libstdc++: array Source File

libstdc++

experimental/array
Go to the documentation of this file.
1// <experimental/array> -*- C++ -*-
2
3// Copyright (C) 2015-2026 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
44namespace std _GLIBCXX_VISIBILITY(default)
45{
46_GLIBCXX_BEGIN_NAMESPACE_VERSION
47
48namespace experimental
49{
50inline 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
63template<typename _Dest, typename... _Types>
64 struct __make_array_elem
65 {
66 using type = _Dest;
67 };
68
69template<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.
87template <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
95template <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.
103template <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
requires_hosted.h
std::true_type
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition type_traits:119
std::false_type
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:122
std::forward
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition move.h:72
std::experimental::fundamentals_v2::make_array
constexpr array< typename __make_array_elem< _Dest, _Types... >::type, sizeof...(_Types)> make_array(_Types &&... __t)
Create a std::array from a variable-length list of arguments.
Definition experimental/array:90
std::experimental::fundamentals_v2::to_array
constexpr array< remove_cv_t< _Tp >, _Nm > to_array(_Tp(&__a)[_Nm]) noexcept(is_nothrow_constructible< remove_cv_t< _Tp >, _Tp & >::value)
Create a std::array from an array.
Definition experimental/array:105
std
ISO C++ entities toplevel namespace is std.
std::make_index_sequence
make_integer_sequence< size_t, _Num > make_index_sequence
Alias template make_index_sequence.
Definition utility.h:528
std::index_sequence
integer_sequence< size_t, _Idx... > index_sequence
Alias template index_sequence.
Definition utility.h:524
std::experimental
Namespace for features defined in ISO Technical Specifications.
std::array
A standard container for storing a fixed size sequence of elements.
Definition array:104
std::is_nothrow_constructible
is_nothrow_constructible
Definition type_traits:1343
array
type_traits