructible(_Tp, const _Tp&)>>
1238  { };
1239 
1240  /// is_trivially_copy_constructible
1241  template<typename _Tp>
1243  : public __is_trivially_copy_constructible_impl<_Tp>
1244  {
1245  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1246  "template argument must be a complete class or an unbounded array");
1247  };
1248 
1249  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1250  struct __is_trivially_move_constructible_impl;
1251 
1252  template<typename _Tp>
1253  struct __is_trivially_move_constructible_impl<_Tp, false>
1254  : public false_type { };
1255 
1256  template<typename _Tp>
1257  struct __is_trivially_move_constructible_impl<_Tp, true>
1258  : public __and_<__is_move_constructible_impl<_Tp>,
1259  integral_constant<bool,
1260  __is_trivially_constructible(_Tp, _Tp&&)>>
1261  { };
1262 
1263  /// is_trivially_move_constructible
1264  template<typename _Tp>
1266  : public __is_trivially_move_constructible_impl<_Tp>
1267  {
1268  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1269  "template argument must be a complete class or an unbounded array");
1270  };
1271 
1272  /// is_trivially_assignable
1273  template<typename _Tp, typename _Up>
1275  : public __bool_constant<__is_trivially_assignable(_Tp, _Up)>
1276  {
1277  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1278  "template argument must be a complete class or an unbounded array");
1279  };
1280 
1281  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1282  struct __is_trivially_copy_assignable_impl;
1283 
1284  template<typename _Tp>
1285  struct __is_trivially_copy_assignable_impl<_Tp, false>
1286  : public false_type { };
1287 
1288  template<typename _Tp>
1289  struct __is_trivially_copy_assignable_impl<_Tp, true>
1290  : public __bool_constant<__is_trivially_assignable(_Tp&, const _Tp&)>
1291  { };
1292 
1293  /// is_trivially_copy_assignable
1294  template<typename _Tp>
1296  : public __is_trivially_copy_assignable_impl<_Tp>
1297  {
1298  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1299  "template argument must be a complete class or an unbounded array");
1300  };
1301 
1302  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1303  struct __is_trivially_move_assignable_impl;
1304 
1305  template<typename _Tp>
1306  struct __is_trivially_move_assignable_impl<_Tp, false>
1307  : public false_type { };
1308 
1309  template<typename _Tp>
1310  struct __is_trivially_move_assignable_impl<_Tp, true>
1311  : public __bool_constant<__is_trivially_assignable(_Tp&, _Tp&&)>
1312  { };
1313 
1314  /// is_trivially_move_assignable
1315  template<typename _Tp>
1317  : public __is_trivially_move_assignable_impl<_Tp>
1318  {
1319  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1320  "template argument must be a complete class or an unbounded array");
1321  };
1322 
1323  /// is_trivially_destructible
1324  template<typename _Tp>
1326  : public __and_<__is_destructible_safe<_Tp>,
1327  __bool_constant<__has_trivial_destructor(_Tp)>>
1328  {
1329  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1330  "template argument must be a complete class or an unbounded array");
1331  };
1332 
1333 
1334  /// has_virtual_destructor
1335  template<typename _Tp>
1337  : public integral_constant<bool, __has_virtual_destructor(_Tp)>
1338  {
1339  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1340  "template argument must be a complete class or an unbounded array");
1341  };
1342 
1343 
1344  // type property queries.
1345 
1346  /// alignment_of
1347  template<typename _Tp>
1349  : public integral_constant<std::size_t, alignof(_Tp)>
1350  {
1351  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
1352  "template argument must be a complete class or an unbounded array");
1353  };
1354 
1355  /// rank
1356  template<typename>
1357  struct rank
1358  : public integral_constant<std::size_t, 0> { };
1359 
1360  template<typename _Tp, std::size_t _Size>
1361  struct rank<_Tp[_Size]>
1362  : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
1363 
1364  template<typename _Tp>
1365  struct rank<_Tp[]>
1366  : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
1367 
1368  /// extent
1369  template<typename, unsigned _Uint>
1370  struct extent
1371  : public integral_constant<std::size_t, 0> { };
1372 
1373  template<typename _Tp, unsigned _Uint, std::size_t _Size>
1374  struct extent<_Tp[_Size], _Uint>
1375  : public integral_constant<std::size_t,
1376  _Uint == 0 ? _Size : extent<_Tp,
1377  _Uint - 1>::value>
1378  { };
1379 
1380  template<typename _Tp, unsigned _Uint>
1381  struct extent<_Tp[], _Uint>
1382  : public integral_constant<std::size_t,
1383  _Uint == 0 ? 0 : extent<_Tp,
1384  _Uint - 1>::value>
1385  { };
1386 
1387 
1388  // Type relations.
1389 
1390  /// is_same
1391  template<typename _Tp, typename _Up>
1392  struct is_same
1393 #ifdef _GLIBCXX_BUILTIN_IS_SAME_AS
1394  : public integral_constant<bool, _GLIBCXX_BUILTIN_IS_SAME_AS(_Tp, _Up)>
1395 #else
1396  : public false_type
1397 #endif
1398  { };
1399 
1400 #ifndef _GLIBCXX_BUILTIN_IS_SAME_AS
1401  template<typename _Tp>
1402  struct is_same<_Tp, _Tp>
1403  : public true_type
1404  { };
1405 #endif
1406 
1407  /// is_base_of
1408  template<typename _Base, typename _Derived>
1409  struct is_base_of
1410  : public integral_constant<bool, __is_base_of(_Base, _Derived)>
1411  { };
1412 
1413  template<typename _From, typename _To,
1414  bool = __or_<is_void<_From>, is_function<_To>,
1415  is_array<_To>>::value>
1416  struct __is_convertible_helper
1417  {
1418  typedef typename is_void<_To>::type type;
1419  };
1420 
1421 #pragma GCC diagnostic push
1422 #pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
1423  template<typename _From, typename _To>
1424  class __is_convertible_helper<_From, _To, false>
1425  {
1426  template<typename _To1>
1427  static void __test_aux(_To1) noexcept;
1428 
1429  template<typename _From1, typename _To1,
1430  typename = decltype(__test_aux<_To1>(std::declval<_From1>()))>
1431  static true_type
1432  __test(int);
1433 
1434  template<typename, typename>
1435  static false_type
1436  __test(...);
1437 
1438  public:
1439  typedef decltype(__test<_From, _To>(0)) type;
1440  };
1441 #pragma GCC diagnostic pop
1442 
1443  /// is_convertible
1444  template<typename _From, typename _To>
1446  : public __is_convertible_helper<_From, _To>::type
1447  { };
1448 
1449  template<typename _From, typename _To,
1450  bool = __or_<is_void<_From>, is_function<_To>,
1451  is_array<_To>>::value>
1452  struct __is_nt_convertible_helper
1453  : is_void<_To>
1454  { };
1455 
1456 #pragma GCC diagnostic push
1457 #pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
1458  template<typename _From, typename _To>
1459  class __is_nt_convertible_helper<_From, _To, false>
1460  {
1461  template<typename _To1>
1462  static void __test_aux(_To1) noexcept;
1463 
1464  template<typename _From1, typename _To1>
1465  static
1466  __bool_constant<noexcept(__test_aux<_To1>(std::declval<_From1>()))>
1467  __test(int);
1468 
1469  template<typename, typename>
1470  static false_type
1471  __test(...);
1472 
1473  public:
1474  using type = decltype(__test<_From, _To>(0));
1475  };
1476 #pragma GCC diagnostic pop
1477 
1478  // helper trait for unique_ptr<T[]>, shared_ptr<T[]>, and span<T, N>
1479  template<typename _ToElementType, typename _FromElementType>
1480  using __is_array_convertible
1481  = is_convertible<_FromElementType(*)[], _ToElementType(*)[]>;
1482 
1483  // is_nothrow_convertible for C++11
1484  template<typename _From, typename _To>
1485  struct __is_nothrow_convertible
1486  : public __is_nt_convertible_helper<_From, _To>::type
1487  { };
1488 
1489 #if __cplusplus > 201703L
1490  /// is_nothrow_convertible
1491  template<typename _From, typename _To>
1492  struct is_nothrow_convertible
1493  : public __is_nt_convertible_helper<_From, _To>::type
1494  { };
1495 
1496  /// is_nothrow_convertible_v
1497  template<typename _From, typename _To>
1498  inline constexpr bool is_nothrow_convertible_v
1499  = is_nothrow_convertible<_From, _To>::value;
1500 #endif // C++2a
1501 
1502  // Const-volatile modifications.
1503 
1504  /// remove_const
1505  template<typename _Tp>
1507  { typedef _Tp type; };
1508 
1509  template<typename _Tp>
1510  struct remove_const<_Tp const>
1511  { typedef _Tp type; };
1512 
1513  /// remove_volatile
1514  template<typename _Tp>
1516  { typedef _Tp type; };
1517 
1518  template<typename _Tp>
1519  struct remove_volatile<_Tp volatile>
1520  { typedef _Tp type; };
1521 
1522  /// remove_cv
1523  template<typename _Tp>
1524  struct remove_cv
1525  { using type = _Tp; };
1526 
1527  template<typename _Tp>
1528  struct remove_cv<const _Tp>
1529  { using type = _Tp; };
1530 
1531  template<typename _Tp>
1532  struct remove_cv<volatile _Tp>
1533  { using type = _Tp; };
1534 
1535  template<typename _Tp>
1536  struct remove_cv<const volatile _Tp>
1537  { using type = _Tp; };
1538 
1539  /// add_const
1540  template<typename _Tp>
1541  struct add_const
1542  { typedef _Tp const type; };
1543 
1544  /// add_volatile
1545  template<typename _Tp>
1547  { typedef _Tp volatile type; };
1548 
1549  /// add_cv
1550  template<typename _Tp>
1551  struct add_cv
1552  {
1553  typedef typename
1555  };
1556 
1557 #if __cplusplus > 201103L
1558 
1559 #define __cpp_lib_transformation_trait_aliases 201304
1560 
1561  /// Alias template for remove_const
1562  template<typename _Tp>
1563  using remove_const_t = typename remove_const<_Tp>::type;
1564 
1565  /// Alias template for remove_volatile
1566  template<typename _Tp>
1567  using remove_volatile_t = typename remove_volatile<_Tp>::type;
1568 
1569  /// Alias template for remove_cv
1570  template<typename _Tp>
1571  using remove_cv_t = typename remove_cv<_Tp>::type;
1572 
1573  /// Alias template for add_const
1574  template<typename _Tp>
1575  using add_const_t = typename add_const<_Tp>::type;
1576 
1577  /// Alias template for add_volatile
1578  template<typename _Tp>
1579  using add_volatile_t = typename add_volatile<_Tp>::type;
1580 
1581  /// Alias template for add_cv
1582  template<typename _Tp>
1583  using add_cv_t = typename add_cv<_Tp>::type;
1584 #endif
1585 
1586  // Reference transformations.
