C / C++ / MFC

Re: ReadFile () reads Junk characters when tried to read from COM1 Port

17-May-11 4:13

That's what your printf() statement looks like?

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pandit8417-May-11 4:16

pandit84

17-May-11 4:16

oops I am sorry

printf("The date %s", ptr) ;

Re: ReadFile () reads Junk characters when tried to read from COM1 Port

David Crow17-May-11 4:38

Re: ReadFile () reads Junk characters when tried to read from COM1 Port

17-May-11 4:38

Ok, so are you using communications events?

pandit8417-May-11 18:51

pandit84

17-May-11 18:51

No I am not using communication event. I have tried using

::WaitCommEvent

. But it never get any event and it goes into continuous wait state. So I have removed that and tried to read the Port using ::ReadFile () without using any event.

Re: ReadFile () reads Junk characters when tried to read from COM1 Port

David Crow18-May-11 1:49

Re: ReadFile () reads Junk characters when tried to read from COM1 Port

18-May-11 1:49

pandit84 wrote:
. But it never get any event and it goes into continuous wait state.

Which means nothing is available to read.

pandit84 wrote:
So I have removed that and tried to read the Port using ::ReadFile () without using any event.

So reading what's not available (to read) seemed like a better idea?

kakan17-May-11 21:22

kakan

17-May-11 21:22

You just got to use overlapped I/O when you are using COM ports. There are some classes/samples here. Just search for a suitable article.

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Re: ReadFile () reads Junk characters when tried to read from COM1 Port

pandit8418-May-11 20:23

pandit84

18-May-11 20:23

Finally this solution works for me. What I did is

1. In ReadFile() - Read from different COM port. E.G Writing is done on COM1 and Reading is Done on COM2. As I was having only 1 COM Port . I installed Virtual Port Software on my machine and Paired COM1 and COM2

2. ReadFile() provided a buffer of exact size which I used in WriteFile () method.

Start child window in maximize state

_Flaviu17-May-11 1:53

_Flaviu

17-May-11 1:53

Is there a method to start a child window ( in a MDI application ) without get a flikering ? I try in this way :

void CMainFrame::OnOpenChildWindow() 
{
	POSITION pos = theApp.GetFirstDocTemplatePosition();
	CMultiDocTemplate* pDocTemplate = (CMultiDocTemplate*)theApp.GetNextDocTemplate(pos);
	pDocTemplate = (CMultiDocTemplate*)theApp.GetNextDocTemplate(pos);
	pDocTemplate->OpenDocumentFile(NULL);
	pChild = (CMDIChildWnd*)MDIGetActive();
	if(pChild)MDIMaximize(pChild);
}

but because I have a little code ( that takes time ) in OnNewDocument() , I see child window that is opening in restore state , and after that child window is maximized ...

Re: Start child window in maximize state

Chris Meech17-May-11 2:25

Chris Meech

17-May-11 2:25

You might want to try the OnCreate message for your child window instead. I think you can adjust settings, Eg., window position, state, etc, in this message so that the window opens maximized. Smile | :)

Chris Meech
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In theory there is no difference between theory and practice. In practice there is. [Yogi Berra]

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How to remove flicker effect?

hemant102716-May-11 23:07

hemant1027

16-May-11 23:07

Hi all

I am creating an application in win32 api(c++ not MFC) and when i resize window the portion of non affected window is also get redrawn that causes flicker effect.so can anyone inform me how to handle WM_PAINT message so that only affected part of window will redraw??

Its urgent... Thank you in advance...

--
Thanks and Regards

Hemant metalia
hemant_metalia@yahoo.com

Re: How to remove flicker effect?

Luc Pattyn17-May-11 0:07

Luc Pattyn

17-May-11 0:07

Hi,

I see three factors here:

1.
the repaint job holds a region, only things inside the region needs repainting, so your painting code could take that into account; however, the repaint region often is larger than necessary, so this may well be insufficient.

2.
improving the paint code performance is always a good idea, it also reduces the disturbance, hence flicker, you would notice. It does not avoid it, just makes it less annoying.

3.
the real solution is using double-buffering, where the actual painting happens in a memory-based buffer, then that buffer gets painted in one swoop to the screen, without erasing the current content. You'll have to Google for details in C++, I'm not able to provide you any code as I work mostly in C#.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.

Re: How to remove flicker effect?

