Are "#define new DEBUG_NEW" and "#undef THIS_FILE" etc. actually necessary?

Question

When you create a new MFC application, the wizard creates the following block of code in almost every CPP file:

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

and sometimes it also adds this:

#undef THIS_FILE
static char THIS_FILE[] = __FILE__;

I would like to remove this code from my CPP files if it is redundant. I am using an MFC app with C++/CLI on VS2008.

I have tried running in Debug after deleting this code from a CPP, and it seems to work fine. "new"ing variables work fine, there are no leaks, and ASSERT dialogs show the correct filename and jump to the offending line.

Can anyone tell me what it does and whether it's safe to delete it?

Thanks
[d3m0n]

Answer 1

It is perfectly safe to delete this. It's a debugging aid; leaving it in will generate warnings in the output window of any memory leaks you have when the program exits.