1587 
1588  /// remove_reference
1589  template<typename _Tp>
1591  { typedef _Tp type; };
1592 
1593  template<typename _Tp>
1594  struct remove_reference<_Tp&>
1595  { typedef _Tp type; };
1596 
1597  template<typename _Tp>
1598  struct remove_reference<_Tp&&>
1599  { typedef _Tp type; };
1600 
1601  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1602  struct __add_lvalue_reference_helper
1603  { typedef _Tp type; };
1604 
1605  template<typename _Tp>
1606  struct __add_lvalue_reference_helper<_Tp, true>
1607  { typedef _Tp& type; };
1608 
1609  /// add_lvalue_reference
1610  template<typename _Tp>
1612  : public __add_lvalue_reference_helper<_Tp>
1613  { };
1614 
1615  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
1616  struct __add_rvalue_reference_helper
1617  { typedef _Tp type; };
1618 
1619  template<typename _Tp>
1620  struct __add_rvalue_reference_helper<_Tp, true>
1621  { typedef _Tp&& type; };
1622 
1623  /// add_rvalue_reference
1624  template<typename _Tp>
1626  : public __add_rvalue_reference_helper<_Tp>
1627  { };
1628 
1629 #if __cplusplus > 201103L
1630  /// Alias template for remove_reference
1631  template<typename _Tp>
1632  using remove_reference_t = typename remove_reference<_Tp>::type;
1633 
1634  /// Alias template for add_lvalue_reference
1635  template<typename _Tp>
1636  using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1637 
1638  /// Alias template for add_rvalue_reference
1639  template<typename _Tp>
1640  using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1641 #endif
1642 
1643  // Sign modifications.
1644 
1645  // Utility for constructing identically cv-qualified types.
1646  template<typename _Unqualified, bool _IsConst, bool _IsVol>
1647  struct __cv_selector;
1648 
1649  template<typename _Unqualified>
1650  struct __cv_selector<_Unqualified, false, false>
1651  { typedef _Unqualified __type; };
1652 
1653  template<typename _Unqualified>
1654  struct __cv_selector<_Unqualified, false, true>
1655  { typedef volatile _Unqualified __type; };
1656 
1657  template<typename _Unqualified>
1658  struct __cv_selector<_Unqualified, true, false>
1659  { typedef const _Unqualified __type; };
1660 
1661  template<typename _Unqualified>
1662  struct __cv_selector<_Unqualified, true, true>
1663  { typedef const volatile _Unqualified __type; };
1664 
1665  template<typename _Qualified, typename _Unqualified,
1666  bool _IsConst = is_const<_Qualified>::value,
1667  bool _IsVol = is_volatile<_Qualified>::value>
1668  class __match_cv_qualifiers
1669  {
1670  typedef __cv_selector<_Unqualified, _IsConst, _IsVol> __match;
1671 
1672  public:
1673  typedef typename __match::__type __type;
1674  };
1675 
1676  // Utility for finding the unsigned versions of signed integral types.
1677  template<typename _Tp>
1678  struct __make_unsigned
1679  { typedef _Tp __type; };
1680 
1681  template<>
1682  struct __make_unsigned<char>
1683  { typedef unsigned char __type; };
1684 
1685  template<>
1686  struct __make_unsigned<signed char>
1687  { typedef unsigned char __type; };
1688 
1689  template<>
1690  struct __make_unsigned<short>
1691  { typedef unsigned short __type; };
1692 
1693  template<>
1694  struct __make_unsigned<int>
1695  { typedef unsigned int __type; };
1696 
1697  template<>
1698  struct __make_unsigned<long>
1699  { typedef unsigned long __type; };
1700 
1701  template<>
1702  struct __make_unsigned<long long>
1703  { typedef unsigned long long __type; };
1704 
1705 #if defined(__GLIBCXX_TYPE_INT_N_0)
1706  template<>
1707  struct __make_unsigned<__GLIBCXX_TYPE_INT_N_0>
1708  { typedef unsigned __GLIBCXX_TYPE_INT_N_0 __type; };
1709 #endif
1710 #if defined(__GLIBCXX_TYPE_INT_N_1)
1711  template<>
1712  struct __make_unsigned<__GLIBCXX_TYPE_INT_N_1>
1713  { typedef unsigned __GLIBCXX_TYPE_INT_N_1 __type; };
1714 #endif
1715 #if defined(__GLIBCXX_TYPE_INT_N_2)
1716  template<>
1717  struct __make_unsigned<__GLIBCXX_TYPE_INT_N_2>
1718  { typedef unsigned __GLIBCXX_TYPE_INT_N_2 __type; };
1719 #endif
1720 #if defined(__GLIBCXX_TYPE_INT_N_3)
1721  template<>
1722  struct __make_unsigned<__GLIBCXX_TYPE_INT_N_3>
1723  { typedef unsigned __GLIBCXX_TYPE_INT_N_3 __type; };
1724 #endif
1725 
1726  // Select between integral and enum: not possible to be both.
1727  template<typename _Tp,
1728  bool _IsInt = is_integral<_Tp>::value,
1729  bool _IsEnum = is_enum<_Tp>::value>
1730  class __make_unsigned_selector;
1731 
1732  template<typename _Tp>
1733  class __make_unsigned_selector<_Tp, true, false>
1734  {
1735  using __unsigned_type
1736  = typename __make_unsigned<__remove_cv_t<_Tp>>::__type;
1737 
1738  public:
1739  using __type
1740  = typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
1741  };
1742 
1743  class __make_unsigned_selector_base
1744  {
1745  protected:
1746  template<typename...> struct _List { };
1747 
1748  template<typename _Tp, typename... _Up>
1749  struct _List<_Tp, _Up...> : _List<_Up...>
1750  { static constexpr size_t __size = sizeof(_Tp); };
1751 
1752  template<size_t _Sz, typename _Tp, bool = (_Sz <= _Tp::__size)>
1753  struct __select;
1754 
1755  template<size_t _Sz, typename _Uint, typename... _UInts>
1756  struct __select<_Sz, _List<_Uint, _UInts...>, true>
1757  { using __type = _Uint; };
1758 
1759  template<size_t _Sz, typename _Uint, typename... _UInts>
1760  struct __select<_Sz, _List<_Uint, _UInts...>, false>
1761  : __select<_Sz, _List<_UInts...>>
1762  { };
1763  };
1764 
1765  // Choose unsigned integer type with the smallest rank and same size as _Tp
1766  template<typename _Tp>
1767  class __make_unsigned_selector<_Tp, false, true>
1768  : __make_unsigned_selector_base
1769  {
1770  // With -fshort-enums, an enum may be as small as a char.
1771  using _UInts = _List<unsigned char, unsigned short, unsigned int,
1772  unsigned long, unsigned long long>;
1773 
1774  using __unsigned_type = typename __select<sizeof(_Tp), _UInts>::__type;
1775 
1776  public:
1777  using __type
1778  = typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
1779  };
1780 
1781  // wchar_t, char8_t, char16_t and char32_t are integral types but are
1782  // neither signed integer types nor unsigned integer types, so must be
1783  // transformed to the unsigned integer type with the smallest rank.
1784  // Use the partial specialization for enumeration types to do that.
1785 #if defined(_GLIBCXX_USE_WCHAR_T)
1786  template<>
1787  struct __make_unsigned<wchar_t>
1788  {
1789  using __type
1790  = typename __make_unsigned_selector<wchar_t, false, true>::__type;
1791  };
1792 #endif
1793 
1794 #ifdef _GLIBCXX_USE_CHAR8_T
1795  template<>
1796  struct __make_unsigned<char8_t>
1797  {
1798  using __type
1799  = typename __make_unsigned_selector<char8_t, false, true>::__type;
1800  };
1801 #endif
1802 
1803  template<>
1804  struct __make_unsigned<char16_t>
1805  {
1806  using __type
1807  = typename __make_unsigned_selector<char16_t, false, true>::__type;
1808  };
1809 
1810  template<>
1811  struct __make_unsigned<char32_t>
1812  {
1813  using __type
1814  = typename __make_unsigned_selector<char32_t, false, true>::__type;
1815  };
1816 
1817  // Given an integral/enum type, return the corresponding unsigned
1818  // integer type.
1819  // Primary template.
1820  /// make_unsigned
1821  template<typename _Tp>
1823  { typedef typename __make_unsigned_selector<_Tp>::__type type; };
1824 
1825  // Integral, but don't define.
1826  template<>
1827  struct make_unsigned<bool>;
1828 
1829 
1830  // Utility for finding the signed versions of unsigned integral types.
1831  template<typename _Tp>
1832  struct __make_signed
1833  { typedef _Tp __type; };
1834 
1835  template<>
1836  struct __make_signed<char>
1837  { typedef signed char __type; };
1838 
1839  template<>
1840  struct __make_signed<unsigned char>
1841  { typedef signed char __type; };
1842 
1843  template<>
1844  struct __make_signed<unsigned short>
1845  { typedef signed short __type; };
1846 
1847  template<>
1848  struct __make_signed<unsigned int>
1849  { typedef signed int __type; };
1850 
1851  template<>
1852  struct __make_signed<unsigned long>
1853  { typedef signed long __type; };
1854 
1855  template<>
1856  struct __make_signed<unsigned long long>
1857  { typedef signed long long __type; };
1858 
1859 #if defined(__GLIBCXX_TYPE_INT_N_0)
1860  template<>
1861  struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_0>
1862  { typedef __GLIBCXX_TYPE_INT_N_0 __type; };
1863 #endif
1864 #if defined(__GLIBCXX_TYPE_INT_N_1)
1865  template<>
1866  struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_1>
1867  { typedef __GLIBCXX_TYPE_INT_N_1 __type; };
1868 #endif
1869 #if defined(__GLIBCXX_TYPE_INT_N_2)
1870  template<>
1871  struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_2>
1872  { typedef __GLIBCXX_TYPE_INT_N_2 __type; };
1873 #endif
1874 #if defined(__GLIBCXX_TYPE_INT_N_3)
1875  template<>
1876  struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_3>
1877  { typedef __GLIBCXX_TYPE_INT_N_3 __type; };
1878 #endif
1879 
1880  // Select between integral and enum: not possible to be both.
1881  template<typename _Tp,
1882  bool _IsInt = is_integral<_Tp>::value,
1883  bool _IsEnum = is_enum<_Tp>::value>
1884  class __make_signed_selector;
1885 
1886  template<typename _Tp>
1887  class __make_signed_selector<_Tp, true, false>
1888  {
1889  using __signed_type
1890  = typename __make_signed<__remove_cv_t<_Tp>>::__type;
1891 
1892  public:
1893  using __type
1894  = typename __match_cv_qualifiers<_Tp, __signed_type>::__type;
1895  };
1896 
1897  // Choose signed integer type with the smallest rank and same size as _Tp
1898  template<typename _Tp>
1899  class __make_signed_selector<_Tp, false, true>
1900  {
1901  typedef typename __make_unsigned_selector<_Tp>::__type __unsigned_type;
1902 
1903  public:
1904  typedef typename __make_signed_selector<__unsigned_type>::__type __type;
1905  };
1906 
1907  // wchar_t, char16_t and char32_t are integral types but are neither
1908  // signed integer types nor unsigned integer types, so must be
1909  // transformed to the signed integer type with the smallest rank.
1910  // Use the partial specialization for enumeration types to do that.
1911 #if defined(_GLIBCXX_USE_WCHAR_T)
1912  template<>
1913  struct __make_signed<wchar_t>
1914  {
1915  using __type
1916  = typename __make_signed_selector<wchar_t, false, true>::__type;
1917  };
1918 #endif
1919 
1920 #if defined(_GLIBCXX_USE_CHAR8_T)
1921  template<>
1922  struct __make_signed<char8_t>
1923  {
1924  using __type
1925  = typename __make_signed_selector<char8_t, false, true>::__type;
1926  };
1927 #endif
1928 
1929  template<>
1930  struct __make_signed<char16_t>
1931  {
1932  using __type
1933  = typename __make_signed_selector<char16_t, false, true>::__type;
1934  };
1935 
1936  template<>
1937  struct __make_signed<char32_t>
1938  {
1939  using __type
1940  = typename __make_signed_selector<char32_t, false, true>::__type;
1941  };
1942 
1943  // Given an integral/enum type, return the corresponding signed
1944  // integer type.
