WinXP中的ManualResetEvent问题嵌入式

Question

我在使用带有超时参数的ManualResetEvent类时遇到问题。 WinXP嵌入式平台上特别发生此问题。该代码在其他Windows平台上完美工作。我正在与TCP服务器进行通信。在我的客户端代码中，我连接到服务器并产生一个新线程，所以工作就是持续监视数据的接收套接字。我在主线程中发送数据。代码片段如下所示：

internal void initSocket() 
{ 
    ..... 
    ..... 
    if (socket.Connected) 
    { 
     Tracing.info("Connected to server"); 
     ReceiveThread = new Thread(new ThreadStart(StartReceiving)); 
     ReceiveThread.Start(); 
    } 
} 

/// <summary> 
/// Sends a request to Server and waits for its response. 
/// </summary> 
/// <param name="msg"></param> 
/// <param name="timeout">Timeout time, when </param> 
/// <returns></returns> 
private CdcMessage sendSync(CdcMessage msg, int timeout) 
{ 
    resultMessage = null; 

    // store current messageId... 
    resultMessagePackageId = msg.MessageId; 

    String msgToSend = msg.serialize(); 

    Tracing.debug("SEND : >> " + msgToSend); 
    socketWriter.WriteLine(msgToSend); 

    // Wait for response from read thread... 
    resultReceivedEvent = new ManualResetEvent(false); 
    bool bReponseSent = resultReceivedEvent.WaitOne(timeout); 

    if (!bReponseSent) 
    { 
     resultMessage = null; 
    } 

    return resultMessage; 

} 

/// <summary> 
/// Thread function which continuously checks for the 
/// data from server. It will read the data only if it 
/// is available 
/// </summary> 
public void StartReceiving() 
{ 
    while (Connected) 
    { 
     try 
     { 
      Thread.Sleep(100); 

      String response = socketReader.ReadLine(); 

      Tracing.info("Raw data received = " + response); 

      resultMessage = CdcMessage.deserialize(response); 

      Tracing.info("Deserialized response = " + resultMessage); 

      if (resultMessage == null) 
      { 
       continue; 
      } 
      else if (resultMessage.IsHeartbeat) 
      { 
       Tracing.debug("Heartbeat"); 
       socketWriter.WriteLine(response); 
      } 
      else if (!resultMessage.MessageId.Equals(resultMessagePackageId)) 
      { 
       // not the correct package id...reject... 
       Tracing.warn("REJECTED: Package-ID: " + resultMessage.MessageId); 
       continue; 
      } 
      else 
      { 
       resultReceivedEvent.Set(); 
       Tracing.info("StartReceiving() : Received data"); 
       Tracing.debug("RECEIVED: >> " + response); 
      } 
     } 
     catch (NullReferenceException nre) 
     { 
      Tracing.error("StartReceiving(): Socket doesn't exist!", nre); 
      close(); 
      break; 
     } 
     catch (ObjectDisposedException ode) 
     { 
      Tracing.error("StartReceiving(): Socket is disposed!", ode); 
      close(); 
      break; 
     } 
     catch (IOException ex) 
     { 
      Tracing.error("StartReceiving(): Socket IO-Exception!", ex); 
      close(); 
      break; 
     } 
    } 
} 

我强调了代码的重要方面。据观察，WaitOne（超时）功能在大多数Windows操作系统上没有任何问题。但在嵌入式XP中，我观察到一个问题。 WaitOne几乎立即返回，没有从接收线程收到数据。

我所做的是通过将-1传递给WaitOne来使INFINITE的超时。在这种情况下，我可以解决问题。但是这会产生其他副作用（例如，如果服务器已关闭，那么WaitOne永远不会返回！）

有人可以帮我解决这个问题吗？

Answer 1

我不知道我正确地理解你的代码，但线

socketWriter.WriteLine(msgToSend); 
resultReceivedEvent = new ManualResetEvent(false); 
bool bReponseSent = resultReceivedEvent.WaitOne(timeout); 

看起来很奇怪我。我认为这将是更好的：

resultReceivedEvent.Reset(); 
socketWriter.WriteLine(msgToSend); 
bool bReponseSent = resultReceivedEvent.WaitOne(timeout); 

如果创建新的前旧的ManualResetEvent被设定有可能是潜在的竞争状态。在这里似乎没有理由创建一个新的ManualResetEvent实例。只需在旧实例上调用Reset，并确保在发送消息之前将其重置。