Elysian Shadows

As I understand it, malloc and new both call HeapAlloc internally. The program I'm working on at the moment is a win32 application, so portability isn't really an issue. I'm not sure what the overhead in malloc and new does and if its really necessary or not. So if anyone knows please tell me.

Depends. If your using C++ libraries use new. If your using C libraries use malloc.

I would go into more detail but google a mouse click away.

I have never even heard of anybody bypassing malloc() or new on a win32 platform and just directly calling heapAlloc(). Either the overhead is absolutely tiny, or (more than likely) the overhead is inlined and optimized away by the compiler, so it's free. I wouldn't bother.

I looked through malloc.c and the overhead is really tiny. First it checks to see if you're trying to allocate more memory than the system could possibly allow. Then it checks to see if _crtheap (which I imagine is a handle to the default process heap) is null. After that it calls HeapAlloc and if that succeeds the function returns. You can supply your own memory handling function that's called in the event that HeapAlloc fails. This function is called until HeapAlloc can succeed or your function returns 0.
If anyone wants to try to do this then first call _set_new_mode(1), then call _set_new_handler passing a function like this:
int NewHandler(size_t size). To stop malloc from calling your new handler function call _set_new_mode(0). To clear the new handler call _set_new_handler(0).

Damn, that's good to know. Thanks for reporting the find.

It seems you would mainly use win32's native heap functions for dealing with user created heaps.