[boost] weak_ptr doc problem

The weak_ptr docs says this: weak_ptr(); Effects: Constructs an **empty** weak_ptr. Postconditions: use_count() == 0. long use_count() const; Returns: if *this is **empty**, an unspecified nonnegative value; otherwise, the number of shared_ptr objects that share ownership with *this. use_count() seems underspecified and contradicts weak_ptr(). It should return exactly 0 when *this is empty. -- Daniel Wallin