emweb
Touch up documentation on Wt::WSignal
The documentation was missing qualifications concerning under which conditions the signal would NOT be disconnected. That is, for instance if you pass a lambda function object (which doesn't inherit from Wt::Core::observable), Wt::WSignal has no way to unregister or disconnect the signal.
By the way, it looks like there's no way to disconnect from a Wt::WSignal, right? After this code:
other->widget_changed().connect([](){std::cout << "bark\n";});
the only way for that signal handler to get disconnected is if other deletes its widget_changed signal (which will remove all listeners)? I guess that makes sense...that's why you have Wt::Core::observable, right?
connect() always returns connection object, on which you can call disconnect(), so you can always disconnect a slot.
The slot isn't really automatically disconnected when the observable goes away, so it's inaccurate to say so. What really happens is that the slot is wrapped in a function that checks whether the observing_ptr is valid before executing the slot. As it is right now, the slot will not be cleaned up; it simply won't do anything.
Thank you for your pointers! I just noticed this undocumented Wt::Signals::connection when perusing the source. I verified that the return value is mentioned in the docs! (https://www.webtoolkit.eu/wt/doc/reference/html/classWt_1_1Signal.html#aed69704ae147dbb551c3074c8214940c) Thank you for the pointer!