47 struct weak_iterator  struct
55     typedef std::set<weak_ptr<Derived> > set_type;
56     typedef typename set_type::iterator base_iterator;
58     weak_iterator()  in weak_iterator()  function
65     weak_iterator(base_iterator iter, set_type *set)  in weak_iterator()  argument
76     shared_ptr<Derived> const &dereference() const  in dereference()
81     void increment()  in increment()
87     bool equal(weak_iterator<Derived> const &that) const  in equal()
92     void satisfy_()  in satisfy_()
105     shared_ptr<Derived> cur_;
106     base_iterator iter_;
107     set_type *set_;