libstdc++
experimental/type_traits
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1// Variable Templates For Type Traits -*- C++ -*-
2
3// Copyright (C) 2014-2024 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file experimental/type_traits
26 * This is a TS C++ Library header.
27 *
28 * This header defines variable templates for the C++14 type traits.
29 *
30 * Equivalent variable templates are defined in namespace `std` since C++17.
31 * @see variable_templates
32 *
33 * @ingroup libfund-ts
34 * @since C++14
35 */
36
37//
38// N3932 Variable Templates For Type Traits (Revision 1)
39//
40
41#ifndef _GLIBCXX_EXPERIMENTAL_TYPE_TRAITS
42#define _GLIBCXX_EXPERIMENTAL_TYPE_TRAITS 1
43
44#ifdef _GLIBCXX_SYSHDR
45#pragma GCC system_header
46#endif
47
48#if __cplusplus >= 201402L
49
50#include <type_traits>
51#include <experimental/bits/lfts_config.h>
52
53namespace std _GLIBCXX_VISIBILITY(default)
54{
55_GLIBCXX_BEGIN_NAMESPACE_VERSION
56
57namespace experimental
58{
59inline namespace fundamentals_v1
60{
61/** @defgroup lfts_variable_templates Variable template for type traits
62 * @ingroup libfund-ts
63 * @since Library Fundamentals TS v1. C++14.
64 * @see variable_templates
65 */
66/** @ingroup lfts_variable_templates
67 * @{
68 */
69#define __cpp_lib_experimental_type_trait_variable_templates 201402
70
71// See C++14 20.10.4.1, primary type categories
72template <typename _Tp>
73 constexpr bool is_void_v = is_void<_Tp>::value;
74template <typename _Tp>
75 constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
76template <typename _Tp>
77 constexpr bool is_integral_v = is_integral<_Tp>::value;
78template <typename _Tp>
79 constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
80template <typename _Tp>
81 constexpr bool is_array_v = is_array<_Tp>::value;
82template <typename _Tp>
83 constexpr bool is_pointer_v = is_pointer<_Tp>::value;
84template <typename _Tp>
85 constexpr bool is_lvalue_reference_v = is_lvalue_reference<_Tp>::value;
86template <typename _Tp>
87 constexpr bool is_rvalue_reference_v = is_rvalue_reference<_Tp>::value;
88template <typename _Tp>
89 constexpr bool is_member_object_pointer_v =
90 is_member_object_pointer<_Tp>::value;
91template <typename _Tp>
92 constexpr bool is_member_function_pointer_v =
93 is_member_function_pointer<_Tp>::value;
94template <typename _Tp>
95 constexpr bool is_enum_v = is_enum<_Tp>::value;
96template <typename _Tp>
97 constexpr bool is_union_v = is_union<_Tp>::value;
98template <typename _Tp>
99 constexpr bool is_class_v = is_class<_Tp>::value;
100template <typename _Tp>
101 constexpr bool is_function_v = is_function<_Tp>::value;
102
103// See C++14 20.10.4.2, composite type categories
104template <typename _Tp>
105 constexpr bool is_reference_v = is_reference<_Tp>::value;
106template <typename _Tp>
107 constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
108template <typename _Tp>
109 constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
110template <typename _Tp>
111 constexpr bool is_object_v = is_object<_Tp>::value;
112template <typename _Tp>
113 constexpr bool is_scalar_v = is_scalar<_Tp>::value;
114template <typename _Tp>
115 constexpr bool is_compound_v = is_compound<_Tp>::value;
116template <typename _Tp>
117 constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
118
119// See C++14 20.10.4.3, type properties
120template <typename _Tp>
121 constexpr bool is_const_v = is_const<_Tp>::value;
122template <typename _Tp>
123 constexpr bool is_volatile_v = is_volatile<_Tp>::value;
124template <typename _Tp>
125 constexpr bool is_trivial_v = is_trivial<_Tp>::value;
126template <typename _Tp>
127 constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
128template <typename _Tp>
129 constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
130#pragma GCC diagnostic push
131#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
132template <typename _Tp>
133 constexpr bool is_pod_v = is_pod<_Tp>::value;
134template <typename _Tp>
135 constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
136#pragma GCC diagnostic pop
137template <typename _Tp>
138 constexpr bool is_empty_v = is_empty<_Tp>::value;
139template <typename _Tp>
140 constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
141template <typename _Tp>
142 constexpr bool is_abstract_v = is_abstract<_Tp>::value;
143template <typename _Tp>
144 constexpr bool is_final_v = is_final<_Tp>::value;
