CODEWITHSUNDEEP
rust
David
David

Reputation: 469

Rust no_std split_at_mut function "no method named `split_mut_at` found for type" compilation error in rust stable

I am trying to extract bits of code from an embedded rust example that does not compile. A lot of these old embedded examples don't compile because they use nightly and they quickly become broken and neglected. 

let mut buffer : [u8; 2048] = [0;2048];
// some code to fill the buffer here
// say we want to split the buffer at position 300
let (request_buffer, response_buffer) = buffer.split_mut_at(300);

This example uses #![no_std] so there is no standard library to link to and must have compiled at some point so the function split_mut_at must have worked at some point. I am using IntelliJ rust AND Visual Studio Code as the IDE but neither IDE's can point me to the definition of the split_mut_at function. There is a minefield of crates and use statements in the example and there is no clear way to pin-point where some function comes without huge trial and error effort.

btw, split_at_mut can usually be found in std::string::String

Is there a rust command that tells you what crate a function belongs to in your project? It always takes so long to update rust-docs when doing a rust update. Surely that can help!

Upvotes: 0

Views: 442

Answers (1)

Daniel Robertson
Daniel Robertson

Reputation: 1394

You're looking for slice::split_at_mut (note the mut at the end). It is listed in the nightly docs here and the stable docs here. It is also indeed available with #![no_std]. It is defined in libcore here.

As a general rule of thumb when a function x from core or std has a mutable and immutable variant, the function requiring a immutable reference is named x and the function requiring a mutable reference is named x_mut.

Upvotes: 1

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