C / C++ / MFC

26-Jun-06 4:39

Hey guys,

When I'm running my debugger, I am getting a strange problem that keeps occuring. If I click run, the debugger follow throughs the whole source code and gives me an access violation of 0xC0000005. If I do a run to cursor, then I am forced by the debugger to provide the location of CRT0.C. The program runs fine without the debugger, just doesnt output the correct results. Would anyone know the reason for that?

Thanks

Robbie

David Crow26-Jun-06 4:42

26-Jun-06 4:42

capricious_001 wrote:
If I click run...

Is that F5 or Ctrl+F5?

capricious_001 wrote:
The program runs fine...just doesnt output the correct results.

How can a program run fine but not output the correct results?

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

capricious_00126-Jun-06 4:59

26-Jun-06 4:59

DavidCrow wrote:

Is that F5 or Ctrl+F5?

With F5 I get an access violation. CTRL+F5 produces no run-time error and the program is executed.

DavidCrow wrote:
How can a program run fine but not output the correct results?

It does not fail at run-time, meaning there are no run-time errors, but the results it outputs, say to console, is not whats expected.

Sarath C26-Jun-06 4:51

Sarath C

26-Jun-06 4:51

check for missing resources.

SaRath.

"It is your attitude, not your aptitude, that determines your altitude - Zig Ziglar."
My Blog | Understanding State Pattern in C++

capricious_00126-Jun-06 5:01

26-Jun-06 5:01

SaRath C wrote:
check for missing resources.

What do you mean? Resources in the preprocesser directives? The debuggers resources? Or somewhere else?

Sarath C26-Jun-06 5:05

Sarath C

26-Jun-06 5:05

there's might have entries in the DoDataExchange function of deleted resources!

SaRath.

"It is your attitude, not your aptitude, that determines your altitude - Zig Ziglar."
My Blog | Understanding State Pattern in C++

capricious_00126-Jun-06 5:19

a map Resizing a map file;

26-Jun-06 5:19

SaRath C wrote:
there's might have entries in the DoDataExchange function of deleted resources!

Hey Sarath,

Do have any good tuts on how to use it, because msdn doesnt provide a good reference and I tried googling it, and the usage of it is vague.

I'm not using MFC, so if there is an alternate way of retreiving the desired output from this function would you know how?

hatemtalbi26-Jun-06 4:27

26-Jun-06 4:27

Hi all,

I created a map file like this :
HANDLE hMap=CreateFileMapping(hFile, NULL, _dwProtect, 0, _dwSize, _strMapName);

but now I need to increase its size and create a new view on it!! does someone know how to to that the right way??

Thank you so much Smile | :)

David Crow26-Jun-06 4:37

26-Jun-06 4:37

hatemtalbi wrote:
but now I need to...create a new view on it!!

To start over, can't you just call UnmapViewOfFile() followed by CloseHandle()?

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

hatemtalbi26-Jun-06 4:50

26-Jun-06 4:50

Yes, I did all that. But when I call mapViewOfFile() the secon time the whole size of the maapped file !!!

David Crow26-Jun-06 5:05

26-Jun-06 5:05

hatemtalbi wrote:
But when I call mapViewOfFile() the secon time the whole size of the maapped file !!!

Your sentence is incomplete. What happens when you call MapViewOfFile() the second time?

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

hatemtalbi26-Jun-06 5:10

26-Jun-06 5:10

for example when I resize the file from 4KB to 8KB, I expect that MapViewOfFile() return a buffer size of 8KB but I get only 4KB !!!

James Brown26-Jun-06 6:42

James Brown

26-Jun-06 6:42

This is to be expected - that is how file-mapping objects work.

You should use the ZwResizeSection native-API if you want to resize the file-mapping object. Lots of info on google about this.

James

http://www.catch22.net

hatemtalbi26-Jun-06 6:46

26-Jun-06 6:46

Sorry, I typed ZwResizeSection in google but I didn't get any results !!
please could you check the word orthography

thank you

Tabs with right close button (Firefox like)

James Brown26-Jun-06 7:43

James Brown

26-Jun-06 7:43

my mistake. try:

ZwExtendSection

http://www.catch22.net

Moak26-Jun-06 4:00

Moak

26-Jun-06 4:00

Hi,

I would like to change the standard CTabCtrl to get a little button on the far right side.

The number of tabs should be dynamic, so the control must reserve some space for the button (it shall not draw over the button when there is a high number of tabs). Do I need to write an ownerdraw control or maybe I can reuse CTabCtrl? Thanks for help.

/M

Re: Tabs with right close button (Firefox like)

Sarath C26-Jun-06 4:23

Sarath C

26-Jun-06 4:23

google in CP for owner-drawn tab control

Sa^Rath.

"Do Next Thing..."
My Blog | Understanding State Pattern in C++

Re: Tabs with right close button (Firefox like)

Moak27-Jun-06 0:26

Moak

27-Jun-06 0:26

Does this mean I have to write an ownerdraw control to get this functionality?

How to know if a pointer is valid?

hatemtalbi26-Jun-06 3:43

26-Jun-06 3:43

Hey,

does someone know how to check if a pointer is valid (was allocated by the application and can be used without problem) or no?

David Crow26-Jun-06 3:48

Re: How to know if a pointer is valid? [modified]

26-Jun-06 3:48

Have you looked into IsBadCodePtr(), IsBadReadPtr(), IsBadWritePtr(), or IsBadStringPtr()?

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

Stephen Hewitt26-Jun-06 16:53

Stephen Hewitt

26-Jun-06 16:53

You are asking for trouble if you rely on these APIs to tell if memory is safe to use. For example with heaps when you free a block it doesn't mean the memory is deallocated straight away; it can be marked as free and recycled. This is how heaps work. In short if IsBadReadPtr returns TRUE you know for sure that the memory isn't safe to read; but if it returns FALSE it does ***NOT*** mean that the memory is safe to use - it could be on the heap's free list for example. These API are only meant for debugging purposes and not for memory management in the manner your post alludes to.

Steve

David Crow27-Jun-06 3:08

27-Jun-06 3:08

Stephen Hewitt wrote:
These API are only meant for debugging purposes and not for memory management in the manner your post alludes to.

Hence my question. Smile | :)

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

Viorel.26-Jun-06 3:52

Viorel.

26-Jun-06 3:52

In Windows you can try IsBadReadPtr, IsBadWritePtr and IsBadStringPtr.

In MFC you can try AfxIsValidAddress and AfxIsValidString.

In case of run-time library, you can try _CrtIsValidPointer, _CrtIsValidHeapPointer and _CrtIsMemoryBlock.

hatemtalbi26-Jun-06 3:57