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

From: Peter Dimov (pdimov_at_[hidden])
Date: 2007-02-23 12:22:06

Gottlob Frege wrote:
> On 2/23/07, Frank Mori Hess <frank.hess_at_[hidden]> wrote:
>>>
>>> Could you give a short example of how that would look with using
>>> bind and a simple free function expecting a pointer or reference to
>>> an object that should be tracked?
>>
>> Attached.
>>
>
>> From the attached:
>  boost::shared_ptr<coordinate> coord(new coordinate);
>  coord->x = 5;
>  sig.connect(boost::bind(&myfunction, boost::signalslib::track(coord,
> boost::ref(coord->x))));

I actually like the suggestion of just offering a way to add the tracked 
pointers manually. Either

sig.connect( boost::bind( myfunction, boost::ref(coord->x) ), coord );

or

sig.connect( boost::bind( myfunction, boost::ref(coord->x) ).track( coord );

Both look better on a syntactic level to me. In addition, I suspect that 
signalslib::track contains a race condition that is avoided by the other 
alternatives (but I haven't actually looked at it so I might be wrong; it's 
possible, if somewhat tedious, to implement it correctly).