C / C++ / MFC

Aabid4-Jan-09 23:11

4-Jan-09 23:11

This Code gives output as Access violation ...Can anybody tell me what is wrong there....

#include <windows.h>
#include <stdio.h>
void main()
{
char * szTemp, *cmdline;

cmdline = (char *)malloc(sizeof (char) * 1000);
if(cmdline)
{
strcpy(cmdline, "skdjofhdsjfodhfjdhgkjfhgkjdfhgkfhgkjdfhgk");
int len = strlen(cmdline);

szTemp = (char *)malloc(sizeof (len) + 1);
if(szTemp)
{
strcpy(szTemp, cmdline);
puts(szTemp);
}
}
if(cmdline)
{
free(cmdline);
cmdline = NULL;
}
if(szTemp)
{
//Access Violation When We Free szTemp
free(szTemp);
szTemp = NULL;
}

return;
}

Re: Access Violation ....Very Interesting

CPallini4-Jan-09 23:16

CPallini

4-Jan-09 23:16

Oh, yes, it is veeeeery interesting.
Big Grin | :-D

BTW: The error is in the line below, can you spot it?

Aabid wrote:
szTemp = (char *)malloc(sizeof (len) + 1);

Hint: sizeof(len) is 4!
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: Access Violation ....Very Interesting

ThatsAlok4-Jan-09 23:26

ThatsAlok

4-Jan-09 23:26

Aabid wrote:
szTemp = (char *)malloc(sizeof (len) + 1);

I believe it should be (char *)malloc(sizeof (char)* len + 1);. actually you need to have buffer copy commandline into szTemp. but instead of allocating proper buffer to it, you are allocating on buffer for 4 character + 1 for NULL.

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Re: Access Violation ....Very Interesting

CPallini4-Jan-09 23:42

CPallini

4-Jan-09 23:42

ThatsAlok believe it should be (char *)malloc(sizeof (char)* len + 1);.

That should be

sizeof(char) * (len+1)

if sizeof(char) was indeed relevant... Roll eyes | :rolleyes:

Pardon my nitpick attitude. Big Grin | :-D

Re: Access Violation ....Very Interesting

ThatsAlok4-Jan-09 23:48

ThatsAlok

4-Jan-09 23:48

CPallini wrote:
if sizeof(char) was indeed relevant...

Yeap i know.. Old programming bad-habit Smile | :)

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Re: Access Violation ....Very Interesting

CPallini5-Jan-09 1:16

CPallini

5-Jan-09 1:16

Actually it is a good habit and proves helpful when dealing with TCHARs.
Big Grin | :-D

Re: Access Violation ....Very Interesting

Radhakrishnan G.4-Jan-09 23:39

Radhakrishnan G.

4-Jan-09 23:39

Please check the statement
szTemp = (char *)malloc(sizeof (len) + 1);
check with following
szTemp = (char *)malloc(len + 1);

Re: Access Violation ....Very Interesting

Radhakrishnan G.4-Jan-09 23:40

Radhakrishnan G.

4-Jan-09 23:40

sorry I was late..
Please ingnoe

#pragma

zon_cpp4-Jan-09 22:58

zon_cpp

4-Jan-09 22:58

Hi!
how do i work with

#pragma

command, to ignore a warning number in my project? (in Compiling)
please help me

Zo.Naderi-Iran

Re: #pragma

CPallini4-Jan-09 23:12

CPallini

4-Jan-09 23:12

What about documentation [^]?
Smile | :)

Re: #pragma

ThatsAlok4-Jan-09 23:23

ThatsAlok

4-Jan-09 23:23

you....... hummm Poke tongue | ;-P

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Re: #pragma

ThatsAlok4-Jan-09 23:22

ThatsAlok

4-Jan-09 23:22

// Disable warning messages 4507 and 4034.
#pragma warning( disable : 4507 34 )

// Issue warning 4385 only once.
#pragma warning( once : 4385 )

// Report warning 4164 as an error.
#pragma warning( error : 164 )

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Re: #pragma

zon_cpp4-Jan-09 23:30

zon_cpp

4-Jan-09 23:30

thanks
but, where i write this command in my MFC project?

Zo.Naderi-Iran

Re: #pragma

ThatsAlok4-Jan-09 23:47

ThatsAlok

4-Jan-09 23:47

you can write this in any header/C/C++ file, above your code!

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Re: #pragma

zon_cpp4-Jan-09 23:45

zon_cpp

4-Jan-09 23:45

oh, ok, thanks
i write this command in first line of Header file.
this is right,
thank you

Zo.Naderi-Iran

Re: #pragma

ThatsAlok5-Jan-09 0:10

ThatsAlok

5-Jan-09 0:10

my pleasure!

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

information Bitmap Structure

CuteAshaVC++4-Jan-09 21:52

CuteAshaVC++

4-Jan-09 21:52

How to read Bitmap file using BITMAPFILEHEADER structure. Can any one give some guideline regarding this ?

Re: information Bitmap Structure

Mark Salsbery4-Jan-09 22:07

Mark Salsbery

4-Jan-09 22:07

All the info you need to parse and load a BMP file is linked to in the
BITMAPFILEHEADER documentation. Here's the link:

Bitmap Storage[^]

There's all kinds of examples around, probably many here on Code Project Dot Com.

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: information Bitmap Structure

CuteAshaVC++4-Jan-09 22:16

CuteAshaVC++

4-Jan-09 22:16

i used that BITMAPFILEHEADER structure, but bfType variable in that structure is not giving proper value, i.e it is giving 0 instead of "BM".please further give some more solution in this.

Re: information Bitmap Structure

Emil - Gabriel5-Jan-09 4:13

Emil - Gabriel

5-Jan-09 4:13

"please further give" some more info on what you're trying to do.

Re: information Bitmap Structure

CuteAshaVC++5-Jan-09 16:25

CuteAshaVC++

5-Jan-09 16:25

Actually i m trying to change the bitmap of an exe externally without making any changes in resource file(.rc) of that application.now i m able to retrieve the bitmap file data as well as exe bitmap data, but unable to change exe bitmap.it errazing original bitmap of an exe, when i m calling UpdateResource function of MFC.

Re: information Bitmap Structure

Emil - Gabriel5-Jan-09 19:50

Emil - Gabriel

5-Jan-09 19:50

If you can't get the correct values for the BITMAPINFOHEADER structure (the 'BM' signature), then the resource you're trying to edit is probably not a bitmap or it is compressed.

Re: information Bitmap Structure

Mark Salsbery5-Jan-09 6:01

Mark Salsbery

5-Jan-09 6:01

Then the structure isn't valid or you're doing something wrong.

You'll need to post the code you're using to read the header structure(s).

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: information Bitmap Structure

Hamid_RT4-Jan-09 22:48

Hamid_RT

4-Jan-09 22:48

Seehere[^] it explains to you all you need.

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

design pattern

hrishiS4-Jan-09 21:43

hrishiS

4-Jan-09 21:43

Hi experts,
could anyone please tell me where can I find docs(or sites), to learn design pattern implementation using c++/ vc++(MFC).

Thank u so much
Himanghsu

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