libstdc++
experimental/tuple
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1 // <experimental/tuple> -*- C++ -*-
2 
3 // Copyright (C) 2014-2025 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
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24 
25 /** @file experimental/tuple
26  * This is a TS C++ Library header.
27  * @ingroup libfund-ts
28  */
29 
30 #ifndef _GLIBCXX_EXPERIMENTAL_TUPLE
31 #define _GLIBCXX_EXPERIMENTAL_TUPLE 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 <tuple>
42 #include <bits/invoke.h>
43 #include <experimental/bits/lfts_config.h>
44 
45 namespace std _GLIBCXX_VISIBILITY(default)
46 {
47 _GLIBCXX_BEGIN_NAMESPACE_VERSION
48 
49 namespace experimental
50 {
51 inline namespace fundamentals_v1
52 {
53  // See C++14 20.4.2.5, tuple helper classes
54  template <typename _Tp>
55  constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
56 
57 #define __cpp_lib_experimental_tuple 201402
58 
59  template <typename _Fn, typename _Tuple, std::size_t... _Idx>
60  constexpr decltype(auto)
61  __apply_impl(_Fn&& __f, _Tuple&& __t, std::index_sequence<_Idx...>)
62  {
63  return std::__invoke(std::forward<_Fn>(__f),
64  std::get<_Idx>(std::forward<_Tuple>(__t))...);
65  }
66 
67  template <typename _Fn, typename _Tuple>
68  constexpr decltype(auto)
69  apply(_Fn&& __f, _Tuple&& __t)
70  {
71  using _Indices =
72  std::make_index_sequence<tuple_size_v<std::decay_t<_Tuple>>>;
73  return experimental::__apply_impl(std::forward<_Fn>(__f),
74  std::forward<_Tuple>(__t),
75  _Indices{});
76  }
77 } // namespace fundamentals_v1
78 } // namespace experimental
79 
80 _GLIBCXX_END_NAMESPACE_VERSION
81 } // namespace std
82 
83 #endif // C++14
84 
85 #endif // _GLIBCXX_EXPERIMENTAL_TUPLE