1945  // Primary template.
1946  /// make_signed
1947  template<typename _Tp>
1949  { typedef typename __make_signed_selector<_Tp>::__type type; };
1950 
1951  // Integral, but don't define.
1952  template<>
1953  struct make_signed<bool>;
1954 
1955 #if __cplusplus > 201103L
1956  /// Alias template for make_signed
1957  template<typename _Tp>
1958  using make_signed_t = typename make_signed<_Tp>::type;
1959 
1960  /// Alias template for make_unsigned
1961  template<typename _Tp>
1962  using make_unsigned_t = typename make_unsigned<_Tp>::type;
1963 #endif
1964 
1965  // Array modifications.
1966 
1967  /// remove_extent
1968  template<typename _Tp>
1970  { typedef _Tp type; };
1971 
1972  template<typename _Tp, std::size_t _Size>
1973  struct remove_extent<_Tp[_Size]>
1974  { typedef _Tp type; };
1975 
1976  template<typename _Tp>
1977  struct remove_extent<_Tp[]>
1978  { typedef _Tp type; };
1979 
1980  /// remove_all_extents
1981  template<typename _Tp>
1982  struct remove_all_extents
1983  { typedef _Tp type; };
1984 
1985  template<typename _Tp, std::size_t _Size>
1986  struct remove_all_extents<_Tp[_Size]>
1987  { typedef typename remove_all_extents<_Tp>::type type; };
1988 
1989  template<typename _Tp>
1990  struct remove_all_extents<_Tp[]>
1991  { typedef typename remove_all_extents<_Tp>::type type; };
1992 
1993 #if __cplusplus > 201103L
1994  /// Alias template for remove_extent
1995  template<typename _Tp>
1996  using remove_extent_t = typename remove_extent<_Tp>::type;
1997 
1998  /// Alias template for remove_all_extents
1999  template<typename _Tp>
2000  using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
2001 #endif
2002 
2003  // Pointer modifications.
2004 
2005  template<typename _Tp, typename>
2006  struct __remove_pointer_helper
2007  { typedef _Tp type; };
2008 
2009  template<typename _Tp, typename _Up>
2010  struct __remove_pointer_helper<_Tp, _Up*>
2011  { typedef _Up type; };
2012 
2013  /// remove_pointer
2014  template<typename _Tp>
2016  : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
2017  { };
2018 
2019  /// add_pointer
2020  template<typename _Tp, bool = __or_<__is_referenceable<_Tp>,
2021  is_void<_Tp>>::value>
2023  { typedef _Tp type; };
2024 
2025  template<typename _Tp>
2026  struct __add_pointer_helper<_Tp, true>
2027  { typedef typename remove_reference<_Tp>::type* type; };
2028 
2029  template<typename _Tp>
2030  struct add_pointer
2031  : public __add_pointer_helper<_Tp>
2032  { };
2033 
2034 #if __cplusplus > 201103L
2035  /// Alias template for remove_pointer
2036  template<typename _Tp>
2037  using remove_pointer_t = typename remove_pointer<_Tp>::type;
2038 
2039  /// Alias template for add_pointer
2040  template<typename _Tp>
2041  using add_pointer_t = typename add_pointer<_Tp>::type;
2042 #endif
2043 
2044  template<std::size_t _Len>
2045  struct __aligned_storage_msa
2046  {
2047  union __type
2048  {
2049  unsigned char __data[_Len];
2050  struct __attribute__((__aligned__)) { } __align;
2051  };
2052  };
2053 
2054  /**
2055  * @brief Alignment type.
2056  *
2057  * The value of _Align is a default-alignment which shall be the
2058  * most stringent alignment requirement for any C++ object type
2059  * whose size is no greater than _Len (3.9). The member typedef
2060  * type shall be a POD type suitable for use as uninitialized
2061  * storage for any object whose size is at most _Len and whose
2062  * alignment is a divisor of _Align.
2063  */
2064  template<std::size_t _Len, std::size_t _Align =
2065  __alignof__(typename __aligned_storage_msa<_Len>::__type)>
2067  {
2068  union type
2069  {
2070  unsigned char __data[_Len];
2071  struct __attribute__((__aligned__((_Align)))) { } __align;
2072  };
2073  };
2074 
2075  template <typename... _Types>
2076  struct __strictest_alignment
2077  {
2078  static const size_t _S_alignment = 0;
2079  static const size_t _S_size = 0;
2080  };
2081 
2082  template <typename _Tp, typename... _Types>
2083  struct __strictest_alignment<_Tp, _Types...>
2084  {
2085  static const size_t _S_alignment =
2086  alignof(_Tp) > __strictest_alignment<_Types...>::_S_alignment
2087  ? alignof(_Tp) : __strictest_alignment<_Types...>::_S_alignment;
2088  static const size_t _S_size =
2089  sizeof(_Tp) > __strictest_alignment<_Types...>::_S_size
2090  ? sizeof(_Tp) : __strictest_alignment<_Types...>::_S_size;
2091  };
2092 
2093  /**
2094  * @brief Provide aligned storage for types.
2095  *
2096  * [meta.trans.other]
2097  *
2098  * Provides aligned storage for any of the provided types of at
2099  * least size _Len.
2100  *
2101  * @see aligned_storage
2102  */
2103  template <size_t _Len, typename... _Types>
2105  {
2106  private:
2107  static_assert(sizeof...(_Types) != 0, "At least one type is required");
2108 
2109  using __strictest = __strictest_alignment<_Types...>;
2110  static const size_t _S_len = _Len > __strictest::_S_size
2111  ? _Len : __strictest::_S_size;
2112  public:
2113  /// The value of the strictest alignment of _Types.
2114  static const size_t alignment_value = __strictest::_S_alignment;
2115  /// The storage.
2117  };
2118 
2119  template <size_t _Len, typename... _Types>
2120  const size_t aligned_union<_Len, _Types...>::alignment_value;
2121 
2122  // Decay trait for arrays and functions, used for perfect forwarding
2123  // in make_pair, make_tuple, etc.
2124  template<typename _Up,
2125  bool _IsArray = is_array<_Up>::value,
2126  bool _IsFunction = is_function<_Up>::value>
2127  struct __decay_selector;
2128 
2129  // NB: DR 705.
2130  template<typename _Up>
2131  struct __decay_selector<_Up, false, false>
2132  { typedef __remove_cv_t<_Up> __type; };
2133 
2134  template<typename _Up>
2135  struct __decay_selector<_Up, true, false>
2136  { typedef typename remove_extent<_Up>::type* __type; };
2137 
2138  template<typename _Up>
2139  struct __decay_selector<_Up, false, true>
2140  { typedef typename add_pointer<_Up>::type __type; };
2141 
2142  /// decay
2143  template<typename _Tp>
2144  class decay
2145  {
2146  typedef typename remove_reference<_Tp>::type __remove_type;
2147 
2148  public:
2149  typedef typename __decay_selector<__remove_type>::__type type;
2150  };
2151 
2152  // __decay_t (std::decay_t for C++11).
2153  template<typename _Tp>
2154  using __decay_t = typename decay<_Tp>::type;
2155 
2156  template<typename _Tp>
2158 
2159  // Helper which adds a reference to a type when given a reference_wrapper
2160  template<typename _Tp>
2161  struct __strip_reference_wrapper
2162  {
2163  typedef _Tp __type;
2164  };
2165 
2166  template<typename _Tp>
2167  struct __strip_reference_wrapper<reference_wrapper<_Tp> >
2168  {
2169  typedef _Tp& __type;
2170  };
2171 
2172  template<typename _Tp>
2173  using __decay_and_strip = __strip_reference_wrapper<__decay_t<_Tp>>;
2174 
2175 
2176  // Primary template.
2177  /// Define a member typedef @c type only if a boolean constant is true.
2178  template<bool, typename _Tp = void>
2179  struct enable_if
2180  { };
2181 
2182  // Partial specialization for true.
2183  template<typename _Tp>
2184  struct enable_if<true, _Tp>
2185  { typedef _Tp type; };
2186 
2187  // __enable_if_t (std::enable_if_t for C++11)
2188  template<bool _Cond, typename _Tp = void>
2189  using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
2190 
2191  template<typename... _Cond>
2192  using _Require = __enable_if_t<__and_<_Cond...>::value>;
2193 
2194  // Primary template.
2195  /// Define a member typedef @c type to one of two argument types.
2196  template<bool _Cond, typename _Iftrue, typename _Iffalse>
2197  struct conditional
2198  { typedef _Iftrue type; };
2199 
2200  // Partial specialization for false.
2201  template<typename _Iftrue, typename _Iffalse>
2202  struct conditional<false, _Iftrue, _Iffalse>
2203  { typedef _Iffalse type; };
2204 
2205  // __remove_cvref_t (std::remove_cvref_t for C++11).
2206  template<typename _Tp>
2207  using __remove_cvref_t
2208  = typename remove_cv<typename remove_reference<_Tp>::type>::type;
2209 
2210  /// common_type
2211  template<typename... _Tp>
2212  struct common_type;
2213 
2214  // Sfinae-friendly common_type implementation:
2215 
2216  struct __do_common_type_impl
2217  {
2218  template<typename _Tp, typename _Up>
2219  using __cond_t
2220  = decltype(true ? std::declval<_Tp>() : std::declval<_Up>());
2221 
2222  // if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
2223  // denotes a valid type, let C denote that type.
2224  template<typename _Tp, typename _Up>
2225  static __success_type<__decay_t<__cond_t<_Tp, _Up>>>
2226  _S_test(int);
2227 
2228 #if __cplusplus > 201703L
2229  // Otherwise, if COND-RES(CREF(D1), CREF(D2)) denotes a type,
2230  // let C denote the type decay_t<COND-RES(CREF(D1), CREF(D2))>.
2231  template<typename _Tp, typename _Up>
2232  static __success_type<__remove_cvref_t<__cond_t<const _Tp&, const _Up&>>>
2233  _S_test_2(int);
2234 #endif
2235 
2236  template<typename, typename>
2237  static __failure_type
2238  _S_test_2(...);
2239 
2240  template<typename _Tp, typename _Up>
2241  static decltype(_S_test_2<_Tp, _Up>(0))
2242  _S_test(...);
2243  };
2244 
2245  // If sizeof...(T) is zero, there shall be no member type.
2246  template<>
2247  struct common_type<>
2248  { };
2249 
2250  // If sizeof...(T) is one, the same type, if any, as common_type_t<T0, T0>.
2251  template<typename _Tp0>
2252  struct common_type<_Tp0>
2253  : public common_type<_Tp0, _Tp0>
2254  { };
2255 
2256  // If sizeof...(T) is two, ...
2257  template<typename _Tp1, typename _Tp2,
2258  typename _Dp1 = __decay_t<_Tp1>, typename _Dp2 = __decay_t<_Tp2>>
2259  struct __common_type_impl
2260  {
2261  // If is_same_v<T1, D1> is false or is_same_v<T2, D2> is false,
2262  // let C denote the same type, if any, as common_type_t<D1, D2>.
2263  using type = common_type<_Dp1, _Dp2>;
2264  };
2265 
2266  template<typename _Tp1, typename _Tp2>
2267  struct __common_type_impl<_Tp1, _Tp2, _Tp1, _Tp2>
2268  : private __do_common_type_impl
2269  {
2270  // Otherwise, if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
2271  // denotes a valid type, let C denote that type.
