C / C++ / MFC

<br />
bool ReadPort()<br />
{<br />
     long int dwSize = 0;<br />
     bool hResult = false;<br />
     std::string sb = "";<br />
     DWORD dwEventMask;<br />
<br />
     if(!SetCommMask(hComm, EV_RXCHAR)) /* Setting Event Type */<br />
	 {	<br />
        return hResult;<br />
     }<br />
<br />
	if(WaitCommEvent(hComm, &dwEventMask, NULL)) /* Waiting For Event to Occur */<br />
	{<br />
		char szBuf[1024];<br />
		DWORD dwIncommingReadSize;<br />
<br />
		do<br />
		{<br />
			if(ReadFile(hComm, &szBuf, 1024, &dwIncommingReadSize, NULL) != 0)<br />
			{<br />
				if(dwIncommingReadSize > 0)<br />
				{<br />
					dwSize += dwIncommingReadSize;<br />
				    sb.append(szBuf);<br />
				}<br />
				hResult = true;<br />
			}<br />
<br />
			else<br />
			{<br />
				unsigned long error = ::GetLastError();<br />
				hResult = false;<br />
				printf("the error while reading error is %dl\n", error);<br />
				break;<br />
			}<br />
		} while(dwIncommingReadSize > 0);<br />
<br />
		*readData = new char[dwSize];<br />
		strcpy(*readData, sb.c_str());<br />
		return hResult;<br />
	}<br />
    else<br />
    {<br />
		return hResult;<br />
    }<br />
<br />
}<br />

void TestDlg::CloseRecord()
{
	m_staGradient12.SetWindowTextA("Status:Stopped");
	if(hRecording)
	{
			SuspendThread(hRecording);
			DWORD lpExitCode;
			GetExitCodeThread(hRecording,&lpExitCode);
			TerminateThread(hRecording,lpExitCode);
			CloseHandle(hRecording);//Thread handle
			CloseHandle(file_rec);//Event handle
			hRecording = NULL;
			file_rec = NULL;
			OnCancel();//Here only I got error sometime
	}
}

DWORD WINAPI Recording(LPVOID pParam)//Thread
{	
	TestDlg* pTSRecording = (TestDlg*)pParam;
	fptr1 = fopen(def_filename,"w");
	while(::WaitForSingleObject(pTSRecording->file_rec,0)==WAIT_TIMEOUT)
	{
 	pTSRecording->ReceiveData(pbuff);//Recieving data from the device
	fwrite(pbuff,1,sizeof(pbuff),fptr1);
	CFile file(def_filename,CFile::shareDenyNone|CFile::modeRead);
	int x = file.GetLength();//for getting the length of the file after every succesive write
	file.Close();
	if(x>=a)//enters when file is reached 100 MB x is current length a is 100 MB defined
	{
		fclose(fptr1);
		a=0;
		pTSRecording->CloseDevice();
		break;
	}	
		
	}
	pTSRecording->CloseRecord();
	return 0;
}