libxev

Also worth checking out libxev[1] by Mitchell Hashimoto. It’s a Zig based event loop (similar to libuv) inspired by Tigerbeetle’s implementation. [1] https://github.com/mitchellh/libxev

Ghostty uses Mach ports on OS X in addition to kqueue. Source is here: https://github.com/mitchellh/libxev/blob/main/src/backend/kq...

I'm surprised that whatever IO primitive is used on Mac doesn't work on OpenBSD. Mac has select and some variant of kqueue, right? What is ghostty doing there that doesn't work on OpenBSD? E.g., here it is kqueue-aware on FreeBSD: https://github.com/mitchellh/libxev/blob/34fa50878aec6e5fa8f... Might not be that different to add OpenBSD. Someone would begin here: https://github.com/mitchellh/libxev/blob/main/src/backend/kq... It's about 1/3 tests and 2/3 mostly-designed-to-be-portable code. Some existing gaps for FreeBSD, but fixing those (and adding OpenBSD to some switch/enums) should get you most of the way there.

It scales to complex examples as well. Retained memory would be handled with its own allocator: for a large data structure like an LRU cache, one would initialize it with a pointer to the allocator, and use that internally to manage the memory. Blocking (or rather, non-blocking, which is clearly what you meant) IO is a different story. Zig had an async system, but it had problems and got removed a couple point releases ago. There's libxev[0] for evented programs, from Mitchell Hashimoto. It's not mature yet but it offers a good solution to single-threaded concurrency and non-blocking IO. I don't think Zig is the best choice for multithreaded programs, however, unless they're carefully engineered to share little to no memory (using message passing, for instance). You'd have to take care of locking and atomic ops manually, and unlike memo

io_uring support is obviously great & excellent, fulfills the "high performance" part well. brought an immediately smile to my face. i was not expecting "Wasm + WASI" support at all. that's very cool. implementation is wasi_poll.zig (https://github.com/mitchellh/libxev/blob/main/src/backend/wa...). not to be unkind, but this makes me wonder very much if WASI is already missing the mark, if polling is the solution offered. gotta say, this is some very understandable clean code. further enhancing my sense that i really ought be playing with zig.

For zig take a look at https://github.com/mitchellh/libxev and https://github.com/rsepassi/zigcoro

You might be interested in a pure Zig implementation of these primitives by Mitchell in his "libxev" event loop library: https://github.com/mitchellh/libxev

As said by @laserbeam there is no implementation of concurrency built-in Zig language, just primitives. There is one event loop in the stdlib, but it has some limitations and there is some discussion to change it or remove it https://github.com/ziglang/zig/issues/8224 Some Zig libraries implementing an event loop: - libxev by Mitchell Hashimoto https://github.com/mitchellh/libxev - one from the Tigerbeetle DB https://github.com/tigerbeetledb/tigerbeetle/tree/main/src/i... They both use kernel concurrency features (io_uring/epool on Linux, kqueue on MacOS). They are quite low level and do not implement a lightweight threading model comparable to Go concurrency.