2272  using type = decltype(_S_test<_Tp1, _Tp2>(0));
2273  };
2274 
2275  // If sizeof...(T) is two, ...
2276  template<typename _Tp1, typename _Tp2>
2277  struct common_type<_Tp1, _Tp2>
2278  : public __common_type_impl<_Tp1, _Tp2>::type
2279  { };
2280 
2281  template<typename...>
2282  struct __common_type_pack
2283  { };
2284 
2285  template<typename, typename, typename = void>
2286  struct __common_type_fold;
2287 
2288  // If sizeof...(T) is greater than two, ...
2289  template<typename _Tp1, typename _Tp2, typename... _Rp>
2290  struct common_type<_Tp1, _Tp2, _Rp...>
2291  : public __common_type_fold<common_type<_Tp1, _Tp2>,
2292  __common_type_pack<_Rp...>>
2293  { };
2294 
2295  // Let C denote the same type, if any, as common_type_t<T1, T2>.
2296  // If there is such a type C, type shall denote the same type, if any,
2297  // as common_type_t<C, R...>.
2298  template<typename _CTp, typename... _Rp>
2299  struct __common_type_fold<_CTp, __common_type_pack<_Rp...>,
2300  __void_t<typename _CTp::type>>
2301  : public common_type<typename _CTp::type, _Rp...>
2302  { };
2303 
2304  // Otherwise, there shall be no member type.
2305  template<typename _CTp, typename _Rp>
2306  struct __common_type_fold<_CTp, _Rp, void>
2307  { };
2308 
2309  template<typename _Tp, bool = is_enum<_Tp>::value>
2310  struct __underlying_type_impl
2311  {
2312  using type = __underlying_type(_Tp);
2313  };
2314 
2315  template<typename _Tp>
2316  struct __underlying_type_impl<_Tp, false>
2317  { };
2318 
2319  /// The underlying type of an enum.
2320  template<typename _Tp>
2322  : public __underlying_type_impl<_Tp>
2323  { };
2324 
2325  template<typename _Tp>
2326  struct __declval_protector
2327  {
2328  static const bool __stop = false;
2329  };
2330 
2331  template<typename _Tp>
2332  auto declval() noexcept -> decltype(__declval<_Tp>(0))
2333  {
2334  static_assert(__declval_protector<_Tp>::__stop,
2335  "declval() must not be used!");
2336  return __declval<_Tp>(0);
2337  }
2338 
2339  /// result_of
2340  template<typename _Signature>
2341  class result_of;
2342 
2343  // Sfinae-friendly result_of implementation:
2344 
2345 #define __cpp_lib_result_of_sfinae 201210
2346 
2347  struct __invoke_memfun_ref { };
2348  struct __invoke_memfun_deref { };
2349  struct __invoke_memobj_ref { };
2350  struct __invoke_memobj_deref { };
2351  struct __invoke_other { };
2352 
2353  // Associate a tag type with a specialization of __success_type.
2354  template<typename _Tp, typename _Tag>
2355  struct __result_of_success : __success_type<_Tp>
2356  { using __invoke_type = _Tag; };
2357 
2358  // [func.require] paragraph 1 bullet 1:
2359  struct __result_of_memfun_ref_impl
2360  {
2361  template<typename _Fp, typename _Tp1, typename... _Args>
2362  static __result_of_success<decltype(
2363  (std::declval<_Tp1>().*std::declval<_Fp>())(std::declval<_Args>()...)
2364  ), __invoke_memfun_ref> _S_test(int);
2365 
2366  template<typename...>
2367  static __failure_type _S_test(...);
2368  };
2369 
2370  template<typename _MemPtr, typename _Arg, typename... _Args>
2371  struct __result_of_memfun_ref
2372  : private __result_of_memfun_ref_impl
2373  {
2374  typedef decltype(_S_test<_MemPtr, _Arg, _Args...>(0)) type;
2375  };
2376 
2377  // [func.require] paragraph 1 bullet 2:
2378  struct __result_of_memfun_deref_impl
2379  {
2380  template<typename _Fp, typename _Tp1, typename... _Args>
2381  static __result_of_success<decltype(
2382  ((*std::declval<_Tp1>()).*std::declval<_Fp>())(std::declval<_Args>()...)
2383  ), __invoke_memfun_deref> _S_test(int);
2384 
2385  template<typename...>
2386  static __failure_type _S_test(...);
2387  };
2388 
2389  template<typename _MemPtr, typename _Arg, typename... _Args>
2390  struct __result_of_memfun_deref
2391  : private __result_of_memfun_deref_impl
2392  {
2393  typedef decltype(_S_test<_MemPtr, _Arg, _Args...>(0)) type;
2394  };
2395 
2396  // [func.require] paragraph 1 bullet 3:
2397  struct __result_of_memobj_ref_impl
2398  {
2399  template<typename _Fp, typename _Tp1>
2400  static __result_of_success<decltype(
2401  std::declval<_Tp1>().*std::declval<_Fp>()
2402  ), __invoke_memobj_ref> _S_test(int);
2403 
2404  template<typename, typename>
2405  static __failure_type _S_test(...);
2406  };
2407 
2408  template<typename _MemPtr, typename _Arg>
2409  struct __result_of_memobj_ref
2410  : private __result_of_memobj_ref_impl
2411  {
2412  typedef decltype(_S_test<_MemPtr, _Arg>(0)) type;
2413  };
2414 
2415  // [func.require] paragraph 1 bullet 4:
2416  struct __result_of_memobj_deref_impl
2417  {
2418  template<typename _Fp, typename _Tp1>
2419  static __result_of_success<decltype(
2420  (*std::declval<_Tp1>()).*std::declval<_Fp>()
2421  ), __invoke_memobj_deref> _S_test(int);
2422 
2423  template<typename, typename>
2424  static __failure_type _S_test(...);
2425  };
2426 
2427  template<typename _MemPtr, typename _Arg>
2428  struct __result_of_memobj_deref
2429  : private __result_of_memobj_deref_impl
2430  {
2431  typedef decltype(_S_test<_MemPtr, _Arg>(0)) type;
2432  };
2433 
2434  template<typename _MemPtr, typename _Arg>
2435  struct __result_of_memobj;
2436 
2437  template<typename _Res, typename _Class, typename _Arg>
2438  struct __result_of_memobj<_Res _Class::*, _Arg>
2439  {
2440  typedef __remove_cvref_t<_Arg> _Argval;
2441  typedef _Res _Class::* _MemPtr;
2442  typedef typename conditional<__or_<is_same<_Argval, _Class>,
2443  is_base_of<_Class, _Argval>>::value,
2444  __result_of_memobj_ref<_MemPtr, _Arg>,
2445  __result_of_memobj_deref<_MemPtr, _Arg>
2446  >::type::type type;
2447  };
2448 
2449  template<typename _MemPtr, typename _Arg, typename... _Args>
2450  struct __result_of_memfun;
2451 
2452  template<typename _Res, typename _Class, typename _Arg, typename... _Args>
2453  struct __result_of_memfun<_Res _Class::*, _Arg, _Args...>
2454  {
2455  typedef typename remove_reference<_Arg>::type _Argval;
2456  typedef _Res _Class::* _MemPtr;
2457  typedef typename conditional<is_base_of<_Class, _Argval>::value,
2458  __result_of_memfun_ref<_MemPtr, _Arg, _Args...>,
2459  __result_of_memfun_deref<_MemPtr, _Arg, _Args...>
2460  >::type::type type;
2461  };
2462 
2463  // _GLIBCXX_RESOLVE_LIB_DEFECTS
2464  // 2219. INVOKE-ing a pointer to member with a reference_wrapper
2465  // as the object expression
2466 
2467  // Used by result_of, invoke etc. to unwrap a reference_wrapper.
2468  template<typename _Tp, typename _Up = __remove_cvref_t<_Tp>>
2469  struct __inv_unwrap
2470  {
2471  using type = _Tp;
2472  };
2473 
2474  template<typename _Tp, typename _Up>
2475  struct __inv_unwrap<_Tp, reference_wrapper<_Up>>
2476  {
2477  using type = _Up&;
2478  };
2479 
2480  template<bool, bool, typename _Functor, typename... _ArgTypes>
2481  struct __result_of_impl
2482  {
2483  typedef __failure_type type;
2484  };
2485 
2486  template<typename _MemPtr, typename _Arg>
2487  struct __result_of_impl<true, false, _MemPtr, _Arg>
2488  : public __result_of_memobj<__decay_t<_MemPtr>,
2489  typename __inv_unwrap<_Arg>::type>
2490  { };
2491 
2492  template<typename _MemPtr, typename _Arg, typename... _Args>
2493  struct __result_of_impl<false, true, _MemPtr, _Arg, _Args...>
2494  : public __result_of_memfun<__decay_t<_MemPtr>,
2495  typename __inv_unwrap<_Arg>::type, _Args...>
2496  { };
2497 
2498  // [func.require] paragraph 1 bullet 5:
2499  struct __result_of_other_impl
2500  {
2501  template<typename _Fn, typename... _Args>
2502  static __result_of_success<decltype(
2503  std::declval<_Fn>()(std::declval<_Args>()...)
2504  ), __invoke_other> _S_test(int);
2505 
2506  template<typename...>
2507  static __failure_type _S_test(...);
2508  };
2509 
2510  template<typename _Functor, typename... _ArgTypes>
2511  struct __result_of_impl<false, false, _Functor, _ArgTypes...>
2512  : private __result_of_other_impl
2513  {
2514  typedef decltype(_S_test<_Functor, _ArgTypes...>(0)) type;
2515  };
2516 
2517  // __invoke_result (std::invoke_result for C++11)
2518  template<typename _Functor, typename... _ArgTypes>
2519  struct __invoke_result
2520  : public __result_of_impl<
2521  is_member_object_pointer<
2522  typename remove_reference<_Functor>::type
2523  >::value,
2524  is_member_function_pointer<
2525  typename remove_reference<_Functor>::type
2526  >::value,
2527  _Functor, _ArgTypes...
2528  >::type
2529  { };
2530 
2531  template<typename _Functor, typename... _ArgTypes>
2532  struct result_of<_Functor(_ArgTypes...)>
2533  : public __invoke_result<_Functor, _ArgTypes...>
2534  { };
2535 
2536 #if __cplusplus >= 201402L
2537  /// Alias template for aligned_storage
2538  template<size_t _Len, size_t _Align =
2539  __alignof__(typename __aligned_storage_msa<_Len>::__type)>
2541 
2542  template <size_t _Len, typename... _Types>
2543  using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
2544 
2545  /// Alias template for decay
2546  template<typename _Tp>
2547  using decay_t = typename decay<_Tp>::type;
2548 
2549  /// Alias template for enable_if
2550  template<bool _Cond, typename _Tp = void>
2552 
2553  /// Alias template for conditional
2554  template<bool _Cond, typename _Iftrue, typename _Iffalse>
2555  using conditional_t = typename conditional<_Cond, _Iftrue, _Iffalse>::type;
2556 
2557  /// Alias template for common_type
2558  template<typename... _Tp>
2559  using common_type_t = typename common_type<_Tp...>::type;
2560 
2561  /// Alias template for underlying_type
2562  template<typename _Tp>
2563  using underlying_type_t = typename underlying_type<_Tp>::type;
2564 
2565  /// Alias template for result_of
2566  template<typename _Tp>
2568 #endif // C++14
2569 
2570 #if __cplusplus >= 201703L || !defined(__STRICT_ANSI__) // c++17 or gnu++11
2571 #define __cpp_lib_void_t 201411
2572  /// A metafunction that always yields void, used for detecting valid types.
