libstdc++-v3/testsuite/29_atomics/atomic_flag/wait_notify/1.cc

   1 // { dg-options "-std=gnu++2a" }
   2 // { dg-do run { target c++2a } }
   3 // { dg-require-gthreads "" }
   4 // { dg-additional-options "-pthread" { target pthread } }
   5
   6 // Copyright (C) 2020-2021 Free Software Foundation, Inc.
   7 //
   8 // This file is part of the GNU ISO C++ Library.  This library is free
   9 // software; you can redistribute it and/or modify it under the
  10 // terms of the GNU General Public License as published by the
  11 // Free Software Foundation; either version 3, or (at your option)
  12 // any later version.
  13
  14 // This library is distributed in the hope that it will be useful,
  15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 // GNU General Public License for more details.
  18
  19 // You should have received a copy of the GNU General Public License along
  20 // with this library; see the file COPYING3.  If not see
  21 // <http://www.gnu.org/licenses/>.
  22
  23 #include <atomic>
  24 #include <chrono>
  25 #include <condition_variable>
  26 #include <concepts>
  27 #include <mutex>
  28 #include <thread>
  29
  30 #include <testsuite_hooks.h>
  31
  32 int
  33 main()
  34 {
  35   using namespace std::literals::chrono_literals;
  36
  37   std::mutex m;
  38   std::condition_variable cv;
  39   std::unique_lock<std::mutex> l(m);
  40
  41   std::atomic_flag a;
  42   std::atomic_flag b;
  43   std::thread t([&]
  44                 {
  45                   {
  46                     // This ensures we block until cv.wait(l) starts.
  47                     std::lock_guard<std::mutex> ll(m);
  48                   }
  49                   cv.notify_one();
  50                   a.wait(false);
  51                   b.test_and_set();
  52                   b.notify_one();
  53                 });
  54
  55   cv.wait(l);
  56   std::this_thread::sleep_for(100ms);
  57   a.test_and_set();
  58   a.notify_one();
  59   b.wait(false);
  60   t.join();
  61
  62   VERIFY( a.test() );
  63   VERIFY( b.test() );
  64   return 0;
  65 }