Crate nexio 

nexio — a verified, single-core io_uring runtime.

Design constraints

1. Owned buffers only. The kernel holds a raw pointer from SQE submission until the matching CQE arrives. Borrowed &mut [u8] cannot model an external, uncancellable writer.

2. Leak-until-real-completion cancellation. Dropping an in-flight op submits a best-effort ASYNC_CANCEL and moves the buffer into the reactor slab. Buffer freed only when the real CQE lands.

3. !Send tasks, one reactor per thread. No work-stealing. Multi-core: N independent reactors + SO_REUSEPORT sharding.

4. Verification-first. Pure-Rust layer (slab, Op state machine) targets Miri + Kani. Syscall-adjacent layer targets integration tests at high queue depth.

Re-exports

pub use blocking::spawn_blocking;

pub use executor::block_on;

pub use executor::join2;

pub use executor::select2;

pub use executor::spawn;

pub use executor::yield_now;

pub use executor::JoinSet;

pub use profile::HardwareProfile;

pub use reactor::Reactor;

Modules

addr

Asynchronous address resolution.

blocking

A thread pool for work that would block the reactor thread.

buf

Owned buffer types.

compat

Adapters between nexio’s owned-buffer streams and the poll-based I/O traits the wider ecosystem uses (tokio::io::AsyncRead/AsyncWrite, and hyper’s Read/Write).

executor

Single-threaded !Send task executor.

fs

Asynchronous file I/O backed by io_uring using owned buffers.

net

Networking on top of the nexio reactor.

process

Spawning and talking to child processes.

profile

Self-adaptive hardware and OS profile.

reactor

Thread-local io_uring reactor.

signal

Signal handling.

sync

Asynchronous synchronization primitives and channels.

time

Asynchronous time utilities: io_uring timeouts on the io_uring backend, the reactor’s timer map on the portable backend.

Functions

io_uring_available

Return true if io_uring is compiled in and permitted by the kernel/sandbox in the current process.

run_sharded

Run factory(i) to completion on threads independent reactors, one OS thread each, and return every result in shard order.

run_sharded_auto

Run factory(i) on one shard per available CPU (respecting Linux cgroup quotas), returning every shard’s result in shard order.

Attribute Macros

main

Marks an async fn main to be executed on the nexio runtime.

test

Marks an async fn test to be executed on the nexio runtime.