FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
		NULL,
		GetLastError(),
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
		(LPTSTR) &lpMsgBuf,
		0,
		NULL 
	);

	sprintf(Temp, "WARNING:  %s Failed with the following error: \n%s\nPort: %d\n", (char*)ErrorText, lpMsgBuf, m_nPortNr); 
	MessageBox(NULL, Temp, "Application Error", MB_ICONSTOP);

	LocalFree(lpMsgBuf);
	delete[] Temp;
}

//
// Write a character.
//
void CSerialPortEx::WriteChar(CSerialPortEx* port)
{
	BOOL bWrite = TRUE;
	BOOL bResult = TRUE;

	DWORD BytesSent = 0;

	ResetEvent(port->m_hWriteEvent);

	// Gain ownership of the critical section
	EnterCriticalSection(&port->m_csCommunicationSync);

	if (bWrite)
	{
		// Initailize variables
		port->m_ov.Offset = 0;
		port->m_ov.OffsetHigh = 0;

		// Clear buffer
		PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

		bResult = WriteFile(port->m_hComm,							// Handle to COMM Port
							port->m_szWriteBuffer,					// Pointer to message buffer in calling finction
							port->m_nToSend,								// Length of message to send
							&BytesSent,								// Where to store the number of bytes sent
							&port->m_ov);							// Overlapped structure

		// deal with any error codes
		if (!bResult)  
		{
			DWORD dwError = GetLastError();
			switch (dwError)
			{
				case ERROR_IO_PENDING:
					{
						// continue to GetOverlappedResults()
						BytesSent = 0;
						bWrite = FALSE;
						break;
					}
				default:
					{
						// all other error codes
						port->ProcessErrorMessage("WriteFile()");
					}
			}
		} 
		else
		{
			LeaveCriticalSection(&port->m_csCommunicationSync);
		}
	} // end if(bWrite)

	if (!bWrite)
	{
		bWrite = TRUE;
	
		bResult = GetOverlappedResult(port->m_hComm,	// Handle to COMM port 
									  &port->m_ov,		// Overlapped structure
									  &BytesSent,		// Stores number of bytes sent
									  TRUE); 			// Wait flag

		LeaveCriticalSection(&port->m_csCommunicationSync);

		// deal with the error code 
		if (!bResult)  
		{
			port->ProcessErrorMessage("GetOverlappedResults() in WriteFile()");
		}	
	} // end if (!bWrite)

	// Verify that the data size send equals what we tried to send
	if (BytesSent != port->m_nToSend)
	{
		TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d\n", BytesSent, strlen((char*)port->m_szWriteBuffer));
	}
}

//
// Character received. Inform the owner
//
void CSerialPortEx::ReceiveChar(CSerialPortEx* port, COMSTAT comstat)
{
	BOOL  bRead = TRUE; 
	BOOL  bResult = TRUE;
	DWORD dwError = 0;
	DWORD BytesRead = 0;
	unsigned char RXBuff=0;

	for (;;) 
	{ 
		// Gain ownership of the comm port critical section.
		// This process guarantees no other part of this program 
		// is using the port object. 
		
		EnterCriticalSection(&port->m_csCommunicationSync);

		// ClearCommError() will update the COMSTAT structure and
		// clear any other errors.
		
		bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

		LeaveCriticalSection(&port->m_csCommunicationSync);

		// start forever loop.  I use this type of loop because I
		// do not know at runtime how many loops this will have to
		// run. My solution is to start a forever loop and to
		// break out of it when I have processed all of the
		// data available.  Be careful with this approach and
		// be sure your loop will exit.
		// My reasons for this are not as clear in this sample 
		// as it is in my production code, but I have found this 
		// solutiion to be the most efficient way to do this.
		
		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,					// 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("ReadFile()");
							break;
						} 
				}
			}
			else
			{
				// ReadFile() returned complete. It is not necessary to call GetOverlappedResults()
				bRead = TRUE;
			}
		}  // close if (bRead)

		if (!bRead)
		{
			bRead = TRUE;
			bResult = GetOverlappedResult(port->m_hComm,	// Handle to COMM port 
										  &port->m_ov,		// Overlapped structure
										  &BytesRead,		// Stores number of bytes read
										  TRUE); 			// Wait flag

			// deal with the error code 
			if (!bResult)  
			{
				port->ProcessErrorMessage("GetOverlappedResults() in ReadFile()");
			}	
		}  // close if (!bRead)
				
		LeaveCriticalSection(&port->m_csCommunicationSync);

		// notify parent that a byte was received
		::SendMessage((port->m_pOwner)->m_hWnd, WM_COMM_RXCHAR, (WPARAM) RXBuff, (LPARAM) port->m_nPortNr);
	} // end forever loop		

}

//
// Write a string to the port
//
void CSerialPortEx::WriteToPort(BYTE* string,int nLength)
{		
//	assert(m_hComm != 0);
	if(m_hComm==0) 
	{
		::AfxMessageBox("error strange");
		return;
	}
	
	memset(m_szWriteBuffer, 0, m_nWriteBufferSize);
	memcpy(m_szWriteBuffer, string,nLength);
	m_nToSend=nLength;

	// set event for write
	SetEvent(m_hWriteEvent);
}

//
// Return the device control block
//
DCB CSerialPortEx::GetDCB()
{
	return m_dcb;
}

//
// Return the communication event masks
//
DWORD CSerialPortEx::GetCommEvents()
{
	return m_dwCommEvents;
}

