821206 - using DEBUG_NEW

[hamidi]

hi all
this is the whole of my program:

#include "stdafx.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

void main()
{
char *p=new char[10];
delete[] p;
}

i'm using visual studio .net
when i trace the flow of the program i see that the following override
of operator new in afxmem.cpp is called:

Ln 68: void* __cdecl operator new[](size_t nSize, LPCSTR lpszFileName,
int nLine)

i expect the overriden operator delete[] with the appropriate
prototype is called, that is:

Ln 83: void __cdecl operator delete[](void* pData, LPCSTR /*
lpszFileName */,
int /* nLine */)

but this is not the case. instead, the following operator delete[] is
called:

Ln 377: void __cdecl operator delete[](void* p)

why?

[John Harrison]

"hamidi" <ha****@yahoo.c om> wrote in message
news:85******** *************** ***@posting.goo gle.com...

hi all
this is the whole of my program:

#include "stdafx.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

void main()
{
char *p=new char[10];
delete[] p;
}

i'm using visual studio .net
when i trace the flow of the program i see that the following override
of operator new in afxmem.cpp is called:

Ln 68: void* __cdecl operator new[](size_t nSize, LPCSTR lpszFileName,
int nLine)

i expect the overriden operator delete[] with the appropriate
prototype is called, that is:

Ln 83: void __cdecl operator delete[](void* pData, LPCSTR /*
lpszFileName */,
int /* nLine */)

but this is not the case. instead, the following operator delete[] is
called:

Ln 377: void __cdecl operator delete[](void* p)

why?

Why not? There is no requirement for new and delete to have matching
argument types. And how could the compiler know that the delete you expect
to be called should be called? One delete looks exactly the same as another.

john

[Karl Heinz Buchegger]

hamidi wrote:

hi all
this is the whole of my program:

#include "stdafx.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

void main()
{
char *p=new char[10];
delete[] p;
}

i'm using visual studio .net
when i trace the flow of the program i see that the following override
of operator new in afxmem.cpp is called:

Ln 68: void* __cdecl operator new[](size_t nSize, LPCSTR lpszFileName,
int nLine)

i expect the overriden operator delete[] with the appropriate
prototype is called, that is:

Ln 83: void __cdecl operator delete[](void* pData, LPCSTR /*
lpszFileName */,
int /* nLine */)

but this is not the case. instead, the following operator delete[] is
called:

Ln 377: void __cdecl operator delete[](void* p)

why?

Why not?
The additional arguments in the new operator are used to track
memory allocations and where in your source they have happend.
A table is built which stores the memory address, the filename
and the linenumber. When a delete[] is done the corresponding entry
is removed from that table, so when the program finally exits, this
table theoretically should be empty. If it is not, the system can
tell you: "You made a memory allocation in file xxx at line yyy.
This memory has never been deleted".
So what could your form of delete[] tell the system what it doesn't
already know?

--
Karl Heinz Buchegger
kb******@gascad .at