Struct apigpio::Subscription

pub struct Subscription { /* fields omitted */ }

Subscription to a GPIO pin.

Contains a watch::Receiver<GpioChange>. To unsubscribe from notifications, simply drop the Subscription.

Methods from Deref<Target = Receiver<GpioChange>>

pub fn borrow(&self) -> Ref<T>

Returns a reference to the most recently sent value

Outstanding borrows hold a read lock. This means that long lived borrows could cause the send half to block. It is recommended to keep the borrow as short lived as possible.

Examples

use tokio::sync::watch;

let (_, rx) = watch::channel("hello");
assert_eq!(*rx.borrow(), "hello");

pub async fn recv(&'_ mut self) -> Option<T>

Attempts to clone the latest value sent via the channel.

If this is the first time the function is called on a Receiver instance, then the function completes immediately with the current value held by the channel. On the next call, the function waits until a new value is sent in the channel.

None is returned if the Sender half is dropped.

Examples

use tokio::sync::watch;

#[tokio::main]
async fn main() {
    let (tx, mut rx) = watch::channel("hello");

    let v = rx.recv().await.unwrap();
    assert_eq!(v, "hello");

    tokio::spawn(async move {
        tx.broadcast("goodbye").unwrap();
    });

    // Waits for the new task to spawn and send the value.
    let v = rx.recv().await.unwrap();
    assert_eq!(v, "goodbye");

    let v = rx.recv().await;
    assert!(v.is_none());
}

Trait Implementations

impl Deref for Subscription

type Target = Receiver<GpioChange>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for Subscription

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.