Re: CString Convert to LPCTSTR - C / C++ / MFC Discussion Boards

C^hris L^osinger13-Sep-06 5:08

13-Sep-06 5:08

you are mixing C/C++ runtime libraries.

make sure all libraries that link into your final EXE are using the same C/C++ RTL . check this in Project/Settings/General (Microsoft Foundation Classes) and Project/Settings/ C/C++ / Code Generation / Use Runtime library.

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CString Convert to LPCTSTR

rxgmoral13-Sep-06 3:59

rxgmoral

13-Sep-06 3:59

CString Convert to LPCTSTR
i write DLL file,it is static dll
i want CString type Convert to LPCTSTR
but error

Code:
<<<<<<<<<<<dll file="">>>>>>>>>
<<<<<<<a.h>>>>>>>
class AFX_NOVTABLE dll
{
public:
__declspec(dllexport) LPCTSTR Fun();
};

<<<<<<<a.cpp>>>>>>
LPCTSTR dll::Fun()
{
CString Rxg=_T("rxg");
LPCTSTR lpszStr=Rxg.GetBuffer();
return lpszStr;
}

<<<<<<<<exe>>>>>>>>>
#pragma comment(lib,"dll.lib")
#include "A.h"
..................
dll d;
LPCTSTR b=d.Fun();

error,why
thank Smile | :)

Re: CString Convert to LPCTSTR

prasad_som13-Sep-06 4:05

prasad_som

13-Sep-06 4:05

rxgmoral wrote:
error,

what it states ?

Prasad
Notifier using ATL

Re: CString Convert to LPCTSTR

Zac Howland13-Sep-06 4:20

Zac Howland

13-Sep-06 4:20

CString has an operator for casting to LPCTSTR. There is no need to write code to do it, it is already done for you.

On top of all that, you are creating a memory leak while trying to duplicate code that is written for you.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: CString Convert to LPCTSTR

toxcct13-Sep-06 4:21

toxcct

13-Sep-06 4:21

rxgmoral wrote:
LPCTSTR dll::Fun()
{
CString Rxg=_T("rxg");
LPCTSTR lpszStr=Rxg.GetBuffer();
return lpszStr;
}

you return a local pointer...

TOXCCT >>> GEII power

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Re: CString Convert to LPCTSTR

David Crow13-Sep-06 4:30

David Crow

13-Sep-06 4:30

rxgmoral wrote:
LPCTSTR lpszStr=Rxg.GetBuffer();

If you aren't going to be modifying the contents of Rxg, there's no need to call GetBuffer().

rxgmoral wrote:
error,why

Don't know.

"Talent without discipline is like an octopus on roller skates. There's plenty of movement, but you never know if it's going to be forward, backwards, or sideways." - H. Jackson Brown, Jr.

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

Re: CString Convert to LPCTSTR

Steve S13-Sep-06 6:34

Steve S

13-Sep-06 6:34

1. First, you have a CString which is only temporary. When Fun() ends, the CString object will be destructed.
2. As has been pointed out, GetBuffer() isn't needed, since there's a perfectly good cast operator for LPCTSTR.
3. As written, the temporary CString (Rxg) will get locked by GetBuffer(). This will no doubt cause problems when the temporary is destructed, since the CString data is now locked.

To get string data back from the DLL function, you could pass in a destination buffer and size as parameters, and after checking size, you can then fill in the string. To retain the semantics of Fun(), have it return the address of the destination buffer (although the parameter should be LPTSTR, not LPCTSTR).

Steve S
Developer for hire

Re: CString Convert to LPCTSTR

ThatsAlok13-Sep-06 18:51

ThatsAlok

13-Sep-06 18:51

rxgmoral wrote:
LPCTSTR dll::Fun()
{
CString Rxg=_T("rxg");
LPCTSTR lpszStr=Rxg.GetBuffer();
return lpszStr;
}

better you make memory in heap before sending it outside of function.. though getbuffer create the memory in heap.. but it need subsequent call of releasebuffer for releasing the memory.. which is rather difficult from out side better would be....
LPTSTR lpszStr=new TCHAR[Rxg.GetLength()+1];
lstrcpy(lpszStr,Rxg);
return lpszStr;

"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
Support CRY- Child Relief and You

Re: CString Convert to LPCTSTR

Hamid_RT14-Sep-06 8:39

Hamid_RT

14-Sep-06 8:39

if you want to use GetBuffer then call ReleaseBuffer

WhiteSky

[Message Deleted]

KKumarTG13-Sep-06 3:44

KKumarTG

13-Sep-06 3:44

[Message Deleted]

Re: Exception in C++

Cedric Moonen13-Sep-06 3:46

Cedric Moonen

13-Sep-06 3:46

Yes, it's called a debugger Roll eyes | :rolleyes:

