Question about some code that should crash but does not (release vs. debug & VS2003 vs. VS2008) - C / C++ / MFC Discussion Boards

ashish8patil2-Jul-09 20:22

2-Jul-09 20:22

What is woring in my following codes run time error is occuring for both code

int main()
{LPTSTR strResult;
LPTSTR strDefault=L"no";

DWORD d=255;
GetPrivateProfileString(L"data",L"Patchcab ",
strDefault,strResult,d,
L"D:\\TMP\\patchpolicy.ini");
printf("%s",strResult);

}

int main()
{
LPTSTR strResult=L"";
LPTSTR strDefault=L"no";

DWORD d=255;
GetPrivateProfileString(L"data",L"Patchcab ",strDefault,strResult
,d,L"D:\\TMP\\patchpolicy.ini");
printf("%s",strResult);
}

Re: GetPrivateProfileString() problem

«_Superman_»2-Jul-09 20:34

«_Superman_»

2-Jul-09 20:34

There is no memory allocated for the LpReturnedString parameter.
You're declaring it as LPTSTR strResult which is only a pointer.
You will need to do this -

TCHAR strResult[255];
DWORD d = 255;

Also change printf to _tprintf.

«_Superman_»
I love work. It gives me something to do between weekends.

Re: GetPrivateProfileString() problem

ashish8patil2-Jul-09 21:31

ashish8patil

2-Jul-09 21:31

thanks a lot.

STL find errors

thelonesquirrely2-Jul-09 13:34

thelonesquirrely

2-Jul-09 13:34

Hey, I think this is just a little mistake somewhere. I am new to using the STL algorithms, so i am totally botching it somehow.

My code looks like this:

typedef std::string Node;
typedef std::vector<Node> Cluster;

and down in the code i want to do this:
bool contains (const Cluster& cl, const Node& n)
{
Cluster::iterator it = find (cl.begin (), cl.end (), n);
(it == cl.end ()) ? return false : return true;
}

is that possible? or am i not allowed to do that? Thanks in advance!

Re: STL find errors

«_Superman_»2-Jul-09 16:49

«_Superman_»

2-Jul-09 16:49

Looks good except for the last return.
It should be return (it == cl.end ()) ? false : true;

«_Superman_»
I love work. It gives me something to do between weekends.

Re: STL find errors

CPallini2-Jul-09 20:48

CPallini

2-Jul-09 20:48

«_Superman_» wrote:
It should be return (it == cl.end ()) ? false : true;

return (it != cl.end());

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Re: STL find errors

«_Superman_»2-Jul-09 21:35

«_Superman_»

2-Jul-09 21:35

«_Superman_»
I love work. It gives me something to do between weekends.

Question about some code that should crash but does not (release vs. debug & VS2003 vs. VS2008)

Maximilien2-Jul-09 9:23

Maximilien

2-Jul-09 9:23

Howdy'

I have some very bad code that should crash but I'm having difficulty figuring out why it does not crash (or even give out warnings); it works in VS2003 in release&debug and in VS2008 in debug, not in release.

class Info
{
public:
	Info();
	Info(std::wstring s1, std::wstring s2);// : m_string1(_T("")),m_string2(_T("")){};
	std::wstring m_string2;
};
struct myStruct
{
	std::vector <Info*> m_JobInfoVector;
};

m_MyStruct = (myStruct*)malloc(sizeof (myStruct) );
ZeroMemory(m_MyStruct, sizeof(myStruct));
Info* p = new Info( std::wstring(_T("allo"))  );
m_MyStruct->m_JobInfoVector.clear();

Question : What happens to the vector member when the ZeroMemory is called ? and why it does not crash in debug but it does in release ?
Confused | :confused:

Thanks.
Max.

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Re: Question about some code that should crash but does not (release vs. debug & VS2003 vs. VS2008)

Stuart Dootson2-Jul-09 10:32

Stuart Dootson

2-Jul-09 10:32

Why worry? The code is erronous, so the result of executing it is undefined. Just replace your malloc with new myStruct...and don't, just don't ever write over a class with something like ZeroMemory - it just doesn't make sense. You have constructors to initialise structs and classes in C++.

But anyway - the error is in comparison of iterators (which clear does) - in VS2008, Debug mode iterators are different to Release mode iterators unless you specifically enable iterator debugging, which probably has something to do with it.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: Question about some code that should crash but does not (release vs. debug & VS2003 vs. VS2008)

Maximilien2-Jul-09 12:57

Maximilien

2-Jul-09 12:57

I know that, but I was wondering why it did not crash; anyway, the code has been fixed.

Thanks. Smile | :)

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Re: Question about some code that should crash but does not (release vs. debug & VS2003 vs. VS2008)

Christopher W. Smith2-Jul-09 20:39

Christopher W. Smith

2-Jul-09 20:39

I think you are assuming that a struct in C++ works the same way as a struct in plain old C, but alas it doesn't... well not really anyway.

When you introduce non-primitive data types into structs in C++ they cease to be simple "data structures" and become basically the same as classes only their members default to public instead of private.

My guess is when you try to overwrite the object you are writing over the beginning of its virtual table which probably contains extra debug information in debug mode. In release mode you are then probably overwriting more important class data.

