objective-cclangheader-filesivar

Is there any way to add an iVar that's not in the header file (not using LLVM 2.0 or later) in Objective-C?

I recently learned that you can add ivar in a class extension with LLVM2.0. (gcc can't do this) This is somehow really private iVar because other users don't it's existence since it's not in the header file. like:

//SomeClass.h
@interface SomeClass : NSObject {

}
@end

//SomeClass.m
@interface SomeClass ()
{
    NSString *reallyPrivateString;
}
@end

@implementation SomeClass

@end

But this does rely on the compiler. Is there any other way to declare an ivar that's not in the header file?

Solution

  • The only place to declare instance variables is in the interface or a class extension (which is really an extension of the interface). But you can effectively add instance variables at any time with the modern runtime using the associated object functions.