RE: [Boost-Users] Preventing Cycles with shared_ptr

From: Jim.Hyslop (jim.hyslop_at_[hidden])
Date: 2003-07-17 09:36:23

Jason Winnebeck wrote:
> I am converting my old network library that uses explicit memory 
> management to use shared_ptr where appropriate.  So far this has gone 
> well but I am having problem with cycles.
[...]

> One could use a weak pointer in the Generator to the 
> Listener, but then 
> the Listener may die as soon as it is registered.
That's OK, though - each time the Generator wants to use the Listener, it
constructs a shared_ptr out of the weak_ptr it has. If the shared_ptr is
NULL, the Generator knows the Listener has gone away, and can take the
appropriate steps to unregister the Listener.

> ... the Listener is defined by the user. So I prefer to 
> make the task as easy as possible on the user -- so I want to 
> allow the 
> user to use weak or strong references if possible so he 
> doesn't have to 
> worry about cycles.
If you want to make things easy for the user, don't offer them a choice.
Choice means complexity. Complexity is bad. Require the user to use a
shared_ptr to the Generator.

-- 
Jim