Re: SetWindowPos causing crash

=?Utf-8?B?Um9iS2lubmV5MQ==?= <>
Mon, 15 Oct 2007 09:44:02 -0700
"Joseph M. Newcomer" wrote:

Are you using threads?

The advice about the call stack needs to be slightly modified if you have multiple
threads, use the Debug menu item, Threads... to see the call stacks for individual

There are some issues about OnInitDialog; for example it calls the superclass
OnInitDialog, and so on up the chain, until it reaches the top CDialog, which issues a
call to the virtual method DoDataExchange(), which calls the DoDataExchange of your class,
which calls the DoDataExchange() of the superclass, etc., until it gets to the highest
class. Then when the highest function returns, the next one down runs, and so on.

There is also an issue if you have autobuddy spin controls and OnEnChange handlers for the
associated edit control. There are issues about some controls may not be bound at the
time, leading to the same problem I described for the OnSize handler.

On Fri, 12 Oct 2007 09:44:01 -0700, RobKinney1
<> wrote:

After some long hours working on this subject, we have determined that the
SetWindowPos is probably not the problem. We are thinking that this just
happens to be the statement that the processor is chewing on while somewhere
else something is erroring out.

Man, we are so close but just have about 2 or 3 of these annoying bugs
before we are done!

Thank you everyone for your help /suggestions! If I figure out what the
root of the cause was, I will be sure to post back to let everyone know.



Joseph M. Newcomer [MVP]
MVP Tips:

Hello Joe. Thanks again for posting.

Indeed, I am using threads. When I get back to the testing environment, I
will try looking in the Debug -> Threads... item to see if I can see the call

For now, I will paste the OnInitDialog function incase you may see something
at a glance that is suspicious...

BOOL CViewer::OnInitDialog()


    // last I see of this thread right here if this is not commented out
        SetWindowPos(NULL, windowPositionX, windowPositionY, VIDEOPREVIEW_WIDTH,
    catch(CException* pEx)
        TCHAR szErr[1024];
        pEx->GetErrorMessage ( szErr, 255 );

        // error is logged here in my code...
                           // error is logged here in my code... I will take
this catch(...) out later after I figure out what the problem is. However,
this, nor the Catch above ever gets run.


    ReaquireStream = true;

    /* temp -- comment out for now to see if this could be creating a problem
    // create right-click menu
    hMenu = ::CreatePopupMenu();
    // if the menu was created sucessfully, add the menu items
    if (NULL != hMenu)
        ::AppendMenu(hMenu, MF_STRING, 1, "Add ...");


    } // end IF the menu was created sucessfully

    // start the timer
    n_Timer = SetTimer(3333 + Offset, 5000, NULL); // allow 5 seconds to elapse
 // 10-09-07 -- changed so that the timer event is more unique by adding the
slot number offset

    // 3rd Party Initialization totalling 10 lines
//(some I have deleted from this post per confidentially agreement :~[
// ( I have replaced some material with ... so I am able to post it here on
the net)
    HRESULT hr = CoCreateInstance(CLSID_..., NULL, CLSCTX_INPROC_SERVER, ...,
(void**) &m_obj);

        AfxMessageBox(_T("Can't instantiate ... object"));
        return hr;

    m_obj->put_...((long) m_hWnd);
    m_obj->Set...((long) m_hWnd, UWM_...MESSAGE); m_obj->put_...(...);

// last I see of this thread if SetWindowPos is commneted out... nothing
else ever happens including the timer event.

    return TRUE; // return TRUE unless you set the focus to a control
                  // EXCEPTION: OCX Property Pages should return FALSE

} // end OnInitDialog ()

It usually gets stuck at the SetWindowPos(), but if I comment it out, the
constructor will complete. ( I really have logging on each line so I can
tell exactly how far the OnInitDialog is making it).

So how is this called? Well, from my base class makes a call like this
multiple times (with different indexToPlace values):

ViewerWindow is of type CViewerThread. CViewerThread is a derived from
CWinThread. Its Run looks like this:
(dlg is defined as CViewer * dlg; in the CViewerThread.h)
int CViewerThread::Run()
     running = true;

    dlg = new CViewer();

    dlg->ConnectToWhere = ConnectToWhere;
    dlg->RegistryDeviceNumber = RegistryDeviceNumber;

    dlg->windowPositionX = windowPositionX;
    dlg->windowPositionY = windowPositionY;

    // pass on the pointer to the ... struct entry
    dlg->TDPz = TDPz;

    // pass on the available list
    dlg->AvailableList = AvailableList;


        CNetClientApp::LogData(true, "((HT)) CAM %i: E.", RegistryDeviceNumber);



    // run the message pump
    MSG MSG_Temp;

        // pump any messages that may need to be processed
        while (PeekMessage(&MSG_Temp, NULL, NULL, NULL, PM_REMOVE))

        // wait 10 ms then check again

    } // end WHILE not to exit thread

    // tell the window to destroy itself
    dlg->SendMessage(WM_DESTROY, 0, 0);

    running = false;

    return 0;

} // end Run

So basically, it goes like:
BaseClass CreateThread() -> CViewerThread Creates Window -> CView
OnInitDialog called and crashes.

Is there anything wrong with this code?

It works for hours and about 20 to 40 cycles, then it just starts having
these problems whenever the SetWindowPos is called.

Hope this is not an overload of info... just wanted to make sure everything
was there. Please don't spend too much time on it -- I know everyone's time
is valuable.

Thanks again!


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