libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.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, c++11, c++14
  10 // <optional>
  11
  12 // template <class T, class... Args>
  13 //   constexpr optional<T> make_optional(Args&&... args);
  14
  15 #include <optional>
  16 #include <string>
  17 #include <memory>
  18 #include <cassert>
  19
  20 #include "test_macros.h"
  21
  22 int main(int, char**)
  23 {
  24     {
  25         constexpr auto opt = std::make_optional<int>('a');
  26         static_assert(*opt == int('a'));
  27     }
  28     {
  29         std::string s = "123";
  30         auto opt = std::make_optional<std::string>(s);
  31         assert(*opt == "123");
  32     }
  33     {
  34         std::unique_ptr<int> s = std::make_unique<int>(3);
  35         auto opt = std::make_optional<std::unique_ptr<int>>(std::move(s));
  36         assert(**opt == 3);
  37         assert(s == nullptr);
  38     }
  39     {
  40         auto opt = std::make_optional<std::string>(4u, 'X');
  41         assert(*opt == "XXXX");
  42     }
  43
  44   return 0;
  45 }