[whytevuhuni]

Here's a problem with that:

    Cannot start a runtime from within a runtime. This happens because a function (like `block_on`) attempted to block the current thread while the thread is being used to drive asynchronous tasks.

https://play.rust-lang.org/?version=stable&mode=debug&editio...

[thinkharderdev]

Right, because this would deadlock. But it seems like Zig would have the same issue. If I am running something in a evented IO system and then I try and do some blocking IO inside it then I will get a deadlock. The idea that you can write libraries that are agnostic to the asynchronous runtime seems fanciful to me beyond trivial examples.

[dwattttt]

Fixed it for you

https://play.rust-lang.org/?version=stable&mode=debug&editio...

[tcfhgj]

just pass around handles like you do in zig, alright?

also: spawn_blocking for blocking code

[whytevuhuni]

But that's the thing, idiomatic Rust sync code almost never passes around handles, even when they need to do I/O.

You might be different, and you might start doing that in your code, but almost none of either std or 3rd party libraries will cooperate with you.

The difference with Zig is not in its capabilities, but rather in how the ecosystem around its stdlib is built.

The equivalent in Rust would be if almost all I/O functions in std would be async; granted that would be far too expensive and disruptive given how async works.