串口操作WriteFile在win98下正常，win2000下出错，请帮忙up或提供线索！

Question

可能是你的程序有问题，没有细看你的程序，但是WriteFile是可以在2000下很好的运行。

Answer 1

writefile应该是没错的，查查其他的错，2000下对句柄的检查比98更严格

Answer 2

兄弟，串口通讯在2000/NT下CreateFile()一定要设置OVERLAPPED结构呀

Answer 3

如果在CreateFile（）指定了OVERLAPPED结构，那WriteFile也应该指定OVERLAPPED
但却NULL，肯定不行的（特别在win2000/NT下）
我以前也碰到同样的问题，开始在98下没有考虑OVERLAPPED结构，能正确发送和接收，但在2000下，就无办法通过，后来仔细一看CSDN才醒悟过来最好，把CreateFile()的代码也拿来看看如果指定了OVERLAPPED结构，就要用GetLastError()来确定操作的结果
请看：void CSerialPort::WriteChar()
{
// 将m_szWriteBuff里的字符发送到输入缓冲区
BOOL bWrite=TRUE; // 
BOOL bResult=TRUE; // 函数操作情况 DWORD BytesSend=0; // 发送字节数
DWORD dwError=0;

ResetEvent(m_hWriteEvents); EnterCriticalSection(&m_csCommunicationSync); if (bWrite)
{
// 初始化异步结构:进行端口操作时这两个参数被忽略
m_ov.Offset=0;
m_ov.OffsetHigh=0; // 清空缓冲区
// PURGE_TXABORT: 既使发送操作没有完成，也终止所有的重叠发送操作，立即返回
// PURGE_RXABORT: 既使接收操作没有完成，也终止所有的重叠发送操作，立即返回
// PRUGE_TXCLEAR: 清除发送缓冲区
// PRUGE_RXCLEAR: 清除接收缓冲区
PurgeComm(m_hCom,PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR); bResult = WriteFile(m_hCom,
m_szWriteBuff,
strlen((char*)m_szWriteBuff),
&BytesSend,
&m_ov
);
if (!bResult)
{  //出错
switch(dwError = GetLastError())
{
case ERROR_IO_PENDING:
{
BytesSend=0;
bWrite=FALSE;
break;
}
default:
{
ProcessErrorMsg("WriteFile()");
break;
}
} //end switch(dwError == GetLastError())
}
else
{
LeaveCriticalSection(&m_csCommunicationSync);
}
} // end if (bWrite) if (!bWrite)
{
bWrite=true; bResult=GetOverlappedResult(m_hCom,
&m_ov,
&BytesSend,
true); LeaveCriticalSection(&m_csCommunicationSync); if (!bResult)
{
ProcessErrorMsg("GetOverlappedResutl()");
}
} // end if (!bWrite) if (BytesSend != strlen((char*)m_szWriteBuff))
{
TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d\n", BytesSend, strlen((char*)m_szWriteBuff));
}
}希望对你有帮助。

Answer 4

OVERLAPPED overlapped; //OVERLAPPED structure
OVERLAPPED overlappedwrite;
OVERLAPPED overlappedread;overlapped.Internal=0;
overlapped.InternalHigh=0;
overlapped.Offset=0;
overlapped.OffsetHigh=0;
overlapped.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL); //这个很重要，不信你可以注释掉，看看结果会怎样。FHandle = CreateFile(
                                PortName,
                                GENERIC_READ || GENERIC_WRITE,
                                0, // Not shared
                                NULL, // No security attributes
                                OPEN_EXISTING,
                                FILE_FLAG_OVERLAPPED||FILE_ATTRIBUTE_NORMAL ,
                                0
                              );.........overlappedwrite.Internal=0;
overlappedwrite.InternalHigh=0;
overlappedwrite.Offset=0;
overlappedwrite.OffsetHigh=0;
overlappedwrite.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);
//这个很重要，不信你可以注释掉，看看结果会怎样。WriteFile( FHandle,&csp,dwDataSize,&nSent, &overlappedwrite);
{
   error=GetLastError();
   if (error==ERROR_IO_PENDING)//写成功
   {
//以下是读，可不管
       GetOverlappedResult(com_handle,&overlappedwrite,&dwNumBytesWritten,TRUE);
       overlappedread.Internal=0;
       overlappedread.InternalHigh=0;
       overlappedread.Offset=0; overlappedread.OffsetHigh=0; overlappedread.hEvent=::CreateEvent(NULL,TRUE,FALSE,NULL);
COMSTAT comstat;
DWORD dwLength;
DWORD dwError;
DWORD dwEvtMask=0;
BOOL serive=TRUE;
Sleep(delaytime);
while (serive)
{
WaitCommEvent(com_handle,&dwEvtMask,&overlappedread);
ClearCommError(com_handle,&dwError,&comstat);
dwLength=comstat.cbInQue;
if (dwLength<1)
{
           break;
}
BOOL fReadStat=FALSE;
memset(Bytes,0,sizeof(dwLength));
fReadStat=::ReadFile(com_handle,&Bytes,dwLength,&dwBytesTransferred,&overlappedread);
  }
}系统是win2000
//一定要考虑OVERLAPPED,不然没法做。

Answer 5

qiuanhong(练从难处练,用从易处用) :
大哥，“系统是win2000一定要考虑OVERLAPPED,不然没法做。”真的这样吗？
我因为比较讨厌OVERLAPPED时的WriteFile的操作才没有使用OVERLAPPED的方式来操作。
这下我惨了，还是得用这个讨厌的东西！
不过真的很感谢你。

Answer 6

做好了，别忘了再来这里跟贴，大家学习学习!!!!!
呵呵~~~~fei