C / C++ / MFC

31-Jul-02 6:35

Hi. I have some fundamental questions about dialog box and property sheet. Most ultimately have to do with program design and memory management.

Dialog Box:

Is the following good program design?

-----
MyBox mBox;

if (mBox.DoModal == IDOK)

// Is it good program design to get data from a dialog box after it has been closed/distroyed?

DataType = mBox.GetData();
-----

Dialog Box & Property Sheet:

What do you think about declare all dialog box and/or property sheets as private data member rather than local data member?

In general, I want to make sure there is not memory leak with dealing with dialog box and/or property sheet and local data members.

Thanks,
Kuphryn

Joaquín M López Muñoz31-Jul-02 6:43

31-Jul-02 6:43

Question 1: It is not only good style, but also about the only reasonable way to retrieve data entered by the user into the dialog. Go ahead with this solution.

Question 2: I don't know how keeping these private will help you prevent memory leaks. Could you be more specific?

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

valikac31-Jul-02 6:50

31-Jul-02 6:50

Thanks.

If you declare a dialog box locally, what if the function goes out of stack? If it is local, you can create a new box and delete each box every time.

Again, I would like to make sure everything is safe and good program design.

Kuphryn

Joaquín M López Muñoz31-Jul-02 6:55

31-Jul-02 6:55

I'm still not very sure about what your question is, but in general you should prefer to declare variables locally rather than as member variables (unless there are compelling reasons not to do so).

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

valikac31-Jul-02 6:56

31-Jul-02 6:56

Here is an example of the second questions.

-----
Class MyClass()
{
void TestFunc();
privete MyDialogBox *dBox;
}

void MyClass::TestFunc()
{
dBox = new MyDialogBox;

if (MyDialogBox->DoModal == IDOK)
...

delete dBox;
dBox = NULL;
}
-----

In the code above, MyDialogBox is created on the heap instead of being a local call.

Kuphryn

Joaquín M López Muñoz31-Jul-02 6:59

31-Jul-02 6:59

It is much better to do it this way:

class MyClass
{
void TestFunc();
};

void MyClass::TestFunc()
{
MyDialogBox dBox;

if (dBox.DoModal() == IDOK)
...

}

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

valikac31-Jul-02 9:11

socket monitor, is it possible?

31-Jul-02 9:11

Thanks. Nicely explained.

Kuphryn

includeh1031-Jul-02 6:17

includeh10

31-Jul-02 6:17

how to know info about sockets currently run in a PC?
the sockets are created by other apps.
info includes ports, addresses for both side of sockets.
is it possible?
thx

includeh10

jmkhael31-Jul-02 6:22

jmkhael

31-Jul-02 6:22

one link http://www.sysinternals.com/ntw2k/source/tcpview.shtml

Papa
Murex Co.

while (TRUE)
Papa.WillLove ( Bebe ) ;

jmkhael31-Jul-02 6:24

jmkhael

31-Jul-02 6:24

another one http://www.sysinternals.com/ntw2k/freeware/tdimon.shtml

Papa
Murex Co.

while (TRUE)
Papa.WillLove ( Bebe ) ;

includeh1031-Jul-02 6:28

includeh10

31-Jul-02 6:28

thank u!
before i try, i want to know if it is only avaliable on NT and win2k?

a flower ... Rose | [Rose]

includeh10

jmkhael31-Jul-02 6:32

jmkhael

31-Jul-02 6:32

there's a version for win 95/98/Me also, check it out at www.sysinternals.com

Papa
Murex Co.

while (TRUE)
Papa.WillLove ( Bebe ) ;

includeh1031-Jul-02 7:15

includeh10

31-Jul-02 7:15

i downloaded 20 (or all) zips from the company. they look very wanderful!
i will go through to find key code.
i think u use them before, u should be an expert about the stories.

thx again

2 flowers ... Rose | [Rose]

includeh10

lucy31-Jul-02 10:16

lucy

31-Jul-02 10:16

another tool: in MS-DOS command window, type "netstat -a".

