Re: Cannot use DEBUG_NEW to trace this leak.

From:
David Wilkinson <no-reply@effisols.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Wed, 23 Jan 2008 15:21:47 -0500
Message-ID:
<efC1V2fXIHA.6140@TK2MSFTNGP02.phx.gbl>
Simon wrote:

Hi,

I have some old code that I am trying to use in my current project.
It uses standard lib and vectors.

The error I get is as follows.

//---------------
Detected memory leaks!
Dumping objects ->
{193} normal block at 0x016DA0A8, 16 bytes long.
Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD
Object dump complete.
//---------------

it does not tell me where the leak comes from.

I have narrowed down the code as follow where the error could be.
I would rather not change the code as much as possible.

//-------
// in the constructor
m_pData = new std::string[ someKnownSize + 1]
memset( m_pData, 0, (n+1)*sizeof(std::string) );
..

//-------
// The destructor
if( NULL != m_pData )
   delete [] ( m_pData );
m_pData = NULL;
m_nSize = 0;

//-------
// in a function
void add( std::string &s, int len )
{
   m_pData[m_nSize++] = std::string(s, len ) ;
}

//-------

if I remove the lines m_pData[m_nSize++] = std::string(s, len ) ;
then I have no leak.

The file with the error does not use #include "stdafx.h", (but it has
#include "windows.h")
and as such I cannot use:

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

What could be the problem and how can I find the leak?


Simon:

Is this in the application class? The application object (theApp) is a global
object, and the leak reporting mechanism may not work correctly.

If so, you might move this code to InitInstance().

Also, as Giovanni says, your design seems strange here.

--
David Wilkinson
Visual C++ MVP

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