Question

Does anyone know how I can, in platform-independent C++ code prevent an object from being created on the heap? That is, for a class ‘Foo’, I want to prevent users from doing this:

Foo *ptr = new Foo; 

and only allow them to do this:

Foo myfooObject; 

Does anyone have any ideas?

Cheers,

Answer 1

Nick’s answer is a good starting point, but incomplete, as you actually need to overload:

private:     void* operator new(size_t);          // standard new     void* operator new(size_t, void*);   // placement new     void* operator new[](size_t);        // array new     void* operator new[](size_t, void*); // placement array new 

(Good coding practice would suggest you should also overload the delete and delete[] operators — I would, but since they’re not going to get called it isn’t really necessary.)

Pauldoo is also correct that this doesn’t survive aggregating on Foo, although it does survive inheriting from Foo. You could do some template meta-programming magic to HELP prevent this, but it would not be immune to ‘evil users’ and thus is probably not worth the complication. Documentation of how it should be used, and code review to ensure it is used properly, are the only ~100% way.