145template <typename _Tp>
146 constexpr bool is_signed_v = is_signed<_Tp>::value;
147template <typename _Tp>
148 constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
149template <typename _Tp, typename... _Args>
150 constexpr bool is_constructible_v = is_constructible<_Tp, _Args...>::value;
151template <typename _Tp>
152 constexpr bool is_default_constructible_v =
153 is_default_constructible<_Tp>::value;
154template <typename _Tp>
155 constexpr bool is_copy_constructible_v = is_copy_constructible<_Tp>::value;
156template <typename _Tp>
157 constexpr bool is_move_constructible_v = is_move_constructible<_Tp>::value;
158template <typename _Tp, typename _Up>
159 constexpr bool is_assignable_v = is_assignable<_Tp, _Up>::value;
160template <typename _Tp>
161 constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
162template <typename _Tp>
163 constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
164template <typename _Tp>
165 constexpr bool is_destructible_v = is_destructible<_Tp>::value;
166template <typename _Tp, typename... _Args>
167 constexpr bool is_trivially_constructible_v =
168 is_trivially_constructible<_Tp, _Args...>::value;
169template <typename _Tp>
170 constexpr bool is_trivially_default_constructible_v =
171 is_trivially_default_constructible<_Tp>::value;
172template <typename _Tp>
173 constexpr bool is_trivially_copy_constructible_v =
174 is_trivially_copy_constructible<_Tp>::value;
175template <typename _Tp>
176 constexpr bool is_trivially_move_constructible_v =
177 is_trivially_move_constructible<_Tp>::value;
178template <typename _Tp, typename _Up>
179 constexpr bool is_trivially_assignable_v =
180 is_trivially_assignable<_Tp, _Up>::value;
181template <typename _Tp>
182 constexpr bool is_trivially_copy_assignable_v =
183 is_trivially_copy_assignable<_Tp>::value;
184template <typename _Tp>
185 constexpr bool is_trivially_move_assignable_v =
186 is_trivially_move_assignable<_Tp>::value;
187template <typename _Tp>
188 constexpr bool is_trivially_destructible_v =
189 is_trivially_destructible<_Tp>::value;
190template <typename _Tp, typename... _Args>
191 constexpr bool is_nothrow_constructible_v =
192 is_nothrow_constructible<_Tp, _Args...>::value;
193template <typename _Tp>
194 constexpr bool is_nothrow_default_constructible_v =
195 is_nothrow_default_constructible<_Tp>::value;
196template <typename _Tp>
197 constexpr bool is_nothrow_copy_constructible_v =
198 is_nothrow_copy_constructible<_Tp>::value;
199template <typename _Tp>
200 constexpr bool is_nothrow_move_constructible_v =
201 is_nothrow_move_constructible<_Tp>::value;
202template <typename _Tp, typename _Up>
203 constexpr bool is_nothrow_assignable_v =
204 is_nothrow_assignable<_Tp, _Up>::value;
205template <typename _Tp>
206 constexpr bool is_nothrow_copy_assignable_v =
207 is_nothrow_copy_assignable<_Tp>::value;
208template <typename _Tp>
209 constexpr bool is_nothrow_move_assignable_v =
210 is_nothrow_move_assignable<_Tp>::value;
211template <typename _Tp>
212 constexpr bool is_nothrow_destructible_v =
213 is_nothrow_destructible<_Tp>::value;
214template <typename _Tp>
215 constexpr bool has_virtual_destructor_v =
216 has_virtual_destructor<_Tp>::value;
217
218// See C++14 20.10.5, type property queries
219template <typename _Tp>
220 constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
221template <typename _Tp>
222 constexpr size_t rank_v = rank<_Tp>::value;
223template <typename _Tp, unsigned _Idx = 0>
224 constexpr size_t extent_v = extent<_Tp, _Idx>::value;
225
226// See C++14 20.10.6, type relations
227template <typename _Tp, typename _Up>
228 constexpr bool is_same_v = false;
229template <typename _Tp>
230 constexpr bool is_same_v<_Tp, _Tp> = true;
231template <typename _Base, typename _Derived>
232 constexpr bool is_base_of_v = is_base_of<_Base, _Derived>::value;
233template <typename _From, typename _To>
234 constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
235/// @}
236
237 // 3.3.2, Other type transformations
238 // invocation_type (still unimplemented)
239 // raw_invocation_type (still unimplemented)
240 // invocation_type_t (still unimplemented)
241 // raw_invocation_type_t (still unimplemented)
242} // namespace fundamentals_v1
243
244inline namespace fundamentals_v2
245{
246/**
247 * @defgroup lfts_detect Detection idiom
248 * @ingroup libfund-ts
249 * @since Library Fundamentals TS v2. C++14.
