xref: /llvm-project/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp (revision 31cbe0f240f660f15602c96b787c58a26f17e179)
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 // UNSUPPORTED: c++03
18 
19 #include <tuple>
20 #include <type_traits>
21 
22 #include "test_macros.h"
23 
24 template <class T, std::size_t N>
test()25 void test()
26 {
27     static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
28                                    std::tuple_size<T> >::value), "");
29     static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
30                                    std::tuple_size<const T> >::value), "");
31     static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
32                                    std::tuple_size<volatile T> >::value), "");
33     static_assert((std::is_base_of<std::integral_constant<std::size_t, N>,
34                                    std::tuple_size<const volatile T> >::value), "");
35 }
36 
main(int,char **)37 int main(int, char**)
38 {
39     test<std::tuple<>, 0>();
40     test<std::tuple<int>, 1>();
41     test<std::tuple<char, int>, 2>();
42     test<std::tuple<char, char*, int>, 3>();
43 
44   return 0;
45 }
46