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

["Dan Alderman" <d alderman 180sw com>]

Thanks Maurizio, works great :-)

Dan.
----- Original Message -----
From: "Maurizio Umberto Puxeddu" <mauriziopuxeddu yahoo it>
To: "Dan Alderman" <d alderman 180sw com>
Cc: <gtkmm-list gnome org>
Sent: Tuesday, April 22, 2003 9:32 PM
Subject: Re: [gtkmm] Using a despatcher to provide thread safe signals
withparameters


> 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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>
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