C / C++ / MFC

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

Re: convert a CString variable to unsigned long long

16-May-11 21:55

Yes, but he wants string to long long.

The best things in life are not things.

Richard MacCutchan16-May-11 21:54

Re: convert a CString variable to unsigned long long

16-May-11 21:54

I would guess you probably need this[^].

The best things in life are not things.

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

David Crow

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?

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather

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

Abhijit_Satpute17-May-11 4:59

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

17-May-11 4:59

With the help of Task manager. The application memory increases and decreases when we add and delete columns respectively.

Regards,
Abhijit

David Crow17-May-11 5:03

David Crow

17-May-11 5:03

Abhijit_Satpute wrote:
With the help of Task manager.

Not a good choice. TM does not tell you how much memory your program is using, but the amount of address space that is in use, which differs from the amount of that address space your program is actually using.

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

Abhijit_Satpute17-May-11 5:25

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

17-May-11 5:25

So please suggest me some good tool which can tell me exact memory used by my application.

Regards,
Abhijit

David Crow17-May-11 5:51

David Crow

17-May-11 5:51

Abhijit_Satpute wrote:
So please suggest me some good tool which can tell me exact memory used by my application.

In all sincerity, why do you think you need to know this?

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

Abhijit_Satpute17-May-11 19:58

Start application at specific time

17-May-11 19:58

My japanese client is using Task Manager to see the memory. So i need to convince him that it is not a memory leak.
Japanese clients are very hard to convince.

Regards,
Abhijit

Pranit Kothari15-May-11 22:00

15-May-11 22:00

Hello,
I wanted to create an application in which I wanted to start my application at specific time, say I wanted to start my application at every 3 PM. If my computer is not on at 3 PM, I must be able to start it on later time as well.

I using VC++/MFC application.

Happy Programming.

Richard MacCutchan15-May-11 22:09

15-May-11 22:09

It would be simpler to use the Windows Task Scheduler.

The best things in life are not things.

Pranit Kothari16-May-11 0:30

16-May-11 0:30

I have tried to use various examples finding Windows Scheduler with VC++. But almost every application give one or other COM exception. Can I have a link or example which shows use of windows scheduler with VC++/MFC.

Here are some links I have tried,

http://msdn.microsoft.com/en-us/library/aa381915(v=vs.85).aspx[^]

http://msdn.microsoft.com/en-us/library/aa446855(v=vs.85).aspx[^]

In second example I am getting exception in

ITask *pITask;
  LPCWSTR lpcwszTaskName;
  lpcwszTaskName = L"Test App";
  hr = pITS->Activate(lpcwszTaskName,
                      IID_ITask,
                      (IUnknown**) &pITask);
  
  pITS->Release();
  if (FAILED(hr))
  {
     wprintf(L"Failed calling ITaskScheduler::Activate; error = 0x%x\n",hr);
     CoUninitialize();
     return 1;
}

Richard MacCutchan16-May-11 1:08

16-May-11 1:08

I meant use Task Scheduler instead of writing a program.

The best things in life are not things.

Pranit Kothari16-May-11 1:12

16-May-11 1:12

I meant use Task Scheduler instead of writing a program.

That would be the best choice if I am making application for myself. I wanted to create Application.

Regards

ShilpiP16-May-11 1:46

ShilpiP

16-May-11 1:46

Reason : Please read the first line of example.
"This example attempts to run an existing task. This example assumes that the task and the test task already exist on the local computer."

Check this
http://msdn.microsoft.com/en-us/magazine/cc163350.aspx

"Every Little Smile can touch Somebody's Heart...
May we find Hundreds of Reasons to Smile Everyday... and
May WE be the Reason for someone else to smile always!" (ICAN)

Pranit Kothari16-May-11 2:02

16-May-11 2:02

Hi Shilpi,
Actually I used Notepad.exe as well, but got exception. Then I tried chrome.exe, though Chrome Browser running on my system. But doesn't work.

Regards

ShilpiP16-May-11 2:11

ShilpiP

16-May-11 2:11

Did you manually add the Scheduled task of notepad and chrome ??
Go to control panel -> Scheduled task -> Add Scheduled task and than check for this task using your code.

"Every Little Smile can touch Somebody's Heart...
May we find Hundreds of Reasons to Smile Everyday... and
May WE be the Reason for someone else to smile always!" (ICAN)

Pranit Kothari16-May-11 2:34

16-May-11 2:34

Great! Its working now.

Thanks and Regards