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The C and C++ Include Header Files

cat -n /usr/include/c++/15/experimental/array

     1	// <experimental/array> -*- C++ -*-
     2	
     3	// Copyright (C) 2015-2025 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/array
    26	 *  This is a TS C++ Library header.
    27	 *  @ingroup libfund-ts
    28	 */
    29	
    30	#ifndef _GLIBCXX_EXPERIMENTAL_ARRAY
    31	#define _GLIBCXX_EXPERIMENTAL_ARRAY 1
    32	
    33	#ifdef _GLIBCXX_SYSHDR
    34	#pragma GCC system_header
    35	#endif
    36	
    37	#include <bits/requires_hosted.h> // experimental is currently omitted
    38	
    39	#if __cplusplus >= 201402L
    40	
    41	#include <array>
    42	#include <experimental/type_traits>
    43	
    44	namespace std _GLIBCXX_VISIBILITY(default)
    45	{
    46	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    47	
    48	namespace experimental
    49	{
    50	inline namespace fundamentals_v2
    51	{
    52	#define __cpp_lib_experimental_make_array 201505
    53	  /**
    54	   * @defgroup make_array Array creation functions
    55	   * @ingroup libfund-ts
    56	   *
    57	   * Array creation functions as described in N4529,
    58	   * Working Draft, C++ Extensions for Library Fundamentals, Version 2
    59	   *
    60	   * @{
    61	   */
    62	
    63	template<typename _Dest, typename... _Types>
    64	  struct __make_array_elem
    65	  {
    66	    using type = _Dest;
    67	  };
    68	
    69	template<typename... _Types>
    70	  struct __make_array_elem<void, _Types...>
    71	  : common_type<_Types...>
    72	  {
    73	    template <typename>
    74	      struct __is_reference_wrapper : false_type
    75	      {};
    76	
    77	    template <typename _Up>
    78	      struct __is_reference_wrapper<reference_wrapper<_Up>> : true_type
    79	      {};
    80	
    81	    static_assert(!__or_<__is_reference_wrapper<decay_t<_Types>>...>::value,
    82	                  "make_array must be used with an explicit target type when"
    83	                  "any of the arguments is a reference_wrapper");
    84	  };
    85	
    86	/// Create a std::array from a variable-length list of arguments.
    87	template <typename _Dest = void, typename... _Types>
    88	  constexpr
    89	  array<typename __make_array_elem<_Dest, _Types...>::type, sizeof...(_Types)>
    90	  make_array(_Types&&... __t)
    91	  {
    92	    return {{ std::forward<_Types>(__t)... }};
    93	  }
    94	
    95	template <typename _Tp, size_t _Nm, size_t... _Idx>
    96	  constexpr array<remove_cv_t<_Tp>, _Nm>
    97	  __to_array(_Tp (&__a)[_Nm], index_sequence<_Idx...>)
    98	  {
    99	    return {{__a[_Idx]...}};
   100	  }
   101	
   102	/// Create a std::array from an array.
   103	template <typename _Tp, size_t _Nm>
   104	  constexpr array<remove_cv_t<_Tp>, _Nm>
   105	  to_array(_Tp (&__a)[_Nm])
   106	  noexcept(is_nothrow_constructible<remove_cv_t<_Tp>, _Tp&>::value)
   107	  {
   108	    return experimental::__to_array(__a, make_index_sequence<_Nm>{});
   109	  }
   110	
   111	  /// @} group make_array
   112	} // namespace fundamentals_v2
   113	} // namespace experimental
   114	
   115	_GLIBCXX_END_NAMESPACE_VERSION
   116	} // namespace std
   117	
   118	#endif // C++14
   119	
   120	#endif // _GLIBCXX_EXPERIMENTAL_ARRAY