Cédric Moonen
Software developer

Charting control [Updated - v1.1]

Re: Exception in C++

Zac Howland13-Sep-06 4:13

Zac Howland

13-Sep-06 4:13

If you are the one throwing it, and you are using Microsoft's compiler, you can use the __FILE__ and __LINE__ directives as a part of your exception message.

class custom_exception : public exception
{
public:
	custom_exception(const string& file, const string& line, const string& msg)
	{
		_Msg = file;
		_Msg += ":";
		_Msg += line;
		_Msg += "::";
		_Msg += msg;
	}

	string getMessage() const
	{
		return _Msg;
	}
private:
	string _Msg;
};

void MyFunction() throw(...)
{
	// something went wrong, need to throw
	throw custom_exception(__FILE__, __LINE__, "Something went wrong here!");
}

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: [Message Deleted]

ThatsAlok13-Sep-06 18:52

ThatsAlok

13-Sep-06 18:52

KKumarTG wrote:
[Message Deleted]

Message Deletion is sin here!

"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
Support CRY- Child Relief and You

Re: [Message Deleted]

Hamid_RT14-Sep-06 8:39

Hamid_RT

14-Sep-06 8:39

Wheres your question?

WhiteSky

matlab file (m-file) to c++

Haoman1713-Sep-06 3:42

Haoman17

13-Sep-06 3:42

how can I convert a matlab file to c++??????

please help me!!!!!!!!;)

Re: matlab file (m-file) to c++

Jun Du13-Sep-06 8:15

Jun Du

13-Sep-06 8:15

I am not aware of any m2c converter, but this CP article shows you can build a DLL from a m-file and then call it in C/C++ applications.

Best,
Jun

Share OpenGL Displaylists in MDI Applications

olaebo13-Sep-06 2:59

olaebo

13-Sep-06 2:59

Hi,
is it possible to share OpenGL Displaylists in MDI Applications? I would like to do the following:
1) compile some displaylists
2) Make some CView CDocument Objects
3) Use all or some of the displaylists in different CView`s

Many Thanks
Olaf

Re: Share OpenGL Displaylists in MDI Applications

nadiric13-Sep-06 5:46

nadiric

13-Sep-06 5:46

I believe display lists are limited to an OpenGL rendering context. Although you can share rendering contexts across windows (by changing the device context), they must all share the same pixel format. (found in OpenGL Superbible pg. 658)

hRC = wglCreateContext(hDC); //initially create rendering context
wglMakeCurrent(hDC,hRC); //change to a different hDC, keeping the original hRC

Can't say I have actually done this...

Re: Share OpenGL Displaylists in MDI Applications

cmk13-Sep-06 8:07

cmk

13-Sep-06 8:07

wglShareLists

...cmk

Save the whales - collect the whole set

Vc++ express edition

Anu_Bala13-Sep-06 2:49

Anu_Bala

13-Sep-06 2:49

Hi,
We have developed one Win32 Console application in vc++6 and(named as A.exe),we are using this exe in my vc++ 6 application in shared memory and it works correctly.

But i created that win32 Console Application(A.exe) in vc++2005 Express edition,( built with no error, i got a EXE)my vc++6 application shows some application error.

I compared that vc++ 6 EXE(A.exe) and Vc++2005 Express edition(A.exe),vc++6 shows 246KB but express edition EXE shows only 88KB.

Whats the problem in this?

Anu

Re: Vc++ express edition

David Crow13-Sep-06 2:59

David Crow

13-Sep-06 2:59

Anu_Bala wrote:

I compared that vc++ 6 EXE(A.exe) and Vc++2005 Express edition(A.exe),vc++6 shows 246KB but express edition EXE shows only 88KB.

Whats the problem in this?

Why would you think that's a problem? The size of a program on disk is indicative of very little.

Re: Vc++ express edition

Anu_Bala13-Sep-06 18:04

Anu_Bala

13-Sep-06 18:04

When i use this A.exe in my application it shows application error so i thought the size is vary from previuos thats why the error has occured.
Is there any solution for this?

Anu

windows explorer

radhika2813-Sep-06 2:18

radhika28

13-Sep-06 2:18

Hi,
How can we display windows explorer in the tree control,which is placed in the form view .

Thanks in advance,
Radhika.

Re: windows explorer

sujtha13-Sep-06 2:22

sujtha

13-Sep-06 2:22

Create splitter control. Inside the splitter control , create the tree control on left side and list control on right side.

Re: windows explorer

radhika2813-Sep-06 2:46

radhika28

13-Sep-06 2:46

i want to display files and folders from the windows explorer into a treecontrol which is placed in a form view of my application.How can i do that.

Thanks in advance,
Radhika.

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