1//===---------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===---------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___FWD_VARIANT_H
10#define _LIBCPP___FWD_VARIANT_H
11
12#include <__config>
13#include <__cstddef/size_t.h>
14
15#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16# pragma GCC system_header
17#endif
18
19_LIBCPP_BEGIN_NAMESPACE_STD
20
21#if _LIBCPP_STD_VER >= 17
22
23template <class... _Types>
24class variant;
25
26template <class _Tp>
27struct variant_size;
28
29template <class _Tp>
30inline constexpr size_t variant_size_v = variant_size<_Tp>::value;
31
32template <size_t _Ip, class _Tp>
33struct variant_alternative;
34
35template <size_t _Ip, class _Tp>
36using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type;
37
38inline constexpr size_t variant_npos = static_cast<size_t>(-1);
39
40template <size_t _Ip, class... _Types>
41_LIBCPP_HIDE_FROM_ABI constexpr variant_alternative_t<_Ip, variant<_Types...>>& get(variant<_Types...>&);
42
43template <size_t _Ip, class... _Types>
44_LIBCPP_HIDE_FROM_ABI constexpr variant_alternative_t<_Ip, variant<_Types...>>&& get(variant<_Types...>&&);
45
46template <size_t _Ip, class... _Types>
47_LIBCPP_HIDE_FROM_ABI constexpr const variant_alternative_t<_Ip, variant<_Types...>>& get(const variant<_Types...>&);
48
49template <size_t _Ip, class... _Types>
50_LIBCPP_HIDE_FROM_ABI constexpr const variant_alternative_t<_Ip, variant<_Types...>>&& get(const variant<_Types...>&&);
51
52template <class _Tp, class... _Types>
53_LIBCPP_HIDE_FROM_ABI constexpr _Tp& get(variant<_Types...>&);
54
55template <class _Tp, class... _Types>
56_LIBCPP_HIDE_FROM_ABI constexpr _Tp&& get(variant<_Types...>&&);
57
58template <class _Tp, class... _Types>
59_LIBCPP_HIDE_FROM_ABI constexpr const _Tp& get(const variant<_Types...>&);
60
61template <class _Tp, class... _Types>
62_LIBCPP_HIDE_FROM_ABI constexpr const _Tp&& get(const variant<_Types...>&&);
63
64#endif // _LIBCPP_STD_VER >= 17
65
66_LIBCPP_END_NAMESPACE_STD
67
68#endif // _LIBCPP___FWD_VARIANT_H
69