Re: [GUI] The register/unregister callbacks issue

Peter Achten writes:

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In my opinion a programmer should not have to register/unregister callbacks explicitly.

I don't understand what you're proposing in its place.

You say that on X you do need to [un]register callbacks and on Windows you use a filter function to determine whether or not to use the callback. Either way, it seems that there is some mechanism which lets the backend (windows, X, Motif, etc) know that you no longer need to receive events of that type so the API is going to have to provide appropriate functions. That is, there will be a way to register to receive those events and a way to stop receiving those events. Whether they register and unregister a callback or change a bitset defining which events to receive or do something else is largely irrelevant. What I am saying is that a good GUI program already tells the user (and

At 14:51 19-3-03 +0000, Alistair Reid wrote: therefore also the backend) what events it will respond to. It will disable/enable menu(elements), it will disable/enable window(elements). As a consequence the API has no need for an additional register/unregister mechanism. The filter function is a convenient and light-weight means of additionally telling the backend what kind of events you're (not) interested in in case of enabled gui elements (in particular mouse and keyboard events). Regards, Peter