Rhuros17-May-11 1:02

Rhuros

17-May-11 1:02

As Luc said take a look at double buffering, this code project article might help.

But in general terms you will need to modifiy you paint routine to do all your drawing to a compatible memDC, once drawing is complete you'll need to blit the area you require to the screen DC.

Re: How to remove flicker effect?

Hans Dietrich17-May-11 2:15

17-May-11 2:15

What Luc said, plus consider using BeginDeferWindowPos(), DeferWindowPos(), EndDeferWindowPos() in your WM_SIZE handler. These APIs allow you to accumulate the movement of multiple windows (controls), and them update them all when the repositioning is finished.

Best wishes,
Hans

convert a CString variable to unsigned long long

VCProgrammer16-May-11 21:31

VCProgrammer

16-May-11 21:31

Hi all,

I want to convert a CString variable to unsigned long long . I know for long we can do it using api atol(long);

but what to use for unsigned long long...

Anybody please help

modified on Tuesday, May 17, 2011 3:44 AM

Re: convert a CString variable to unsigned long long

Hans Dietrich16-May-11 21:52

16-May-11 21:52

Like this:

unsigned long long x = 12345;
CString xx;
xx.Format(_T("%I64u"), x);

Note that the case of I64 matters.

You can look up other formats here: http://msdn.microsoft.com/en-us/library/56e442dc%28v=VS.90%29.aspx[^]

Best wishes,
Hans

Re: convert a CString variable to unsigned long long

Richard MacCutchan16-May-11 21:55

Richard MacCutchan

16-May-11 21:55

Yes, but he wants string to long long.

The best things in life are not things.

Re: convert a CString variable to unsigned long long

Richard MacCutchan16-May-11 21:54

Richard MacCutchan

16-May-11 21:54

I would guess you probably need this[^].

The best things in life are not things.

Re: convert a CString variable to unsigned long long

Hans Dietrich16-May-11 22:24

16-May-11 22:24

Correct, my 5.

Best wishes,
Hans

Memory leak in CListCtrl::InsertColumn() and CListCtrl::DeleteColumn(). Can anybody explain why this is happning?

Abhijit_Satpute16-May-11 18:34

Re: Memory leak in CListCtrl::InsertColumn() and CListCtrl::DeleteColumn(). Can anybody explain why this is happning?

16-May-11 18:34

Hi friends,

I have written simple program of adding and removing columns from using CListCtrl of MFC.
Behavior of the application:
1. When Add button is clicked, its adds 1000 columns to the List control.
2. When Remove Button is clicked it removes the last added 1000 columns from the List Control.

So, when 1000 columns are added to the List Control using InsertColumn() function of MFC, memory usages increased by certain amount(For e.g Say by 500KB), but when we remove the added 1000 columns from the List Control using DeleteColumn() function, the memory is not freed as it was added during the addition of 1000 columns(Only 300KB is freed, resulting in 200KB of Memory Leak).

Create the sample MFC Application and use the below code.

ListControlDlg.cpp

void CListControlDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	DDX_Control(pDX, IDC_LIST, m_List);
}

BEGIN_MESSAGE_MAP(CListControlDlg, CDialog)
	.
	.
	.
	ON_BN_CLICKED(IDC_BUTTON1, OnBnClickedAdd)
	ON_BN_CLICKED(IDC_BUTTON2, OnBnClickedRemove)
END_MESSAGE_MAP()

BOOL CListControlDlg::OnInitDialog()
{
   .
   .
   .
   // TODO: Add extra initialization here
   m_Count = 1;
}

void CListControlDlg::OnBnClickedAdd()
{
	// TODO: Add your control notification handler code here
	//Add 1000 colums in List Control
	int max_limit = m_Count + 1000;
	CString columnstr = "Column";
	CString Columnno = "";
	for (int i = m_Count; i <= max_limit; i++)
	{
		Columnno.Format("%d", i);
		CString columnstrTemp = columnstr + Columnno;
		m_List.InsertColumn(i, columnstrTemp, LVCFMT_LEFT, 80);
	}
	m_Count = max_limit;
}

void CListControlDlg::OnBnClickedRemove()
{
	// TODO: Add your control notification handler code here
	//Removes 1000 colums in List Control
	int max_limit = m_Count - 1000;
	CString columnstr = "Column";
	CString Columnno = "";
	for (int i = m_Count; i >= max_limit - 1; i--)
	{
		Columnno.Format("%d", i);
		CString columnstrTemp = columnstr + Columnno;
		m_List.DeleteColumn(i);
	}
	m_Count = max_limit;
}

