54 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9// <tuple>10 11// template <class... Types> class tuple;12 13// template <class... Types>14// class tuple_size<tuple<Types...>>15// : public integral_constant<size_t, sizeof...(Types)> { };16//17// LWG #2212 says that tuple_size and tuple_element must be18// available after including <utility>19 20#include <cstddef>21#include <utility>22#include <type_traits>23 24#include "test_macros.h"25 26template <class T, std::size_t N, class U, std::size_t idx>27void test()28{29 static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,30 std::tuple_size<T> >::value), "");31 static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,32 std::tuple_size<const T> >::value), "");33 static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,34 std::tuple_size<volatile T> >::value), "");35 static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,36 std::tuple_size<const volatile T> >::value), "");37 static_assert((std::is_same<typename std::tuple_element<idx, T>::type, U>::value), "");38 static_assert((std::is_same<typename std::tuple_element<idx, const T>::type, const U>::value), "");39 static_assert((std::is_same<typename std::tuple_element<idx, volatile T>::type, volatile U>::value), "");40 static_assert((std::is_same<typename std::tuple_element<idx, const volatile T>::type, const volatile U>::value), "");41}42 43int main(int, char**)44{45 test<std::pair<int, int>, 2, int, 0>();46 test<std::pair<int, int>, 2, int, 1>();47 test<std::pair<const int, int>, 2, int, 1>();48 test<std::pair<int, volatile int>, 2, volatile int, 1>();49 test<std::pair<char *, int>, 2, char *, 0>();50 test<std::pair<char *, int>, 2, int, 1>();51 52 return 0;53}54