How can I call a private destructor from a shared_ptr?

Question

I have a resource_manager class which maintains a std::vector > internally. resource_manager i

Answer 1

Perhaps declare shared_ptr<resource> as a friend? shared_ptr doesn't call the constructor, and should only destruct if your resource manager releases the pointer before all clients have destroyed their shared_ptrs. This won't allow clients to break the protection, but will allow clients to keep a resource alive against the resource_manager's "will."

Answer 2

You can pass a custom deleter to the shared pointer. So just create a deleter functor or function (up to you) which in turn is a friend of your class:

class Secret
{
  ~Secret() { }
  friend class SecretDeleter;
  friend void SecretDelFunc(Secret *);
};

class SecretDeleter
{
public:
  void operator()(Secret * p) { delete p; }
};

void SecretDelFunc(Secret * p) { delete p; }

std::shared_ptr<Secret> sp1(new Secret, SecretDeleter());
std::shared_ptr<Secret> sp2(new Secret, SecretDelFunc);