DLL hell with msvcrt.dll

Jim Crafton31-Jul-02 6:15

31-Jul-02 6:15

OK I have my app which I am trying to test on other machines
I have built it as a Multi threaded DLL so I am using the MSVCRT.dll
as well as the MSVCP60.dll due to C++ and STL

On my machine (a win2K box) all is well.
On the two NT server 4 sp6 machines where I ahve tried to run it all is NOT well.

I put the exe plus my lib's .dll and the msvcrt.dll and msvcp60.dll all in the same directory.
I try and run the app (it is a console app) and I get this:
"The procedure entry point __lc_collate_cp could not be located in the dynamic link library MSVCRT.dll"
Hmm...well I drag a copy of depends.exe over and open the app in it and it reports no errors ( i.e. problems with linked functions that don't exist), and in fact reports that the version of MSVCRT.dll I am using is the one in the app's directory (naturally), NOT the one in winnt\system32\.

The one in the c:\winnt\system32\ dir has a version of 4.20.6201 and the one I am using (or need to use) is 6.10.8924.0

I had always understood that you should avoid replacing the stuff in system32 to prevent breakage in other apps.
Should I in fact change the installer to just overwrite it (if it is older than mine) ?
This app will be installed on server machines so I am a but leery of doing this.

Any suggestions will be greatly appreciated, and I happily send you a virtual beer !

Joaquín M López Muñoz31-Jul-02 6:41

31-Jul-02 6:41

Well, this masks the error rather than solve it, but have you considered statically linking the pogram? When I have to release an applicaton I always choose this option to save me the hassle and latenight calls from clients Smile | :)

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Jim Crafton31-Jul-02 7:27

31-Jul-02 7:27

Yeah thats what I am getting readyto do now but I am REALLY pissed off that I have to resort to this. Stupid fsckin' MS, pardon my french....

Daniel Lohmann31-Jul-02 8:52

Daniel Lohmann

31-Jul-02 8:52

Jim Crafton wrote:
Hmm...well I drag a copy of depends.exe over and open the app in it and it reports no errors ( i.e. problems with linked functions that don't exist), and in fact reports that the version of MSVCRT.dll I am using is the one in the app's directory (naturally), NOT the one in winnt\system32\.

The one in the c:\winnt\system32\ dir has a version of 4.20.6201 and the one I am using (or need to use) is 6.10.8924.0

I had always understood that you should avoid replacing the stuff in system32 to prevent breakage in other apps.
Should I in fact change the installer to just overwrite it (if it is older than mine) ?
This app will be installed on server machines so I am a but leery of doing this.

Yes, you should change the installer to overwrite it.

Depends.exe seems to give you the wrong hint here Frown | :-(

The problem is, that on NT4 (and maybe also Win2k, but not XP) MSVCRT.dll is a so-called "well-known DLL" (the list of well-known DLLs is stored in the registry at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\KnownDLLs).

These DLLs are never loaded side-by-side, because they are a vital part of the OS. For well-known DLLS always the copy in %SYSTEMROOT%\System32 is taken.

While this makes much sense for the "really vital" OS DLLs e.g. kernel32.dll and advapi32.dll, which are heavily dependend on each other and replacing one of them side-by-side with another version could break the whole system, I never understood why msvcrt.dll is also on this list. But on NT4 it is! Mad | :mad:

So the official and recommended way is to replace it. However, msvcrt.dll is the very best tested thing from MS and, (regarding DLL-Hell) in no way comparable with MFC or Common Controls: Every of their own application and every OS component depends on it Poke tongue | ;-P

. So it is rather safe to replace it with a newer version (and do the damned reboot afterwards). In fact, I have never heard of any problem with replacing it.

