template class restriction

Question

I\'m wondering if there is any way to restrict generating code for a template using custom conditions in my case i want to function foo to be called only if template class T has

Answer 1

Yes, following technique can be used (for public inheritance). It will cause an overhead of just one pointer initialization.

Edit: Re-writing

template
struct IsParentChild
{
  static Parent* Check (Child *p) { return p; }
  Parent* (*t_)(Child*);
  IsParentChild() : t_(&Check) {} // function instantiation only
};

template
void foo ()
{
  IsParentChild check;
// ...
}