On Thu, Jun 13, 2019 at 5:08 PM Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > I do not believe that posix itself actually requires that at all, > although extended standards may. So I tried to see if I could find what this perhaps alludes to. And I suspect it's not in the read/write thing, but the pthreads side talks about atomicity. Interesting, but I doubt if that's actually really intentional, since the non-thread read/write behavior specifically seems to avoid the whole concurrency issue. The pthreads atomicity thing seems to be about not splitting up IO and doing it in chunks when you have m:n threading models, but can be (mis-)construed to have threads given higher atomicity guarantees than processes. Linus