좀 더 솔직해 지자..

DWORD BaudRate;
    switch (baud) {
         case 110  : BaudRate = CBR_110; break;
         case 300  : BaudRate = CBR_300 ; break;
         case 600  : BaudRate = CBR_600 ; break;
         case 1200  : BaudRate = CBR_1200; break;
         case 2400  : BaudRate = CBR_2400; break;
         case 4800  : BaudRate = CBR_4800; break;
         case 9600  : BaudRate = CBR_9600; break;
         case 14400  : BaudRate = CBR_14400; break;
         case 19200  : BaudRate = CBR_19200; break;
         case 38400  : BaudRate = CBR_38400; break;
         case 56000  : BaudRate = CBR_56000; break;
         case 57600  : BaudRate = CBR_57600; break;
         case 115200  : BaudRate = CBR_115200; break;
         case 128000  : BaudRate = CBR_128000; break;
         case 256000  : BaudRate = CBR_256000; break;
    }

    CString strPort;

    strPort.Format("COM%d", nPort);

    m_hComm = CreateFile(strPort, GENERIC_READ|GENERIC_WRITE, 0, NULL,

                                       OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);

    if (m_hComm == INVALID_HANDLE_VALUE)  // if(m_hComm == (HANDLE) - 1)
         return FALSE;

...이런 식으로 사용하란다!

예제)

SetInit(char PortName[], DWORD xBaud, int StopBit , int ByteSize)

{

       m_osRead.offset = 0;         //OVERLAPPED m_osRead,m_osWrite;

       m_osRead.offsetHigh = 0;   

       if(!(m_osRead.hEvent = CreateEvent(NULL,TRUE,FALSE,NULL)))

                  return  FALSE;

       DWORD dwBaud = 0;

       switch(xBaud)

       {

               case 1:     dwBaud   =  CBR_1200;    break;

                                ........(생략)

       }

       //Com port open

       m_hCom = CreateFile(PortName,   GENERIC_READ | GENERIC_WRITE, 0

                                       ,NULL ,OPEN_EXISTING

                                       ,FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED

                                       ,NULL);

       if(m_hCom == (HANDLE) - 1)  return FALSE; 

        //Com port EVENT Setting 

        SetCommMask(m_hCom, EV_RXCHAR);

        //통신 버퍼 초기화

        SetupComm(m_hCom,4096, 4096);

        //Timeout  설정

        COMMTIMEOUTS CommTimeOuts  commtimeouts;
        CommTimeOuts.ReadIntervalTimeout         = 0xFFFFFFFF;    //문자읽기 사이의 최대 시간
        CommTimeOuts.ReadTotalTimeoutMultiplier  = 0;                 //문자의 증가자
        CommTimeOuts.ReadTotalTimeoutConstant    = 0;               //밀리초 단위의 상수
        CommTimeOuts.WriteTotalTimeoutMultiplier = 100;               //문자의 증가자
        CommTimeOuts.WriteTotalTimeoutConstant     = 0 ;             //밀리초 단위의 상수
        SetCommTimeouts (hComm, &CommTimeOuts);

}