Preventing Stack Allocation

I don''t think you want this to be an exception, since allocating on the stack is fundamentally a compile time error. Detecing an error at runtime that could be detected at compile time is suboptimal. Consider instead this type of construct:

class OnHeapOnly {
  public:
    OnHeapOnly() {}
    static void free(OnHeapOnly * ptr) { delete ptr; }
  private:
    ~OnHeapOnly() {}
};

void f(void) {
  OnHeapOnly a; // error

  OnHeapOnly * ptr = new OnHeapOnly(); // ok

  // ...

  delete ptr; // error

  OnHeapOnly::free(ptr); // fine

}

Ahhhhh yes. I see.

Is would like to prevent stack allocation of a hierarchy of classes. Is there any way to put code in the base class to prevent derived classes from being stack allocated (without putting extra code in the child classes).

I think this is not exactly what you want, but it may work for you:

class OnHeap {
public:
   .... //some useful stuff


  void *operator new (size_t) { return ::new Base; }
  void operator delete (void *mem) { ::delete mem; }

protected: //allow the derived classes to call the constructor

  OnHeap () {}
  ~OnHeap () {}
};

...

OnHeap o;  //error

OnHeap *o = new OnHeap; //ok

delete o;

And as far as I know you can use the OnHeap''s version of new and delete for the derived classes... The only thing you need to do is to declare their constructors as protected.

Oxyd

- Unreadable code is code written on a piece of paper, but not the one, in which the programmer is using a space in the place you don''t.
- Real programmers aren''t afraid of goto

quote:

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Original post by Oxyd
And as far as I know you can use the OnHeap''s version of new and delete for the derived classes... The only thing you need to do is to declare their constructors as protected.

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Actually, you just need to protect the destructor, either via protected: or private:.

MSN

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