2573  template<typename...> using void_t = void;
2574 #endif
2575 
2576  /// Implementation of the detection idiom (negative case).
2577  template<typename _Default, typename _AlwaysVoid,
2578  template<typename...> class _Op, typename... _Args>
2579  struct __detector
2580  {
2581  using value_t = false_type;
2582  using type = _Default;
2583  };
2584 
2585  /// Implementation of the detection idiom (positive case).
2586  template<typename _Default, template<typename...> class _Op,
2587  typename... _Args>
2588  struct __detector<_Default, __void_t<_Op<_Args...>>, _Op, _Args...>
2589  {
2590  using value_t = true_type;
2591  using type = _Op<_Args...>;
2592  };
2593 
2594  // Detect whether _Op<_Args...> is a valid type, use _Default if not.
2595  template<typename _Default, template<typename...> class _Op,
2596  typename... _Args>
2597  using __detected_or = __detector<_Default, void, _Op, _Args...>;
2598 
2599  // _Op<_Args...> if that is a valid type, otherwise _Default.
2600  template<typename _Default, template<typename...> class _Op,
2601  typename... _Args>
2602  using __detected_or_t
2603  = typename __detected_or<_Default, _Op, _Args...>::type;
2604 
2605  /// @} group metaprogramming
2606 
2607  /**
2608  * Use SFINAE to determine if the type _Tp has a publicly-accessible
2609  * member type _NTYPE.
2610  */
2611 #define _GLIBCXX_HAS_NESTED_TYPE(_NTYPE) \
2612  template<typename _Tp, typename = __void_t<>> \
2613  struct __has_##_NTYPE \
2614  : false_type \
2615  { }; \
2616  template<typename _Tp> \
2617  struct __has_##_NTYPE<_Tp, __void_t<typename _Tp::_NTYPE>> \
2618  : true_type \
2619  { };
2620 
2621  template <typename _Tp>
2622  struct __is_swappable;
2623 
2624  template <typename _Tp>
2625  struct __is_nothrow_swappable;
2626 
2627  template<typename... _Elements>
2628  class tuple;
2629 
2630  template<typename>
2631  struct __is_tuple_like_impl : false_type
2632  { };
2633 
2634  template<typename... _Tps>
2635  struct __is_tuple_like_impl<tuple<_Tps...>> : true_type
2636  { };
2637 
2638  // Internal type trait that allows us to sfinae-protect tuple_cat.
2639  template<typename _Tp>
2640  struct __is_tuple_like
2641  : public __is_tuple_like_impl<__remove_cvref_t<_Tp>>::type
2642  { };
2643 
2644  template<typename _Tp>
2645  _GLIBCXX20_CONSTEXPR
2646  inline
2647  _Require<__not_<__is_tuple_like<_Tp>>,
2648  is_move_constructible<_Tp>,
2649  is_move_assignable<_Tp>>
2650  swap(_Tp&, _Tp&)
2651  noexcept(__and_<is_nothrow_move_constructible<_Tp>,
2652  is_nothrow_move_assignable<_Tp>>::value);
2653 
2654  template<typename _Tp, size_t _Nm>
2655  _GLIBCXX20_CONSTEXPR
2656  inline
2657  __enable_if_t<__is_swappable<_Tp>::value>
2658  swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
2659  noexcept(__is_nothrow_swappable<_Tp>::value);
2660 
2661  namespace __swappable_details {
2662  using std::swap;
2663 
2664  struct __do_is_swappable_impl
2665  {
2666  template<typename _Tp, typename
2667  = decltype(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))>
2668  static true_type __test(int);
2669 
2670  template<typename>
2671  static false_type __test(...);
2672  };
2673 
2674  struct __do_is_nothrow_swappable_impl
2675  {
2676  template<typename _Tp>
2677  static __bool_constant<
2678  noexcept(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))
2679  > __test(int);
2680 
2681  template<typename>
2682  static false_type __test(...);
2683  };
2684 
2685  } // namespace __swappable_details
2686 
2687  template<typename _Tp>
2688  struct __is_swappable_impl
2689  : public __swappable_details::__do_is_swappable_impl
2690  {
2691  typedef decltype(__test<_Tp>(0)) type;
2692  };
2693 
2694  template<typename _Tp>
2695  struct __is_nothrow_swappable_impl
2696  : public __swappable_details::__do_is_nothrow_swappable_impl
2697  {
2698  typedef decltype(__test<_Tp>(0)) type;
2699  };
2700 
2701  template<typename _Tp>
2702  struct __is_swappable
2703  : public __is_swappable_impl<_Tp>::type
2704  { };
2705 
2706  template<typename _Tp>
2707  struct __is_nothrow_swappable
2708  : public __is_nothrow_swappable_impl<_Tp>::type
2709  { };
2710 
2711 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
2712 #define __cpp_lib_is_swappable 201603
2713  /// Metafunctions used for detecting swappable types: p0185r1
2714 
2715  /// is_swappable
2716  template<typename _Tp>
2718  : public __is_swappable_impl<_Tp>::type
2719  {
2720  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
2721  "template argument must be a complete class or an unbounded array");
2722  };
2723 
2724  /// is_nothrow_swappable
2725  template<typename _Tp>
2727  : public __is_nothrow_swappable_impl<_Tp>::type
2728  {
2729  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
2730  "template argument must be a complete class or an unbounded array");
2731  };
2732 
2733 #if __cplusplus >= 201402L
2734  /// is_swappable_v
2735  template<typename _Tp>
2736  _GLIBCXX17_INLINE constexpr bool is_swappable_v =
2738 
2739  /// is_nothrow_swappable_v
2740  template<typename _Tp>
2741  _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_v =
2743 #endif // __cplusplus >= 201402L
2744 
2745  namespace __swappable_with_details {
2746  using std::swap;
2747 
2748  struct __do_is_swappable_with_impl
2749  {
2750  template<typename _Tp, typename _Up, typename
2751  = decltype(swap(std::declval<_Tp>(), std::declval<_Up>())),
2752  typename
2753  = decltype(swap(std::declval<_Up>(), std::declval<_Tp>()))>
2754  static true_type __test(int);
2755 
2756  template<typename, typename>
2757  static false_type __test(...);
2758  };
2759 
2760  struct __do_is_nothrow_swappable_with_impl
2761  {
2762  template<typename _Tp, typename _Up>
2763  static __bool_constant<
2764  noexcept(swap(std::declval<_Tp>(), std::declval<_Up>()))
2765  &&
2766  noexcept(swap(std::declval<_Up>(), std::declval<_Tp>()))
2767  > __test(int);
2768 
2769  template<typename, typename>
2770  static false_type __test(...);
2771  };
2772 
2773  } // namespace __swappable_with_details
2774 
2775  template<typename _Tp, typename _Up>
2776  struct __is_swappable_with_impl
2777  : public __swappable_with_details::__do_is_swappable_with_impl
2778  {
2779  typedef decltype(__test<_Tp, _Up>(0)) type;
2780  };
2781 
2782  // Optimization for the homogenous lvalue case, not required:
2783  template<typename _Tp>
2784  struct __is_swappable_with_impl<_Tp&, _Tp&>
2785  : public __swappable_details::__do_is_swappable_impl
2786  {
2787  typedef decltype(__test<_Tp&>(0)) type;
2788  };
2789 
2790  template<typename _Tp, typename _Up>
2791  struct __is_nothrow_swappable_with_impl
2792  : public __swappable_with_details::__do_is_nothrow_swappable_with_impl
2793  {
2794  typedef decltype(__test<_Tp, _Up>(0)) type;
2795  };
2796 
2797  // Optimization for the homogenous lvalue case, not required:
2798  template<typename _Tp>
2799  struct __is_nothrow_swappable_with_impl<_Tp&, _Tp&>
2800  : public __swappable_details::__do_is_nothrow_swappable_impl
2801  {
2802  typedef decltype(__test<_Tp&>(0)) type;
2803  };
2804 
2805  /// is_swappable_with
2806  template<typename _Tp, typename _Up>
2808  : public __is_swappable_with_impl<_Tp, _Up>::type
2809  { };
2810 
2811  /// is_nothrow_swappable_with
2812  template<typename _Tp, typename _Up>
2814  : public __is_nothrow_swappable_with_impl<_Tp, _Up>::type
2815  { };
2816 
2817 #if __cplusplus >= 201402L
2818  /// is_swappable_with_v
2819  template<typename _Tp, typename _Up>
2820  _GLIBCXX17_INLINE constexpr bool is_swappable_with_v =
2822 
2823  /// is_nothrow_swappable_with_v
2824  template<typename _Tp, typename _Up>
2825  _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_with_v =
2827 #endif // __cplusplus >= 201402L
2828 
2829 #endif// c++1z or gnu++11
2830 
2831  // __is_invocable (std::is_invocable for C++11)
2832 
2833  // The primary template is used for invalid INVOKE expressions.
2834  template<typename _Result, typename _Ret,
2835  bool = is_void<_Ret>::value, typename = void>
2836  struct __is_invocable_impl : false_type { };
2837 
2838  // Used for valid INVOKE and INVOKE<void> expressions.
2839  template<typename _Result, typename _Ret>
2840  struct __is_invocable_impl<_Result, _Ret,
2841  /* is_void<_Ret> = */ true,
2842  __void_t<typename _Result::type>>
2843  : true_type
2844  { };
2845 
2846 #pragma GCC diagnostic push
2847 #pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
2848  // Used for INVOKE<R> expressions to check the implicit conversion to R.
2849  template<typename _Result, typename _Ret>
2850  struct __is_invocable_impl<_Result, _Ret,
2851  /* is_void<_Ret> = */ false,
2852  __void_t<typename _Result::type>>
2853  {
2854  private:
2855  // The type of the INVOKE expression.
2856  // Unlike declval, this doesn't add_rvalue_reference.
2857  static typename _Result::type _S_get();
2858 
2859  template<typename _Tp>
2860  static void _S_conv(_Tp);
2861 
2862  // This overload is viable if INVOKE(f, args...) can convert to _Tp.
