On Wednesday 30 June 2004 11:14 am, Neal Coombes wrote:
However, I would venture to claim that a signal being called without any slots is not a rare case. In fact I'd guess that might be the most likely case. Certainly, as a library writer, I cannot assume that all the signals I provide to my users are going to be used in every application.
My suggestion is to provide a default combiner that does the bare minimum, just call the slots:
namespace boost { struct default_combiner { typedef void result_type;
template<typename InputIterator> result_type operator()(InputIterator first, InputIterator last) const { while (first != last) *first++; } }; }
I believe this would solve the problem without restricting use of default signals to objects with default constructors, or to signals with at least one slot connected.
If you don't want to get any results back, just specify the return type of the slots as void, e.g., change boost::signal<int(int, int)> s; to boost::signal<void(int, int)> s; Doug