c – WaitForSingleObject()

class A
{
   public:  
   A(){  
         m_event =  CreateEvent(NULL,false,NULL);       // create an event with initial value as non-signalled
         m_thread = _beginthread(StaticThreadEntry,this);    // create a thread 
      }

   static void StaticThreadEntry(A *  obj) {  obj->ThreadEntry();  }

   void ThreadEntry();
};

void A::ThreadEntry()
{
     WaitforSingleObject(m_event,INFINITE);
}


int main()
{
        A a;

        SetEvent(m_event);     // sets the event to signalled state which causes the running thread to terminate 

        WaitForSingleObject(m_thread,INFINITE);  // waits for the thread to terminate

        return 0;
 }

问题：

当运行上面的代码时,有时(5个中的1个)它会挂起并且控件卡在WaitforSingleObject()的调用中(在main函数内).代码总是调用SetEvent()函数来确保线程终止在调用Wait()函数之前.

我没有看到为什么它应该挂起来的任何理由？