2863  template<typename _Tp, typename = decltype(_S_conv<_Tp>(_S_get()))>
2864  static true_type
2865  _S_test(int);
2866 
2867  template<typename _Tp>
2868  static false_type
2869  _S_test(...);
2870 
2871  public:
2872  using type = decltype(_S_test<_Ret>(1));
2873  };
2874 #pragma GCC diagnostic pop
2875 
2876  template<typename _Fn, typename... _ArgTypes>
2877  struct __is_invocable
2878  : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
2879  { };
2880 
2881  template<typename _Fn, typename _Tp, typename... _Args>
2882  constexpr bool __call_is_nt(__invoke_memfun_ref)
2883  {
2884  using _Up = typename __inv_unwrap<_Tp>::type;
2885  return noexcept((std::declval<_Up>().*std::declval<_Fn>())(
2886  std::declval<_Args>()...));
2887  }
2888 
2889  template<typename _Fn, typename _Tp, typename... _Args>
2890  constexpr bool __call_is_nt(__invoke_memfun_deref)
2891  {
2892  return noexcept(((*std::declval<_Tp>()).*std::declval<_Fn>())(
2893  std::declval<_Args>()...));
2894  }
2895 
2896  template<typename _Fn, typename _Tp>
2897  constexpr bool __call_is_nt(__invoke_memobj_ref)
2898  {
2899  using _Up = typename __inv_unwrap<_Tp>::type;
2900  return noexcept(std::declval<_Up>().*std::declval<_Fn>());
2901  }
2902 
2903  template<typename _Fn, typename _Tp>
2904  constexpr bool __call_is_nt(__invoke_memobj_deref)
2905  {
2906  return noexcept((*std::declval<_Tp>()).*std::declval<_Fn>());
2907  }
2908 
2909  template<typename _Fn, typename... _Args>
2910  constexpr bool __call_is_nt(__invoke_other)
2911  {
2912  return noexcept(std::declval<_Fn>()(std::declval<_Args>()...));
2913  }
2914 
2915  template<typename _Result, typename _Fn, typename... _Args>
2916  struct __call_is_nothrow
2917  : __bool_constant<
2918  std::__call_is_nt<_Fn, _Args...>(typename _Result::__invoke_type{})
2919  >
2920  { };
2921 
2922  template<typename _Fn, typename... _Args>
2923  using __call_is_nothrow_
2924  = __call_is_nothrow<__invoke_result<_Fn, _Args...>, _Fn, _Args...>;
2925 
2926  // __is_nothrow_invocable (std::is_nothrow_invocable for C++11)
2927  template<typename _Fn, typename... _Args>
2928  struct __is_nothrow_invocable
2929  : __and_<__is_invocable<_Fn, _Args...>,
2930  __call_is_nothrow_<_Fn, _Args...>>::type
2931  { };
2932 
2933 #pragma GCC diagnostic push
2934 #pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
2935  struct __nonesuchbase {};
2936  struct __nonesuch : private __nonesuchbase {
2937  ~__nonesuch() = delete;
2938  __nonesuch(__nonesuch const&) = delete;
2939  void operator=(__nonesuch const&) = delete;
2940  };
2941 #pragma GCC diagnostic pop
2942 
2943 #if __cplusplus >= 201703L
2944 # define __cpp_lib_is_invocable 201703
2945 
2946  /// std::invoke_result
2947  template<typename _Functor, typename... _ArgTypes>
2948  struct invoke_result
2949  : public __invoke_result<_Functor, _ArgTypes...>
2950  { };
2951 
2952  /// std::invoke_result_t
2953  template<typename _Fn, typename... _Args>
2954  using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
2955 
2956  /// std::is_invocable
2957  template<typename _Fn, typename... _ArgTypes>
2958  struct is_invocable
2959  : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
2960  {
2961  static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
2962  "_Fn must be a complete class or an unbounded array");
2963  };
2964 
2965  /// std::is_invocable_r
2966  template<typename _Ret, typename _Fn, typename... _ArgTypes>
2967  struct is_invocable_r
2968  : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>::type
2969  {
2970  static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
2971  "_Fn must be a complete class or an unbounded array");
2972  };
2973 
2974  /// std::is_nothrow_invocable
2975  template<typename _Fn, typename... _ArgTypes>
2976  struct is_nothrow_invocable
2977  : __and_<__is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>,
2978  __call_is_nothrow_<_Fn, _ArgTypes...>>::type
2979  {
2980  static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
2981  "_Fn must be a complete class or an unbounded array");
2982  };
2983 
2984  template<typename _Result, typename _Ret, typename = void>
2985  struct __is_nt_invocable_impl : false_type { };
2986 
2987  template<typename _Result, typename _Ret>
2988  struct __is_nt_invocable_impl<_Result, _Ret,
2989  __void_t<typename _Result::type>>
2990  : __or_<is_void<_Ret>,
2991  __is_nothrow_convertible<typename _Result::type, _Ret>>
2992  { };
2993 
2994  /// std::is_nothrow_invocable_r
2995  template<typename _Ret, typename _Fn, typename... _ArgTypes>
2996  struct is_nothrow_invocable_r
2997  : __and_<__is_nt_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>,
2998  __call_is_nothrow_<_Fn, _ArgTypes...>>::type
2999  { };
3000 
3001  /// std::is_invocable_v
3002  template<typename _Fn, typename... _Args>
3003  inline constexpr bool is_invocable_v = is_invocable<_Fn, _Args...>::value;
3004 
3005  /// std::is_nothrow_invocable_v
3006  template<typename _Fn, typename... _Args>
3007  inline constexpr bool is_nothrow_invocable_v
3008  = is_nothrow_invocable<_Fn, _Args...>::value;
3009 
3010  /// std::is_invocable_r_v
3011  template<typename _Ret, typename _Fn, typename... _Args>
3012  inline constexpr bool is_invocable_r_v
3013  = is_invocable_r<_Ret, _Fn, _Args...>::value;
3014 
3015  /// std::is_nothrow_invocable_r_v
3016  template<typename _Ret, typename _Fn, typename... _Args>
3017  inline constexpr bool is_nothrow_invocable_r_v
3018  = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
3019 #endif // C++17
3020 
3021 #if __cplusplus >= 201703L
3022 # define __cpp_lib_type_trait_variable_templates 201510L
3023 template <typename _Tp>
3024  inline constexpr bool is_void_v = is_void<_Tp>::value;
3025 template <typename _Tp>
3026  inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
3027 template <typename _Tp>
3028  inline constexpr bool is_integral_v = is_integral<_Tp>::value;
3029 template <typename _Tp>
3030  inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
3031 template <typename _Tp>
3032  inline constexpr bool is_array_v = is_array<_Tp>::value;
3033 template <typename _Tp>
3034  inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
3035 template <typename _Tp>
3036  inline constexpr bool is_lvalue_reference_v =
3037  is_lvalue_reference<_Tp>::value;
3038 template <typename _Tp>
3039  inline constexpr bool is_rvalue_reference_v =
3040  is_rvalue_reference<_Tp>::value;
3041 template <typename _Tp>
3042  inline constexpr bool is_member_object_pointer_v =
3043  is_member_object_pointer<_Tp>::value;
3044 template <typename _Tp>
3045  inline constexpr bool is_member_function_pointer_v =
3046  is_member_function_pointer<_Tp>::value;
3047 template <typename _Tp>
3048  inline constexpr bool is_enum_v = is_enum<_Tp>::value;
3049 template <typename _Tp>
3050  inline constexpr bool is_union_v = is_union<_Tp>::value;
3051 template <typename _Tp>
3052  inline constexpr bool is_class_v = is_class<_Tp>::value;
3053 template <typename _Tp>
3054  inline constexpr bool is_function_v = is_function<_Tp>::value;
3055 template <typename _Tp>
3056  inline constexpr bool is_reference_v = is_reference<_Tp>::value;
3057 template <typename _Tp>
3058  inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
3059 template <typename _Tp>
3060  inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
3061 template <typename _Tp>
3062  inline constexpr bool is_object_v = is_object<_Tp>::value;
3063 template <typename _Tp>
3064  inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
3065 template <typename _Tp>
3066  inline constexpr bool is_compound_v = is_compound<_Tp>::value;
3067 template <typename _Tp>
3068  inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
3069 template <typename _Tp>
3070  inline constexpr bool is_const_v = is_const<_Tp>::value;
3071 template <typename _Tp>
3072  inline constexpr bool is_volatile_v = is_volatile<_Tp>::value;
3073 template <typename _Tp>
3074  inline constexpr bool is_trivial_v = is_trivial<_Tp>::value;
3075 template <typename _Tp>
3076  inline constexpr bool is_trivially_copyable_v =
3077  is_trivially_copyable<_Tp>::value;
3078 template <typename _Tp>
3079  inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
3080 template <typename _Tp>
3081  inline constexpr bool is_pod_v = is_pod<_Tp>::value;
3082 template <typename _Tp>
3083  inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
3084 template <typename _Tp>
3085  inline constexpr bool is_empty_v = is_empty<_Tp>::value;
3086 template <typename _Tp>
3087  inline constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
3088 template <typename _Tp>
3089  inline constexpr bool is_abstract_v = is_abstract<_Tp>::value;
3090 template <typename _Tp>
3091  inline constexpr bool is_final_v = is_final<_Tp>::value;
3092 template <typename _Tp>
3093  inline constexpr bool is_signed_v = is_signed<_Tp>::value;
3094 template <typename _Tp>
3095  inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
3096 template <typename _Tp, typename... _Args>
3097  inline constexpr bool is_constructible_v =
3098  is_constructible<_Tp, _Args...>::value;
3099 template <typename _Tp>
3100  inline constexpr bool is_default_constructible_v =
3101  is_default_constructible<_Tp>::value;
3102 template <typename _Tp>
3103  inline constexpr bool is_copy_constructible_v =
3104  is_copy_constructible<_Tp>::value;
3105 template <typename _Tp>
3106  inline constexpr bool is_move_constructible_v =
3107  is_move_constructible<_Tp>::value;
3108 template <typename _Tp, typename _Up>
3109  inline constexpr bool is_assignable_v = is_assignable<_Tp, _Up>::value;
3110 template <typename _Tp>
3111  inline constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
3112 template <typename _Tp>
3113  inline constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
3114 template <typename _Tp>
3115  inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
3116 template <typename _Tp, typename... _Args>
3117  inline constexpr bool is_trivially_constructible_v =
3118  is_trivially_constructible<_Tp, _Args...>::value;
3119 template <typename _Tp>
3120  inline constexpr bool is_trivially_default_constructible_v =
3121  is_trivially_default_constructible<_Tp>::value;
3122 template <typename _Tp>
3123  inline constexpr bool is_trivially_copy_constructible_v =
3124  is_trivially_copy_constructible<_Tp>::value;
3125 template <typename _Tp>
3126  inline constexpr bool is_trivially_move_constructible_v =
3127  is_trivially_move_constructible<_Tp>::value;
3128 template <typename _Tp, typename _Up>
3129  inline constexpr bool is_trivially_assignable_v =
3130  is_trivially_assignable<_Tp, _Up>::value;
3131 template <typename _Tp>
3132  inline constexpr bool is_trivially_copy_assignable_v =
3133  is_trivially_copy_assignable<_Tp>::value;
3134 template <typename _Tp>
3135  inline constexpr bool is_trivially_move_assignable_v =
3136  is_trivially_move_assignable<_Tp>::value;
3137 template <typename _Tp>
3138  inline constexpr bool is_trivially_destructible_v =
3139  is_trivially_destructible<_Tp>::value;
3140 template <typename _Tp, typename... _Args>
3141  inline constexpr bool is_nothrow_constructible_v =
3142  is_nothrow_constructible<_Tp, _Args...>::value;
3143 template <typename _Tp>
3144  inline constexpr bool is_nothrow_default_constructible_v =
3145  is_nothrow_default_constructible<_Tp>::value;
3146 template <typename _Tp>
3147  inline constexpr bool is_nothrow_copy_constructible_v =
3148  is_nothrow_copy_constructible<_Tp>::value;
3149 template <typename _Tp>
3150  inline constexpr bool is_nothrow_move_constructible_v =
3151  is_nothrow_move_constructible<_Tp>::value;
3152 template <typename _Tp, typename _Up>
3153  inline constexpr bool is_nothrow_assignable_v =
3154  is_nothrow_assignable<_Tp, _Up>::value;
3155 template <typename _Tp>
3156  inline constexpr bool is_nothrow_copy_assignable_v =
3157  is_nothrow_copy_assignable<_Tp>::value;
3158 template <typename _Tp>
3159  inline constexpr bool is_nothrow_move_assignable_v =
3160  is_nothrow_move_assignable<_Tp>::value;
3161 template <typename _Tp>
3162  inline constexpr bool is_nothrow_destructible_v =
3163  is_nothrow_destructible<_Tp>::value;
3164 template <typename _Tp>
3165  inline constexpr bool has_virtual_destructor_v =
3166  has_virtual_destructor<_Tp>::value;
3167 template <typename _Tp>
3168  inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
3169 template <typename _Tp>
3170  inline constexpr size_t rank_v = rank<_Tp>::value;
3171 template <typename _Tp, unsigned _Idx = 0>
3172  inline constexpr size_t extent_v = extent<_Tp, _Idx>::value;
3173 #ifdef _GLIBCXX_BUILTIN_IS_SAME_AS
3174 template <typename _Tp, typename _Up>
3175  inline constexpr bool is_same_v = _GLIBCXX_BUILTIN_IS_SAME_AS(_Tp, _Up);
3176 #else
3177 template <typename _Tp, typename _Up>
3178  inline constexpr bool is_same_v = std::is_same<_Tp, _Up>::value;
3179 #endif
3180 template <typename _Base, typename _Derived>
3181  inline constexpr bool is_base_of_v = is_base_of<_Base, _Derived>::value;
3182 template <typename _From, typename _To>
3183  inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
3184 
3185 #ifdef _GLIBCXX_HAVE_BUILTIN_HAS_UNIQ_OBJ_REP
3186 # define __cpp_lib_has_unique_object_representations 201606
3187  /// has_unique_object_representations
3188  template<typename _Tp>
3189  struct has_unique_object_representations
3190  : bool_constant<__has_unique_object_representations(
3191  remove_cv_t<remove_all_extents_t<_Tp>>
3192  )>
3193  {
3194  static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
3195  "template argument must be a complete class or an unbounded array");
3196  };
3197 
3198  template<typename _Tp>
3199  inline constexpr bool has_unique_object_representations_v
3200  = has_unique_object_representations<_Tp>::value;
3201 #endif
3202 
3203 #ifdef _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE
3204 # define __cpp_lib_is_aggregate 201703
3205  /// is_aggregate
3206  template<typename _Tp>
3207  struct is_aggregate
3208  : bool_constant<__is_aggregate(remove_cv_t<_Tp>)>
3209  { };
3210 
3211  /// is_aggregate_v
3212  template<typename _Tp>
3213  inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
3214 #endif
3215 #endif // C++17
3216 
3217 #if __cplusplus > 201703L
3218  /// Remove references and cv-qualifiers.
