Zio - async I/O framework based on libxev

Calder-Ty · November 3, 2025, 8:05pm

9 posts were split to a new topic: Thoughts on AI Coding

lalinsky · November 4, 2025, 12:30pm

I’ve refactored the coroutine code to be completely standalone, not depending on anything else inside zio, in case anybody wants to use it. Could even turn it into a library on its own. Also added RISC V support. And had a little fun implementing tiny channel for ping-pong test. Stack reservation on virtual memory will be a part of this standalone lib soon.

github.com/lalinsky/zio

src/coroutines.zig

main

// zig fmt: off
// SPDX-FileCopyrightText: 2025 Lukáš Lalinský
// SPDX-License-Identifier: Apache-2.0

const std = @import("std");
const print = std.debug.print;
const Allocator = std.mem.Allocator;
const builtin = @import("builtin");
const assert = std.debug.assert;

pub const DEFAULT_STACK_SIZE = if (builtin.os.tag == .windows) 2 * 1024 * 1024 else 256 * 1024; // 2MB on Windows, 256KB elsewhere - TODO: investigate why Windows needs much more stack

pub const stack_alignment = 16;
pub const Stack = []align(stack_alignment) u8;
pub const StackPtr = [*]align(stack_alignment) u8;

const WindowsTIB = extern struct {
    fiber_data: u64, // TEB offset 0x20
    deallocation_stack: u64, // TEB offset 0x1478
    stack_base: u64, // TEB offset 0x08

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lalinsky · November 4, 2025, 6:42pm

This took a bit of refactoring, to satisfy the way std.Io wants to do closures, but I have the first version of async/concurrent/await/cancel working. Now that I have this done, I/O operations should go much quicker. The zig-0.16 branch has a long way to go though, as std.posix is being removed and the code in libxev depends on it.