class Channel(T)

• Channel(T)
• Reference
• Object

Overview

A Channel enables concurrent communication between fibers.

They allow communicating data between fibers without sharing memory and without having to worry about locks, semaphores or other special structures.

channel = Channel(Int32).new

spawn do
  channel.send(0)
  channel.send(1)
end

channel.receive # => 0
channel.receive # => 1

NOTE Althought a Channel(Nil) or any other nilable types like Channel(Int32?) are valid they are discouraged since from certain methods or constructs it receiving a nil as data will be indistinguishable from a closed channel.

Defined in:

Constructors

• .new(capacity = 0)

Class Method Summary

• .non_blocking_select(ops : Indexable(SelectAction))
• .non_blocking_select(*ops : SelectAction)
• .receive_first(channels : Tuple | Array)
• .receive_first(*channels)
• .select(ops : Indexable(SelectAction), has_else)

  DEPRECATED Use Channel.non_blocking_select

• .select(ops : Indexable(SelectAction))
• .select(*ops : SelectAction)
• .select_impl(ops : Indexable(SelectAction), non_blocking)
• .send_first(value, channels : Tuple | Array)
• .send_first(value, *channels)

Instance Method Summary

• #close : Nil

  Closes the channel.

• #closed?
• #inspect(io : IO) : Nil

  Appends a String representation of this object which includes its class name, its object address and the values of all instance variables.

• #pretty_print(pp)
• #receive

  Receives a value from the channel.

• #receive?

  Receives a value from the channel.

• #receive_impl(&)
• #receive_internal
• #send(value : T)

  Sends a value to the channel.

Constructor Detail

Class Method Detail

Instance Method Detail

class Person
  def initialize(@name : String, @age : Int32)
  end
end

Person.new("John", 32).inspect # => #<Person:0x10fd31f20 @name="John", @age=32>

channel = Channel(Int32).new
spawn do
  channel.send(1)
end
channel.receive # => 1