Re: [Boost-users] Event system using signals2

Subject: Re: [Boost-users] Event system using signals2
From: Frank Mori Hess (fmhess_at_[hidden])
Date: 2011-10-28 21:25:36

On Friday, October 28, 2011, Chris Cranford wrote:
> // base class for event system tracking
> class EventTrackedObject : public boost::signal2::trackable {
> public:
>   EventTrackedObject() { }
>   ~EventTrackedObject() { }
> };
> 
> class MyObject : public EventTrackedObject {
> public:
>   MyObject(EventDispatcher* pDispatcher) {
>     pDispatcher->addListener(E_MY_EVENT,
> boost::bind(&MyObject::OnMyEvent, this));
>   }
>   ~MyObject() { }
> 
>   void OnMyEvent(void) { }
> };
> 
> The problem with this I found is that the tracked object appears to be
> getting copied at the time the boost::bind is passing itself to the
> addListener() method.  Is there a way to avoid this so that the
> tracked object's disconnect happens as expected?

I don't see how thats possible.  Is it failing to disconnect just because 
the bind functor is getting copied into a boost::function due to the 
prototype of addListener?  As was posted here recently, I don't think 
boost::function support visit_each to allow detection of trackable objects.  
One possibility is to make addListener pass its functor parameter as a 
template type instead of a boost::function.