C / C++ / MFC

Rajkumar R31-Jan-08 19:14

Rajkumar R

31-Jan-08 19:14

verify this

raju.k wrote:
Lfile.Write("",b_Temp.GetLength());

rowdy_vc++31-Jan-08 19:38

rowdy_vc++

31-Jan-08 19:38

yes.. i checked ..but ..its shown same ....not write the serial NUMBER in file

raju.k

Cedric Moonen31-Jan-08 20:11

Cedric Moonen

31-Jan-08 20:11

Wow, did you even read the documentation of the Write function ? You pass an empty string ("") to be written in the file and then you specify that its size is b_Temp.GetLength() (meaning that's the number of bytes that needs to be written in the file).
Common, don't you think it's about time you look at the documentation and try to understand it before guessing what the different functions might be doing ? It's been one week you are working on this problem.

Cédric Moonen
Software developer

Charting control [v1.2]

vijay_aroli31-Jan-08 20:24

vijay_aroli

31-Jan-08 20:24

Cedric Moonen wrote:
don't you think it's about time you look at the documentation and try to understand it before guessing what the different functions might be doing ?

Oh... Please sir, Don't be harsh on him. This poor chap just has an experience of 1.2 months. wait... it should be 1.4 months now. Wink | ;)

Seriously, I wonder if he is really using a debugger. Big Grin | :-D

Regards,
Vijay.

Cedric Moonen31-Jan-08 20:55

Cedric Moonen

31-Jan-08 20:55

Okay, I'll give you some hints so that you can understand what's wrong with your code. But you really need to learn to use documentation efficiently.

And please, when you post code, use the formatting tags. And read the posting guidelines at the top of this forum.
BTW, you would confuse much less people if you use the word "line number" instead of "serial number". Well I suppose that's what you want to do ? Add a line number in front of each line in the file ? It took me quite a lot of time to understand it...

So, here we go:

<blockquote class="FQ"><div class="FQA">raju.k wrote:</div>CFile Lfile("path of the file name", CFile::modeReadWrite);</blockquote>

I suppose this is pseudo code and that you actually pass the correct file path ?

raju.k wrote:
while(Lfile.GetLength())

So, here you have basically in infinite loop because the size of your file will never decrease.

raju.k wrote:
b_Temp=big_string;
big_string.Format(_T("%d. %s"),iver+1,b_Temp);
big_Array.Add(big_string);
++iver;

You never actually read something from your file so, your strings won't contain anything usefull (only the previous values that you have put in).

raju.k wrote:
b_Temp=big_string;
b_Temp.Format("%s\n",big_Array.GetAt(i-1));

This is not needed because you can directly use the string in the array instead of using yet another one. And the first line doesn't have any purpose neither.

raju.k wrote:
Lfile.Write("",b_Temp.GetLength());

This problem has already been discussed in the previous posts: you write an empty string to your file but you still write some garbage characters.

Cédric Moonen
Software developer

Charting control [v1.2]

David Crow1-Feb-08 3:38

David Crow

1-Feb-08 3:38

raju.k wrote:
in this code is not created the serial numbers in file
...
Lfile.Write("",b_Temp.GetLength());

Did you stop to wonder why?

If you went to pour the contents of an empty cup into the sink, would you then wonder why the sink remained dry?

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

DLL rebase

George_George31-Jan-08 18:40

31-Jan-08 18:40

Hello everyone,

I want to learn what DLL rebase is, currently I am reading, http://msdn2.microsoft.com/en-us/library/ms810432.aspx, but find the theory part is too brief and I can not understand,

1. Why we need rebase;
2. When we need rebase;
3. How do the rebase;
4. Performance impact.

Any other documents to refer? From MSDN, this is the only one I found.

thanks in advance,
George

Stephen Hewitt3-Feb-08 12:42

3-Feb-08 12:42

See here[^].

Steve

George_George3-Feb-08 14:04

3-Feb-08 14:04

Thanks Steve!

Good link! What is A function imported by ordinal?

regards,
George

Stephen Hewitt3-Feb-08 14:09

3-Feb-08 14:09

There are two ways to import a function from a DLL:
- By name.
- By ordinal.

When you import by ordinal the importing module refers to the function by index and not by name.

Steve

George_George3-Feb-08 14:22

3-Feb-08 14:22

Thanks Steve!

1.

Stephen Hewitt wrote:
refers to the function by index

By index? Looks interesting. Could you recommend some samples?

regards,
George

Stephen Hewitt3-Feb-08 15:19

3-Feb-08 15:19

Try looking here[^] for a start.

Steve

George_George3-Feb-08 15:37

3-Feb-08 15:37

Thanks Steve,

Good link and I read through it about how to use .DEF to make export by ordinal. But how to use (import) function by ordinal?