--

Daniel Lohmann

http://www.losoft.de

Jim Crafton31-Jul-02 10:23

31-Jul-02 10:23

Thanks for hte info ! I will change the installer to do this then.
I had never heard about the "well known DLL" issue, and while I kind of understand it, that REALLY sucks. I wonder what would happen if you were to just remove the entry?
Curiously, I just walked over to the one of the machines and opened regedit and I saw a number of DLLs under the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\KnownDLLs key but NOT msvcrt.dll - is this one hardcoded somewhere else I wonder ?

Daniel Lohmann31-Jul-02 13:39

Daniel Lohmann

31-Jul-02 13:39

Jim Crafton wrote:
Curiously, I just walked over to the one of the machines and opened regedit and I saw a number of DLLs under the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\KnownDLLs key but NOT msvcrt.dll - is this one hardcoded somewhere else I wonder ?

Oh sorry - I was not able to check this (no NT4 box available here Smile | :)

).

AFAIR (it's some time ago I struggled about this topic) the "know-dll" property is a transitive property. This means, that every DLL that is implicitly loaded from a known-dll is also treated as known-dll (The whole mechanism is for stability purposes, so this makes sense). I simply assume that some of the DLLs imports msvcrt.dll.

Hm...

I just checked it on my XP box. Using the "WinObj" tool from http://www.sysinternals.com[^] you can view all dlls that are actually treated as a known dll (also the imported ones). And I had to find out that even on XP msvcrt.dll is a member of this list Cry | :((

Obviously you just not ran into problems on Win2k and above, because it is shipped with a newer version of msvcrt.dll. Your side-by-side copy has never been loaded on any version of NT, it is just wasting disk space...

--

Daniel Lohmann

http://www.losoft.de
(Hey, this page is worth looking! You can find some free and handy NT tools there Big Grin | :-D

)

Drawing text

rsasalm_31-Jul-02 6:12

rsasalm_

31-Jul-02 6:12

Hi all,

I am learning window programming.
I want to draw text when my mouse moves on client rectangle.
I have two alternatives to choose from
1. TextOut
2. DrawText
Which one should I use and why?

I try with the simple test code using TextOut to draw text at point(10,30) on client rect
But I don't get it work.

the code is as follow:

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc ;
PAINTSTRUCT ps ;
RECT rect ;
TCHAR szBuff[10] = "Hello";

switch (message)
{

.....

case WM_MOUSEMOVE:

hdc = BeginPaint (hwnd, &ps) ;
TextOut (hdc, 10, 30, szBuff, lstrlen(szBuff));
EndPaint (hwnd, &ps) ;

return 0 ;

..........

}
}

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("HelloWin") ;
HWND hwnd ;
MSG msg ;
WNDCLASS wndclass ;

wndclass.style = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS ;
wndclass.lpfnWndProc = WndProc ;
wndclass.cbClsExtra = 0 ;
wndclass.cbWndExtra = 0 ;
wndclass.hInstance = hInstance ;
wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION) ;
wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ;
wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
wndclass.lpszMenuName = NULL ;
wndclass.lpszClassName = szAppName ;

if (!RegisterClass (&wndclass))
{
MessageBox (NULL, TEXT ("This program requires Windows NT!"),
szAppName, MB_ICONERROR) ;
return 0 ;
}
hwnd = CreateWindow (szAppName, // window class name
TEXT ("The Hello Program"), // window caption
WS_OVERLAPPEDWINDOW, // window style
CW_USEDEFAULT, // initial x position
CW_USEDEFAULT, // initial y position
CW_USEDEFAULT, // initial x size
CW_USEDEFAULT, // initial y size
NULL, // parent window handle
NULL, // window menu handle
hInstance, // program instance handle
NULL) ; // creation parameters

ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ;

while (GetMessage (&msg, NULL, 0, 0))
{
TranslateMessage (&msg) ;
DispatchMessage (&msg) ;
}
return msg.wParam ;
}

Once I get the above code to work then I would like that text "Hello" is followed when I move my mouse on the client area.
I would appreciate if you could give my a sample code for that or any suggesion.

Thanks in advance
regards
/rsasalm

Re: Drawing text

Jim Crafton31-Jul-02 6:21