# The parallel\Channel class

(0.9.0)

## Unbuffered Channels

An unbuffered channel will block on calls to parallel\Channel::send() until there is a receiver, and block on calls to parallel\Channel::recv() until there is a sender. This means an unbuffered channel is not only a way to share data among tasks but also a simple method of synchronization.

An unbuffered channel is the fastest way to share data among tasks, requiring the least copying.

## Buffered Channels

A buffered channel will not block on calls to parallel\Channel::send() until capacity is reached, calls to parallel\Channel::recv() will block until there is data in the buffer.

## Closures over Channels

A powerful feature of parallel channels is that they allow the exchange of closures between tasks (and runtimes).

When a closure is sent over a channel the closure is buffered, it doesn't change the buffering of the channel transmitting the closure, but it does effect the static scope inside the closure: The same closure sent to different runtimes, or the same runtime, will not share their static scope.

This means that whenever a closure is executed that was transmitted by a channel, static state will be as it was when the closure was buffered.

## Anonymous Channels

The anonymous channel constructor allows the programmer to avoid assigning names to every channel: parallel will generate a unique name for anonymous channels.

## Class synopsis

final parallel\Channel {
/* Anonymous Constructor */
public __construct ( )
public __construct ( int `$capacity` )
/* Access */
public make ( string `$name` ) : Channel
public make ( string `$name` , int `$capacity` ) : Channel
public open ( string `$name` ) : Channel
/* Sharing */
public recv ( ) : mixed
public send ( mixed `$value` ) : void
/* Closing */
public close ( ) : void
/* Constant for Infinitely Buffered */
const Infinite ;
}

## Table of Contents

- parallel\Channel::__construct — Channel Construction
- parallel\Channel::make — Access
- parallel\Channel::open — Access
- parallel\Channel::recv — Sharing
- parallel\Channel::send — Sharing
- parallel\Channel::close — Closing