I think that we can rely on the fact that set will not change, but see: https://en.wikipedia.org/wiki/Multiset
I'm sorry, I don't understand why you say that? I don't want a multiset semantic, only a set semantic.
BTW, the error "File exists" is not really helpful. -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html