Re: [Boost-users] [signals] thread-safe post-disconnect() cleanup

From: Timmo Stange (ts_at_[hidden])
Date: 2007-02-23 16:50:19

Frank Mori Hess wrote:

> However, my way also allows track() to be called an arbitrary number of 
> times before connecting the slot.  How would multiple tracked objects be 
> handled with a track(p).connect()/.connect_to() syntax? 

I suppose track() would return a reference to the slot_type, so that
you could do:

signal_type::slot_type( f, p1.get(), p2.get() ).track( p1 ).track( p2 
).connect_to(...);

> If you allow 
> track to take varying numbers of arguments, it requires the user to know 
> how many tracked objects there will be at compile time.  Being able to 
> call track() multiple times only requires knowing the number of tracked 
> objects at run time, which might be handy if the tracked objects are being 
> collected in a container.  I suppose you could overload track to accept a 
> container argument.
> 
> Also, support for the first alternative could be easily implemented using 
> the second, since whatever object is returned by signal::track() will have 
> both a reference to the signal and the slot in its connect() function.

Another question is if both alternatives should be provided, or if
tracking should only work when you create a slot_type object explicitly.

I'd also like to mention that you can effectively hide the tracking from
the connection setup site with the original implementation. If you only
provide a typedef for the functor you want to be used for the
connection, visit_each can collect the information automatically (or
at least in a way invisible to the connecting code).

Regards

Timmo Stange