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// <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 be
18// 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

source code of libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp