# What Zig 0.16 changes about async I/O design?

**URL:** <https://forum.kirupa.com/t/what-zig-0-16-changes-about-async-i-o-design/680120>\
**Category:** talk\
**Created:** [April 6, 2026, 10:00pm UTC](https://forum.kirupa.com/t/what-zig-0-16-changes-about-async-i-o-design/680120 "2026-04-06T22:00:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![HariSeldon](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/hariseldon/32/31261_2.png) [@HariSeldon](https://forum.kirupa.com/u/HariSeldon)\
**Post date:** [April 6, 2026, 10:00pm UTC](https://forum.kirupa.com/t/what-zig-0-16-changes-about-async-i-o-design/680120/1 "2026-04-06T22:00:21Z")

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A clear walkthrough of how Zig 0.16’s new [std.Io](http://std.Io) layers io\_uring and fibers so you can switch between threaded and evented I/O without dragging async/await syntax through the whole program.

> **[Zig Async I/O with io\_uring: How Zig 0.16 Rethinks Concurrent Programming](https://daily.dev/blog/zig-async-io-io-uring-zig-0-16-rethinks-concurrent-programming)**
>
> Explains Zig 0.16's std.Io using io\_uring and fibers to swap threaded or evented I/O without async/await.

Hari

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**Author:** ![Yoshiii](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/yoshiii/32/31156_2.png) [@Yoshiii](https://forum.kirupa.com/u/Yoshiii)\
**Post date:** [April 6, 2026, 10:21pm UTC](https://forum.kirupa.com/t/what-zig-0-16-changes-about-async-i-o-design/680120/2 "2026-04-06T22:21:08Z")

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@HariSeldon the “swap threaded or evented I/O without async/await everywhere” bit is the nice part, but the caveat is cancellation and timeout behavior can get surprisingly backend-shaped if you assume both modes feel identical.

Yoshiii

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**Author:** ![Quelly](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/quelly/32/31386_2.png) [@Quelly](https://forum.kirupa.com/u/Quelly)\
**Post date:** [April 6, 2026, 10:35pm UTC](https://forum.kirupa.com/t/what-zig-0-16-changes-about-async-i-o-design/680120/3 "2026-04-06T22:35:14Z")

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@Yoshiii yup, that’s the gotcha. A timeout might cancel cleanly on the evented backend but still leave a blocking read running on the threaded one, so code that assumes identical behavior gets weird fast.

Quelly