Re: PPC 2003 Thread
- From: Channa <Channa@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Wed, 13 Apr 2005 15:11:03 -0700
Hi Tobey,
Thanks for your insight. I tested the thread as you'd mentioned. I
could see that the ExitThread(0) get executed. But, the WaitForSingleObject()
call never get the signal. Very strange??
BTW, this same executable runs just fine in PPC 2002 platform. I am
using HP Jornada and Dell Axim X5 as PPC 2002s. For PPC 2003s, I am trying HP
iPAQ hx 2000 and Dell Axim x50v. I do not know if this is platform specific
or just a bug somewhere?
Thanks,
-Channa.
"Paul G. Tobey [eMVP]" wrote:
> I've done this many, many times and it *does* work, generally. I just took
> your code, added the bits that needed to be added to make it run (opening
> the port, closing the thread handle when you're done with it), ported it
> back to plain Win32 using global functions, and it works just fine. It
> might be helpful to put some debug messages in the thread so you can tell
> whether the thread is blocked at WaitCommEvent() or ReadFile() when you try
> to terminate it...
>
> Paul T.
>
> "Channa" <Channa@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> news:B5F8F028-AB9E-4270-B839-25A45E528DBD@xxxxxxxxxxxxxxxx
> > Hi Tobey,
> >
> > Thanks for the quick reply. I tried without changing the priority but,
> > it still do not signal... Any other suggetions?
> >
> > Thanks again,
> > -Channa.
> >
> > "Paul G. Tobey [eMVP]" wrote:
> >
> >> You know that time-critical threads only run till completion, right? Not
> >> a
> >> good choice for something like this. Try it without changing thread
> >> priority and see what happens then.
> >>
> >> Paul T.
> >>
> >> "Channa" <Channa@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> >> news:7F513D6A-A7D3-439A-81D5-0753702568A8@xxxxxxxxxxxxxxxx
> >> > Hi Tobey,
> >> >
> >> > Here it is for you...
> >> >
> >> >
> >> > // Create a read thread for reading data from the communication port.
> >> > This
> >> > section
> >> > // of code is part of one of the clsSerialControl class memeber
> >> > function
> >> > // hReadThread and hCommPort are private member variables
> >> > ....
> >> > hReadThread = CreateThread (NULL, 0x100000, PortReadThread, this, 0,
> >> > &dwThreadID);
> >> > if(hReadThread == NULL)
> >> > {
> >> > // Could not create the read thread.
> >> > }
> >> > //Bump the thread priority up.
> >> > SetThreadPriority(hReadThread, THREAD_PRIORITY_TIME_CRITICAL);
> >> > ....
> >> >
> >> > DWORD WINAPI PortReadThread (LPVOID lpvoid)
> >> > {
> >> > BYTE Byte;
> >> > DWORD dwBytesTransferred,dwCommModemStatus;
> >> > BOOL bReadResult;
> >> > COMSTAT cs;
> >> > DWORD dwError;
> >> >
> >> > clsSerialControl *pNCP = (clsSerialControl *) lpvoid;
> >> >
> >> > while (pNCP->hCommPort != INVALID_HANDLE_VALUE)
> >> > {
> >> > // Specify a set of events to be monitored for the port.
> >> > SetCommMask (pNCP->hCommPort, EV_RXCHAR|EV_ERR);
> >> >
> >> > // Wait for an event to occur for the port.
> >> > if (WaitCommEvent(pNCP->hCommPort, &dwCommModemStatus, 0) !=
> >> > 0)
> >> > {
> >> > if (dwCommModemStatus & EV_RXCHAR)
> >> > {
> >> > // Loop for waiting for the data.
> >> > do
> >> > {
> >> > // Read the data from the serial port.
> >> > bReadResult = ReadFile(pNCP->hCommPort, &Byte, 1,
> >> > &dwBytesTransferred, 0);
> >> > if(bReadResult && (dwBytesTransferred == 1))
> >> > pNCP->gbInputBuffer.PutByte(Byte);
> >> > }while(bReadResult && (dwBytesTransferred == 1));
> >> > }
> >> > else
> >> > {
> >> > ClearCommError(pNCP->hCommPort,&dwError,&cs);
> >> > }
> >> > }
> >> > }
> >> >
> >> > ExitThread(0);
> >> > return 0;
> >> > }
> >> >
> >> > BOOL clsSerialControl::CloseCommPort()
> >> > {
> >> > DWORD dwError;
> >> > HANDLE hClosePort;
> >> >
> >> > if (hCommPort != INVALID_HANDLE_VALUE)
> >> > {
> >> > hClosePort = hCommPort;
> >> > hCommPort = INVALID_HANDLE_VALUE;
> >> >
> >> > // Close the communication port.
> >> > if (!CloseHandle (hClosePort))
> >> > {
> >> > dwError = GetLastError ();
> >> > return FALSE;
> >> > }
> >> > WaitForSingleObject(hReadThread, INFINITE);
> >> > }
> >> > return TRUE;
> >> > }
> >> >
> >> > Thanks,
> >> > -Channa.
> >> >
> >> > "Paul G. Tobey [eMVP]" wrote:
> >> >
> >> >> At a guess, because you're waiting on the wrong handle. Show us a 30
> >> >> line
> >> >> or less sample, including the thread procedure, which demonstrates the
> >> >> problem.
> >> >>
> >> >> Paul T.
> >> >>
> >> >> "Channa" <Channa@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> >> >> news:F24C0CD4-49AA-4C6F-BBF9-2A5A39AD1A67@xxxxxxxxxxxxxxxx
> >> >> > Hi,
> >> >> >
> >> >> > I have an app created originally for PPC 2002 using eVC++ v3.0
> >> >> > and,
> >> >> > it
> >> >> > has been migrated to PPC 2003 platform using eVC++ v4.0.
> >> >> >
> >> >> > I have been noticing some odd behaviour since recently, and
> >> >> > thought
> >> >> > of
> >> >> > asking if anybody else have experienced the same and worked around
> >> >> > already? I
> >> >> > have a separate thread reading the COM port. I am noticing that
> >> >> > although
> >> >> > this
> >> >> > thread exit normally, the main process do not get signaled state
> >> >> > (using
> >> >> > WaitForSingleObject INFINITEly)!
> >> >> >
> >> >> > I did trace using Kernel Tracker tool and noticed that the two
> >> >> > threads
> >> >> > (main- and the COM-port-reading-thread) got blocked. I used to use
> >> >> > "return"
> >> >> > for exiting the COM port reading thread. So, I changed it to
> >> >> > ExitThread(),
> >> >> > and now, the COM port reading thread get terminated but the main
> >> >> > process
> >> >> > do
> >> >> > not get signaled and the Kernel Tracker tool shows that my main
> >> >> > thread
> >> >> > is
> >> >> > still being blocked. I have no idea is to why?
> >> >> >
> >> >> > Any input would be appreciated.
> >> >> > Thanks in advance,
> >> >> > -Channa.
> >> >> >
> >> >>
> >> >>
> >> >>
> >>
> >>
> >>
>
>
>
.
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