Struct Channel

pub struct Channel<M, T, const N: usize>
where
    M: RawMutex,
{ /* private fields */ }

A bounded channel for communicating between asynchronous tasks with backpressure.

The channel will buffer up to the provided number of messages. Once the buffer is full, attempts to send new messages will wait until a message is received from the channel.

All data sent will become available in the same order as it was sent.

Implementations

impl<M, T, const N: usize> Channel<M, T, N>

where M: RawMutex,

pub const fn new() -> Self

Establish a new bounded channel. For example, to create one with a NoopMutex:

use embassy_sync::channel::Channel;
use embassy_sync::blocking_mutex::raw::NoopRawMutex;

// Declare a bounded channel of 3 u32s.
let mut channel = Channel::<NoopRawMutex, u32, 3>::new();

pub fn poll_receive(&self, cx: &mut Context<'_>) -> Poll<T>

Poll the channel for the next message

pub fn poll_ready_to_receive(&self, cx: &mut Context<'_>) -> Poll<()>

Allows a poll_fn to poll until the channel is ready to receive

pub fn poll_ready_to_send(&self, cx: &mut Context<'_>) -> Poll<()>

Allows a poll_fn to poll until the channel is ready to send

pub fn sender(&self) -> Sender<'_, M, T, N>

Get a sender for this channel.

pub fn receiver(&self) -> Receiver<'_, M, T, N>

Get a receiver for this channel.

pub fn dyn_sender(&self) -> DynamicSender<'_, T>

Get a sender for this channel using dynamic dispatch.

pub fn dyn_receiver(&self) -> DynamicReceiver<'_, T>

Get a receiver for this channel using dynamic dispatch.

pub fn send(&self, message: T) -> SendFuture<'_, M, T, N>

Send a value, waiting until there is capacity.

Sending completes when the value has been pushed to the channel’s queue. This doesn’t mean the value has been received yet.

pub fn try_send(&self, message: T) -> Result<(), TrySendError<T>>

Attempt to immediately send a message.

This method differs from send by returning immediately if the channel’s buffer is full, instead of waiting.

Errors

If the channel capacity has been reached, i.e., the channel has n buffered values where n is the argument passed to Channel, then an error is returned.

pub fn receive(&self) -> ReceiveFuture<'_, M, T, N>

Receive the next value.

If there are no messages in the channel’s buffer, this method will wait until a message is sent.

pub fn ready_to_receive(&self) -> ReceiveReadyFuture<'_, M, T, N>

Is a value ready to be received in the channel

If there are no messages in the channel’s buffer, this method will wait until there is at least one

pub fn try_receive(&self) -> Result<T, TryReceiveError>

Attempt to immediately receive a message.

This method will either receive a message from the channel immediately or return an error if the channel is empty.

pub const fn capacity(&self) -> usize

Returns the maximum number of elements the channel can hold.

pub fn free_capacity(&self) -> usize

Returns the free capacity of the channel.

This is equivalent to capacity() - len()

pub fn clear(&self)

Clears all elements in the channel.

pub fn len(&self) -> usize

Returns the number of elements currently in the channel.

pub fn is_empty(&self) -> bool

Returns whether the channel is empty.

pub fn is_full(&self) -> bool

Returns whether the channel is full.