C / C++ / MFC

4-Jan-06 21:40

In embedded systems there is a use of function pointer

But where can we use this in VC++.
Cool | :cool:

Vikas Amin
Embin Technology
Bombay
vikas.amin@embin.com

Owner drawn4-Jan-06 21:51

Owner drawn

4-Jan-06 21:51

CALLBACK's

Love Forgives--Love Gives--Jesus is Love Smile | :)

<marquee direction="up" height="50" scrolldelay="1" step="1" scrollamount="1" style="background-color:'#44ccff'">
--Owner Drawn
--Nothing special
--Defeat is temporary but surrender is permanent
--Never say quits
--Jesus is Lord

Prakash Nadar4-Jan-06 21:51

4-Jan-06 21:51

vikas amin wrote:
In embedded systems there is a use of function pointer

But where can we use this in VC++

C++ virtual functions employes virtual table, which contains pointers to the virtual functions.

Think broadly, functions pointers can be designed and used in C/C++ and not neccessarly in Embedded system.

Callback functions are an example, Windproc is another example, many Win32 enumeration APIs employ function pointers.

-Prakash

vikas amin4-Jan-06 23:14

4-Jan-06 23:14

Can u tell me some example application
where i can implemt such things.

Cool | :cool:

Vikas Amin
Embin Technology
Bombay
vikas.amin@embin.com

Prakash Nadar4-Jan-06 23:24

4-Jan-06 23:24

vikas amin wrote:
Can u tell me some example application
where i can implemt such things.

google them Wink | ;)

-Prakash

vikas amin4-Jan-06 23:57

4-Jan-06 23:57

k thanks

Vikas Amin
Embin Technology
Bombay
vikas.amin@embin.com

Debug Vs Release

<color>Aljechin 4-Jan-06 21:37

<color>Aljechin

4-Jan-06 21:37

Could someone please explain me the actual differences? My colleague says its possible for one to get the entire source code of an application if the debug mode output is shipped. MSDN says the compiler will generate Debugging symbols. What are they? Why it will ship the source code with the output? What happens internally when I change the active configuration (debug to release and vice versa) and build the project?

Many thanks,
Aljechin Alexander

Eytukan4-Jan-06 21:43

4-Jan-06 21:43

release mode'd be the optimized one. while you are in development phase, you can use debugg mode. but once the program is perfectly ready , you shoud choose "release" mode. it will bring down the size completely.

>"My colleague says its possible for one to get the entire source code of an application if the debug mode output is shipped"

that's not true.

Check this one^

"But your mind is very complex, very tricky. It makes simple things complicated. -- that's its work. And for centuries it has been trained for only one thing: to make things so complicated that your life becomes impossible."- Osho

<marquee scrollamount="1" scrolldelay="1" direction="up" height="10" step="1">--[V]--

<color>Aljechin 4-Jan-06 23:34

<color>Aljechin

4-Jan-06 23:34

Thank you for reply. Quite an informative article.

Aljechin Alexander Cool | :cool:

Anilkumar K V5-Jan-06 0:44

Anilkumar K V

5-Jan-06 0:44

Better to do development in Release mode only. In case any issues change to Debug and correct then back to Release. as the code base increases and an error occurred at the end of development when changed to Release mode ONLY....What you do?

Anilkumar

Eytukan5-Jan-06 0:55

5-Jan-06 0:55

that's why then and there i take a copy of my project and test it with the Release Mode, mostly to check its size. and if i ever have problem in it. we have people here who can solve it at any point of time.so i never worry Smile | :)

<marquee scrollamount="1" scrolldelay="1" direction="up" height="10" step="1">--[V]--

ThatsAlok8-Jan-06 19:01

ThatsAlok

8-Jan-06 19:01

T-1000 wrote:
we have people here who can solve it at any point of time.so i never worry

Where ?

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

Eytukan8-Jan-06 20:21

8-Jan-06 20:21

here means, only CP!! and mostly people lik you Big Grin | :-D

<marquee scrollamount="1" scrolldelay="1" direction="up" height="10" step="1">--[V]--

Eytukan24-Jan-06 21:18

24-Jan-06 21:18

tester

S Douglas5-Jan-06 1:11

S Douglas

5-Jan-06 1:11

anilFirst wrote:
error occurred at the end of development when changed to Release mode ONLY....What you do?

Testing, that’s how you solve this problem. You should be testing the code base as you add features.

In other words at the very least stop development every once and a while and build a release version. Test all of features possible to insure everything works.

ZeePain! wrote:
This seems like one of those programs that started small, grew incrementally, building internal pressure, and finally barfed all over its source code sneakers. Or something.

thedailywtf.com[^]

Using a DLL having its own DialogProcedure

Stephen Hewitt9-Jan-06 2:23

Stephen Hewitt

9-Jan-06 2:23

When you're developing an application it is generally done using a debug build. The developer should build a release build from time to time to make sure no weird stuff is going on (release mode only bugs). Obviously the QA department should be testing the release builds. If you get a release only bug I have found that often the cause is related to the fact that in a debug build uninitialized locals are initialized to 0xCCCCCCCC (interestingly 0xCC in an __asm int 3 which is a breakpoint) but in release build no initialization is performed. The /GZ compiler option (Catch Release-Build Errors in Debug Build) can be a big help. Among other things this suppresses the 0xCCCCCCCC fill. This often makes the release only bugs show up in debug builds.

