Re: interthread communication
I`m writing a small demo example which simulates the hole stuff. At
the moment it seems to work but maybe there are several big or small
errors inside the code. By the way according to the protocok the
maximal amount of time where to data will be txd by the serial port
could be 1s - but should be round about 100ms.
I installed one buffer in my sdi application - pressing this button
simulate new incoming ethernet frame packets.
void TestDlg::OnBnClickedButton1()
{
//creating some data
CByteArray *pData = new CByteArray;
const BYTE cbyte[] = "byte";
for(int i=0;i<sizeof(cbyte);i++)
pData->Add(cbyte[i]);
//tx these data to the serial-collect thread
m_collectThread->PostThreadMessage(UWM_GET_NEW_DATA, (WPARAM)pData,
0);
}
void CSerialCollectData::OnGetNewData(WPARAM wParam, LPARAM lParam)
{
CByteArray *pData = (CByteArray *)wParam;
// Queue q -> from your example "queuetest"
if(!q.AddTail(pData))
{ /* failed */
TRACE(_T("queue is full\n"));
return;
} /* failed */
else
long n = InterlockedIncrement(&count);
if(FIRST_DATA)
{
FIRST_DATA = FALSE;
//tell writerthread that first data arrived
::PostThreadMessage(WriterTheadID, UWM_START_WRITER,
(WPARAM)&q, (LPARAM)&count);
}
}
void CSerialWriterThread::OnStartWriter(WPARAM wParam, LPARAM lParam)
{
Queue *q = (Queue *)wParam;
pcnt = (long *)lParam;
WriteData(q);
}
void CSerialWriterThread::WriteData(Queue *q)
{
CByteArray *pData;
BOOL running = TRUE;
DWORD EventMask;
HANDLE objects[2];
objects[0] = ShutdownEvent;
hEvent = CreateEvent(NULL,false, false, _T(""));
EventMask = FT_EVENT_MODEM_STATUS;
while(running)
{
//simulate write (CByteArray *pData) to serial port (with
this small sleep delay)
::Sleep(200 + rand() % 500);
//waiting for the CTS_HIGH event, which should occur after
round about 25ms -> we wait 50ms
DWORD result = WaitForSingleObject(hEvent, 50);
switch(result)
{
case WAIT_TIMEOUT:
//send a PostThreadMessage to main-thread telling there
must be something wrong and continue
break;
case WAIT_OBJECT_0:
//shutdown event
return; //or running = FALSE
case WAIT_OBJECT_0 + 1:
//everthing is ok
break;
default:
ASSERT(FALSE); // unknown error
return;
}
if(q->GetSize() > 1)
{ //more than one packet -> transmit new packet
LPVOID p = q->RemoveHead();
long n = InterlockedDecrement(pcnt);
pData = (CByteArray *) p;
}
}
}
Where do I have to delete the CByteArray *pData = new CByteArray; in
the OnClickButton routine?
CSerialWriterThread::CSerialWriterThread(void)
{
ShutdownEvent = ::CreateEvent(NULL, // security
TRUE, // manual-reset
FALSE, // not signaled
NULL); // anonymous
}
According to one of your hints, I tried to install a shutdown event;
but how can I shutdown this thread, if e.g. the timeout error occured
several times? Writing a PostThreadMessage from the main-thread to
this thread and calling the function CSerialWriterThread::Shutdown( )?
void CSerialWriterThread::Shutdown( )
{
SetEvent(ShutdownEvent);
::WaitForSingleObject(m_hThread, INFINITE);
}
best regards
Hans