C++ (Cpp) ACE_RW_Thread_Mutex примеры использования

Пример #1

int
Reader_Task::svc (void)
{
  ACE_Profile_Timer timer;
  ACE_Profile_Timer::ACE_Elapsed_Time elapsed_time;

  barrier_.wait ();
  // Wait at the barrier.

  // We start an ACE_Profile_Timer here...
  timer.start ();

  for (size_t iterations = 1;
       iterations <= n_iterations;
       iterations++)
    {
      ACE_Thread::yield ();

      int result = 0;

      {
#if defined (RW_MUTEX)
        ACE_Read_Guard<ACE_RW_Thread_Mutex> g (rw_mutex);
#else
        ACE_Guard<ACE_Thread_Mutex> g (mutex);
#endif /* RW_MUTEX */
        find_last ();
#if defined (RW_MUTEX)
        if (use_try_upgrade)
          result =
            rw_mutex.tryacquire_write_upgrade ();
#endif /* RW_MUTEX */

        // True, when we were able to upgrade.
        if (result == 0 && use_try_upgrade)
          {
            //find_last (); try to find something which is not in
            //there
            upgraded++;
            continue;
          }
      }

      if (result == -1 && errno == EBUSY // we tried and failed
          || !use_try_upgrade)           // we did not try at all
        {
#if defined (RW_MUTEX)
          ACE_Write_Guard<ACE_RW_Thread_Mutex> g (rw_mutex);
#else
          ACE_Guard<ACE_Thread_Mutex> g (mutex);
#endif /* RW_MUTEX */

          not_upgraded++;
          find_last ();
        }
      else if (result == -1 && errno != EBUSY)
        ACE_ERROR ((LM_ERROR,
                    ACE_TEXT (" (%t) failure in upgrading to write lock!\n"),
                    1));
    }

  // Stop the timer.
  timer.stop ();
  timer.elapsed_time (elapsed_time);

  this->time_Calculation_.report_time (elapsed_time);

  return 0;
}

Пример #2

Файл: Reader_Writer_Test.cpp Проект: BackupTheBerlios/pyasynchio-svn

static void *
reader (void *)
{
  ACE_DEBUG ((LM_DEBUG, ACE_TEXT (" (%t) reader starting\n")));

  // We use a random pause, around 2msec with 1msec jittering.
  int usecs = 1000 + ACE_OS::rand() % 2000;
  ACE_Time_Value pause(0, usecs);

  for (size_t iterations = 1; iterations <= n_iterations; iterations++)
    {
      ACE_OS::sleep (pause);
      ACE_Read_Guard<ACE_RW_Thread_Mutex> g (rw_mutex);
      // int n = ++current_readers;
      // ACE_DEBUG ((LM_DEBUG, ACE_TEXT (" (%t) I'm reader number %d\n"), n));

      if (current_writers > 0)
        ACE_DEBUG ((LM_DEBUG, ACE_TEXT (" (%t) writers found!!!\n")));

      ACE_thread_t data = shared_data;

      for (size_t loop = 1; loop <= n_loops; loop++)
        {
          ACE_Thread::yield ();

          if (!ACE_OS::thr_equal (shared_data, data))
            ACE_DEBUG ((LM_DEBUG,
                        ACE_TEXT (" (%t) somebody changed %d to %d\n"),
                        data, shared_data));
        }

      int result = rw_mutex.tryacquire_write_upgrade ();

      if (result == 0)
        {
          current_readers--;
          current_writers++;

          ACE_DEBUG ((LM_DEBUG,
                      ACE_TEXT ("(%t) upgraded to write lock!\n")));

          ACE_thread_t self = ACE_Thread::self ();

          shared_data = self;
          data = self;

          for (size_t loop = 1; loop <= n_loops; loop++)
            {
              if (ACE_OS::thr_equal (shared_data, data) == 0)
                ACE_DEBUG ((LM_DEBUG,
                            ACE_TEXT ("(%t) upgraded writer error: somebody changed %d to %d\n"),
                            data,
                            shared_data));
            }

          current_writers--;
          // we were a writer
        }
      else if (result == -1 && errno == EBUSY)
        {
          current_readers--;
          // we were still a reader

          ACE_DEBUG ((LM_DEBUG,
                      ACE_TEXT ("(%t) could not upgrade to write lock!\n")));

        }
      else // result == -1
        {
# if defined (ACE_LACKS_RWLOCK_T)
          // In this case we do not have native RW locks, but therefore the
          // emulation, which supports upgradable write locks.
          ACE_ERROR ((LM_ERROR,
                      ACE_TEXT ("(%t) failure in upgrading to write lock!\n"),
                      1));
# else
          // In this case we have native RW locks support, but native RW
          // locks do not support upgrading!
          ACE_DEBUG ((LM_DEBUG,
                      ACE_TEXT ("(%t) no support for upgradable write locks!\n"),
                      1));
# endif /* ACE_LACKS_RWLOCK_T */
        }
      //ACE_DEBUG ((LM_DEBUG, ACE_TEXT (" (%t) done with reading guarded data\n")));

      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("(%t) reader finished %d iterations at %T\n"),
                  iterations));
    }
  return 0;
}