C / C++ / MFC

13-Mar-06 22:02

what is the diff b/w heapalloc and new .
Pls help me.

never say die

Stephen Hewitt13-Mar-06 22:07

13-Mar-06 22:07

new uses HeapAlloc internally. But it also adds caching and small block heaps and the like on top of it. new is a C++ keyword where as HeapAlloc is a Win32 API function.

Steve

sunit513-Mar-06 22:20

13-Mar-06 22:20

Thanks for the answer.
But i want to know is there any thing like private heap and Global heap?
Pls help me

never say die

Stephen Hewitt13-Mar-06 22:24

13-Mar-06 22:24

No. Win32 supports multiple heaps, you can create your own by calling HeapCreate and keep it to yourself - I guess in that case you could consider it private. Can you explain what you’re trying to do specifically? Maybe then I can be of more help.

Steve

sunit513-Mar-06 22:33

13-Mar-06 22:33

Actually a project has been given to me which connects the client to IIS Server via soap.I have been assigned to devlope further.So any memory allocation done on Server Side using Heapalloc. When I asked the reason ,i was told that memory is bound(within) to the process so it has been done using HeapAlloc.

If u can help me further,I would be thankful to u

never say die

Stephen Hewitt13-Mar-06 22:38

13-Mar-06 22:38

Calling new in C++ gets its memory from HeapAlloc underneath the hood. But it integrates with the language by:
- Knowing the size of the object it’s allocating (so you don't have to supply it).
- Calls constructors (and delete calls destructors).
- Avoids casts.

In short I'd just use new and delete. But beware:
If you allocate with new you must free with delete and if you allocate with HeapAlloc you must free it with HeapFree - You can't allocate some memory with new and free the same memory with HeapFree for example.

Steve

sunit513-Mar-06 22:46

13-Mar-06 22:46

That means if a memory allocation requires construtor for intialization then use new rather than HeapAlloc

never say die

Stephen Hewitt13-Mar-06 22:48

13-Mar-06 22:48

You could use the a placment new but that's rather advanced.

Steve

sunit513-Mar-06 22:56

13-Mar-06 22:56

Thanx a lot

never say die

toxcct13-Mar-06 22:09

toxcct

13-Mar-06 22:09

i don't find HeapAlloc()[^] that similar to new operator...

why not using the language operator, so that it will always work regardless of the plateform ?!

help needed

_tasleem13-Mar-06 21:42

_tasleem

13-Mar-06 21:42

hi all
i made drawing on dialog through code.
CClientDC dc(this);
dc.moveto();
dc.lineto(); functions
"drawings is complete on dialog now i want that this drawing should be saved on the bitmap file or jpeg file"
for that purpose i m using the code.

CImage Image;
Image.Attach(hBitmap);
Image.Save("D:\\test.bmp");
Image.Detach();

but it require the hBitmap. tell me how to get the hbitmap use the mempry device context to save the the bimtap in memory and then use it or what.
i had tried this code.

CBitmap bmp;
bmp.CreateCompatibleBitmap(dc,400,275);
but no way to get the hbitmap

then i use this code

HDC hdc= CreateCompatibleDC(GetDC()->m_hDC);
HBITMAP hBitmap=CreateCompatibleBitmap(GetDC()->m_hDC,200,200);
SelectObject(hdc,hBitmap);
hBitmap=(HBITMAP)SelectObject(hdc,hBitmap);

and then used it inthe cimage member but it gives empty black bitmap.

ddd

Cool Ju13-Mar-06 22:01

Cool Ju

13-Mar-06 22:01

Hi,

try this

HDC hdc = ::GetDC(hWnd);
CDC dc, memDC;
dc.Attach(hdc);
memDC.CreateCompatibleDC(&dc);
CRect rc;
::GetClientRect(hWnd, &rc);
CSize sz(rc.Width(), rc.Height());
CBitmap bm;
bm.CreateCompatibleBitmap(&dc, sz.cx, sz.cy);
CBitmap *pOldbm = memDC.SelectObject(&bm);
memDC.BitBlt(0, 0, sz.cx, sz.cy, &dc, 0, 0, SRCCOPY);

// now you can do what you need to with bm.m_hObject
memDC.SelectObject(pOldbm);
bm.Detach();
::ReleaseDC(dc.Detach());

Bye,
Cool Ju Cool | :cool:

Dream Ur Destiny

_tasleem13-Mar-06 22:29

_tasleem

13-Mar-06 22:29

HDC hdc = ::GetDC(hWnd);
this line gives error i thinks u had not get mey question i only needed the
HBITMAP variable with ptr to only the drawings not whole window.

ddd

Cool Ju13-Mar-06 23:23

Cool Ju

13-Mar-06 23:23

Hi,

check this link

this[^]

Bye,
Cool Ju Cool | :cool:

Dream Ur Destiny

A question about the radio button

_tasleem14-Mar-06 0:18

_tasleem

14-Mar-06 0:18

thanks for ur reply
there was only problem with my code was the HBITMAP object was not proerly initilzed i mean there was not value in it now i got the pt where i was wrong
once agin thanks.

ddd

pantao55113-Mar-06 21:41

pantao551

13-Mar-06 21:41

Is there any method to make the focus more obvious when it is staying at a radio button?
Because a very thin black dash squre line is not easy to find, especially when there are many radio button in the dialog.

Thanks!

toxcct13-Mar-06 21:44

toxcct

13-Mar-06 21:44

and what are you especting for a "more obvious" focused radio button ?

pantao55113-Mar-06 21:58

pantao551

13-Mar-06 21:58

My program will run on a computer without mouse.
So it is very important to make everything obvious, Especially the focus of the keyboard.
When I use the radio button, especially when the radio button is more than 10 in a dialog, it is difficult to find the focus.

toxcct13-Mar-06 22:06

toxcct

13-Mar-06 22:06

cant the user use the "Tab" key to navigate between the controls, and use mnemonics to access more quickly to a specific control like :

<big>O</big> My radio

to access this radio directly with the keyboard, press Alt+M (as M is underscored)

pantao55113-Mar-06 23:17

pantao551

13-Mar-06 23:17

The key board is not standard.
It has only number keys and moving keys like -> <- up down and enter.
It does not have tab and system keys.

I think I should ask my question like this: ^-^
Is there any way to make the controls of the dialog like radio button or check box highlighted when the focus of the keyboard is staying at them?

Once again, my computer has no mouse.

Thanks!

-- modified at 5:21 Tuesday 14th March, 2006