3219  template<typename _Tp>
3220  struct remove_cvref
3221  {
3222  using type = __remove_cvref_t<_Tp>;
3223  };
3224 
3225  template<typename _Tp>
3226  using remove_cvref_t = __remove_cvref_t<_Tp>;
3227 
3228  /// Identity metafunction.
3229  template<typename _Tp>
3230  struct type_identity { using type = _Tp; };
3231 
3232  template<typename _Tp>
3233  using type_identity_t = typename type_identity<_Tp>::type;
3234 
3235  /// Unwrap a reference_wrapper
3236  template<typename _Tp>
3237  struct unwrap_reference { using type = _Tp; };
3238 
3239  template<typename _Tp>
3240  struct unwrap_reference<reference_wrapper<_Tp>> { using type = _Tp&; };
3241 
3242  template<typename _Tp>
3243  using unwrap_reference_t = typename unwrap_reference<_Tp>::type;
3244 
3245  /// Decay type and if it's a reference_wrapper, unwrap it
3246  template<typename _Tp>
3247  struct unwrap_ref_decay { using type = unwrap_reference_t<decay_t<_Tp>>; };
3248 
3249  template<typename _Tp>
3250  using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;
3251 
3252 #define __cpp_lib_bounded_array_traits 201902L
3253 
3254  /// True for a type that is an array of known bound.
3255  template<typename _Tp>
3256  struct is_bounded_array
3257  : public __is_array_known_bounds<_Tp>
3258  { };
3259 
3260  /// True for a type that is an array of unknown bound.
3261  template<typename _Tp>
3262  struct is_unbounded_array
3263  : public __is_array_unknown_bounds<_Tp>
3264  { };
3265 
3266  template<typename _Tp>
3267  inline constexpr bool is_bounded_array_v
3268  = is_bounded_array<_Tp>::value;
3269 
3270  template<typename _Tp>
3271  inline constexpr bool is_unbounded_array_v
3272  = is_unbounded_array<_Tp>::value;
3273 
3274 #ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
3275 
3276 #define __cpp_lib_is_constant_evaluated 201811L
3277 
3278  constexpr inline bool
3279  is_constant_evaluated() noexcept
3280  { return __builtin_is_constant_evaluated(); }
3281 #endif
3282 
3283  template<typename _From, typename _To>
3284  using __copy_cv = typename __match_cv_qualifiers<_From, _To>::__type;
3285 
3286  template<typename _Xp, typename _Yp>
3287  using __cond_res
3288  = decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
3289 
3290  template<typename _Ap, typename _Bp, typename = void>
3291  struct __common_ref_impl
3292  { };
3293 
3294  // [meta.trans.other], COMMON-REF(A, B)
3295  template<typename _Ap, typename _Bp>
3296  using __common_ref = typename __common_ref_impl<_Ap, _Bp>::type;
3297 
3298  // If A and B are both lvalue reference types, ...
3299  template<typename _Xp, typename _Yp>
3300  struct __common_ref_impl<_Xp&, _Yp&,
3301  __void_t<__cond_res<__copy_cv<_Xp, _Yp>&, __copy_cv<_Yp, _Xp>&>>>
3302  { using type = __cond_res<__copy_cv<_Xp, _Yp>&, __copy_cv<_Yp, _Xp>&>; };
3303 
3304  // let C be remove_reference_t<COMMON-REF(X&, Y&)>&&
3305  template<typename _Xp, typename _Yp>
3306  using __common_ref_C = remove_reference_t<__common_ref<_Xp&, _Yp&>>&&;
3307 
3308  // If A and B are both rvalue reference types, ...
3309  template<typename _Xp, typename _Yp>
3310  struct __common_ref_impl<_Xp&&, _Yp&&,
3311  _Require<is_convertible<_Xp&&, __common_ref_C<_Xp, _Yp>>,
3312  is_convertible<_Yp&&, __common_ref_C<_Xp, _Yp>>>>
3313  { using type = __common_ref_C<_Xp, _Yp>; };
3314 
3315  // let D be COMMON-REF(const X&, Y&)
3316  template<typename _Xp, typename _Yp>
3317  using __common_ref_D = __common_ref<const _Xp&, _Yp&>;
3318 
3319  // If A is an rvalue reference and B is an lvalue reference, ...
3320  template<typename _Xp, typename _Yp>
3321  struct __common_ref_impl<_Xp&&, _Yp&,
3322  _Require<is_convertible<_Xp&&, __common_ref_D<_Xp, _Yp>>>>
3323  { using type = __common_ref_D<_Xp, _Yp>; };
3324 
3325  // If A is an lvalue reference and B is an rvalue reference, ...
3326  template<typename _Xp, typename _Yp>
3327  struct __common_ref_impl<_Xp&, _Yp&&>
3328  : __common_ref_impl<_Yp&&, _Xp&>
3329  { };
3330 
3331  template<typename _Tp, typename _Up,
3332  template<typename> class _TQual, template<typename> class _UQual>
3333  struct basic_common_reference
3334  { };
3335 
3336  template<typename _Tp>
3337  struct __xref
3338  { template<typename _Up> using __type = __copy_cv<_Tp, _Up>; };
3339 
3340  template<typename _Tp>
3341  struct __xref<_Tp&>
3342  { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&; };
3343 
3344  template<typename _Tp>
3345  struct __xref<_Tp&&>
3346  { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&&; };
3347 
3348  template<typename _Tp1, typename _Tp2>
3349  using __basic_common_ref
3350  = typename basic_common_reference<remove_cvref_t<_Tp1>,
3351  remove_cvref_t<_Tp2>,
3352  __xref<_Tp1>::template __type,
3353  __xref<_Tp2>::template __type>::type;
3354 
3355  template<typename... _Tp>
3356  struct common_reference;
3357 
3358  template<typename... _Tp>
3359  using common_reference_t = typename common_reference<_Tp...>::type;
3360 
3361  // If sizeof...(T) is zero, there shall be no member type.
3362  template<>
3363  struct common_reference<>
3364  { };
3365 
3366  // If sizeof...(T) is one ...
3367  template<typename _Tp0>
3368  struct common_reference<_Tp0>
3369  { using type = _Tp0; };
3370 
3371  template<typename _Tp1, typename _Tp2, int _Bullet = 1, typename = void>
3372  struct __common_reference_impl
3373  : __common_reference_impl<_Tp1, _Tp2, _Bullet + 1>
3374  { };
3375 
3376  // If sizeof...(T) is two ...
3377  template<typename _Tp1, typename _Tp2>
3378  struct common_reference<_Tp1, _Tp2>
3379  : __common_reference_impl<_Tp1, _Tp2>
3380  { };
3381 
3382  // If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, ...
3383  template<typename _Tp1, typename _Tp2>
3384  struct __common_reference_impl<_Tp1&, _Tp2&, 1,
3385  void_t<__common_ref<_Tp1&, _Tp2&>>>
3386  { using type = __common_ref<_Tp1&, _Tp2&>; };
3387 
3388  template<typename _Tp1, typename _Tp2>
3389  struct __common_reference_impl<_Tp1&&, _Tp2&&, 1,
3390  void_t<__common_ref<_Tp1&&, _Tp2&&>>>
3391  { using type = __common_ref<_Tp1&&, _Tp2&&>; };
3392 
3393  template<typename _Tp1, typename _Tp2>
3394  struct __common_reference_impl<_Tp1&, _Tp2&&, 1,
3395  void_t<__common_ref<_Tp1&, _Tp2&&>>>
3396  { using type = __common_ref<_Tp1&, _Tp2&&>; };
3397 
3398  template<typename _Tp1, typename _Tp2>
3399  struct __common_reference_impl<_Tp1&&, _Tp2&, 1,
3400  void_t<__common_ref<_Tp1&&, _Tp2&>>>
3401  { using type = __common_ref<_Tp1&&, _Tp2&>; };
3402 
3403  // Otherwise, if basic_common_reference<...>::type is well-formed, ...
3404  template<typename _Tp1, typename _Tp2>
3405  struct __common_reference_impl<_Tp1, _Tp2, 2,
3406  void_t<__basic_common_ref<_Tp1, _Tp2>>>
3407  { using type = __basic_common_ref<_Tp1, _Tp2>; };
3408 
3409  // Otherwise, if COND-RES(T1, T2) is well-formed, ...
3410  template<typename _Tp1, typename _Tp2>
3411  struct __common_reference_impl<_Tp1, _Tp2, 3,
3412  void_t<__cond_res<_Tp1, _Tp2>>>
3413  { using type = __cond_res<_Tp1, _Tp2>; };
3414 
3415  // Otherwise, if common_type_t<T1, T2> is well-formed, ...
3416  template<typename _Tp1, typename _Tp2>
3417  struct __common_reference_impl<_Tp1, _Tp2, 4,
3418  void_t<common_type_t<_Tp1, _Tp2>>>
3419  { using type = common_type_t<_Tp1, _Tp2>; };
3420 
3421  // Otherwise, there shall be no member type.
3422  template<typename _Tp1, typename _Tp2>
3423  struct __common_reference_impl<_Tp1, _Tp2, 5, void>
3424  { };
3425 
3426  // Otherwise, if sizeof...(T) is greater than two, ...
