ACE/examples/Threads/task_one.cpp

   1 // This test program illustrates how the ACE barrier synchronization
   2 // mechanisms work in conjunction with the ACE_Task and the
   3 // ACE_Thread_Manager.  It is instructive to compare this with the
   4 // test_barrier.cpp test to see how they differ.
   5
   6 #include "ace/OS_main.h"
   7 #include "ace/Task.h"
   8 #include "ace/Service_Config.h"
   9
  10
  11 #if defined (ACE_HAS_THREADS)
  12
  13 #include "ace/Task.h"
  14 #include "ace/Barrier.h"
  15
  16 class Barrier_Task : public ACE_Task<ACE_MT_SYNCH>
  17 {
  18 public:
  19   Barrier_Task (ACE_Thread_Manager *thr_mgr,
  20                 int n_threads,
  21                 int n_iterations);
  22
  23   virtual int svc ();
  24   // Iterate <n_iterations> time printing off a message and "waiting"
  25   // for all other threads to complete this iteration.
  26
  27 private:
  28   ACE_Barrier barrier_;
  29   // Reference to the tester barrier.  This controls each
  30   // iteration of the tester function running in every thread.
  31
  32   int n_iterations_;
  33   // Number of iterations to run.
  34 };
  35
  36 Barrier_Task::Barrier_Task (ACE_Thread_Manager *thr_mgr,
  37                             int n_threads,
  38                             int n_iterations)
  39   : ACE_Task<ACE_MT_SYNCH> (thr_mgr),
  40     barrier_ (n_threads),
  41     n_iterations_ (n_iterations)
  42 {
  43   // Create worker threads.
  44   if (this->activate (THR_NEW_LWP, n_threads) == -1)
  45     ACE_ERROR ((LM_ERROR, "%p\n", "activate failed"));
  46 }
  47
  48 // Iterate <n_iterations> time printing off a message and "waiting"
  49 // for all other threads to complete this iteration.
  50
  51 int
  52 Barrier_Task::svc ()
  53 {
  54   // Note that the ACE_Task::svc_run() method automatically adds us to
  55   // the Thread_Manager when the thread begins.
  56
  57   for (int iterations = 1;
  58        iterations <= this->n_iterations_;
  59        iterations++)
  60     {
  61       ACE_DEBUG ((LM_DEBUG, "(%t) in iteration %d\n", iterations));
  62
  63       // Block until all other threads have waited, then continue.
  64       this->barrier_.wait ();
  65     }
  66
  67   // Note that the ACE_Task::svc_run() method automatically removes us
  68   // from the Thread_Manager when the thread exits.
  69
  70   return 0;
  71 }
  72
  73 // Default number of threads to spawn.
  74 static const int DEFAULT_ITERATIONS = 5;
  75
  76 int
  77 ACE_TMAIN (int argc, ACE_TCHAR *argv[])
  78 {
  79   int n_threads = argc > 1 ? ACE_OS::atoi (argv[1]) : ACE_DEFAULT_THREADS;
  80   int n_iterations = argc > 2 ? ACE_OS::atoi (argv[2]) : DEFAULT_ITERATIONS;
  81
  82   Barrier_Task barrier_task (ACE_Thread_Manager::instance (),
  83                              n_threads,
  84                              n_iterations);
  85
  86   // Wait for all the threads to reach their exit point.
  87   ACE_Thread_Manager::instance ()->wait ();
  88
  89   ACE_DEBUG ((LM_DEBUG, "(%t) done\n"));
  90   return 0;
  91 }
  92 #else
  93 int
  94 ACE_TMAIN (int, ACE_TCHAR *[])
  95 {
  96   ACE_ERROR ((LM_ERROR, "threads not supported on this platform\n"));
  97   return 0;
  98 }
  99 #endif /* ACE_HAS_THREADS */