C / C++ / MFC

AndrewG1231 wrote:

So, my question...in order to get this sequence to run several times, say 5 times, and update the window how would I use PostMessage()? Or if I have misunderstood something please let me know.

void CDlg_SpectrumAnalyzer::OnBtnClickedRun()
{          
PostMessage(WM_COMMAND,IDC_SPECTRUM_START,0);
}

AndrewG1231 wrote:

...it executes correctly if called only a single time.

if(!m_inst->StartOperation())
        {
            MessageBox("The Instrument is Currently in use by another function");
            return;
        }

BEGIN_MESSAGE_MAP(CMyDialog, CDiaog)
    ON_BN_CLICKED(IDC_BUTTON, OnClick)
END_MESSAGE_MAP()

void CMyDialog::Acq_Data( void )
{
    while (1)
    {
        // if a STOP event has been signaled [m_pEventStopRequested.SetEvent()]
        if (WaitForSingleObject(m_pEventStopRequested->m_hObject, 0U) == WAIT_OBJECT_0)
        {
            // let OnClick() know that the secondary thread is not running
            m_pEventThreadDone->SetEvent();
            
            return;
        }
        else
            ADCdbInquire(...); // this functon can post messages back to the primary thread
    }
}

/* static */ UINT CMyDialog::Acq_Data( LPVOID lpVoid )
{
    CMyDialog *pDlg = (CMyDialog *) lpVoid;

    pDlg->Acq_Data();

    // once here, the secondary thread is done so post a message
    // back to the primary thread to tell it to enable the button

    return 0;
}

// put these in CMyDialog
CWinThread *m_pThread = NULL;
CEvent *m_pEventStopRequested = new CEvent(FALSE, TRUE); // stop requested (initially no)?
CEvent *m_pEventThreadDone = new CEvent(TRUE, TRUE);     // thread done (initially yes)?

void CMyDialog::OnClick() 
{
    // if the secondary thread is not running
    if (WaitForSingleObject(m_pEventThreadDone->m_hObject, 0U) == WAIT_OBJECT_0)
    {
        // at this point, you could disable the button that
        // started this so that it could not be clicked again

        // set the STOP and DONE events to nonsignaled (haven't happened yet)
        m_pEventStopRequested->ResetEvent();
        m_pEventThreadDone->ResetEvent();

        // start the secondary thread
        m_pThread = AfxBeginThread(Acq_Data, this, THREAD_PRIORITY_HIGHEST);
    }
}

if (WaitForSingleObject(m_pEventStopRequested->m_hObject, 0U) == WAIT_OBJECT_0)
       {
           // let OnClick() know that the secondary thread is not running
           m_pEventThreadDone.SetEvent();
           return;
       }

AndrewG1231 wrote:

However, this piece of code is causing me to get the error, "A nonstatic member reference must be relative to a specific object".

AndrewG1231 wrote:

m_pEventThreadDone.SetEvent();

m_pEventThreadDone->SetEvent();

Dlg_SpectrumAnalyzer.cpp(150): error C2227: left of '->m_hObject' must point to class/struct/union/generic type
1>Dlg_SpectrumAnalyzer.cpp(153): error C2227: left of '->SetEvent' must point to class/struct/union/generic type
1>Dlg_SpectrumAnalyzer.cpp(154): error C2561: 'CDlg_SpectrumAnalyzer::Acq_Data' : function must return a value

UINT CDlg_SpectrumAnalyzer::Acq_Data(LPVOID pParam)
{
	
	CDlg_SpectrumAnalyzer *dlg =(CDlg_SpectrumAnalyzer*) pParam;
	HWND hdlg = dlg->GetSafeHwnd();
	// start data ACQ
	while(1)
	{
	     if (WaitForSingleObject(m_pEventStopRequested->m_hObject, 0U) == WAIT_OBJECT_0)
             {
            // let OnClick() know that the secondary thread is not running
            m_pEventThreadDone->SetEvent();
            return;
	     }
	     else
	     {
			
		dlg->m_inst->ADCdbRead(dlg->m_AcqChan,dlg->m_MaxFreq*2,dlg->m_BuffSize,dlg->m_fulldata,dlg->m_halfdata);
		while(dlg->m_Continue && ! dlg->m_inst->m_Flags.Halt)
			dlg->m_inst->ADCdbInquire(dlg-   >m_halfdata,hdlg,MSG_DRAW_SPECTRUM);

			dlg->m_inst->ADCdbStop();
			//release instrument
			dlg->m_inst->EndOperation();
			
			return 1;
	     }
		 
	}

}

void CDlg_SpectrumAnalyzer::OnBnClickedRun()
{
	// TODO: Add your control notification handler code here
	 if (WaitForSingleObject(m_pEventThreadDone->m_hObject, 0U) == WAIT_OBJECT_0)
    {
        // at this point, you could disable the button that
        // started this so that it could not be clicked again

        // set the STOP and DONE events to nonsignaled (haven't happened yet)
        m_pEventStopRequested->ResetEvent();
        m_pEventThreadDone->ResetEvent();
 
        // start the secondary thread
        m_pThread = AfxBeginThread(Acq_Data, this, THREAD_PRIORITY_HIGHEST);
    }
		
}

AndrewG1231 wrote:

Have I done something foolish in the way I was trying to use your suggestion?

dlg->m_inst->ADCdbRead(dlg->m_AcqChan,dlg->m_MaxFreq*2,dlg->m_BuffSize,dlg->m_fulldata,dlg->m_halfdata);

	while(dlg->m_Continue && ! dlg->m_inst->m_Flags.Halt)
              dlg->m_inst->ADCdbInquire(dlg->m_halfdata,hdlg,MSG_DRAW_SPECTRUM);

dlg->m_inst->ADCdbStop();
//release instrument
dlg->m_inst->EndOperation();

Unhandled exception at 0x012d2ba9 in WinSTM.exe: 0xC0000005: Access violation reading location 0x000002af.

AndrewG1231 wrote:

...I ran into the following problem with the use of the dlg pointer...

AndrewG1231 wrote:

which compiled fine but led to the following runtime error.

Unhandled exception at 0x012d2ba9 in WinSTM.exe: 0xC0000005: Access violation reading location 0x000002af.

Rahul from Poona wrote:

as far as I know byData[1] declares a byte array of variable length

Chris Losinger wrote:

C/C++ does not have variable length arrays.

jschell wrote:

And in common usage the array size would be determined at run time - thus dynamic by most definitions.

Chris Losinger wrote:

that's not really a dynamic array, that's just malloc.

Chris Losinger wrote:

there's nothing 'dynamic' about the array of one. you still have to go and
malloc the memory explicitly.

Chris Losinger wrote:

guess what, words have synonyms.

Chris Losinger wrote:

you know, like when you started using the word "dynamic" to describe what i and
the OP were calling "variable length"

Chris Losinger wrote:

you changed the subject. i didn't follow your lead. hence your confusion.