this post was submitted on 23 Aug 2023
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Rust

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I've been trying to use OneCell, but I keep having errors trying to set it up to handle a mutable vector that I can push to.

I know there's going to be some answers telling me maybe not to use a singleton, but the alternative of passing a vector all around throughout my code is not ergonmic at all.

I've tried lots of things, but this is where I'm at right now. Specifically I'm just having trouble initializing it.

`/**

  • LOG_CELL
  • Stores a vec of Strings that is added to throughout the algorithm with information to report
  • To the end user and developer */ pub static LOG_CELL: OnceLock<&mut Vec> = OnceLock::new();

pub fn set_log() { LOG_CELL.set(Vec::new()); }

pub fn push_log(message: String) { if let Some(vec_of_messages) = LOG_CELL.get() { let something = *vec_of_messages; something.push(message); } } `

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[–] [email protected] 2 points 1 year ago (3 children)

Is the Singleton accessed by one thread or many?

If it's one thread, couldn't you just wrap the Vec in an Rc and then clone your singleton every time you need it in a new scope?

If it's many, you should use channels and a dedicated logging thread imo.

[–] nerdblood 1 points 1 year ago (1 children)

One for now, theoretically many later.

Nice I've never used Rc. Maybe now's my chance to look into it.

[–] [email protected] 3 points 1 year ago* (last edited 1 year ago) (1 children)

Look into Arc, RwLock, and Mutex too.

Later, check out parking_lot and co. and maybe async stuff too.

[–] nerdblood 1 points 1 year ago

Async I have a handle on, but I'll take a look at the others for sure.

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