Module std::sync::mpsc
[−]
[src]
Multi-producer, single-consumer FIFO queue communication primitives.
This module provides message-based communication over channels, concretely defined among three types:
Sender`Sender`SyncSender`SyncSender`Receiver`Receiver`
A Sender`Senderor` or SyncSender`SyncSenderis used to send data to a` is used to send data to a Receiver`Receiver`. Both
senders are clone-able (multi-producer) such that many threads can send
simultaneously to one receiver (single-consumer).
These channels come in two flavors:
An asynchronous, infinitely buffered channel. The
channel()`channel()function will return a` function will return a(Sender, Receiver)`(Sender, Receiver)` tuple where all sends will be asynchronous (they never block). The channel conceptually has an infinite buffer.A synchronous, bounded channel. The
sync_channel()`sync_channel()function will return a` function will return a(SyncSender, Receiver)`(SyncSender, Receiver)` tuple where the storage for pending messages is a pre-allocated buffer of a fixed size. All sends will be synchronous by blocking until there is buffer space available. Note that a bound of 0 is allowed, causing the channel to become a "rendezvous" channel where each sender atomically hands off a message to a receiver.
Disconnection
The send and receive operations on channels will all return a Result`Result`
indicating whether the operation succeeded or not. An unsuccessful operation
is normally indicative of the other half of a channel having "hung up" by
being dropped in its corresponding thread.
Once half of a channel has been deallocated, most operations can no longer
continue to make progress, so Err`Errwill be returned. Many applications will continue to` will be returned. Many applications will
continue to unwrap()`unwrap()` the results returned from this module, instigating a
propagation of failure among threads if one unexpectedly dies.
Examples
Simple usage:
fn main() { use std::thread; use std::sync::mpsc::channel; // Create a simple streaming channel let (tx, rx) = channel(); thread::spawn(move|| { tx.send(10).unwrap(); }); assert_eq!(rx.recv().unwrap(), 10); }use std::thread; use std::sync::mpsc::channel; // Create a simple streaming channel let (tx, rx) = channel(); thread::spawn(move|| { tx.send(10).unwrap(); }); assert_eq!(rx.recv().unwrap(), 10);
Shared usage:
fn main() { use std::thread; use std::sync::mpsc::channel; // Create a shared channel that can be sent along from many threads // where tx is the sending half (tx for transmission), and rx is the receiving // half (rx for receiving). let (tx, rx) = channel(); for i in 0..10 { let tx = tx.clone(); thread::spawn(move|| { tx.send(i).unwrap(); }); } for _ in 0..10 { let j = rx.recv().unwrap(); assert!(0 <= j && j < 10); } }use std::thread; use std::sync::mpsc::channel; // Create a shared channel that can be sent along from many threads // where tx is the sending half (tx for transmission), and rx is the receiving // half (rx for receiving). let (tx, rx) = channel(); for i in 0..10 { let tx = tx.clone(); thread::spawn(move|| { tx.send(i).unwrap(); }); } for _ in 0..10 { let j = rx.recv().unwrap(); assert!(0 <= j && j < 10); }
Propagating panics:
fn main() { use std::sync::mpsc::channel; // The call to recv() will return an error because the channel has already // hung up (or been deallocated) let (tx, rx) = channel::<i32>(); drop(tx); assert!(rx.recv().is_err()); }use std::sync::mpsc::channel; // The call to recv() will return an error because the channel has already // hung up (or been deallocated) let (tx, rx) = channel::<i32>(); drop(tx); assert!(rx.recv().is_err());
Synchronous channels:
fn main() { use std::thread; use std::sync::mpsc::sync_channel; let (tx, rx) = sync_channel::<i32>(0); thread::spawn(move|| { // This will wait for the parent thread to start receiving tx.send(53).unwrap(); }); rx.recv().unwrap(); }use std::thread; use std::sync::mpsc::sync_channel; let (tx, rx) = sync_channel::<i32>(0); thread::spawn(move|| { // This will wait for the parent thread to start receiving tx.send(53).unwrap(); }); rx.recv().unwrap();
Structs
| IntoIter |
An owning iterator over messages on a receiver, this iterator will block
whenever |
| Iter |
An iterator over messages on a receiver, this iterator will block
whenever |
| Receiver |
The receiving-half of Rust's channel type. This half can only be owned by one thread |
| RecvError |
An error returned from the |
| SendError |
An error returned from the |
| Sender |
The sending-half of Rust's asynchronous channel type. This half can only be owned by one thread, but it can be cloned to send to other threads. |
| SyncSender |
The sending-half of Rust's synchronous channel type. This half can only be owned by one thread, but it can be cloned to send to other threads. |
| Handle |
[Unstable] A handle to a receiver which is currently a member of a |
| Select |
[Unstable] The "receiver set" of the select interface. This structure is used to manage a set of receivers which are being selected over. |
Enums
| TryRecvError |
This enumeration is the list of the possible reasons that |
| TrySendError |
This enumeration is the list of the possible error outcomes for the
|
Functions
| channel |
Creates a new asynchronous channel, returning the sender/receiver halves. |
| sync_channel |
Creates a new synchronous, bounded channel. |