No, I don't think you can add ivar to en existing class. There is class_addIvar
function but it doesn't work with existing classes. In your case, SBApplication
already defined so you can't add an ivar into it.
I can suggest very simple solution - static/global (or both) variables. It can be, for example, BOOL
variable if you need just one variable. Or it could be an array of object-variable pairs if you want variable for every class instance. The latter will work just like a class ivar.