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Control.Concurrent.Chan

Portability | non-portable (concurrency).
Stability | experimental
Maintainer | libraries@haskell.org

Contents

The `Chan` type
Operations
Stream interface

Description
Unbounded channels.
Synopsis

data Chan a
newChan :: IO (Chan a)
writeChan :: Chan a -> a -> IO ()
readChan :: Chan a -> IO a
dupChan :: Chan a -> IO (Chan a)
unGetChan :: Chan a -> a -> IO ()
isEmptyChan :: Chan a -> IO Bool
getChanContents :: Chan a -> IO [a]
writeList2Chan :: Chan a -> [a] -> IO ()

The `Chan` type
data Chan a

`Chan` is an abstract type representing an unbounded FIFO channel.

Operations
newChan :: IO (Chan a)
Build and returns a new instance of `Chan`.
writeChan :: Chan a -> a -> IO ()
Write a value to a `Chan`.
readChan :: Chan a -> IO a
Read the next value from the `Chan`.
dupChan :: Chan a -> IO (Chan a)
Duplicate a `Chan`: the duplicate channel begins empty, but data written to either channel from then on will be available from both. Hence this creates a kind of broadcast channel, where data written by anyone is seen by everyone else.
unGetChan :: Chan a -> a -> IO ()
Put a data item back onto a channel, where it will be the next item read.
isEmptyChan :: Chan a -> IO Bool
Returns `True` if the supplied `Chan` is empty.
Stream interface
getChanContents :: Chan a -> IO [a]
Return a lazy list representing the contents of the supplied `Chan`, much like `hGetContents`.
writeList2Chan :: Chan a -> [a] -> IO ()
Write an entire list of items to a `Chan`.
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