Re: Event loop hangup when using TimeoutSource and IdleSource

[Chris Vine <chris cvine freeserve co uk>]

On Thu, 24 Sep 2009 16:28:58 -0400
Jim Hodapp <james hodapp gmail com> wrote:
> 
> That's a good tip, I am inheriting from sigc::trackable for the
> Emsac class. This might be part of the problem. If I don't inherit
> from sigc::trackable, what's the proper way of cleaning up the
> functor slot?
> 
> Thanks,
> 
> Jim

Sorry, our e-mail fetching and dispatching is too quick and we are
trading misaligned e-mails!

Ah well, if you are trying to create slots representing non-static
methods of an object deriving from sigc::trackable in two different
threads, then you are in trouble.  This is a real trap for the unwary
when using libsigc++ in multi-threaded programs.

An alternative is the boost::signal2 library, which is thread safe,
(not boost::signal, which isn't) although I have own (much simpler) one
which I use when thread safety is important which I can send you if you
want.

Otherwise you need to do it by hand.  Be careful though that
sigc::connection is not thread-safe either.

To clean up a functor slot not connected to a sigc::signal object, you
can just let it go out of scope (if a local object) or call delete on
it (if it is allocated on freestore).  If the latter, make sure it was
created in the same thread as the one which deletes it if it represents
a non-static method of an object deriving from sigc::trackable.

Chris