| Copyright | (c) The University of Glasgow 2012 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | libraries@haskell.org |
| Stability | experimental |
| Portability | non-portable (requires STM) |
| Safe Haskell | Trustworthy |
| Language | Haskell98 |
Control.Concurrent.STM.TBQueue
Contents
Description
TBQueue is a bounded version of TQueue. The queue has a maximum
capacity set when it is created. If the queue already contains the
maximum number of elements, then writeTBQueue blocks until an
element is removed from the queue.
The implementation is based on the traditional purely-functional queue representation that uses two lists to obtain amortised O(1) enqueue and dequeue operations.
- data TBQueue a
- newTBQueue :: Int -> STM (TBQueue a)
- newTBQueueIO :: Int -> IO (TBQueue a)
- readTBQueue :: TBQueue a -> STM a
- tryReadTBQueue :: TBQueue a -> STM (Maybe a)
- peekTBQueue :: TBQueue a -> STM a
- tryPeekTBQueue :: TBQueue a -> STM (Maybe a)
- writeTBQueue :: TBQueue a -> a -> STM ()
- unGetTBQueue :: TBQueue a -> a -> STM ()
- isEmptyTBQueue :: TBQueue a -> STM Bool
- isFullTBQueue :: TBQueue a -> STM Bool
TBQueue
TBQueue is an abstract type representing a bounded FIFO channel.
Build and returns a new instance of TBQueue
newTBQueueIO :: Int -> IO (TBQueue a) Source
IO version of newTBQueue. This is useful for creating top-level
TBQueues using unsafePerformIO, because using
atomically inside unsafePerformIO isn't
possible.
readTBQueue :: TBQueue a -> STM a Source
Read the next value from the TBQueue.
tryReadTBQueue :: TBQueue a -> STM (Maybe a) Source
A version of readTBQueue which does not retry. Instead it
returns Nothing if no value is available.
peekTBQueue :: TBQueue a -> STM a Source
Get the next value from the TBQueue without removing it,
retrying if the channel is empty.
tryPeekTBQueue :: TBQueue a -> STM (Maybe a) Source
A version of peekTBQueue which does not retry. Instead it
returns Nothing if no value is available.
writeTBQueue :: TBQueue a -> a -> STM () Source
Write a value to a TBQueue; blocks if the queue is full.
unGetTBQueue :: TBQueue a -> a -> STM () Source
Put a data item back onto a channel, where it will be the next item read. Blocks if the queue is full.