objective c - ObjC: can't subclass NSUserNotification -

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as title says, can't subclass nsusernotification. well, can write , compile subclass can't subclassed objects @ runtime: if create instance of subclass , test class @ runtime _nsconcreteusernotification. why?

you run class cluster. not subclassed, discussed here: http://www.mikeash.com/pyblog/friday-qa-2010-03-12-subclassing-class-clusters.html


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