xref: /llvm-project/libcxx/test/std/thread/thread.jthread/joinable.pass.cpp (revision 121ed5c1985356436d0040dbe81bca26992b1fae)
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: no-threads
10 // UNSUPPORTED: c++03, c++11, c++14, c++17
11 // XFAIL: availability-synchronization_library-missing
12 
13 // [[nodiscard]] bool joinable() const noexcept;
14 
15 #include <atomic>
16 #include <cassert>
17 #include <concepts>
18 #include <thread>
19 #include <type_traits>
20 
21 #include "make_test_thread.h"
22 #include "test_macros.h"
23 
24 static_assert(noexcept(std::declval<const std::jthread&>().joinable()));
25 
26 int main(int, char**) {
27   // Default constructed
28   {
29     const std::jthread jt;
30     std::same_as<bool> decltype(auto) result = jt.joinable();
31     assert(!result);
32   }
33 
34   // Non-default constructed
35   {
36     const std::jthread jt                    = support::make_test_jthread([] {});
37     std::same_as<bool> decltype(auto) result = jt.joinable();
38     assert(result);
39   }
40 
41   // Non-default constructed
42   // the thread of execution has not finished
43   {
44     std::atomic_bool done                    = false;
45     const std::jthread jt                    = support::make_test_jthread([&done] { done.wait(false); });
46     std::same_as<bool> decltype(auto) result = jt.joinable();
47     done                                     = true;
48     done.notify_all();
49     assert(result);
50   }
51 
52   return 0;
53 }
54