libstdc++-v3/include/experimental/type_traits

   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 #pragma GCC system_header
  45
  46 #if __cplusplus >= 201402L
  47
  48 #include <type_traits>
  49 #include <experimental/bits/lfts_config.h>
  50
  51 namespace std _GLIBCXX_VISIBILITY(default)
  52 {
  53 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  54
  55 namespace experimental
  56 {
  57 inline namespace fundamentals_v1
  58 {
  59 /** @defgroup lfts_variable_templates Variable template for type traits
  60  * @ingroup libfund-ts
  61  * @since Library Fundamentals TS v1. C++14.
  62  * @see variable_templates
  63  */
  64 /** @ingroup lfts_variable_templates
  65  * @{
  66  */
  67 #define __cpp_lib_experimental_type_trait_variable_templates 201402
  68
  69 // See C++14 20.10.4.1, primary type categories
  70 template <typename _Tp>
  71   constexpr bool is_void_v = is_void<_Tp>::value;
  72 template <typename _Tp>
  73   constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
  74 template <typename _Tp>
  75   constexpr bool is_integral_v = is_integral<_Tp>::value;
  76 template <typename _Tp>
  77   constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
  78 template <typename _Tp>
  79   constexpr bool is_array_v = is_array<_Tp>::value;
  80 template <typename _Tp>
  81   constexpr bool is_pointer_v = is_pointer<_Tp>::value;
  82 template <typename _Tp>
  83   constexpr bool is_lvalue_reference_v = is_lvalue_reference<_Tp>::value;
  84 template <typename _Tp>
  85   constexpr bool is_rvalue_reference_v = is_rvalue_reference<_Tp>::value;
  86 template <typename _Tp>
  87   constexpr bool is_member_object_pointer_v =
  88     is_member_object_pointer<_Tp>::value;
  89 template <typename _Tp>
  90   constexpr bool is_member_function_pointer_v =
  91     is_member_function_pointer<_Tp>::value;
  92 template <typename _Tp>
  93   constexpr bool is_enum_v = is_enum<_Tp>::value;
  94 template <typename _Tp>
  95   constexpr bool is_union_v = is_union<_Tp>::value;
  96 template <typename _Tp>
  97   constexpr bool is_class_v = is_class<_Tp>::value;
  98 template <typename _Tp>
  99   constexpr bool is_function_v = is_function<_Tp>::value;
 100
 101 // See C++14 20.10.4.2, composite type categories
 102 template <typename _Tp>
 103   constexpr bool is_reference_v = is_reference<_Tp>::value;
 104 template <typename _Tp>
 105   constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
 106 template <typename _Tp>
 107   constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
 108 template <typename _Tp>
 109   constexpr bool is_object_v = is_object<_Tp>::value;
 110 template <typename _Tp>
 111   constexpr bool is_scalar_v = is_scalar<_Tp>::value;
 112 template <typename _Tp>
 113   constexpr bool is_compound_v = is_compound<_Tp>::value;
 114 template <typename _Tp>
 115  constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
 116
 117 // See C++14 20.10.4.3, type properties
 118 template <typename _Tp>
 119   constexpr bool is_const_v = is_const<_Tp>::value;
 120 template <typename _Tp>
 121   constexpr bool is_volatile_v = is_volatile<_Tp>::value;
 122 template <typename _Tp>
 123   constexpr bool is_trivial_v = is_trivial<_Tp>::value;
 124 template <typename _Tp>
 125   constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
 126 template <typename _Tp>
 127   constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
 128 #pragma GCC diagnostic push
 129 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 130 template <typename _Tp>
 131   constexpr bool is_pod_v = is_pod<_Tp>::value;
 132 template <typename _Tp>
 133   constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
 134 #pragma GCC diagnostic pop
 135 template <typename _Tp>
 136   constexpr bool is_empty_v = is_empty<_Tp>::value;
 137 template <typename _Tp>
 138   constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
 139 template <typename _Tp>
 140   constexpr bool is_abstract_v = is_abstract<_Tp>::value;
 141 template <typename _Tp>
 142   constexpr bool is_final_v = is_final<_Tp>::value;
 143 template <typename _Tp>
 144   constexpr bool is_signed_v = is_signed<_Tp>::value;
 145 template <typename _Tp>
 146   constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
 147 template <typename _Tp, typename... _Args>
 148   constexpr bool is_constructible_v = is_constructible<_Tp, _Args...>::value;