Steve

torbeli4-Jan-06 21:34

torbeli

4-Jan-06 21:34

Hi,

does anybody know how I can setup a DLL having its own Dialogprocedure?
I have tried with LoadLibrary/GetProcadress etc. I am able to call any functions that
are within the DLL. But when i Try to do a DialogBox(....) it seems to be rather "complicated".
I keep getting the 1814 error (The specified resource name cannot be found in the image file)
I have tried to have all files available in same directory. No Luck. My Code looks like this:

HINSTANCE hDll;
FARPROC aDll;
int rc;
hDll = LoadLibrary((LPSTR)"test.dll");
if ((int)hDll < HINSTANCE_ERROR)
{
ErrMsg();
return(0);
}
aDll = GetProcAddress(hDll, (LPSTR)"TestDialog");
if (aDll==0)
{
ErrMsg();
return(0);
}
rc = DialogBox(hInst, (LPCTSTR)IDD_TEST_DIALOG, hWnd, (DLGPROC) aDll);
if (rc==-1)
ErrMsg();

And i have tried to use the MAKEINTRESOURCE instead. No luck.
Seems to be something with in connection with the Resourcefile, but I am not able to find the one thing that might help me.

We are using Visual C++ 6.0. But we are not using any C++ related programming at all.
It is all pure C-code but with exentsion of *.cpp

Rgds
Torben

Re: Using a DLL having its own DialogProcedure

Prakash Nadar4-Jan-06 21:55

Re: Using a DLL having its own DialogProcedure

4-Jan-06 21:55

torbeli wrote:
rc = DialogBox(hInst, (LPCTSTR)IDD_TEST_DIALOG, hWnd, (DLGPROC) aDll);

try changing to
DialogBox(hDll , (LPCTSTR)IDD_TEST_DIALOG, hWnd, (DLGPROC) aDll);

-Prakash

torbeli4-Jan-06 22:51

torbeli

4-Jan-06 22:51

Tried it. AND IT WORKED. for (i=0; i<1000; i++) Thanks!
One of those 2 days problem solved within 5 minutes having somebody else looking at it!

I, for some reason got confused about the explanation of the DialogBox.
"Handle to application instance". I saw that as the handle to my .exe and not the new DLL
But now I can see that it make sence to use the new handle that I just created with LoadLibrary.

int DialogBox(
HINSTANCE hInstance, // handle to application instance
LPCTSTR lpTemplate, // identifies dialog box template
HWND hWndParent, // handle to owner window
DLGPROC lpDialogFunc // pointer to dialog

Many thanks
Rgds
Torben

Re: Using a DLL having its own DialogProcedure

Prakash Nadar4-Jan-06 23:21

Can i type cast a function ?

4-Jan-06 23:21

torbeli wrote:
int DialogBox(
HINSTANCE hInstance, // handle to application instance
LPCTSTR lpTemplate, // identifies dialog box template
HWND hWndParent, // handle to owner window
DLGPROC lpDialogFunc // pointer to dialog

I think the documentation assumed that the dialog resource would be in the application.

Since in this case the dialog is in the dll, the the instance handle of the dialog should have been passed to the API.

torbeli wrote:
for (i=0; i<1000; i++) Thanks!

You are welcome, I am glad that your problem is solved.

-Prakash

vikas amin4-Jan-06 21:33

Re: Can i type cast a function ?

4-Jan-06 21:33

Can i type cast a function ?{{NO}}

say i have a function as
void Fun(int);

I have a function pointer
void(*p_fun)(int,int);

Can i type cast the p_fun to point to fun .
I know logically this is a big error but is it possible syntactically.

Vikas Amin
Embin Technology
Bombay
vikas.amin@embin.com

Prakash Nadar4-Jan-06 22:00

Re: Can i type cast a function ?

4-Jan-06 22:00

p_fun has been declared that it is a pointer to a funtion with 2 params, so AFIK its not going to work.

-Prakash

Owner drawn4-Jan-06 22:13

Owner drawn

4-Jan-06 22:13

The sample code below illustrates how to use function pointers to call functions that take different parameters than those with which the pointer was declared. The function is cast to the type of the function pointer during the first assignment, then the function pointer is cast to the type of the function to be called. Using typedefs generally makes it easier than casting the pointer directly.

#include <stdio.h>

typedef int  (*myintchartype) (char *, char *);
typedef void (*myvoidtype) (void);
typedef int  (*myintvoidtype) (void);

int func1(char *, char *);
void func2(void);

void main(void)
{
   myintvoidtype ptr;

   ptr = (myintvoidtype) func1;
   ((myintchartype) ptr)("one", "two");

   ptr = (myintvoidtype) func2;
   ((myvoidtype) ptr)();
}

int func1(char *a, char *b)
{
   return printf("func1 took two parameters: %s and %s\n", a, b);
}

void func2(void)
{
   printf("func2 did not take any parameters\n");
}

You can type cast functions.

Love Forgives--Love Gives--Jesus is Love Smile | :)

Re: Can i type cast a function ?

Prakash Nadar4-Jan-06 22:44