crossbeam | Tools for concurrent programming in Rust | Reactive Programming library

I have the following code that is using a bounded channel with capacity (20) less than the total amount of data (32) that I want to send via a crossbeam channel. My goal is to use multiple sender threads (8) and a certain amount (4) of numbers each to a single receiver via a crossbeam channel and for all of this to happen in parallel to optimize efficiency. This is just a small prototype of a bigger problem that I'm trying to solve. However, the code that I have is causing the program to get stuck endlessly and never exit/timeout. I also know why it's happening - r.iter() blocks until the sender is dropped which only happens outside of the scope. I tried various approaches that didn't work:

1. Cloning sender withing each thread and then dropping them (as you can see in the comments)

2. Having the receiver code outside the scope, but that was only letting the final vector contain 20 length instead of the desired 32.

I try to process an array with multiple worker threads, just like Rayon's par_iter() function, but i want to have a mutable reference target, one for each thread.

I have a simple function like this

Please is there a way for sender to delete pending messages sent to mpsc channel (or crossbeam-channel or equivalent) which have not been consumed by the receiver yet? Something like sender.deleteAllPending().

I am practicing rust and decided to create a Matrix ops/factorization project.

Basically I want to be able to process the underlying vector in multiple threads. Since I will be providing each thread non-overlapping indexes (which may or may not be contiguous) and the threads will be joined before the end of whatever function created them, there is no need for a lock /synchronization.

I know that there are several crates that can do this, but I would like to know if there is a relatively idiomatic crate-free way to implement it on my own.

The best I could come up with is (simplified the code a bit):

I'm trying to send a "view" of a read-only data to another thread for processing. Basically the main thread does work, and continuously updates a set of data. Whenever an update occurs, the main thread should send the updated data down to other threads where they will process it in a read-only manner. I do not want to copy the data as it may be very large. (The main thread also keeps a "cache" of the data in-memory anyway.)

I can achieve this with Arc>, where T being my data structure.

However, there is nothing stopping the side threads updating the data. The side threads can simply call lock() and the write to the data.

My question is there something similar to RwLock where the owner/creator of it has the only write access, but all other instances have read-only access? This way I will have compile time checking of any logic bugs that may occur via side threads accidentally updating data.

Regarding these questions:

• Sharing read-only object between threads in Rust?

• How can I pass a reference to a stack variable to a thread?

The above questions suggest solving it with Arc> or Arc> which is all fine. But it still doesn't give compile time enforcement of only one writer.

Additionally: crossbeam or rayon's scoped threads don't help here as I want my side threads to outlive my main thread.

I am trying to make a prime sieve in Rust.

I need several mutable references to the same element of the array, not mutable references to different parts of the array.

For the way this works, I know data races are not a relevant problem, so multiple mutable references are acceptable, but the Rust compiler does not accept my unsafe code.

I am using crossbeam 0.8.0.

I started coding with rust lately and i'm loving it. I'm coding on a project where I want to "wrap" a C-API. In one case I have to define callbacks in Rust, which C can call. I let bindgen created the callbacks. Since the code need to run somewhat asynchronous, i'm using tokio for that.

I create the the main function as tokio::main. In the main function i create 2 async tasks, one listens for channels, the other triggers the message queue in the C-API. If messages are available I want to send them via a channel on the callback function, so i can receive the message on the task, where i am listening for events. Later I want to send these messages via SSE or a GraphQL subscription to several clients.

I can't change the C-Callbacks as they need to be passable to the C-API, and I have to use callbacks, otherwise i dont get the messages.

My latest approach looks simplified like that:

Why does this worK:

I have two slices that are passed from another method: