C / C++ / MFC

Dave Bryant12-Aug-03 12:28

Dave Bryant

12-Aug-03 12:28

You can't do that. The array is actually passed into the function as a pointer, not as an array. This means that sizeof(item) will always be 4. Instead you should either pass through the size of the array as a separate parameter, or even better, use an STL container such as a vector, which includes its size within the container itself.

Dave
http://www.cloudsofheaven.org

Hadi Rezaee12-Aug-03 13:03

Hadi Rezaee

12-Aug-03 13:03

Thanks alot for reply Dave Smile | :)

FlyingDancer12-Aug-03 15:39

FlyingDancer

12-Aug-03 15:39

Here is my thought about your array:

The elements can be linked together,so it is a link list, is it
Maximal index of your array can be used to count the array's size
why do you want to count it in that way?
Here are two ways to find the size of the array
1.Add a function to count the size by using the property of link list like the following:
CountSize(Ietm array)
{
int count=1;
while(array->item!=NULL)
{
count++;
array->item=array->item->item;
}
return count;
}
2.Get the size directly by its maximal index
Maybe it is not very OK.
Smile | :)

jhwurmbach12-Aug-03 23:11

jhwurmbach

12-Aug-03 23:11

The best advice one can give is to call std::vector::size().
[plugSTL]
This would mean that you need to switch to the STL-vectors, but that would be a good idea anyway.
[/plugSTL] Smile | :)

Who is 'General Failure'? And why is he reading my harddisk?!?

GDI: Background image

Hosam Aly Mahmoud12-Aug-03 11:57

12-Aug-03 11:57

Could someone please tell me how to make the background of a dialog a bitmap? I am using MFC on VC++ 6.0.

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Hosam Aly Mahmoud

HPSI12-Aug-03 13:15

HPSI

12-Aug-03 13:15

Take a look at this.

HPS HwndSpy - GUI developer's aid to visually
locate and inspect windows. For the month of August
only, use coupon code CP-81239 for 30% off.

Hosam Aly Mahmoud12-Aug-03 17:54

12-Aug-03 17:54

Thank you very much!

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Hosam Aly Mahmoud

Anonymous12-Aug-03 14:18

Anonymous

12-Aug-03 14:18

like this:

void CAaDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;

// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CRect rect;
GetClientRect(&rect);
CPaintDC dc(this);
CBitmap bitmap;
BITMAP Bitmap;
bitmap.LoadBitmap(IDB_BITMAP1);
bitmap.GetObject(sizeof(BITMAP),&Bitmap);
CDC dcMem;
dcMem.CreateCompatibleDC(&dc);
CBitmap* poldbitmap=dcMem.SelectObject(&bitmap);
dc.StretchBlt(0,0,rect.Width(),rect.Height(),
&dcMem,0,0,Bitmap.bmWidth,Bitmap.bmHeight,SRCCOPY);
dcMem.SelectObject(poldbitmap);
dcMem.DeleteDC();
}
}

void CAaDlg::OnSize(UINT nType, int cx, int cy)
{
CDialog::OnSize(nType, cx, cy);

// TODO: Add your message handler code here
Invalidate(TRUE);
}

may be useful!

Hosam Aly Mahmoud12-Aug-03 17:59

12-Aug-03 17:59

Thank you for your reply. But shouldn't this be handled in the WM_ERASEBKGND message (or the corresponding OnEraseBkgnd function)? Which one is better?
Thank you again.

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Hosam Aly Mahmoud

Memory

Hosam Aly Mahmoud12-Aug-03 11:53

12-Aug-03 11:53

Could you please tell me how to know how much free physical RAM exists on a system at a certain time? Also, if I have a process that allocates RAM using new, is there a way to guarantee that the allocated RAM does not go into the virtual memory, but rather stay in the physical RAM until I delete it (or the process ends)?

Sorry for my language, and thanks for your help.

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Hosam Aly Mahmoud

John M. Drescher12-Aug-03 12:32

12-Aug-03 12:32

GlobalMemoryStatus() and VirtualLock()

John

Hosam Aly Mahmoud12-Aug-03 18:12

12-Aug-03 18:12

Thank you very much. The GlobalMemoryStatus() is great. But I could not understand VirtualLock(). Could you kindly help me with it?

