Is there a reason why weak_ptr's cannot be compared with ==, or tested in a conditional? If I have two weak_ptr's, I thought it to be strange that I have to do: (w1.lock() == w2.lock()) And to test if a weak_ptr is the empty weak_ptr: if ( !(w1.lock()) ) which seems kind of awkward. Looking at the implementation, I see how the copy constructor is defined using lock. I understand what the comments are saying there. Perhaps there are some multithreaded issues that prevent equality testing I don't see. I would like the semantics that w1 and w2 compare to be equal whether or not the object they are pointing to are valid or not. I'm not sure if weak_ptrs become "empty" when the object they point to is destroyed (because there's no way to test for "emptyness" or "nullness" of a weak_ptr), but if they do I can see how the equality test can't work, but not the conditional test. Even so, why is there not an operator == provided that locks both weak_ptr? Is it acceptable (the documentation didn't make it clear to me), to use if ( w1.expired() ) to test if simply if w1 is "null" or "reset". What I am trying to do is have a "current" pointer that takes the value of something I want to be set (or note the fact that nothing is set), but I don't care if the object dies while that pointer is set -- in fact I don't want to keep it alive because I don't have an easy way to call reset on current were I to make it a shared_ptr. Jason