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// $Id$
// This test shows the use of an ACE_Auto_Event as a signaling
// mechanism. Two threads are created (one a reader, the other a
// writer). The reader waits till the writer has completed
// calculations. Upon waking up the reader prints the data calculated
// by the writer. The writer thread calculates the value and signals
// the reader when the calculation completes.
#include "ace/Service_Config.h"
#include "ace/Synch.h"
#include "ace/Singleton.h"
#include "ace/Thread_Manager.h"
#if defined (ACE_HAS_THREADS)
// Shared event between reader and writer. The ACE_Thread_Mutex is
// necessary to make sure that only one ACE_Auto_Event is created.
// The default constructor for ACE_Auto_Event sets it initially into
// the non-signaled state.
typedef ACE_Singleton <ACE_Auto_Event, ACE_Thread_Mutex> EVENT;
// work time for writer
static int work_time;
// Reader thread.
static void *
reader (void *arg)
{
// Shared data via a reference.
int& data = *(int *) arg;
ACE_Thread_Control tc (ACE_Service_Config::thr_mgr ());
// Wait for writer to complete.
ACE_DEBUG ((LM_DEBUG, "(%t) reader: waiting...... \n"));
if (EVENT::instance ()->wait () == -1)
{
ACE_ERROR ((LM_ERROR, "thread wait failed"));
ACE_OS::exit (0);
}
// Read shared data.
ACE_DEBUG ((LM_DEBUG, "(%t) reader: value of data is: %d \n", data));
return 0;
}
// Writer thread.
static void *
writer (void *arg)
{
int& data = *(int *) arg;
ACE_Thread_Control tc (ACE_Service_Config::thr_mgr ());
// Calculate (work).
ACE_DEBUG ((LM_DEBUG, "(%t) writer: working for %d secs\n", work_time));
ACE_OS::sleep (work_time);
// Write shared data.
data = 42;
// Wake up reader.
ACE_DEBUG ((LM_DEBUG, "(%t) writer: calculation complete, waking reader\n"));
if (EVENT::instance ()->signal () == -1)
{
ACE_ERROR ((LM_ERROR, "thread wait failed"));
ACE_OS::exit (0);
}
return 0;
}
int
main (int argc, char **argv)
{
// Shared data: set by writer, read by reader.
int data;
// Work time for writer.
work_time = argc == 2 ? atoi (argv[1]) : 5;
// threads manager
ACE_Thread_Manager& tm = *ACE_Service_Config::thr_mgr ();
// Create reader thread.
if (tm.spawn (reader, (void *) &data) == -1)
ACE_ERROR_RETURN ((LM_ERROR, "thread create for reader failed"), -1);
// Create writer thread.
if (tm.spawn (writer, (void *) &data) == -1)
ACE_ERROR_RETURN ((LM_ERROR, "thread create for writer failed"), -1);
// Wait for both.
if (tm.wait () == -1)
ACE_ERROR_RETURN ((LM_ERROR, "thread wait failed"), -1);
else
ACE_DEBUG ((LM_ERROR, "graceful exit\n"));
return 0;
}
#else
int
main (int, char *[])
{
ACE_ERROR ((LM_ERROR, "threads not supported on this platform\n"));
return 0;
}
#endif /* ACE_HAS_THREADS */
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