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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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