Regarding System Error Code 995 in Serial Communication

[pra84veen]

Iam calling this function for capturing data. The ReadFile() returns 0 value and GetLastError() gives error 995 bool CSerialPort::bReceiveBytes( unsigned char* x_pcBuffer, unsigned short x_usLengthExpected, unsigned short *x_pusLengthReceived ) { bool bResult = FALSE; unsigned long ulLengthReceived=0; int iResult; iResult = ReadFile( m_comPortHandle, x_pcBuffer[0], x_usLengthExpected, &ulLengthReceived, NULL ); DWORD err1 = GetLastError(); *x_pusLengthReceived = (unsigned short)ulLengthReceived; return( bResult ); }

[CPallini]

pra84veen wrote:

x_pcBuffer[0]

The above is wrong: you should use x_pcBuffer instead. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke

[pra84veen]

hello, thanks for your reply... even though if i replace x_pcBuffer instead of x_pcBuffer[0], i dint get any data into the buffer. but here the return values for ReadFile is 1 but iam unable to capture the data.. Thanks & Regards, praveen

[CPallini]

When return value is 1, ReadFile succeeded. What is the value of ulLengthReceived? :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke

[pra84veen]

the value received by the ulLengthReceived is 0.

void CER2TSerialDlg::OnStartThread()
{
CWinThread *pThread = NULL;
m_SerialCommn->bOpen()
pThread = AfxBeginThread((AFX_THREADPROC)ReadFromModuleThread,NULL);
}

UINT CER2TSerialDlg::ReadFromModuleThread(LPVOID pPARAM)
{
unsigned char ucLengthExpected=10;
char chBuffer[FIFO_SIZE]={0};
unsigned short usReceived=0;

while(TRUE)
{
m_SerialCommn->bReceiveBytes(chBuffer,ucLengthExpected,&usReceived);
}
return 0;
}

bool CSerialPort::bReceiveBytes(char* x_pcBuffer,
unsigned short x_usLengthExpected,
unsigned short *x_pusLengthReceived )
{

unsigned long ulLengthReceived=0;
int iResult;
iResult = ReadFile(m_comPortHandle,
x_pcBuffer[0],
x_usLengthExpected,
ulLengthReceived,
NULL );
DWORD err1 = GetLastError();
*x_pusLengthReceived = (unsigned short)ulLengthReceived;
return( iResult );

}/

Regards praveen

modified on Wednesday, June 11, 2008 1:48 AM

[CPallini]

pra84veen wrote:

iResult = ReadFile(m_comPortHandle, x_pcBuffer[0], x_usLengthExpected, ulLengthReceived, NULL );

That's completely wrong (compiler doesn't complain, does it?). Should be:

ReadFile(m_comPortHandle,
x_pcBuffer,
x_usLengthExpected,
&ulLengthReceived,
NULL );

Please note the ampersand in front of ulLengthReceived. BTW: How did you set serial port timeouts? :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke

[pra84veen]

Even after modification also, iam not able to collect the data The serial port timeouts are

GetCommTimeouts(m_comPortHandle, &sCommTimeOuts);
sCommTimeOuts.ReadIntervalTimeout = 5;//100; //[ms]
sCommTimeOuts.ReadTotalTimeoutMultiplier = 1;//10; //[ms]
sCommTimeOuts.ReadTotalTimeoutConstant = 1;//500; //[ms]
sCommTimeOuts.WriteTotalTimeoutMultiplier = 1;//10; //[ms]
sCommTimeOuts.WriteTotalTimeoutConstant = 1;//100; //[ms]
SetCommTimeouts(m_comPortHandle, &sCommTimeOuts);

Thanks & Regards, Praveen

[CPallini]

Why don't you widen them (you can also set them for a blocking call, just to make a test)? :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke

[pra84veen]

sorry, i dint get you

[pra84veen]

even if i change the values of commtimeouts to

GetCommTimeouts(m_comPortHandle, &sCommTimeOuts);
sCommTimeOuts.ReadIntervalTimeout = 100; //[ms]
sCommTimeOuts.ReadTotalTimeoutMultiplier = 10; //[ms]
sCommTimeOuts.ReadTotalTimeoutConstant = 500; //[ms]
sCommTimeOuts.WriteTotalTimeoutMultiplier = 10; //[ms]
sCommTimeOuts.WriteTotalTimeoutConstant = 100; //[ms]
SetCommTimeouts(m_comPortHandle, &sCommTimeOuts);

i dint observe any change.