//
// Return the output buffer size
//
DWORD CSerialPortEx::GetWriteBufferSize()
{
	return m_nWriteBufferSize;
}

//Extension: not tested
void CSerialPortEx::WriteToPort(CString str)
{
	
	char *buffer=new char[m_nWriteBufferSize];
	memset(buffer,0,m_nWriteBufferSize);
	int nMaxLength=(str.GetLength()+1 > m_nWriteBufferSize) ? str.GetLength()+1 : m_nWriteBufferSize;
	char *temp=str.GetBuffer(nMaxLength);
	memcpy(buffer,temp,str.GetLength());
	str.ReleaseBuffer();
	WriteToPort((BYTE*)buffer,str.GetLength());
}

//Extension: not tested
//DEL int CSerialPortEx::ReadCommBlock(LPSTR lpszBlock, int nMaxLength)
//DEL {
//DEL    BOOL       fReadStat ;
//DEL    COMSTAT    ComStat ;
//DEL    DWORD      dwErrorFlags;
//DEL    DWORD      dwLength;
//DEL    DWORD      dwError;
//DEL 
//DEL    // only try to read number of bytes in queue
//DEL    BOOL ok=ClearCommError( m_hComm, &dwErrorFlags, &ComStat ) ;
//DEL    dwLength = min( (DWORD) nMaxLength, ComStat.cbInQue ) ;
//DEL 
//DEL    if (dwLength > 0)
//DEL    {
//DEL 	  fReadStat = ::ReadFile(m_hComm,lpszBlock,dwLength,&dwLength,&m_ov) ;
//DEL       if (!fReadStat)
//DEL       {
//DEL          if ((dwError=GetLastError()) == ERROR_IO_PENDING)
//DEL          {
//DEL 
//DEL             while(!GetOverlappedResult( m_hComm,
//DEL                &m_ov, &dwLength, TRUE ))
//DEL             {
//DEL                dwError = GetLastError();
//DEL                if(dwError == ERROR_IO_INCOMPLETE)
//DEL                   // normal result if not finished
//DEL                   continue;
//DEL                else
//DEL                {
//DEL                   // an error occurred, try to recover
//DEL                  ClearCommError( m_hComm, &dwErrorFlags, &ComStat ) ;
//DEL                   break;
//DEL                }
//DEL             }
//DEL 	      }
//DEL          else
//DEL          {
//DEL             // some other error occurred
//DEL             dwLength = 0 ;
//DEL             ClearCommError( m_hComm, &dwErrorFlags, &ComStat ) ;
//DEL           }
//DEL       }
//DEL    }
//DEL    return dwLength ;
//DEL }

//Extension: not tested

BYTE* CSerialPortEx::ReadBlock(CSerialPortEx *port, int& readLen)
{
	COMSTAT comstat;
	BOOL  bRead = TRUE; 
	BOOL  bResult = TRUE;
	DWORD dwError = 0;
	DWORD BytesRead = 0;
	DWORD BytesToRead=readLen;
	BYTE* pRec;


		// Gain ownership of the comm port critical section.
		// This process guarantees no other part of this program 
		// is using the port object. 
		
		EnterCriticalSection(&port->m_csCommunicationSync);

		// ClearCommError() will update the COMSTAT structure and
		// clear any other errors.
		
		bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

		LeaveCriticalSection(&port->m_csCommunicationSync);

		// start forever loop.  I use this type of loop because I
		// do not know at runtime how many loops this will have to
		// run. My solution is to start a forever loop and to
		// break out of it when I have processed all of the
		// data available.  Be careful with this approach and
		// be sure your loop will exit.
		// My reasons for this are not as clear in this sample 
		// as it is in my production code, but I have found this 
		// solutiion to be the most efficient way to do this.
		
		if (comstat.cbInQue == 0)
		{
			// break out when all bytes have been read
			readLen=0;
			return NULL;
		}
		else
		{
			BytesToRead= BytesToRead+2 > comstat.cbInQue ? comstat.cbInQue : BytesToRead+2;
			pRec=new BYTE[BytesToRead];
		}

		EnterCriticalSection(&port->m_csCommunicationSync);

		if (bRead)
		{
			bResult = ReadFile(port->m_hComm,		// Handle to COMM port 
							   pRec,				// Reader Buffer Pointer
							   BytesToRead,			// to read bytes
							   &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("ReadFile()");
							break;
						} 
				}
			}
			else
			{
				// ReadFile() returned complete. It is not necessary to call GetOverlappedResults()
				bRead = TRUE;
			}
		}  // close if (bRead)

		if (!bRead)
		{
			bRead = TRUE;
			bResult = GetOverlappedResult(port->m_hComm,	// Handle to COMM port 
										  &port->m_ov,		// Overlapped structure
										  &BytesRead,		// Stores number of bytes read
										  TRUE); 			// Wait flag

			// deal with the error code 
			if (!bResult)  
			{
				port->ProcessErrorMessage("GetOverlappedResults() in ReadFile()");
			}	
		}  // close if (!bRead)
				
		LeaveCriticalSection(&port->m_csCommunicationSync);
		
		readLen=BytesRead;
		return pRec;

		// notify parent that a byte was received
//		::SendMessage((port->m_pOwner)->m_hWnd, WM_COMM_RXCHAR, (WPARAM)pRec, (LPARAM) BytesRead);

}