ERROR_OPERATION_ABORTED with serial comms

[jimjim733]

Hi there, I have created a thread that just monitors the serial port, but as soon as the com port receives any data, the GetOverlappedResult issues an ERROR_OPERATION_ABORTED error. Please can you take a look at my code, I cannot see what is going on. Thanks Jim :confused:

#define READ_TIMEOUT 500 // Milliseconds

UINT CPageOneDialog::monitorPTZThread(LPVOID pParam)
{
DWORD dwRead, dwRes;
BOOL fWaitingOnRead = FALSE;
OVERLAPPED osReader = {0};
char ptzControlCommPort[14];
struct PTZCommStruct *pPTZStruct = (struct PTZCommStruct *)pParam;

// Open the comm port.
sprintf(ptzControlCommPort,"\\\\\\\\.\\\\COM%d",PTZCTRLPORT+1);
pPTZStruct->hPTZSerial = CreateFile( ptzControlCommPort,
			  GENERIC\_READ | GENERIC\_WRITE,
			  0,    // must be opened with exclusive-access
			  NULL, // no security attributes
			  OPEN\_EXISTING, // must use OPEN\_EXISTING
			  FILE\_FLAG\_OVERLAPPED,    // overlapped I/O
			  NULL  // hTemplate must be NULL for comm devices
			  );


// Create the overlapped event.
osReader.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

if(osReader.hEvent == NULL)
{
	// Error creatiing overlapped event, abort.
	pPTZStruct->pWnd->PostMessage(UWM\_READER\_SHUTTING\_DOWN);
	return 0;
} 

while(pPTZStruct->nPTZCommTerminate == 0)
{
	if(!fWaitingOnRead)
	{
		// Issue read Operation.
		if(!ReadFile(pPTZStruct->hPTZSerial,PTZbuffer, MAX\_BUFFER\_SIZE, &dwRead, &osReader))
		{
			if(GetLastError() != ERROR\_IO\_PENDING) // read not delayed
			{
				// Error in comms - report!!!
				return 0;
			}
			else
			{
				fWaitingOnRead = TRUE;
			}
		}
		else
		{
			// \*\*\*Read the data
		}
	}
	else
	{
		dwRes = WaitForSingleObject(osReader.hEvent, READ\_TIMEOUT);
		switch(dwRes)
		{
			// Read Completed
		case WAIT\_OBJECT\_0:
			if(!GetOverlappedResult(pPTZStruct->hPTZSerial, &osReader, &dwRead, FALSE))
			{
				DWORD dwError = GetLastError();
				switch(dwError)
				{
					case ERROR\_HANDLE\_EOF:
						return 0;
						break;
					case ERROR\_IO\_PENDING:
						return 0;
						break;
					case ERROR\_IO\_INCOMPLETE:
						return 0;
						break;
					case ERROR\_OPERATION\_ABORTED:
						return 0;
						break;
					default:
						// error in comms - report
						Dump1("Serial Read Error %d\\r\\n", ::GetLastError());
						return 0;
						break;
				}
			}
			else
			{
				// \*\*\*Read the Data 
			}
			fWaitingOnRead = FALSE;