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Hosam Aly Mahmoud

John M. Drescher12-Aug-03 19:15

12-Aug-03 19:15

I'll see what I can find. Here is an article that better describes what VirtualLock does.

http://www.privacy.nb.ca/cryptography/archives/coderpunks/new/1999-02/0160.html[^]

[EDIT]
Here is an old link that shows a few examples of using virtual memory functions:
http://www.labri.fr/Perso/~betrema/winnt/virtmm.html[^]
[/EDIT]
John

Hosam Aly Mahmoud16-Aug-03 17:34

16-Aug-03 17:34

Thank you for your reply, and sorry for my late reply. I read the two links, and thanks a lot for the second one. The first one, however, made me rethink about using VirtualLock(). But I think that if my application does not lose focus, then it will keep my application fast. Is that right? Now I have another problem: how can I keep my application in the foreground? Should I make my process' priority "Real Time"? How can I do that?

Thank you very much.

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Hosam Aly Mahmoud

John M. Drescher17-Aug-03 17:47

17-Aug-03 17:47

Hosam Aly Mahmoud wrote:
But I think that if my application does not lose focus, then it will keep my application fast.

Yes it will. As long as the application is not minimized it will not page out unless another process needs memory. When the application is minimized windows sets the working set size to zero thus paging out your application. Different windows versions will handle this alittle differently. I think NT4 will page all of your applicaton out immediatly causing a long delay. I am a little unsure of this. I worked on this two years ago for an application that needed to hold 256MB of images in memory at a time.

Hosam Aly Mahmoud wrote:
how can I keep my application in the foreground?
Don't allow the main window to be minimized. I made the minimize button hide the window instead of minimize and it fixed the problem.

John

Hosam Aly Mahmoud17-Aug-03 18:09

17-Aug-03 18:09

Thanks for your efforts and time.

John M. Drescher wrote:
I made the minimize button hide the window instead of minimize and it fixed the problem

I think I will disable the minimize button. That should be enough.

John M. Drescher wrote:
As long as the application is not minimized it will not page out unless another process needs memory.

So what if another process does need memory? How can I delay all other processes and make them wait until I am finished?

Hosam Aly Mahmoud

John M. Drescher17-Aug-03 18:53

17-Aug-03 18:53

Hosam Aly Mahmoud wrote:
So what if another process does need memory? How can I delay all other processes and make them wait until I am finished?

If another process needs memory it may affect the working set of your process. When all the physical memory of the system is exausted the cpu will trim the working set of all processes (other than the one requesting additional memory).

Hosam Aly Mahmoud wrote:
How can I delay all other processes and make them wait until I am finished?

Maybe setting the process priority to real time may solve your problem.

John

Hosam Aly Mahmoud17-Aug-03 21:37

17-Aug-03 21:37

Thank you very much for your help John! I do not know how I could thank you, but here is a try: Rose | [Rose]

John M. Drescher wrote:
Maybe setting the process priority to real time may solve your problem.

I thought it would, but I do not know how to do it. Could you please tell me (or give me a link)? I would very much appreciate it.

Thank you for all your help!

Hosam Aly Mahmoud

Dave Bryant12-Aug-03 12:33

Dave Bryant

12-Aug-03 12:33

Not sure about how to tell how much RAM is free off the top of my head, but you can probably find out by looking at the memory management functions in MSDN.

Regarding locking allocated memory into physical memory, take a look at the VirtualLock() and VirtualUnlock() functions. These allow you to do exactly what you want.

Dave
http://www.cloudsofheaven.org

Hosam Aly Mahmoud12-Aug-03 18:15

12-Aug-03 18:15

Thank you for your reply. I am sorry, but I could not use VirtualLock(). I am still a beginner, so I do not understand what is meant by a "memory page". Second, do I have to use VirtualAlloc() or can I allocate using new? What is the difference?

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Hosam Aly Mahmoud