Of your examples, I believe only dereferencing 0 is undefined behavior. The rest are, I believe, implementation defined. It is implementation defined behavior w

Of your examples, I believe only dereferencing 0 is undefined behavior. The rest are, I believe, implementation defined. It is implementation defined behavior which allows C to be used across heterogenous systems. I talk about the difference elsewhere in this thread: https://news.ycombinator.com/item?id=10839389 https://news.ycombinator.com/item?id=10839389