So if you wrote the following:
[magicObject performSelector:@selector(performMagicWithNumber:) withObject:[NSNumber numberWithInteger:2] afterDelay:1.0];

As a C function:

performMagicWithNumber(magicObject , 2);

Obviously you don’t have the delay there, and your acting upon the “magicObject”

I think your confusing event driven programming, with OO programming (Cocoa Programming is both).

In terms of the hand off between objects in OO programming, as soon as you call a method on a object, that method is carried out. Once that method has completed control returns to the object that called that method. This is exactly the same way that functions work in procedural programming.

Classes are simply structs under the hood, and methods are simply functions that can only be called on a single class. OO programming just makes code cleaner and more maintainable.

Most Cocoa applications are also event driven, so when you touch a iPhone’s screen it triggers off a chain of events. But unless the application is threaded, this event has to wait until the current thread is idle until it can be carried out. Things still get queued like in procedural programming, but obviously events can come in in a variety of orders if an application is being driven by the user.

I am familiar using performSelector calls to call methods, but I don’t understand how NSNumber is involved with that call? Please explain more on that.
Also, I’m having a lot of difficulty with understanding the hand off from one class to the next. Since, unlike procedural programming where the computer waits for a function to complete before continuing with the next line of code, Objective C just keeps on going regardless if the method(function) has completed.

Thanks in advance for your help!