3427  template<typename _Tp1, typename _Tp2, typename... _Rest>
3428  struct common_reference<_Tp1, _Tp2, _Rest...>
3429  : __common_type_fold<common_reference<_Tp1, _Tp2>,
3430  __common_type_pack<_Rest...>>
3431  { };
3432 
3433  // Reuse __common_type_fold for common_reference<T1, T2, Rest...>
3434  template<typename _Tp1, typename _Tp2, typename... _Rest>
3435  struct __common_type_fold<common_reference<_Tp1, _Tp2>,
3436  __common_type_pack<_Rest...>,
3437  void_t<common_reference_t<_Tp1, _Tp2>>>
3438  : public common_reference<common_reference_t<_Tp1, _Tp2>, _Rest...>
3439  { };
3440 
3441 #endif // C++2a
3442 
3443 _GLIBCXX_END_NAMESPACE_VERSION
3444 } // namespace std
3445 
3446 #endif // C++11
3447 
3448 #endif // _GLIBCXX_TYPE_TRAITS
std::is_void
is_void
Definition: type_traits:193
std::is_nothrow_copy_constructible
is_nothrow_copy_constructible
Definition: type_traits:1037
std::is_nothrow_destructible
is_nothrow_destructible
Definition: type_traits:886
std::is_member_function_pointer
is_member_function_pointer
Definition: type_traits:466
std::alignment_of
alignment_of
Definition: type_traits:1348
std::is_trivially_constructible
is_trivially_constructible
Definition: type_traits:1180
std::is_nothrow_swappable_v
constexpr bool is_nothrow_swappable_v
is_nothrow_swappable_v
Definition: type_traits:2741
std::is_integral
is_integral
Definition: type_traits:365
std::is_nothrow_move_constructible
is_nothrow_move_constructible
Definition: type_traits:1058
std::is_empty
is_empty
Definition: type_traits:709
std::add_lvalue_reference
add_lvalue_reference
Definition: type_traits:1611
std::common_type
common_type
Definition: type_traits:2212
std::is_nothrow_swappable_with_v
constexpr bool is_nothrow_swappable_with_v
is_nothrow_swappable_with_v
Definition: type_traits:2825
std::is_nothrow_copy_assignable
is_nothrow_copy_assignable
Definition: type_traits:1150
std::is_constructible
is_constructible
Definition: type_traits:900
std::is_pod
is_pod
Definition: type_traits:691
std::is_union
is_union
Definition: type_traits:478
std::result_of
result_of
Definition: type_traits:2341
std::is_nothrow_default_constructible
is_nothrow_default_constructible
Definition: type_traits:985
std::is_lvalue_reference
is_lvalue_reference
Definition: type_traits:426
std::is_function
is_function
Definition: type_traits:191
std::remove_volatile
remove_volatile
Definition: type_traits:1515
std::is_trivial
is_trivial
Definition: type_traits:663
std::is_nothrow_assignable
is_nothrow_assignable
Definition: type_traits:1129
std::remove_reference
remove_reference
Definition: type_traits:1590
std::has_virtual_destructor
has_virtual_destructor
Definition: type_traits:1336
std::is_nothrow_move_assignable
is_nothrow_move_assignable
Definition: type_traits:1171
std::is_member_pointer
is_member_pointer
Definition: type_traits:553
std::is_trivially_move_constructible
is_trivially_move_constructible
Definition: type_traits:1265
std::is_move_assignable
is_move_assignable
Definition: type_traits:1109
std::is_swappable_v
constexpr bool is_swappable_v
is_swappable_v
Definition: type_traits:2736
std::result_of_t
typename result_of< _Tp >::type result_of_t
Alias template for result_of.
Definition: type_traits:2567
std::is_volatile
is_volatile
Definition: type_traits:654
std::is_member_object_pointer
is_member_object_pointer
Definition: type_traits:452
std::add_volatile
add_volatile
Definition: type_traits:1546
std::is_trivially_move_assignable
is_trivially_move_assignable
Definition: type_traits:1316
std::is_move_constructible
is_move_constructible
Definition: type_traits:951
std::is_fundamental
is_fundamental
Definition: type_traits:540
std::make_signed
make_signed
Definition: type_traits:1948
std::decay
decay
Definition: type_traits:2144
std::underlying_type_t
typename underlying_type< _Tp >::type underlying_type_t
Alias template for underlying_type.
Definition: type_traits:2563
std::is_null_pointer
is_null_pointer (LWG 2247).
Definition: type_traits:513
std::make_unsigned
make_unsigned
Definition: type_traits:1822
std
ISO C++ entities toplevel namespace is std.
std::add_cv_t
typename add_cv< _Tp >::type add_cv_t
Alias template for add_cv.
Definition: type_traits:1583
std::aligned_storage_t
typename aligned_storage< _Len, _Align >::type aligned_storage_t
Alias template for aligned_storage.
Definition: type_traits:2540
std::is_final
is_final
Definition: type_traits:723
std::__add_pointer_helper
add_pointer
Definition: type_traits:2022
std::remove_volatile_t
typename remove_volatile< _Tp >::type remove_volatile_t
Alias template for remove_volatile.
Definition: type_traits:1567
c++config.h
std::is_compound
is_compound
Definition: type_traits:564
std::is_pointer
is_pointer
Definition: type_traits:420
std::remove_all_extents_t
typename remove_all_extents< _Tp >::type remove_all_extents_t
Alias template for remove_all_extents.
Definition: type_traits:2000
std::decay_t
typename decay< _Tp >::type decay_t
Alias template for decay.
Definition: type_traits:2547
std::false_type
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:78
std::add_pointer_t
typename add_pointer< _Tp >::type add_pointer_t
Alias template for add_pointer.
Definition: type_traits:2041
std::is_const
is_const
Definition: type_traits:234
std::aligned_union::type
aligned_storage< _S_len, alignment_value >::type type
The storage.
Definition: type_traits:2116
std::conditional
Define a member typedef type to one of two argument types.
Definition: type_traits:92
std::remove_all_extents
remove_all_extents
Definition: type_traits:779
std::is_arithmetic
is_arithmetic
Definition: type_traits:534
std::is_array
is_array
Definition: type_traits:399
std::is_convertible
is_convertible
Definition: type_traits:1445
std::is_nothrow_swappable
is_nothrow_swappable
Definition: type_traits:2726
std::aligned_union
Provide aligned storage for types.
Definition: type_traits:2104
std::is_scalar
is_scalar
Definition: type_traits:557
std::is_swappable_with
is_swappable_with
Definition: type_traits:2807
std::remove_const
remove_const
Definition: type_traits:1506
std::is_trivially_assignable
is_trivially_assignable
Definition: type_traits:1274
std::common_type_t
typename common_type< _Tp... >::type common_type_t
Alias template for common_type.
Definition: type_traits:2559
std::remove_const_t
typename remove_const< _Tp >::type remove_const_t
Alias template for remove_const.
Definition: type_traits:1563
std::add_lvalue_reference_t
typename add_lvalue_reference< _Tp >::type add_lvalue_reference_t
Alias template for add_lvalue_reference.
Definition: type_traits:1636
std::is_default_constructible
is_default_constructible
Definition: type_traits:909
std::is_literal_type
is_literal_type
Definition: type_traits:700
std::is_class
is_class
Definition: type_traits:484
std::is_object
is_object
Definition: type_traits:547
std::void_t
void void_t
A metafunction that always yields void, used for detecting valid types.
Definition: type_traits:2573
std::remove_pointer_t
typename remove_pointer< _Tp >::type remove_pointer_t
Alias template for remove_pointer.
Definition: type_traits:2037
std::remove_cv
remove_cv
Definition: type_traits:227
std::integral_constant
integral_constant
Definition: type_traits:57
std::aligned_storage
Alignment type.
Definition: type_traits:2066
std::extent
extent
Definition: type_traits:776
std::__is_nullptr_t
__is_nullptr_t (deprecated extension).
Definition: type_traits:519
std::is_floating_point
is_floating_point
Definition: type_traits:393
std::is_trivially_copy_constructible
is_trivially_copy_constructible
Definition: type_traits:1242
std::is_copy_assignable
is_copy_assignable
Definition: type_traits:1088
std::make_signed_t
typename make_signed< _Tp >::type make_signed_t
Alias template for make_signed.
Definition: type_traits:1958
std::is_swappable
Metafunctions used for detecting swappable types: p0185r1.
Definition: type_traits:2717
std::remove_extent_t
typename remove_extent< _Tp >::type remove_extent_t
Alias template for remove_extent.
Definition: type_traits:1996
std::is_standard_layout
is_standard_layout
Definition: type_traits:681
std::is_enum
is_enum
Definition: type_traits:472
std::rank
rank
Definition: type_traits:1357
std::is_trivially_default_constructible
is_trivially_default_constructible
Definition: type_traits:1189
std::is_reference
is_reference
Definition: type_traits:189
std::enable_if
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:2179
std::remove_reference_t
typename remove_reference< _Tp >::type remove_reference_t
Alias template for remove_reference.
Definition: type_traits:1632
std::is_copy_constructible
is_copy_constructible
Definition: type_traits:930
std::add_cv
add_cv
Definition: type_traits:1551
std::is_abstract
is_abstract
Definition: type_traits:730
std::is_trivially_destructible
is_trivially_destructible
Definition: type_traits:1325
std::add_rvalue_reference
add_rvalue_reference
Definition: type_traits:1625
std::is_base_of
is_base_of
Definition: type_traits:1409
std::remove_extent
remove_extent
Definition: type_traits:1969
std::reference_wrapper
Primary class template for reference_wrapper.
Definition: type_traits:2157
std::__detector
Implementation of the detection idiom (negative case).
Definition: type_traits:2579
std::add_volatile_t
typename add_volatile< _Tp >::type add_volatile_t
Alias template for add_volatile.
Definition: type_traits:1579
std::true_type
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:75
std::add_const_t
typename add_const< _Tp >::type add_const_t
Alias template for add_const.
Definition: type_traits:1575
std::is_nothrow_constructible
is_nothrow_constructible
Definition: type_traits:1016
std::add_const
add_const
Definition: type_traits:1541
std::is_destructible
is_destructible
Definition: type_traits:835
std::is_same
is_same
Definition: type_traits:582
std::is_rvalue_reference
is_rvalue_reference
Definition: type_traits:435
std::enable_if_t
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Definition: type_traits:2551
std::is_trivially_copy_assignable
is_trivially_copy_assignable
Definition: type_traits:1295
c++0x_warning.h
std::is_nothrow_swappable_with
is_nothrow_swappable_with
Definition: type_traits:2813
std::underlying_type
The underlying type of an enum.
Definition: type_traits:2321
std::remove_cv_t
typename remove_cv< _Tp >::type remove_cv_t
Alias template for remove_cv.
Definition: type_traits:1571
std::make_unsigned_t
typename make_unsigned< _Tp >::type make_unsigned_t
Alias template for make_unsigned.
Definition: type_traits:1962
std::conditional_t
typename conditional< _Cond, _Iftrue, _Iffalse >::type conditional_t
Alias template for conditional.
Definition: type_traits:2555
std::add_rvalue_reference_t
typename add_rvalue_reference< _Tp >::type add_rvalue_reference_t
Alias template for add_rvalue_reference.
Definition: type_traits:1640
std::is_assignable
is_assignable
Definition: type_traits:1067
std::is_polymorphic
is_polymorphic
Definition: type_traits:715
std::remove_pointer
remove_pointer
Definition: type_traits:2015
std::is_swappable_with_v
constexpr bool is_swappable_with_v
is_swappable_with_v
Definition: type_traits:2820