CWinThread::Run crash with no meaningful stack

Hi,

When my Com Port is opened the following is used to open it
<pre>
// If COM is open, close it
if( IsOpen() )
{
CloseCOM();
}

// Convert com port index to string
//_stprintf(buf,ComNames[m_PortNumber]); // build COM port name

// Convert com port index to string
m_hComm = CreateFile(m_PortName, GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0 );

// if open ok,
if( m_hComm!=INVALID_HANDLE_VALUE )
{
DCB dcb;

memset( &dcb, 0, sizeof(dcb) );
dcb.DCBlength = sizeof(DCB);

// Get the current state & modify to suit
if( GetCommState( m_hComm, &dcb ) != 0 )
{
dcb.BaudRate = m_dwBaudRate;
dcb.fBinary = TRUE;
dcb.fParity = TRUE;
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fDsrSensitivity = FALSE;
dcb.fOutX = FALSE;
dcb.fNull = FALSE;
dcb.fRtsControl = m_nRtsControl;
dcb.fAbortOnError = FALSE;
dcb.ByteSize = m_bByteSize;
dcb.Parity = m_bParity;
dcb.StopBits = m_bStopBits;
dcb.fBinary = TRUE;
dcb.fNull = FALSE;
dcb.StopBits = m_bStopBits;
dcb.EvtChar = 72;

if( SetCommState( m_hComm, &dcb ) != 0 ) // if OK
{
if( SetCommTimeouts(m_hComm, &m_CommTimeOuts) != 0 )
{
m_fError = FALSE;
}
}

if( (m_fError == FALSE) && (m_fSIRRequired == TRUE) )
{
if( EscapeCommFunction( m_hComm, SETIR ) == 0 )
{
m_fError = TRUE;
}
}
GetCommState( m_hComm, &dcb2 );
}

SwitchDTROff();
SwitchRTSOn();
}
</pre>

In my document I am running a timer that will poll the port every second and queries the device to see if it is still connected
<pre>
void _stdcall PollController(HWND Hwnd,unsigned int a, unsigned int b, DWORD c)
{
static int count = 0xFFFFFFFF;
WORD ec = 0;
CString strTemp;
int ReturnCount;
try
{
//There must be a nicer way of doing this.
CFrameWnd *pMainWnd = (CFrameWnd*)(AfxGetApp()->m_pMainWnd);
if( !pMainWnd ) // if main window not constructed yet, leave.
{ // Required for Win98 which seems to construct/create 1n
// different order from NT & W2K.
return;
}

CCriticalSection c_s;

// Create object for Single Lock
CSingleLock lock(&c_s);

// Lock
lock.Lock();

CView *pView = (CView *)pMainWnd->GetActiveView();

//validate the ProgView ptr
if(NULL != pView)
{
CDocument *pDoc = pView->GetDocument();

//validate the document ptr
if(NULL != pDoc)
{
if( pDoc->IsCommunicating() )
{
ReturnCount = 3;
}
else
{
ReturnCount = 6;
}

// Update the display only every 3 * interval
// But allow 1st update immediately
if( count == 0xFFFFFFFF ) // if first time through
{
count = 0;
}
else
{
count++;
if( count < ReturnCount ) // if not time yet
{
return; // don't do it
}
count = 0; // do it, resetting count
}

g_ComPort.PurgeRX();
g_ComPort.PurgeTX();
pDoc->RefreshDeviceType();

}
}

// Unlock
lock.Unlock();
}
catch(...)
{
TRACE("\nPollController crashed");
}
}
</pre>

This code, just free running, with the device regularly power cycled, will crash as described in the original post, but at differing regularities.

Thanks

Tony