class Foo {};


class OwnsAFoo
{
private:

   std::shared_ptr<Foo> owned;

public:
   OwnsAFoo(std::shared_ptr<Foo> foo): owned(foo)
   {}
}


int main()
{
   std::shared_ptr<Foo> a = new Foo;

   OwnsAFoo *owner = new OwnsAFoo(a);

   a = nullptr;

   delete owner; // Foo is destroyed inside of OwnsAFoo
}