Re: [sigc] how to use signal as slot?

[Regis Duchesne <hpreg vmware com>]

IIRC sigc::signal now has a make_slot() method that returns a sigc::slot. When that returned slot is invoked, 
it emits the signal.
—
hpreg

> Le 7 sept. 2015 à 7:48 PM, Martin Bickel <martin asc-hq org> a écrit :
>
> Hi all,
>
> I'm currently converting an application from sigc++ 1.2 to sigc++ 2 (tested 2.4.1 and 2.2.10).
>
> In 1.2, I could take a signal as a slot and connect it to another signal:
>
> SigC::Signal0<bool> signal_detected;
> SigC::Signal0<bool> alarm;
> signal_detected.connect( alarm );
>
>
> In 2.x , it works for Signals with return type void:
>
> sigc::signal<void> signal_detected;
> sigc::signal<void> warning;
> signal_detected.connect( warning ) ;
>
>
> but changing the return value to bool gives a compiler error:
>
>
> #include <sigc++/sigc++.h>
> #include <iostream>
>
> bool warn_people()
> {
>    std::cout << "There are aliens in the carpark!\n";
>    return true;
> }
>
> int main()
> {
>    sigc::signal<bool> signal_detected;
>    sigc::signal<bool> warning;
>
>    warning.connect( sigc::ptr_fun(warn_people) );
>    signal_detected.connect( warning ) ;
>
>    signal_detected();
>    return 0;
> }
>
>
> /home/martin/software/libsigc++-2.4.1/sigc++/functors/slot.h:103:36: error: void value not ignored as it 
> ought to be
>       return (typed_rep->functor_)();
>
>
> Is there any way to use signals as slots without writing an adaptor function that emits the second signal?
>
> Regards
> Martin
>
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