Re: [gtkmm] Using a despatcher to provide thread safe signals with parameters

[Maurizio Umberto Puxeddu <mauriziopuxeddu yahoo it>]

I think you can push data in a dedicated queue in a thread an pop it in
the dispatcher's callback. Depending on the data structure used, you may
need to protect the queue with a Mutex while you are pushing/poping
objects (it could be simply be a std::list<YourMessage *> instead of a
lock free fifo).

Maurizio Umberto Puxeddu.

On Tue, 2003-04-22 at 18:02, Dan Alderman wrote:
> Hi,
> 
> Can someone here please help me, I think I'm about to go mad.
> 
> I have been looking at the examples provided within the gtkmm/sigc++ et
> al documentation but am still very confused.
> 
> I have 3 distinct parts to a simple system, a GUI (view), some data (a
> model) and a "MegaManipulator" to manipulate the data (controller).  I
> have been using normal signals to notify a drawing area that the
> underlying data that it uses to draw itself has changed.  The underlying
> data is changed by the MegaManipulator in a separate thread created in
> main().  As I am now aware I cannot use normal signals when using
> threads and I need to use a Glib::Dispatcher.  Unfortunately this poses
> a problem for me.  The signal that I have been using sends 2 vital
> pieces of information, the location of the change and it's value (this
> saves redrawing the entire area which is a hex display of a byte
> array).  If I am to use a dispatcher I can no longer send this
> information because it is effectively a Slot0 type signal and not a
> Slot2 which is what I need.
> 
> The SigC::bind method looked like it did what I wanted but it appears I
> can only bind static data and not variables.
> 
> Can someone here provide some insight or examples showing me how I can
> achieve this?  I have looked at dispatcher.cc example which uses a
> Glib::Dispatcher but this doesn't provide any example on how to ship the
> data in a signal.
> 
> Thanks for your help,
> 
> Dan.
> -- 
> =====================================================================
> Dan Alderman                Software Engineer
> 
> OneEighty Software Ltd.     Phone: +44 20 8680 8712
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