C ++升压信号和带有不同参数的插槽？

Question

Can a C++ signal be linked to slots with different parameter lists?

ie one slot takes 1 parameter, the other one takes 2, etc...

And you then call that signal with 1 or 2 parameters and it calls the corresponding slot?

Answer 1

No, the arity of a signal instance is defined by its type. If you examine the definition of the boost::signals2 template class (or the deprecated boost::signals ):

template<typename Signature, 
         typename Combiner = boost::signals2::optional_last_value<R>, 
         typename Group = int, typename GroupCompare = std::less<Group>, 
         typename SlotFunction = boost::function<Signature>, 
         typename ExtendedSlotFunction = boost::function<R (const connection &, T1, T2, ..., TN)>, 
         typename Mutex = boost::signals2::mutex> 
class signal : public boost::signals2::signal_base {

The calling signature of the signal and its slots are fixed in the template parameters.

A workaround would be to define an Event argument type that can contain multiple kinds of data, eg defined by subclasses.