Re: Big Problem! How to overload operator delete?

Lighter wrote:


An operator delete overload is only called as the result of an
exception being thrown from the constructor of an object being created
with the corresponding new expression. That was a mouthful - here's an
example instead:

  void* operator new(std::size_t, float);
  void operator delete(void*, float);

  struct S { S() { throw 0; } };

  void test()
  {
    new (3.5f) S;
  }

In test, operator new is called, the constructor of S is called and
then the operator delete is called as part of stack unwinding.

By the way, this means defining a no_throw operator delete makes no
sense.

When deleting the object, the 'ugly' way is the correct way. For
example, say you have a custom heap, called SpecialHeap, that you want
to allocate and deallocate from:

  void test()
  {
     C* c = new (SpecialHeap) C;

     // ... code that uses c ...

     c->~C();
     operator delete(c, SpecialHeap);
  }

I generally find it easier and safer to use factory functions.

James

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