Multiple Inheritance in Objective C

Cocoa, Coffee and Life


Multiple Inheritance in Objective C is not supported. The reason for not supporting this mechanism might be the fact that it would have been too difficult to include in the language or the authors thought it is a bad programming and design decision. However, in various cases multiple inheritance proves to be helpful. Fortunately objective C does provide some workarounds for achieving multiple inheritance. Following are the options:

Option 1: Message Forwarding

Message Forwarding, as the name suggests, is a mechanism offered by Objective C runtime. When a message is passed to an object and the object does not respond to it, the application crashes. But before crashing the objective c runtime provides a second chance for the program to pass the message to the proper object/class which actually responds to it. After tracing for the message till the top most superclass, the forwardInvocation message is called. By overriding…

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