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 23 template <class... _Types> 24 class variant; 25 26 template <class _Tp> 27 struct variant_size; 28 29 template <class _Tp> 30 inline constexpr size_t variant_size_v = variant_size<_Tp>::value; 31 32 template <size_t _Ip, class _Tp> 33 struct variant_alternative; 34 35 template <size_t _Ip, class _Tp> 36 using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type; 37 38 inline constexpr size_t variant_npos = static_cast<size_t>(-1); 39 40 template <size_t _Ip, class... _Types> 41 _LIBCPP_HIDE_FROM_ABI constexpr variant_alternative_t<_Ip, variant<_Types...>>& get(variant<_Types...>&); 42 43 template <size_t _Ip, class... _Types> 44 _LIBCPP_HIDE_FROM_ABI constexpr variant_alternative_t<_Ip, variant<_Types...>>&& get(variant<_Types...>&&); 45 46 template <size_t _Ip, class... _Types> 47 _LIBCPP_HIDE_FROM_ABI constexpr const variant_alternative_t<_Ip, variant<_Types...>>& get(const variant<_Types...>&); 48 49 template <size_t _Ip, class... _Types> 50 _LIBCPP_HIDE_FROM_ABI constexpr const variant_alternative_t<_Ip, variant<_Types...>>&& get(const variant<_Types...>&&); 51 52 template <class _Tp, class... _Types> 53 _LIBCPP_HIDE_FROM_ABI constexpr _Tp& get(variant<_Types...>&); 54 55 template <class _Tp, class... _Types> 56 _LIBCPP_HIDE_FROM_ABI constexpr _Tp&& get(variant<_Types...>&&); 57 58 template <class _Tp, class... _Types> 59 _LIBCPP_HIDE_FROM_ABI constexpr const _Tp& get(const variant<_Types...>&); 60 61 template <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