libxev

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