libstdc++-v3/testsuite/30_threads/condition_variable_any/50862.cc

   1 // { dg-do run }
   2 // { dg-additional-options "-pthread" { target pthread } }
   3 // { dg-require-effective-target c++11 }
   4 // { dg-require-gthreads "" }
   5 // { dg-require-sched-yield "" }
   6
   7 // Copyright (C) 2011-2022 Free Software Foundation, Inc.
   8 //
   9 // This file is part of the GNU ISO C++ Library.  This library is free
  10 // software; you can redistribute it and/or modify it under the
  11 // terms of the GNU General Public License as published by the
  12 // Free Software Foundation; either version 3, or (at your option)
  13 // any later version.
  14
  15 // This library is distributed in the hope that it will be useful,
  16 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 // GNU General Public License for more details.
  19
  20 // You should have received a copy of the GNU General Public License along
  21 // with this library; see the file COPYING3.  If not see
  22 // <http://www.gnu.org/licenses/>.
  23
  24 #include <condition_variable>
  25 #include <thread>
  26 #include <mutex>
  27 #include <array>
  28 #include <sstream>
  29
  30 struct scoped_thread
  31 {
  32   ~scoped_thread() { if (t.joinable()) t.join(); }
  33   std::thread t;
  34 };
  35
  36 int main()
  37 {
  38   typedef std::unique_lock<std::mutex> Lock;
  39
  40   std::mutex                  m;
  41   std::condition_variable_any cond;
  42   unsigned int                product = 0;
  43   const unsigned int          count = 10;
  44
  45   // writing to stream causes timing changes which makes deadlock easier
  46   // to reproduce - do not remove
  47   std::ostringstream out;
  48
  49   // create consumers
  50   std::array<scoped_thread, 2> threads;
  51   for (std::size_t i = 0; i < threads.size(); ++i)
  52     threads[i].t
  53       = std::thread( [&]
  54                      {
  55                        for (unsigned int i = 0; i < count; ++i)
  56                          {
  57                            std::this_thread::yield();
  58                            Lock lock(m);
  59                            while(product == 0)
  60                              cond.wait(lock);
  61                            out << "got product "
  62                                << std::this_thread::get_id()
  63                                << ' ' << product << std::endl;
  64                            --product;
  65                          }
  66                      } );
  67
  68   // single producer
  69   for (std::size_t i = 0; i < threads.size() * count; ++i)
  70     {
  71       std::this_thread::yield();
  72       Lock lock(m);
  73       ++product;
  74       out << "setting product " << std::this_thread::get_id()
  75           << ' ' << product << std::endl;
  76       cond.notify_one();
  77     }
  78 }