Re: Static signals (was:(no subject) )

[Antonio Coralles <noche suapie reflex at>]

sudrien fusemail com wrote:

> > Message: 5
> > Date: Wed, 16 Mar 2005 08:11:06  0100
> > From: Antonio Coralles <noche suapie reflex at 
> <mailto:noche suapie reflex at>>
>
> > > I have a derived widget - derived from an EventBox. It has a funtion
> "void
> > > doShowHidden(bool);".
> > >
> > > There are several instances of these derived widgets on different
> notebook
> > > pages - so it is not easy to get direct access to them. So is is 
> possible
> > > that I could call all their doShowHidden(bool) functions with a signal?
> > > They will all be either true or false - whatever the state of the
> checkbox
> > > is.
> > >
> > > So... how could I do that? All the examples of signals I've seen call
> > > functions within the same class.
> > >
> > > -Sud.
> >
> > One way of doing this is the following (there may be better ones): Add a
> > static signal to your class, und connect to that static signal in your
> > constructor(s). If you want then to sent a signal to all instances, just
> > trigger the static one ...
> >
> > antionio
>
>
> I /think/ I get what you are saying... but doesn't a static signal require
> a staic function? And static functions can only work with other static
> variables and functions - nothing can happen to specific instances...

Static functions in classes must not acces non-static data, but 
non-static methods may acces static variables/functions.

> And I've not read that signals can propagate to children in libsigc  ...
> It may be easier to maintain a list of pointers somewhere, so I can have
> direct access...
>
> -Sud.
> _______________________________________________

What i mean is something like this:

class Example
{
   public:
   Example()
   {
      signalForAllExamples().connect(sigc::mem_fun(*this, 
&Example::triggerMe));
   }
   Example(const Example& copyMe) { /* the same like for Example() */ }
   void triggerMe() { /* do something */ }  

   static sigc::signal<void> signalForAllExamples() { return 
sig_forAllExamples_; }

   private:
   static sigc::signal<void> sig_forAllExamples_;
};

A simple Example::signalForAllExamples().emit() should then do what you 
want ....

antonio