Extended utilities for working with files and filesystems in Rust.

This is a fork of the fs2-rs crate, the aim for this fork is to support async and replace libc by rustix.

Installation

• std

  [dependencies]
  fs4 = { version = "0.13", features = ["sync"] }
  

• async-std runtime

  [dependencies]
  fs4 = { version = "0.13", features = ["async-std"] }
  

• fs-err v2

  [dependencies]
  fs4 = { version = "0.13", features = ["fs-err2"] }
  

• fs-err-tokio v2

  [dependencies]
  fs4 = { version = "0.13", features = ["fs-err2-tokio"] }
  

• fs-err v3

  [dependencies]
  fs4 = { version = "0.13", features = ["fs-err3"] }
  

• fs-err-tokio v3

  [dependencies]
  fs4 = { version = "0.13", features = ["fs-err3-tokio"] }
  

• smol runtime

  [dependencies]
  fs4 = { version = "0.13", features = ["smol"] }
  

• tokio runtime

  [dependencies]
  fs4 = { version = "0.13", features = ["tokio"] }
  

Features

• file locks.
• file (pre)allocation.
• file allocation information.
• filesystem space usage information.
• async-std support
• fs-err
• smol support
• tokio support

License

fs4 is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE, LICENSE-MIT for details.

Copyright (c) 2025 Al Liu.

Copyright (c) 2015 Dan Burkert.