QT TCP服务端如何判断客户端已断开连接

在用QT写服务端时想要知道客户端是否断开连接，百度一下没有找到方法，看了下帮助文档，得到以下方法，实测可用，如有更好的还请告知

 enum SocketError {
         ConnectionRefusedError,
         RemoteHostClosedError,//客户端断开时出现这个错误
         HostNotFoundError,
         SocketAccessError,
         SocketResourceError,
         SocketTimeoutError,                     /* 5 */
         DatagramTooLargeError,
         NetworkError,
         AddressInUseError,
         SocketAddressNotAvailableError,
         UnsupportedSocketOperationError,        /* 10 */
         UnfinishedSocketOperationError,
         ProxyAuthenticationRequiredError,
         SslHandshakeFailedError,
         ProxyConnectionRefusedError,
         ProxyConnectionClosedError,             /* 15 */
         ProxyConnectionTimeoutError,
         ProxyNotFoundError,
         ProxyProtocolError,
         OperationError,
         SslInternalError,                       /* 20 */
         SslInvalidUserDataError,
         TemporaryError,
         UnknownSocketError = -1
     };

QAbstractSocket::RemoteHostClosedError   1  The remote host closed the connection. Note that the client socket (i.e., this socket) will be closed after the remote close notification has been sent

远程主机关闭连接，注解：client socket 将送出通知后关闭

QAbstractSocket::error() const
Returns the type of error that last occurred.
返回最后出现的错误类型

下面为实现代码

connect(serverConnect, SIGNAL(error(QAbstractSocket::SocketError)),  
                        this, SLOT(MSGError(QAbstractSocket::SocketError)));//建立槽函数，获取错误信息  
  
void DataDisplay::MSGError(QAbstractSocket::SocketError)  
{  
    error = serverConnect->error();  
    switch(error)  
    {  
    case QAbstractSocket::RemoteHostClosedError://客户端断开  
    {  
        QString hostAddress=serverConnect->QAbstractSocket::peerAddress().toString();  
        ui->m_display->insertPlainText(tr("客户端[%1]断开连接\r\n").arg(hostAddress));  
        break;  
    }  
    default:  
    {  
        error = -1;  
        QMessageBox::information(this, "show", serverConnect->errorString());  
        break;  
    }  
    }  
}