int VM_Exit::set_vm_exited() {

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      Thread * thr_cur = ThreadLocalStorage::get_thread_slow();

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

      assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      int num_active = 0;

  {- -------------------------------------------
  (1) まだネイティブコードを実行中のスレッドのために以下の処理を行う.
      (これは終了したことを通達するための処理)

      * VM_Exit::_vm_exited フラグを true にする.
        (See: VM_Exit::wait_if_vm_exited(), VM_Exit::block_if_vm_exited(), VMError::report())

      * ネイティブコードを実行中の全ての JavaThread について, 
        JavaThread::_terminated フィールドの値を 
        JavaThread::_vm_exited 定数に書き換えておく.
        (See: JavaThread::block_if_vm_exited())
      ---------------------------------------- -}

      _shutdown_thread = thr_cur;
      _vm_exited = true;                                // global flag
      for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
        if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
          ++num_active;
          thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
        }

  {- -------------------------------------------
  (1) リターン
      ---------------------------------------- -}

      return num_active;
    }