"Correct" way to return empty shared_ptr?

What is the 'correct' way to return a NULL/empty shared_ptr? For example, this works <snippet> shared_ptr<int> maybe_get_a_pointer() { shared_ptr<int> p; return(p); } </snippet> but seems 'klunky'. I've clearly missed something in the docs/examples somewhere. Can someone point me in the right direction? TIA