void OSThread::pd_initialize() {

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      assert(this != NULL, "check");

  {- -------------------------------------------
  (1) フィールドの初期化
      ---------------------------------------- -}

      _thread_id        = 0;
      _pthread_id       = 0;
      _siginfo = NULL;
      _ucontext = NULL;
      _expanding_stack = 0;
      _alt_sig_stack = NULL;

      sigemptyset(&_caller_sigmask);

      _startThread_lock = new Monitor(Mutex::event, "startThread_lock", true);

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      assert(_startThread_lock !=NULL, "check");
    }