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发表于 2008-11-19 11:38 |只看该作者 |倒序浏览

写了一个Windows下模拟超级终端与串口通信的程序。现在已经能相互通信，但有一个问题：每次我往串口写入数据后，这个数据马上会被负责读串口的线程读到。怎么能象超级终端里那样读和写完全分开？请问怎么解决？

[ 本帖最后由 Wind-Son 于 2008-11-19 11:47 编辑 ]

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Wind-Son

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发表于 2008-11-19 11:40 |只看该作者

代码：

BOOL CComS::Connect(ComParam* p)
{
CString name;

ASSERT(p);

if (m_hCom) {
      ErrMsg(IDS_ERR_COM_AREADY_OPEN);
      return FALSE;
}

name.Format(_T("COM%d"), p->u.Coms.ID);

m_hCom = ::CreateFile(name,
      GENERIC_READ|GENERIC_WRITE,
      0,
      NULL,
      OPEN_EXISTING,
      /*FILE_ATTRIBUTE_NORMAL|*/FILE_FLAG_OVERLAPPED,
      NULL);
if (m_hCom == INVALID_HANDLE_VALUE) {
      ReportLastErr();
      return FALSE;
}

DCB LocalDCB;

LocalDCB.DCBlength = sizeof(LocalDCB);

if (!::GetCommState(m_hCom, &LocalDCB)) {
      ReportLastErr();
      ::CloseHandle(m_hCom);
      return FALSE;
}

LocalDCB.BaudRate = p->u.Coms.Baudrate;
LocalDCB.fBinary = TRUE;
LocalDCB.fParity = FALSE;
LocalDCB.fOutxCtsFlow = FALSE;
LocalDCB.fOutxDsrFlow = FALSE;
LocalDCB.fDtrControl = DTR_CONTROL_DISABLE;//DTR_CONTROL_HANDSHAKE;

LocalDCB.fRtsControl = RTS_CONTROL_DISABLE;//DTR_CONTROL_HANDSHAKE;

LocalDCB.fOutX = FALSE;
LocalDCB.fInX = FALSE;
LocalDCB.fNull = FALSE;
LocalDCB.fNull=FALSE;
LocalDCB.ByteSize = 8;
LocalDCB.Parity = NOPARITY;
LocalDCB.StopBits = ONESTOPBIT;
if (!::SetCommState(m_hCom, &LocalDCB)) {
      ReportLastErr();
      ::CloseHandle(m_hCom);
      return FALSE;
}

DWORD err;
if (!::ClearCommError(m_hCom, &err, NULL)) {
      ReportLastErr();
      return FALSE;
}

memset(&m_ComOverlap, 0, sizeof(OVERLAPPED));
m_ComOverlap.hEvent = ::CreateEvent(NULL, TRUE, FALSE, NULL);
m_Event = ::CreateEvent(NULL, TRUE, FALSE, NULL);

int byteUsedTime = 14400 / 115200 +1 + 1000;
COMMTIMEOUTS timeouts = {20 + byteUsedTime, byteUsedTime, 1000, byteUsedTime , 20};
SetCommTimeouts(m_hCom, &timeouts) ;
SetCommMask(m_hCom, EV_RXCHAR|EV_TXEMPTY );//设置事件驱动的类型

SetupComm(m_hCom, 10204, 5210);
PurgeComm(m_hCom, PURGE_RXCLEAR|PURGE_TXCLEAR|PURGE_RXABORT|PURGE_TXABORT);

InitializeCriticalSection(&m_Critical);

return TRUE;
}

BOOL CComS::Disconnect()
{
DWORD err;

if (!::ClearCommError(m_hCom, &err, NULL))
      ReportLastErr();
if (!::CloseHandle(m_hCom))
      ReportLastErr();
SetEvent(m_ComOverlap.hEvent);
Sleep(100);
if (!::CloseHandle(m_ComOverlap.hEvent))
      ReportLastErr();
if (!::CloseHandle(m_Event))
      ReportLastErr();
m_hCom = NULL;
return TRUE;
}

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eveson

富足长乐

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3楼 [报告]

发表于 2008-11-19 11:41 |只看该作者

没明白问题在哪里

实战分享：从技术角度谈机器学习入门| 【大话IT】RadonDB低门槛向MySQL集群下战书 | ChinaUnix打赏功能已上线！ | 新一代分布式关系型数据库RadonDB知多少？

