> AFAIK that's not supposed to happen if task A checks errno (or other > thread-local value) immediately after returning from the failed call. Tasks > are switched cooperatively within the scheduler thread.
Those semantics are true I think, and I believe will remain true, but they are not obvious. Hopefully this will get documented. The docs for the core::os calls should probably mention that you have to check errno without doing any intermediate I/O. What are the task switch boundaries? Is it just I/O? Or can non-inlined function calls also cause switches (this is for example where Erlang code replacement is allowed to happen). There's no way to know if some function does I/O transitively, so predicting task switches is not necessarily trivial. How often is this pattern used in C code? Are there other examples where thread-local storage is used for library state? jack. _______________________________________________ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
