xref: /llvm-project/libcxx/test/std/utilities/utility/pairs/pairs.pair/ctor.piecewise_construct.pass.cpp (revision da876a157d7985f7f8de906180fa5ad7b685724a)
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 // UNSUPPORTED: c++03
10 
11 // <utility>
12 
13 // template <class T1, class T2> struct pair
14 
15 // template <class... Args1, class... Args2>
16 //     pair(piecewise_construct_t, tuple<Args1...> first_args,
17 //                                 tuple<Args2...> second_args);
18 
19 #include <cassert>
20 #include <tuple>
21 #include <utility>
22 
23 #include "test_macros.h"
24 
test()25 TEST_CONSTEXPR_CXX20 bool test() {
26   {
27     typedef std::pair<int, int*> P1;
28     typedef std::pair<int*, int> P2;
29     typedef std::pair<P1, P2> P3;
30     P3 p3(std::piecewise_construct, std::tuple<int, int*>(3, nullptr),
31           std::tuple<int*, int>(nullptr, 4));
32     assert(p3.first == P1(3, nullptr));
33     assert(p3.second == P2(nullptr, 4));
34   }
35   return true;
36 }
37 
main(int,char **)38 int main(int, char**) {
39   test();
40 #if TEST_STD_VER >= 20
41   static_assert(test());
42 #endif
43 
44   return 0;
45 }
46