250 */
251/** @ingroup lfts_detect
252 * @{
253 */
254#define __cpp_lib_experimental_detect 201505
255
256// [meta.detect]
257
258/// A metafunction that always yields void, used for detecting valid types.
259template<typename...> using void_t = void;
260
261#pragma GCC diagnostic push
262#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
263/// @internal
264struct __nonesuchbase {};
265struct nonesuch : private __nonesuchbase
266{
267 ~nonesuch() = delete;
268 nonesuch(nonesuch const&) = delete;
269 void operator=(nonesuch const&) = delete;
270};
271#pragma GCC diagnostic pop
272
273template<typename _Default, template<typename...> class _Op, typename... _Args>
274 using detected_or = std::__detected_or<_Default, _Op, _Args...>;
275
276template<typename _Default, template<typename...> class _Op, typename... _Args>
277 using detected_or_t = typename detected_or<_Default, _Op, _Args...>::type;
278
279template<template<typename...> class _Op, typename... _Args>
280 using detected_t = detected_or_t<nonesuch, _Op, _Args...>;
281
282template<template<typename...> class _Op, typename... _Args>
283 using is_detected = typename detected_or<void, _Op, _Args...>::__is_detected;
284
285template<template<typename...> class _Op, typename... _Args>
286 constexpr bool is_detected_v = is_detected<_Op, _Args...>::value;
287
288template<typename _Expected, template<typename...> class _Op, typename... _Args>
289 using is_detected_exact = is_same<_Expected, detected_t<_Op, _Args...>>;
290
291template<typename _Expected, template<typename...> class _Op, typename... _Args>
292 constexpr bool is_detected_exact_v
293 = is_detected_exact<_Expected, _Op, _Args...>::value;
294
295template<typename _To, template<typename...> class _Op, typename... _Args>
296 using is_detected_convertible
297 = is_convertible<detected_t<_Op, _Args...>, _To>;
298
299template<typename _To, template<typename...> class _Op, typename... _Args>
300 constexpr bool is_detected_convertible_v
301 = is_detected_convertible<_To, _Op, _Args...>::value;
302/// @}
303
304/**
305 * @defgroup lfts_logical Logical operator traits
306 * @ingroup libfund-ts
307 * @since Library Fundamentals TS v2. C++14.
308 */
309/** @ingroup lfts_logical
310 * @{
311 */
312#define __cpp_lib_experimental_logical_traits 201511
313
314template<typename... _Bn>
315 struct conjunction
316 : __and_<_Bn...>
317 { };
318
319template<typename... _Bn>
320 struct disjunction
321 : __or_<_Bn...>
322 { };
323
324template<typename _Pp>
325 struct negation
326 : __not_<_Pp>
327 { };
328
329template<typename... _Bn>
330 constexpr bool conjunction_v
331 = conjunction<_Bn...>::value;
332
333template<typename... _Bn>
334 constexpr bool disjunction_v
335 = disjunction<_Bn...>::value;
336
337template<typename _Pp>
338 constexpr bool negation_v
339 = negation<_Pp>::value;
340/// @}
341} // namespace fundamentals_v2
342} // namespace experimental
343
344_GLIBCXX_END_NAMESPACE_VERSION
345} // namespace std
346
347#endif // __cplusplus <= 201103L
348
349#endif // _GLIBCXX_EXPERIMENTAL_TYPE_TRAITS