d064.bmp.txt

Visual C++通信编程实例

// Gain ownership of the comm port critical section.
//This process guarantees no other part of this program is using the port object.
EnterCnticaISection(&port->m_csCommunicationSync);
bResult = ClearCommError(port->m_hComm, &dwError, &comstat);
LeaveCnticalSection(&port->m_csCommunicationSync) ;
if (comstat.cbInQue - 0)
{
             //break out when all bytes have been read
 break;
}
EnterCriticalSection(&port->m_csCommunicationSync);
if (bRead)
{
             bResult = ReadFile(port->m_hComm,                             // Handle to COMM port
                                                                                    &RXBuff,                                 // RX Buffer Pointer
                                                                                     1,                                                    11 Read one byte
                                                                        &BytesRead,                        // Stores number of bytes read
                                                                        &port->m_ov);                    // pointer to the m_ov structure
                                                                                                                //deal with the error code
        if (!bResult)
          {
                 switch (dwError = GetLastError(》
        .     {
                        case ERROR_IO_PENDING:
                                        {
                                                                          // asynchronous i/o is still in progress
                                            //Proceed on to GetOverlappedResults();
                                        bRead = FALSE;   '
     break;
                                        }
  default:
                                        {
                                                 //Another error has occured.    Process this error.
                                                                                                               port->ProcessErrorMessage( " ReadFile0 ");
    break;
                                        }
                       }
 else
          {
             // ReadFile() retumed complete. It is not necessary to call GetOverlappedResults()
                bRead = TRUE;
          }
}    //close if (bRead)
if (!bRead)