 149 template <typename _Tp>
 150   constexpr bool is_default_constructible_v =
 151     is_default_constructible<_Tp>::value;
 152 template <typename _Tp>
 153   constexpr bool is_copy_constructible_v = is_copy_constructible<_Tp>::value;
 154 template <typename _Tp>
 155   constexpr bool is_move_constructible_v = is_move_constructible<_Tp>::value;
 156 template <typename _Tp, typename _Up>
 157   constexpr bool is_assignable_v = is_assignable<_Tp, _Up>::value;
 158 template <typename _Tp>
 159   constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
 160 template <typename _Tp>
 161   constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
 162 template <typename _Tp>
 163   constexpr bool is_destructible_v = is_destructible<_Tp>::value;
 164 template <typename _Tp, typename... _Args>
 165   constexpr bool is_trivially_constructible_v =
 166     is_trivially_constructible<_Tp, _Args...>::value;
 167 template <typename _Tp>
 168   constexpr bool is_trivially_default_constructible_v =
 169     is_trivially_default_constructible<_Tp>::value;
 170 template <typename _Tp>
 171   constexpr bool is_trivially_copy_constructible_v =
 172     is_trivially_copy_constructible<_Tp>::value;
 173 template <typename _Tp>
 174   constexpr bool is_trivially_move_constructible_v =
 175     is_trivially_move_constructible<_Tp>::value;
 176 template <typename _Tp, typename _Up>
 177   constexpr bool is_trivially_assignable_v =
 178     is_trivially_assignable<_Tp, _Up>::value;
 179 template <typename _Tp>
 180   constexpr bool is_trivially_copy_assignable_v =
 181     is_trivially_copy_assignable<_Tp>::value;
 182 template <typename _Tp>
 183   constexpr bool is_trivially_move_assignable_v =
 184     is_trivially_move_assignable<_Tp>::value;
 185 template <typename _Tp>
 186   constexpr bool is_trivially_destructible_v =
 187     is_trivially_destructible<_Tp>::value;
 188 template <typename _Tp, typename... _Args>
 189   constexpr bool is_nothrow_constructible_v =
 190     is_nothrow_constructible<_Tp, _Args...>::value;
 191 template <typename _Tp>
 192   constexpr bool is_nothrow_default_constructible_v =
 193     is_nothrow_default_constructible<_Tp>::value;
 194 template <typename _Tp>
 195   constexpr bool is_nothrow_copy_constructible_v =
 196     is_nothrow_copy_constructible<_Tp>::value;
 197 template <typename _Tp>
 198   constexpr bool is_nothrow_move_constructible_v =
 199     is_nothrow_move_constructible<_Tp>::value;
 200 template <typename _Tp, typename _Up>
 201   constexpr bool is_nothrow_assignable_v =
 202     is_nothrow_assignable<_Tp, _Up>::value;
 203 template <typename _Tp>
 204   constexpr bool is_nothrow_copy_assignable_v =
 205     is_nothrow_copy_assignable<_Tp>::value;
 206 template <typename _Tp>
 207   constexpr bool is_nothrow_move_assignable_v =
 208     is_nothrow_move_assignable<_Tp>::value;
 209 template <typename _Tp>
 210   constexpr bool is_nothrow_destructible_v =
 211     is_nothrow_destructible<_Tp>::value;
 212 template <typename _Tp>
 213   constexpr bool has_virtual_destructor_v =
 214     has_virtual_destructor<_Tp>::value;
 215
 216 // See C++14 20.10.5, type property queries
 217 template <typename _Tp>
 218   constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
 219 template <typename _Tp>
 220   constexpr size_t rank_v = rank<_Tp>::value;
 221 template <typename _Tp, unsigned _Idx = 0>
 222   constexpr size_t extent_v = extent<_Tp, _Idx>::value;
 223
 224 // See C++14 20.10.6, type relations
 225 template <typename _Tp, typename _Up>
 226   constexpr bool is_same_v = false;
 227 template <typename _Tp>
 228   constexpr bool is_same_v<_Tp, _Tp> = true;
 229 template <typename _Base, typename _Derived>
 230   constexpr bool is_base_of_v = is_base_of<_Base, _Derived>::value;
 231 template <typename _From, typename _To>
 232   constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
 233 /// @}
 234
 235   // 3.3.2, Other type transformations
 236   // invocation_type (still unimplemented)
 237   // raw_invocation_type (still unimplemented)
 238   // invocation_type_t (still unimplemented)
 239   // raw_invocation_type_t (still unimplemented)
 240 } // namespace fundamentals_v1
 241
 242 inline namespace fundamentals_v2
 243 {
 244 /**
 245  * @defgroup lfts_detect Detection idiom
 246  * @ingroup libfund-ts
 247  * @since Library Fundamentals TS v2. C++14.
