libcxx/test/std/thread/thread.jthread/detach.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: no-threads
  10 // UNSUPPORTED: c++03, c++11, c++14, c++17
  11 // XFAIL: availability-synchronization_library-missing
  12
  13 // void detach();
  14
  15 #include <atomic>
  16 #include <cassert>
  17 #include <chrono>
  18 #include <concepts>
  19 #include <functional>
  20 #include <optional>
  21 #include <system_error>
  22 #include <thread>
  23 #include <type_traits>
  24
  25 #include "make_test_thread.h"
  26 #include "test_macros.h"
  27
  28 int main(int, char**) {
  29   // Effects: The thread represented by *this continues execution without the calling thread blocking.
  30   {
  31     std::atomic_bool start{false};
  32     std::atomic_bool done{false};
  33     std::optional<std::jthread> jt = support::make_test_jthread([&start, &done] {
  34       start.wait(false);
  35       done = true;
  36     });
  37
  38     // If it blocks, it will deadlock here
  39     jt->detach();
  40
  41     jt.reset();
  42
  43     // The other thread continues execution
  44     start = true;
  45     start.notify_all();
  46     while (!done) {
  47     }
  48   }
  49
  50   // Postconditions: get_id() == id().
  51   {
  52     std::jthread jt = support::make_test_jthread([] {});
  53     assert(jt.get_id() != std::jthread::id());
  54     jt.detach();
  55     assert(jt.get_id() == std::jthread::id());
  56   }
  57
  58 #if !defined(TEST_HAS_NO_EXCEPTIONS)
  59   // Throws: system_error when an exception is required ([thread.req.exception]).
  60   // invalid_argument - if the thread is not joinable.
  61   {
  62     std::jthread jt;
  63     try {
  64       jt.detach();
  65       assert(false);
  66     } catch (const std::system_error& err) {
  67       assert(err.code() == std::errc::invalid_argument);
  68     }
  69   }
  70 #endif
  71
  72   std::this_thread::sleep_for(std::chrono::milliseconds{2});
  73   return 0;
  74 }