It’s surprising to me how much people seem to want async in low level languages. Async is very nice in Go, but the reason I reach for a language like Zig is to explicitly control those things. I’m happily writing a Zig project right now using libxev as my io_uring abstraction.
Using async in low level languages goes all the way back to the 1960's, became common in systems languages like Solo Pascal, Modula-2, with Dr.Dobbs and The C/C++ User's Journal having plenty of articles regarding C extensions for similar purposes.
Hardly anything radical.
When I look at historical cases, it seems different from a case today. If I’m a programmer in the 60s wanting async in my “low level language,” what I actually want is to make some of the highest level languages available at the time even more high level in their IO abstractions. As I understand it, C was a high-level language when it was invented, as opposed to assembly with macros. People wanting to add async were extending the state of the art for high level abstraction.
A language doing it today is doing it in the context of an ecosystem where even higher level languages exist and they have made the choice to target a lower level of abstraction.
But Zig's async is being designed to enable this low-level control.