Wind-Son

丰衣足食

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4楼 [报告]

发表于 2008-11-19 11:42 |只看该作者

代码2：

BOOL CComS::Send(LPBYTE pBuf, int len, DWORD MaxTime)
{
BOOL ret = FALSE;
OVERLAPPED overlap;

ASSERT(m_hCom != NULL);
ASSERT(len < 2000);

DWORD written = 0;

SetEvent(m_ComOverlap.hEvent);

memset(&overlap, 0, sizeof(OVERLAPPED));
overlap.hEvent = ::CreateEvent(NULL, TRUE, FALSE, NULL);

EnterCriticalSection(&m_Critical);

BYTE Buf[100] = "rbbttqqyybb";
//if (!::WriteFile(m_hCom, Buf, 10, &written, &overlap)) {

if (!::WriteFile(m_hCom, pBuf, len, &written, &overlap)) {
      if (::GetLastError() == ERROR_IO_PENDING) {
         if (::WaitForSingleObject(overlap.hEvent, MaxTime) == WAIT_OBJECT_0) {
            if (!GetOverlappedResult(m_hCom, &overlap, &written, FALSE))
                  ReportLastErr();
            ret = TRUE;
         }
      }
} else {
      ret = TRUE;
}

if (!::CloseHandle(overlap.hEvent))
      ReportLastErr();

LeaveCriticalSection(&m_Critical);

return ret;
}

DWORD CComS::Receive(LPBYTE pDestBuf, int length, DWORD MaxTime)
{
#define RX_BUF_LEN 10000
static BYTE buffer[RX_BUF_LEN];
static int curOut = -1, curLen = 0;
int tmp, len;

ASSERT(m_hCom != NULL);
ASSERT(length < 2000);

tmp = length;

if (curLen) {
      len = min(length, curLen);
      memcpy(pDestBuf, &buffer[curOut], len);
      length -= len;
      pDestBuf += len;
      curOut += len;
      curLen -= len;
      if (length == 0)
         return len;
}
ASSERT(curLen == 0);

EnterCriticalSection(&m_Critical);

DWORD dwEvtMask = 0;
OVERLAPPED os;
memset(&os, 0, sizeof(OVERLAPPED));
os.hEvent = m_Event;
ResetEvent(m_Event);
SetCommMask(m_hCom, EV_RXCHAR|EV_TXEMPTY);

COMSTAT ComStat;
DWORD dwLength, dwErrorFlags, dwBytesRead;
if (!WaitCommEvent(m_hCom, &dwEvtMask, &os)) {
      if (::WaitForSingleObject(m_ComOverlap.hEvent, 0) == WAIT_OBJECT_0) {
         ResetEvent(m_ComOverlap.hEvent);
         goto out;
      }
      if (GetLastError() != ERROR_IO_PENDING)
         goto out;
      if (::WaitForSingleObject(m_Event, 300) == WAIT_OBJECT_0) {
         if (!GetOverlappedResult(m_hCom, &os, &dwBytesRead, FALSE)) {
            ReportLastErr();
            goto out;
         }
         //break;

      }
      //dwEvtMask = 0;

}

if (dwEvtMask & EV_TXEMPTY) {
      //PurgeComm(m_hCom, PURGE_TXCLEAR|PURGE_TXABORT);

      goto out;
}

if (!(dwEvtMask & EV_RXCHAR))
      goto out;

ClearCommError(m_hCom, &dwErrorFlags, &ComStat) ;
dwLength = ComStat.cbInQue;
if (dwLength > 0) {
      ResetEvent(os.hEvent);
      ASSERT(dwLength <= RX_BUF_LEN);
      if (!ReadFile(m_hCom, buffer, dwLength,
         &dwBytesRead, &os)) {
         ReportLastErr();
      }
      //GetOverlappedResult(m_hCom, &os, &dwBytesRead, TRUE);

      len = min((int)dwBytesRead, length);
      memcpy(pDestBuf, buffer, len);
      curLen = dwBytesRead - len;
      curOut = len;
      length -= len;
}

out:
LeaveCriticalSection(&m_Critical);
return tmp - length;
}