Remember, the sizeof operator is not designed to get the size of an object or its virtual table.

http://en.wikipedia.org/wiki/Virtual_method_table[^]

Chris Smith

Re: Question about some code that should crash but does not (release vs. debug & VS2003 vs. VS2008)

Maximilien3-Jul-09 1:04

Maximilien

3-Jul-09 1:04

Thanks, that's probably it; me think i will look at the memory a little closer.

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how can i get file names dynamically?

santhosh-padamatinti2-Jul-09 8:50

santhosh-padamatinti

2-Jul-09 8:50

hi,
My program creates files dynamically for that I gave location as desktop.
This code I wrote inside a fr loop, that means how many times this loop continues that many number of files will be created. For this situation how can I mention path that should able to generate any number of files.

sampath-padamatinti

Re: how can i get file names dynamically?

Rajesh R Subramanian2-Jul-09 9:24

Rajesh R Subramanian

2-Jul-09 9:24

What are you talking about? You already said that you're creating files on the desktop. What is your query?!

It is a crappy thing, but it's life -^ Carlo Pallini

Re: how can i get file names dynamically?

Stuart Dootson2-Jul-09 9:32

Stuart Dootson

2-Jul-09 9:32

char directory[] = "my desktop";
for (int i=0;i<numFiles;++i)
{
   char filePath[MAX_PATH];
   sprintf(filePath, "%s\\%d.ext", directory, i);
   // Now filePath has a uniquely numbered path?
}

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: how can i get file names dynamically?

Madhu Nair2-Jul-09 18:27

Madhu Nair

2-Jul-09 18:27

In addition to Stuart's reply,

There is an API to create file names, uniquely GetTempFileName

It will give a filename in specified directory with the prefix. It will automatically set a unique file name if you insist to do so. Read the MSDN for detailed information. An example is given here

Re: how can i get file names dynamically?

Stuart Dootson2-Jul-09 20:34

Stuart Dootson

2-Jul-09 20:34

It probably would have been better to reply to the OP rather than me

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: how can i get file names dynamically?

Rajesh R Subramanian2-Jul-09 22:00

Rajesh R Subramanian

2-Jul-09 22:00

Stuart Dootson wrote:
It probably would have been better to reply to the OP rather than me

Hello Madhu Nair, I agree with Stuart.

Sorry, couldn't resist. Laugh | :laugh:

It is a crappy thing, but it's life -^ Carlo Pallini

Re: how can i get file names dynamically?

Stuart Dootson2-Jul-09 22:07

Stuart Dootson

2-Jul-09 22:07

Rajesh R Subramanian wrote:
I agree with Stuart

Of course you do - everyone agrees with me...if they know what's good for them Poke tongue | ;-P

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: how can i get file names dynamically?

Rajesh R Subramanian2-Jul-09 22:09

Rajesh R Subramanian

2-Jul-09 22:09

I'm not sure if you got the pun. I've modified the previous post to make it clearer. Smile | :)

It is a crappy thing, but it's life -^ Carlo Pallini

Re: how can i get file names dynamically?

Stuart Dootson2-Jul-09 22:09

Stuart Dootson

2-Jul-09 22:09

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: how can i get file names dynamically?

David Crow2-Jul-09 9:34

David Crow

2-Jul-09 9:34

I've really no idea as to what you are talking about but if I were to hazard a guess, are you wanting to create a different file each iteration of the loop?

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disable MFC dialog based Microsoft Web Browser showing context menu [modified]

JACyo2-Jul-09 6:39

JACyo

2-Jul-09 6:39

Hi everyone, I got a question about disabling context menu of the web browser and I've searched MSDN, this forum and goole. But seems most of the are either not Dialog Based (most of them use CHtmlView) or not quite same as what I see in my project.

I am using Visual Studio 2005 and Here is my steps of creating the application:

I use MFC application and choose dialog based. Then, in the dialog editor, I add Microsoft Web Browser into the toolbox, and then drag it into the dialog. After that, I right click on that control and choose Add Variable and leave everything default and give it a variable name "myBrowser". Then it automatically creates a explorer.h and explorer.cpp. The explorer.h contains a class declearation of "class CExplorer1 : public CWnd". Then I get stuck at this point. I've tried to declear a message map in explorer.h and find ON_WM_CONTEXTMENU() but seems doesn't work.

From the search of the internet, it seems that I need to implemente IDocHostUIHandler and there I can overload ShowContextMenu() and return S_OK to disable it. But with most of the information I got, seems most of them are for CHtmlView but not CWnd. So, I'd like to ask what I should do to disable the context menu of a Dialog Based Web Browser which inherit CWnd (or my approach is wrong?) and with Visual Studio 2005? (coz I see most of the information are VC++6 and I can't find the same thing in VS2005).

I am new to MFC and these kinds of browser things so my question maybe a stuipd question....
Thanks for any help.

modified on Thursday, July 2, 2009 7:32 PM

Re: disable MFC dialog based Microsoft Web Browser showing context menu

Stuart Dootson2-Jul-09 9:30

Stuart Dootson

2-Jul-09 9:30

I know this article's in VB, but...[^]

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: disable MFC dialog based Microsoft Web Browser showing context menu

JACyo2-Jul-09 15:45

JACyo

2-Jul-09 15:45

thanks, I've found that article too, but I am working with C++...

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