CListControlDlg.h

class CListControlDlg : public CDialog
{
   .
   .
   .
   .
private:
	CListCtrl m_List;
	int m_Count;
public:
	afx_msg void OnBnClickedAdd();
	afx_msg void OnBnClickedRemove();
}

ListControl.rc

IDD_LISTCONTROL_DIALOG DIALOGEX 0, 0, 501, 289
STYLE DS_SETFONT | DS_MODALFRAME | DS_3DLOOK | DS_FIXEDSYS | WS_MAXIMIZEBOX | 
    WS_POPUP | WS_VISIBLE | WS_CAPTION | WS_SYSMENU
EXSTYLE WS_EX_APPWINDOW
FONT 8, "MS Shell Dlg", 0, 0, 0x1
BEGIN
    DEFPUSHBUTTON   "OK",IDOK,444,7,50,16
    PUSHBUTTON      "Cancel",IDCANCEL,389,7,50,16
    CTEXT           "TODO: Place dialog controls here.",IDC_STATIC,7,174,300,
                    8
    CONTROL         "",IDC_LIST,"SysListView32",LVS_REPORT | LVS_ALIGNLEFT | 
                    WS_BORDER | WS_TABSTOP,27,30,454,236,WS_EX_CLIENTEDGE | 
                    WS_EX_LEFTSCROLLBAR
    PUSHBUTTON      "Add",IDC_BUTTON1,247,7,50,14
    PUSHBUTTON      "Remove",IDC_BUTTON2,311,7,50,14
END

Abhijit Satpute.

Hans Dietrich16-May-11 22:20

16-May-11 22:20

[The following assumes that you don't have a mismatched new/free somewhere in your code.]

The way this was explained to me, Windows uses a virtual memory concept to allocate/release in chunks of 'pages' 4096 bytes long. Small memory blocks will come from local heap and it is always in physical memory - this is why freeing memory is not "visible" in Task Manager. Large memory blocks will require additional pages to be allocated, and freeing that memory will be visible.

If you want to dig more deeply into this, there are several excellent articles on leak detection here on CodeProject.

You could also experiment by allocating a large block, waiting 10 seconds, then freeing the block while you are watching Task Manager.

Best wishes,
Hans

Re: Memory leak in CListCtrl::InsertColumn() and CListCtrl::DeleteColumn(). Can anybody explain why this is happning?

Abhijit_Satpute17-May-11 1:45

Re: Memory leak in CListCtrl::InsertColumn() and CListCtrl::DeleteColumn(). Can anybody explain why this is happning?

17-May-11 1:45

Thanks for your reply.
Can you recommend any tool(other than Task Manager) which can give detailed memory status of the application?

Best Regards,
Abhijit Satpute

Hans Dietrich17-May-11 2:04

17-May-11 2:04

Sysinternals has some very good free process monitoring tools:

http://technet.microsoft.com/en-us/sysinternals/bb896653[^]

http://technet.microsoft.com/en-us/sysinternals/bb896645[^]

For leak detection, take a look at Visual Leak Detector - Enhanced Memory Leak Detection for Visual C++[^]

Best wishes,
Hans

Re: Memory leak in CListCtrl::InsertColumn() and CListCtrl::DeleteColumn(). Can anybody explain why this is happning?

Abhijit_Satpute17-May-11 5:00

Re: Memory leak in CListCtrl::InsertColumn() and CListCtrl::DeleteColumn(). Can anybody explain why this is happning?

17-May-11 5:00

Thank you very much Hans.

Regards,
Abhijit

David Crow17-May-11 3:00

Re: Memory leak in CListCtrl::InsertColumn() and CListCtrl::DeleteColumn(). Can anybody explain why this is happning?

17-May-11 3:00

Abhijit_Satpute wrote:
So, when 1000 columns are added to the List Control using InsertColumn() function of MFC, memory usages increased by certain amount(For e.g Say by 500KB), but when we remove the added 1000 columns from the List Control using DeleteColumn() function, the memory is not freed...

How are you verifying this?

Abhijit_Satpute17-May-11 4:59