| Copyright | (c) The University of Glasgow 2001 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | libraries@haskell.org |
| Stability | experimental |
| Portability | non-portable (concurrency) |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
Control.Concurrent.Chan
Description
Unbounded channels.
The channels are implemented withMVars and therefore inherit all the caveats that apply toMVars (possibility of races, deadlocks etc). The stm (software transactional memory) library has a more robust implementation of channels calledTChans.
Chan typeChan is an abstract type representing an unbounded FIFO channel.
readChan ::Chan a ->IO aSource#
Read the next value from theChan. Blocks when the channel is empty. Since the read end of a channel is anMVar, this operation inherits fairness guarantees ofMVars (e.g. threads blocked in this operation are woken up in FIFO order).
ThrowsBlockedIndefinitelyOnMVar when the channel is empty and no other thread holds a reference to the channel.
dupChan ::Chan a ->IO (Chan a)Source#
Duplicate aChan: 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 returnsTrue for allc.)
getChanContents ::Chan a ->IO [a]Source#
Return a lazy list representing the contents of the suppliedChan, much likehGetContents.
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