typedef struct tagSerialPort
{
　BYTE RxBuf[SPRX_BUFLEN];//接收Buffer
　WORD wRxPos; //當(dāng)前接收字節(jié)位置
　WORD wRxLen; //要接收的字節(jié)數(shù)
　BYTE TxBuf[SPTX_BUFLEN];//發(fā)送Buffer
　WORD wTxPos; //當(dāng)前發(fā)送字節(jié)位置
　WORD wTxLen; //要發(fā)送的字節(jié)數(shù)
}SerialPort, * LPSerialPort;

BOOL CSerialPort::InitPort(CWnd *pPortOwner,
// the owner (CWnd) of the port (receives message)
UINT portnr, // portnumber (1..4)
UINT baud, // baudrate
char parity, // parity
UINT databits, // databits
UINT stopbits, // stopbits
DWORD dwCommEvents, // EV_RXCHAR, EV_CTS etc
UINT writebuffersize) // size to the writebuffer
{
　assert(portnr > 0 && portnr < 5);
　assert(pPortOwner != NULL);

　// if the thread is alive: Kill
　if (m_bThreadAlive)
　{
　　do
　　{
　　　SetEvent(m_hShutdownEvent);
　　}
　　while (m_bThreadAlive);
　　TRACE("Thread ended\n");
　}

　// create events
　if (m_ov.hEvent != NULL)
　　ResetEvent(m_ov.hEvent);
　　m_ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

　if (m_hWriteEvent != NULL)
　　ResetEvent(m_hWriteEvent);
　　m_hWriteEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

　if (m_hShutdownEvent != NULL)
　　ResetEvent(m_hShutdownEvent);
　　m_hShutdownEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

　// initialize the event objects
　m_hEventArray[0] = m_hShutdownEvent; // highest priority
　m_hEventArray[1] = m_ov.hEvent;
　m_hEventArray[2] = m_hWriteEvent;

　// initialize critical section
　InitializeCriticalSection(&m_csCommunicationSync);

　// set buffersize for writing and save the owner
　m_pOwner = pPortOwner;

　if (m_szWriteBuffer != NULL)
　　delete []m_szWriteBuffer;
　　m_szWriteBuffer = new char[writebuffersize];

　　m_nPortNr = portnr;

　　m_nWriteBufferSize = writebuffersize;
　　m_dwCommEvents = dwCommEvents;

　　BOOL bResult = FALSE;
　　char *szPort = new char[50];
　　char *szBaud = new char[50];

　　// now it critical!
　　EnterCriticalSection(&m_csCommunicationSync);

　　// if the port is already opened: close it
　if (m_hComm != NULL)
　{
　　CloseHandle(m_hComm);
　　m_hComm = NULL;
　}

　// prepare port strings
　sprintf(szPort, "COM%d", portnr);
　sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits,stopbits);

　// get a handle to the port
　m_hComm = CreateFile(szPort, // communication port string (COMX)
　　GENERIC_READ | GENERIC_WRITE, // read/write types
　　0, // comm devices must be opened with exclusive access
　　NULL, // no security attributes
　　OPEN_EXISTING, // comm devices must use OPEN_EXISTING
　　FILE_FLAG_OVERLAPPED, // Async I/O
　　0); // template must be 0 for comm devices

　if (m_hComm == INVALID_HANDLE_VALUE)
　{
　　// port not found
　　delete []szPort;
　　delete []szBaud;
　　return FALSE;
　}

　// set the timeout values
　m_CommTimeouts.ReadIntervalTimeout = 1000;
　m_CommTimeouts.ReadTotalTimeoutMultiplier = 1000;
　m_CommTimeouts.ReadTotalTimeoutConstant = 1000;
　m_CommTimeouts.WriteTotalTimeoutMultiplier = 1000;
　m_CommTimeouts.WriteTotalTimeoutConstant = 1000;

　// configure
　if (SetCommTimeouts(m_hComm, &m_CommTimeouts))
　{
　　if (SetCommMask(m_hComm, dwCommEvents))
　　{
　　　if (GetCommState(m_hComm, &m_dcb))
　　　{
　　　　m_dcb.fRtsControl = RTS_CONTROL_ENABLE; // set RTS bit high!
　　　　if (BuildCommDCB(szBaud, &m_dcb))
　　　　{
　　　　　if (SetCommState(m_hComm, &m_dcb))
　　　　　　;
　　　　　　// normal operation... continue
　　　　　else
　　　　　　ProcessErrorMessage("SetCommState()");
　　　　}
　　　　else
　　　　　ProcessErrorMessage("BuildCommDCB()");
　　　　}
　　　else
　　　　ProcessErrorMessage("GetCommState()");
　　}
　　else
　　　ProcessErrorMessage("SetCommMask()");
　}
　else
　　ProcessErrorMessage("SetCommTimeouts()");

　delete []szPort;
　delete []szBaud;

　// flush the port
　PurgeComm(m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

　// release critical section
　LeaveCriticalSection(&m_csCommunicationSync);

　TRACE("Initialisation for communicationport %d completed.\nUse Startmonitor to communicate.\n", portnr);

　return TRUE;
}