Struct crossbeam_channel::select::SelectedOperation

pub struct SelectedOperation<'a> {
    token: Token,
    index: usize,
    ptr: *const u8,
    _marker: PhantomData<&'a ()>,
}

A selected operation that needs to be completed.

To complete the operation, call send or recv.

Panics

Forgetting to complete the operation is an error and might lead to deadlocks. If a SelectedOperation is dropped without completion, a panic occurs.

Fields

token: Token

Token needed to complete the operation.

index: usize

The index of the selected operation.

ptr: *const u8

The address of the selected Sender or Receiver.

_marker: PhantomData<&'a ()>

Indicates that Senders and Receivers are borrowed.

Implementations

impl SelectedOperation<'_>

pub fn index(&self) -> usize

Returns the index of the selected operation.

Examples

use crossbeam_channel::{bounded, Select};

let (s1, r1) = bounded::<()>(0);
let (s2, r2) = bounded::<()>(0);
let (s3, r3) = bounded::<()>(1);

let mut sel = Select::new();
let oper1 = sel.send(&s1);
let oper2 = sel.recv(&r2);
let oper3 = sel.send(&s3);

// Only the last operation is ready.
let oper = sel.select();
assert_eq!(oper.index(), 2);
assert_eq!(oper.index(), oper3);

// Complete the operation.
oper.send(&s3, ()).unwrap();

pub fn send<T>(self, s: &Sender<T>, msg: T) -> Result<(), SendError<T>>

Completes the send operation.

The passed Sender reference must be the same one that was used in Select::send when the operation was added.

Panics

Panics if an incorrect Sender reference is passed.

Examples

use crossbeam_channel::{bounded, Select, SendError};

let (s, r) = bounded::<i32>(0);
drop(r);

let mut sel = Select::new();
let oper1 = sel.send(&s);

let oper = sel.select();
assert_eq!(oper.index(), oper1);
assert_eq!(oper.send(&s, 10), Err(SendError(10)));

pub fn recv<T>(self, r: &Receiver<T>) -> Result<T, RecvError>

Completes the receive operation.

The passed Receiver reference must be the same one that was used in Select::recv when the operation was added.

Panics

Panics if an incorrect Receiver reference is passed.

Examples

use crossbeam_channel::{bounded, Select, RecvError};

let (s, r) = bounded::<i32>(0);
drop(s);

let mut sel = Select::new();
let oper1 = sel.recv(&r);

let oper = sel.select();
assert_eq!(oper.index(), oper1);
assert_eq!(oper.recv(&r), Err(RecvError));

Trait Implementations

impl Debug for SelectedOperation<'_>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for SelectedOperation<'_>

fn drop(&mut self)

Executes the destructor for this type.