 248  */
 249 /** @ingroup lfts_detect
 250  * @{
 251  */
 252 #define __cpp_lib_experimental_detect 201505
 253
 254 // [meta.detect]
 255
 256 /// A metafunction that always yields void, used for detecting valid types.
 257 template<typename...> using void_t = void;
 258
 259 #pragma GCC diagnostic push
 260 #pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
 261 /// @internal
 262 struct __nonesuchbase {};
 263 struct nonesuch : private __nonesuchbase
 264 {
 265   ~nonesuch() = delete;
 266   nonesuch(nonesuch const&) = delete;
 267   void operator=(nonesuch const&) = delete;
 268 };
 269 #pragma GCC diagnostic pop
 270
 271 template<typename _Default, template<typename...> class _Op, typename... _Args>
 272   using detected_or = std::__detected_or<_Default, _Op, _Args...>;
 273
 274 template<typename _Default, template<typename...> class _Op, typename... _Args>
 275   using detected_or_t = typename detected_or<_Default, _Op, _Args...>::type;
 276
 277 template<template<typename...> class _Op, typename... _Args>
 278   using detected_t = detected_or_t<nonesuch, _Op, _Args...>;
 279
 280 template<template<typename...> class _Op, typename... _Args>
 281   using is_detected = typename detected_or<void, _Op, _Args...>::__is_detected;
 282
 283 template<template<typename...> class _Op, typename... _Args>
 284   constexpr bool is_detected_v = is_detected<_Op, _Args...>::value;
 285
 286 template<typename _Expected, template<typename...> class _Op, typename... _Args>
 287   using is_detected_exact = is_same<_Expected, detected_t<_Op, _Args...>>;
 288
 289 template<typename _Expected, template<typename...> class _Op, typename... _Args>
 290   constexpr bool is_detected_exact_v
 291     = is_detected_exact<_Expected, _Op, _Args...>::value;
 292
 293 template<typename _To, template<typename...> class _Op, typename... _Args>
 294   using is_detected_convertible
 295     = is_convertible<detected_t<_Op, _Args...>, _To>;
 296
 297 template<typename _To, template<typename...> class _Op, typename... _Args>
 298   constexpr bool is_detected_convertible_v
 299     = is_detected_convertible<_To, _Op, _Args...>::value;
 300 /// @}
 301
 302 /**
 303  * @defgroup lfts_logical Logical operator traits
 304  * @ingroup libfund-ts
 305  * @since Library Fundamentals TS v2. C++14.
 306  */
 307 /** @ingroup lfts_logical
 308  * @{
 309  */
 310 #define __cpp_lib_experimental_logical_traits 201511
 311
 312 template<typename... _Bn>
 313   struct conjunction
 314   : __and_<_Bn...>
 315   { };
 316
 317 template<typename... _Bn>
 318   struct disjunction
 319   : __or_<_Bn...>
 320   { };
 321
 322 template<typename _Pp>
 323   struct negation
 324   : __not_<_Pp>
 325   { };
 326
 327 template<typename... _Bn>
 328   constexpr bool conjunction_v
 329     = conjunction<_Bn...>::value;
 330
 331 template<typename... _Bn>
 332   constexpr bool disjunction_v
 333     = disjunction<_Bn...>::value;
 334
 335 template<typename _Pp>
 336   constexpr bool negation_v
 337     = negation<_Pp>::value;
 338 /// @}
 339 } // namespace fundamentals_v2
 340 } // namespace experimental
 341
 342 _GLIBCXX_END_NAMESPACE_VERSION
 343 } // namespace std
 344
 345 #endif // __cplusplus <= 201103L
 346
 347 #endif // _GLIBCXX_EXPERIMENTAL_TYPE_TRAITS