libcxx/test/std/utilities/utility/pairs/pairs.pair/ctor.piecewise_construct.pass.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-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
  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
  38 int main(int, char**) {
  39   test();
  40 #if TEST_STD_VER >= 20
  41   static_assert(test());
  42 #endif
  43
  44   return 0;
  45 }