I have not found any materials covering it. Any ideas?

regards,
George

Stephen Hewitt3-Feb-08 15:51

3-Feb-08 15:51

Nothing special needs to be done. Here's the def file of my DLL:

LIBRARY Dll.dll
 
EXPORTS
 Exported @ 1 NONAME

Here's the DLL's header file which I include in the EXE and DLL.

// Dll.h
 
#ifndef __DLL_H__INCLUDED__
#define __DLL_H__INCLUDED__
 
#ifdef __cplusplus
extern "C"
{
#endif // __cplusplus
 
void __stdcall Exported();
 
#ifdef __cplusplus
}
#endif // __cplusplus
 
#endif // !__DLL_H__INCLUDED__

In the EXE I link to the DLL's import library and call the function by name:

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
 	Exported();
 
	return 0;
}

If you look at the EXE using Depends (or some other utility offering similar functionality) you'll see no function name is ever mentioned. The name information is in the DLL's import library so the linker can resolve it but it doesn't make it into the EXE or DLL.

Steve

George_George3-Feb-08 16:11

3-Feb-08 16:11

Thanks Steve,

I have read your reply and sample again. Looks like from client (EXE which consumes the DLL) point of view, there is no differences for developer, still

1. invoke function by name;
2. link with import library.

From DLL developer's point of view, we only need to generate a .DEF file, right? This is the only difference?

regards,
George

Stephen Hewitt3-Feb-08 16:15

3-Feb-08 16:15

Yeah, that's pretty much right when statically linking.

Steve

George_George3-Feb-08 16:36

3-Feb-08 16:36

Hi Steve,

I am confused. Static linking? Static linking has nothing to do with DLL, just build a statuc lib and link with it. Also has nothing to do with refer by name or by ordinal.

Stephen Hewitt wrote:
statically linking

regards,
George

Stephen Hewitt3-Feb-08 16:39

3-Feb-08 16:39

There are two ways to use functions in a DLL:
1. Link to the import library of the DLL and the OS takes case of all the details. This is called static linking and is what the examples I've shown have been doing.
2. Link dynamically using LoadLibrary and GetProcAddress.

Steve

George_George3-Feb-08 17:02

Win32 capture Escape and Enter key window message.

3-Feb-08 17:02

Thanks for your help, Steve!

I will try by myself how to use refer by ordinal technique. I think I only need to add a .DEF file to the DLL project and no need to change anything else in EXE project and DLL project.

regards,
George

Hirakawa31-Jan-08 16:52

Hirakawa

31-Jan-08 16:52

Good day. I have a question about how to capture escape and enter key window message in Win32.

Normally in MFC, I will use PreTranslateMessage like below to capture enter and escape key...

BOOL CTestDlg::PreTranslateMessage(MSG* pMsg) 
{
	if (pMsg->message == WM_KEYDOWN) {
		if (pMsg->wParam==VK_ESCAPE || pMsg->wParam==VK_RETURN || pMsg->wParam==VK_CANCEL) {
			return FALSE;
		}
	}

	return CDialog::PreTranslateMessage(pMsg);
}

But somehow it seems that enter key and escape key cannot be captured in Win32 when I waiting for WM_KEYDOWN window message like below:

int CALLBACK TestDlgProc(HWND hDlg, UINT Message, WPARAM wParam, LPARAM lParam)
{
	switch (Message) {
		case WM_KEYDOWN:
			switch (wParam) {
				case VK_ESCAPE:
					MessageBox(NULL, "VK_ESCAPE", "WM_KEYDOWN", MB_OK);
					break;

				case VK_RETURN:
					MessageBox(NULL, "VK_RETURN", "WM_KEYDOWN", MB_OK);
					break;
			}

			break;
	}
}

Please help me. Is there anything I haven't done to make my code work?

Re: Win32 capture Escape and Enter key window message.

Rajkumar R31-Jan-08 22:27

Rajkumar R

31-Jan-08 22:27

I can suggest you 2 approach now,

1) use WM_COMMAND (wparam = IDOK for Enter key, and wparam = IDCANCEL for ESC key) and use different Dlg ID for OK and CANCEL key if your dialog has one.

2) in the main message loop put a route for your pretranslate function

// Main message loop:
	while (GetMessage(&msg, NULL, 0, 0))
	{
		if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
		{ 
                      BOOL bTranslate = TRUE;

                       if (msg.hwnd is your dialog window)
                       {
                         bTranslate = pretranslate(); // get your key message 
                       }

			if (bTranslate)
                            TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}

I didn't tried please try and may us know

Re: Win32 capture Escape and Enter key window message.

Catherine Sea15-Feb-08 15:16

Catherine Sea

15-Feb-08 15:16

Hi,

You can also try SetWindowsHookEx API.

----
Catherine Sea
Dynamsoft Corporation

www.dynamsoft.com
the leading developer of version control and issue tracking software

C++ Interface

George_George31-Jan-08 15:32