C / C++ / MFC

18-Feb-09 19:08

Hello all,

I am creating PROJECT in vc++ 2005.
I got this error while running the program:

Error:

Unhandled exception at 0x7849affe (mfc80ud.dll) APP.exe: 0xC0000005: Access violation reading location 0xcccccccc.

At afxsock.inl file:

Line where error is coming:

AFXSOCK_INLINE int CAsyncSocket::SendTo(const void* lpBuf, int nBufLen, const SOCKADDR* lpSockAddr, int nSockAddrLen, int nFlags)
{ return SendToHelper(lpBuf, nBufLen, lpSockAddr, nSockAddrLen, nFlags);

My code is:

m_sSocket->SendTo(&msg, sizeof(char),MAINW_R_PORT,IP,0);

CAN ANYONE HELP ME IN RECTIFYING THE ERROR.

THANKS

Hamid_RT18-Feb-09 19:15

Hamid_RT

18-Feb-09 19:15

I think your problem of first parameter of SendTo(const void*,how did you se msg?

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

priyankapriyanka19-Feb-09 18:37

19-Feb-09 18:37

i even tried type casting as msg is char datatype but its not working.
Thanks

Cedric Moonen18-Feb-09 20:15

Cedric Moonen

18-Feb-09 20:15

What is msg ? Are you only sending 1 byte of data (sizeof(char) will have 1 as a result) ?

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

priyankapriyanka19-Feb-09 18:39

19-Feb-09 18:39

yes i am sending one byte of data as char msg='v',but its not working.

Thanks

Ash_VCPP18-Feb-09 20:47

18-Feb-09 20:47

Hi,Even i faced the same problem,you must have created some array with new and either forgot to delete it or deleting it after the value is changed.

Thanks A Ton
Ash_VCPP

priyankapriyanka19-Feb-09 18:48

19-Feb-09 18:48

i hav nt created any array as such only one character i am sending with msg='v'.can u please tell me how you solved your problem,i will try to do that

Thanks

Ash_VCPP18-Feb-09 22:21

18-Feb-09 22:21

I dont see any issue with the code, but if you can then please go for win32 socket apis you will feel better....like
1.s = socket(AF_INET, SOCK_STREAM, 0);
2.connect(.....);
3.and finally send() and recv()

Thanks A Ton
Ash_VCPP

priyankapriyanka19-Feb-09 18:58

19-Feb-09 18:58

i am working with connectionless protocol....there is no need of connect there.is there ne diff between win32 socket api or MFC socket API.As i have gone through later one....please do tell me tat.

Thanks alot.

Ash_VCPP19-Feb-09 21:11

19-Feb-09 21:11

well i am not quite sure coz every time i used win32 apis not mfc.......so in that respect i can assist you.......please review ur code to check new-delete funda......i feel somewhere you are deleting a variable from heap whose value is changed.....

Thanks A Ton
Ash_VCPP

priyankapriyanka19-Feb-09 21:59

19-Feb-09 21:59

if u don't mind can i send u code because i am not finding any way to search for the deleted variable
thanks for your reply

Ash_VCPP22-Feb-09 20:04

22-Feb-09 20:04

Hi Priyanka,
You can send me the code in which the problem is with the error message which u are getting.....

Thanks A Ton
Ash_VCPP

Stephen Hewitt19-Feb-09 1:42

Stephen Hewitt

19-Feb-09 1:42

Most likely an uninitialized local variable (the compiler sets these to 0xCCCCCCCC in debug builds).

Steve

priyankapriyanka19-Feb-09 18:53

LoadLibrary cand call MFC DLL's fucntion

19-Feb-09 18:53

there is no uninitialized local variable.....can u please tell me how to check tat is there uninitialized local variable is there or not in solution file or not

akira3218-Feb-09 18:57

akira32

18-Feb-09 18:57

I meet a problem when I call the another MFC DLL's function.

I create two projects.

First project is called maxProjectMFCDLL, which is a MFC DLL project.

maxProjectMFCDLL.def's content as below:

LIBRARY "maxProjectMFCDLL"

EXPORTS
fDoExport @1

maxProjectMFCDLL.cpp's additional content as below:
int fDoExport(int a)
{
MessageBox(NULL,"name","Warn",MB_OK);
return TRUE;
}

Second project is called TestDialog, which is a MFC Dialog project.
I add a button to the dialog and add the function OnBnClickedButton1 for clicking the button.

void CTestDialogDlg::OnBnClickedButton1()
{
typedef int (CALLBACK* D_MYEXPORT)(int);

HMODULE l_mod;
D_MYEXPORT l_export=NULL;
int l_ret=0;

l_mod=LoadLibrary(L"..\\maxProjectMFCDLL.dll");

if (l_mod!=NULL)
{
int a=1;
l_export=(D_MYEXPORT)GetProcAddress(l_mod,"fDoExport");
l_ret=l_export(a);
FreeLibrary(l_mod);
}
}

After I build the Frist and Second projects, run the Second project. VC++ appear a error message(http://cid-fbeb6373d9321a7f.skydrive.live.com/self.aspx/Questions/MFC%20DLL.JPG).
The message is "Run-Time Check Failure #0 - The value of ESP was not properly saved across a function call. This is usually a result of calling a function declared with one callinc convention with a function pointer declared with a different calling convention."

Could somebody tell me how to solve this problem?

I put my complete source code at http://cid-fbeb6373d9321a7f.skydrive.live.com/self.aspx/Questions/3ds%20max%20Plugin%20Two%20Project%20Q2.rar

«_Superman_»18-Feb-09 19:03

«_Superman_»

18-Feb-09 19:03

In maxProjectMFCDLL.cpp declare the function as

int __stdcall fDoExport(int a)
{
MessageBox(NULL,"name","Warn",MB_OK);
return TRUE;
}

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

akira3218-Feb-09 19:11

akira32

18-Feb-09 19:11

Thank you, «_Superman_». I finally solve this problem. May I ask where do you get the answer? (read which book or see which web)

«_Superman_»18-Feb-09 19:17

«_Superman_»

18-Feb-09 19:17

This was from personal experience Smile | :)

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