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I think the biggest issue is that in a vtable you jump directly to the method by index, and with objc_msgsend it looks up a string in a hash table.

Mostly the difference is ints vs. strings in my opinion.

As well in C++ if you don't mark your method virtual you can bypass all the vtable crap.

I love ObjC but method resolution is far more expensive than in C++, especially non-virtual methods.



Method selectors in Obj-C don't have to be strings, as long as you can turn a string into one occasionally.

You do still need to do a hash lookup to get the method implementation, since the selector table changes at runtime and objects have to safely respond to unhandled selectors and all that.


I meant string as in char* not NSString, selectors specifically the SEL datatype are strings

They certainly don't have to be, however, they are.

    SEL selector = @selector(applicationDidBecomeActive:);
    printf("%s",(char*)(void*)selector);
    // Prints applicationDidBecomeActive:




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