The second way, which I've called "interface", although perhaps "inheritance" or some other word would better describe it, is how, for example, WxWindows does things.
Getting off topic here for a second, but thats a bad example. wxWindows uses callbacks (and besides, theres nothing stopping you from subclassing a Tk::Button).

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In reply to (ot) Re: Event based programming: Callbacks or "Interfaces"? by PodMaster
in thread Event based programming: Callbacks or "Interfaces"? by BUU

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