Global operator delete - grammar

I have inherited an unchangeable C struct that contains pointers to (alloc'd) memory.

   typed开发者_如何学Cef struct {
     int id;
     int * val;
   } T;

I would like to use new and delete on these objects, and I was wondering if it was possible to overload delete at global scope. I don't have the option of rewriting the struct / class in the first place. The trouble is I cannot find the correct grammar. This is what I have - it compiles but obviously fails since the function is applied to all delete calls:

   void operator delete(void*p) throw() {
     T * t = reinterpret_cast<T*>(p);
     free(p->val);
   }

Am I attempting the impossible? I have read that the operator delete overload does not have to be a member function, but does that just provide a means to write a generic delete for all pointers?

Hmm, seems like a sledgehammer approach, if you are simply a user of this structure, and worried about the memory management aspect of it, and yet cannot modify it, why don't you wrap it in your code?

i.e.

class Sane_T
{
  public:
   Sane_T() 
   { 
     // do stuff 
   } 

   ~Sane_T()
   {
     // Now cleanup..
     if (_inst.val)
       free(_inst.val);
   }

  private:
    T _inst;
};