Email me

Clippy lints / Restriction

Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::big_endian_bytes: use of `to_be_bytes`

What it meansChecks for the usage of the to_be_bytes method and/or the function from_be_bytes. It is in the restriction group and off by default.

What you see

warning: use of `to_be_bytes`
 --> main.rs:3:15
  |
3 | let _x = 2i32.to_be_bytes();
  |               ^^^^^^^^^^^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#big_endian_bytes
  = note: requested on the command line with `-W clippy::big-endian-bytes`
help: convert to native endian
  |
3 - let _x = 2i32.to_be_bytes();
3 + let _x = 2i32.to_ne_bytes();
  |
help: convert to little endian
  |
3 - let _x = 2i32.to_be_bytes();
3 + let _x = 2i32.to_le_bytes();
  |

Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.

Does it matter?

To ensure use of little-endian or the target’s endianness rather than big-endian.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

How to fix it

Clippy does not fix this one automatically (its suggestion may change behaviour, so it only shows it). Change the code by hand:

Flagged

let _x = 2i32.to_be_bytes();
let _y = 2i64.to_be_bytes();

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

Whole crate (Cargo.toml)

[lints.clippy]
big_endian_bytes = "warn"

In code

#![warn(clippy::big_endian_bytes)]

One run

cargo clippy -- -W clippy::big-endian-bytes

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.

Restrictiongroup
allowdefault level
nofixed by cargo clippy --fix
1.72.0added in Rust

Clippy's own documentation

What it does

Checks for the usage of the to_be_bytes method and/or the function from_be_bytes.

Why restrict this?

To ensure use of little-endian or the target’s endianness rather than big-endian.

Example

let _x = 2i32.to_be_bytes();
let _y = 2i64.to_be_bytes();

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

Related lints

All 847 Clippy lints · Rust compiler errors · Cargo.toml checker

Up next

Related lintclippy::unwrap_usedChecks for .unwrap() or .unwrap_err() calls on Results and .unwrap() call on OptionsRead it next →

Did this answer your question?

Get the receipts by email.

What my AI agents tried this week, with the real numbers: what worked, what flopped, what made money. One email when there is something worth reading.

No spam, never sold. Every email has a one-click unsubscribe.

Popular in the shop

All 124 tools →

Browse: Bundles and kitsHome, family and schoolMoney and businessAI toolsSports and fitnessMaking and hobbiesFood and drinkIndie dev and launchTrading and quant

Free: Landing page teardown iPhone app cost calculator LLM API cost calculator Paid online: $49 Launch Check App builds Articles FAQ