How to overwrite 'new' operation in c++

[Xianzheng Zhou]

Hi all,

I heard new/delete operations could be overwritten with customed functions.

Just wonderring how this could be achieved. Could any one post some
suggestions please

Thanks

Joe

 

[Gianni Mariani]

Hi all,

I heard new/delete operations could be overwritten with customed functions.

You don't "ovwerwite" in C++, you "override".

Just wonderring how this could be achieved. Could any one post some
suggestions please

The FAQ has some ideas:
http://www.parashift.com/c++-faq-lite/freestore-mgmt.html#faq-16.7
http://www.parashift.com/c++-faq-lite/dtors.html#faq-11.14

 

[Barry]

Hi all,

I heard new/delete operations could be overwritten with customed functions.

Just wonderring how this could be achieved. Could any one post some
suggestions please

Most of the cases, you *overload* /operator new/ to manage memory
yourself, as the heap offered by CRT is created to meet common needs,
not for small object allocation, etc.
And on some embedded platform, they even don't provide dynamic memory
allocation, you can only acquire a large trunk, then manage it yourself.
And you can even overload operator new for memory leak detection.
And as a rule of thumb, overload operator new and operator delete in
pair.

And some overloaded operator new is invented to meet special need, a
famous one is ELeave operator new on Symbian.

How to overload operator new? Find it in a textbook.

 

[James Kanze]

I heard new/delete operations could be overwritten with
customed functions.

I presume you mean "overridden", not "overwritten".

Just wonderring how this could be achieved.

In a very real way, it depends on the implementation, but for
all of the implementations I know, if you define an operator new
and an operator delete function, and arrange for them to be
linked in before the standard library is linked in, then your
versions will be used instead of the standard ones.

Note that you should never do this except at the final
application level (e.g. to use a debugging new/delete, instead
of the standard one).