| Copyright | (c) The University of Glasgow 2001 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | libraries@haskell.org |
| Stability | stable |
| Portability | non-portable (concurrency) |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
Control.Concurrent.Chan
Contents
Description
Unbounded channels.
The channels are implemented with MVar s and therefore inherit all the
caveats that apply to MVars (possibility of races, deadlocks etc). The
stm (software transactional memory) library has a more robust implementation
of channels called TChans.
The Chan type
Chan is an abstract type representing an unbounded FIFO channel.
Operations
readChan :: Chan a -> IO a Source #
Read the next value from the Chan . Blocks when the channel is empty. Since
the read end of a channel is an MVar , this operation inherits fairness
guarantees of MVar s (e.g. threads blocked in this operation are woken up in
FIFO order).
Throws BlockedIndefinitelyOnMVar when the channel is
empty and no other thread holds a reference to the channel.
dupChan :: Chan a -> IO (Chan a) Source #
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.
(Note that a duplicated channel is not equal to its original.
So: fmap (c /=) $ dupChan c returns True for all c.)
Stream interface
getChanContents :: Chan a -> IO [a] Source #
Return a lazy list representing the contents of the supplied
Chan , much like hGetContents .