Re: [Boost-users] Problem with boost::signal. How to call just one slotin signal

From: Juho Mäkinen (juho.makinen_at_[hidden])
Date: 2005-06-07 23:48:29

> Allow me to offer a suggestion from what I understand of your description of the problem:
> 1- For your special callback, save it off somewhere as a boost.function<>
> 2- then call the boost.function<> you have saved before calling your signals

Although you said you didn't fully understant my question, I managed
to solve my problem with your suggestions =)

I basicly used boost.function<> instead of the .slot_type, and
for my luck, boost.signal.connect( ) accepted boost.function<>
as it's parameter :)

Thanks alot, 

> Brian
> 
> 
> > -----Original Message-----
> > From: boost-users-bounces_at_[hidden] [mailto:boost-users-
> > bounces_at_[hidden]] On Behalf Of Juho Mäkinen
> > Sent: Monday, June 06, 2005 11:56 PM
> > To: boost-users_at_[hidden]
> > Subject: [Boost-users] Problem with boost::signal. How to call just one
> > slotin signal
> >
> > Hello.
> >
> > I'm having problems with boost::signal. I have a simple callback
> > system:
> >
> > typedef boost::signal<void (const String &)> StringCallbacks;
> > TSharedPtr<StringCallbacks> stringCallbacks;
> >
> > stringCallbacks contains void (Const String &) -callback functions.
> > New callback functions are registered into the callback system with
> > registerCallback -function:
> >
> > template<class VarType>       class SettingUpdater {
> >   private:
> >     VarType & reference;
> >
> >     SettingUpdater(VarType & var) : reference(var) { }
> >
> >   public:
> >     void operator()(const String & setting)
> >     {
> >        // do someting irrelevant for the question here
> >        // with the reference -variable
> >     }
> > };
> >
> > boost::signals::connection registerCallback(StringCallbacks::slot_type
> > callback)
> > {
> >   // PROBLEM: I'd like to call the callback once without calling every
> > callback
> >   // which are possibly registered already into the signal before this.
> >
> >   // Register the new callback into the signal.
> >   return stringCallbacks.get()->connect(callback);
> > }
> >
> > The actual usage of registerCallback:
> > int localVariable;
> > registerCallback(SettingUpdater<int>(localVariable));
> >
> > Question:
> > As you might already see above, I'd like to call the callback function
> > once in the registerCallback function without calling every callback
> > already registered in the stringCallbacks signal.
> > I first tried something like
> > String param = "foo";
> > callback(param);
> > but that won't compile.
> >
> > I also tried callback.get_slot_function()(param);
> > That compiles, but it won't execute the operator() -function in
> > SettingUpdater.
> >
> > Calling the signal will execute all callbacks registered, so the
> > SettingUpdater
> > function seems working. How I can execute the operator() function
> > in SettingUpdater<> inside registerCallback function by the
> > callback parameter passed to registerCallback function?
> >
> > Thanks in advance =)
> >
> >  - Juho Mäkinen
> >
> > _______________________________________________
> > Boost-users mailing list
> > Boost-users_at_[hidden]
> > http://lists.boost.org/mailman/listinfo.cgi/boost-users
> 
> 
> 
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