Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell2010 |
Lifted version of Control.Concurrent.STM
Since: 0.2.1.0
Synopsis
- data STM a
- atomically :: MonadIO m => STM a -> m a
- retrySTM :: STM a
- checkSTM :: Bool -> STM ()
- orElse :: STM a -> STM a -> STM a
- data TVar a
- newTVarIO :: MonadIO m => a -> m (TVar a)
- readTVarIO :: MonadIO m => TVar a -> m a
- newTVar :: a -> STM (TVar a)
- readTVar :: TVar a -> STM a
- writeTVar :: TVar a -> a -> STM ()
- modifyTVar :: TVar a -> (a -> a) -> STM ()
- modifyTVar' :: TVar a -> (a -> a) -> STM ()
- stateTVar :: TVar s -> (s -> (a, s)) -> STM a
- swapTVar :: TVar a -> a -> STM a
- registerDelay :: MonadIO m => Int -> m (TVar Bool)
- mkWeakTVar :: MonadUnliftIO m => TVar a -> m () -> m (Weak (TVar a))
- data TMVar a
- newTMVar :: a -> STM (TMVar a)
- newEmptyTMVar :: STM (TMVar a)
- newTMVarIO :: MonadIO m => a -> m (TMVar a)
- newEmptyTMVarIO :: MonadIO m => m (TMVar a)
- takeTMVar :: TMVar a -> STM a
- putTMVar :: TMVar a -> a -> STM ()
- readTMVar :: TMVar a -> STM a
- tryReadTMVar :: TMVar a -> STM (Maybe a)
- swapTMVar :: TMVar a -> a -> STM a
- tryTakeTMVar :: TMVar a -> STM (Maybe a)
- tryPutTMVar :: TMVar a -> a -> STM Bool
- isEmptyTMVar :: TMVar a -> STM Bool
- mkWeakTMVar :: MonadUnliftIO m => TMVar a -> m () -> m (Weak (TMVar a))
- data TChan a
- newTChan :: STM (TChan a)
- newTChanIO :: MonadIO m => m (TChan a)
- newBroadcastTChan :: STM (TChan a)
- newBroadcastTChanIO :: MonadIO m => m (TChan a)
- dupTChan :: TChan a -> STM (TChan a)
- cloneTChan :: TChan a -> STM (TChan a)
- readTChan :: TChan a -> STM a
- tryReadTChan :: TChan a -> STM (Maybe a)
- peekTChan :: TChan a -> STM a
- tryPeekTChan :: TChan a -> STM (Maybe a)
- writeTChan :: TChan a -> a -> STM ()
- unGetTChan :: TChan a -> a -> STM ()
- isEmptyTChan :: TChan a -> STM Bool
- data TQueue a
- newTQueue :: STM (TQueue a)
- newTQueueIO :: MonadIO m => m (TQueue a)
- readTQueue :: TQueue a -> STM a
- tryReadTQueue :: TQueue a -> STM (Maybe a)
- peekTQueue :: TQueue a -> STM a
- tryPeekTQueue :: TQueue a -> STM (Maybe a)
- writeTQueue :: TQueue a -> a -> STM ()
- unGetTQueue :: TQueue a -> a -> STM ()
- isEmptyTQueue :: TQueue a -> STM Bool
- data TBQueue a
- newTBQueue :: Natural -> STM (TBQueue a)
- newTBQueueIO :: MonadIO m => Natural -> m (TBQueue a)
- readTBQueue :: TBQueue a -> STM a
- tryReadTBQueue :: TBQueue a -> STM (Maybe a)
- flushTBQueue :: TBQueue a -> STM [a]
- peekTBQueue :: TBQueue a -> STM a
- tryPeekTBQueue :: TBQueue a -> STM (Maybe a)
- writeTBQueue :: TBQueue a -> a -> STM ()
- unGetTBQueue :: TBQueue a -> a -> STM ()
- lengthTBQueue :: TBQueue a -> STM Natural
- isEmptyTBQueue :: TBQueue a -> STM Bool
- isFullTBQueue :: TBQueue a -> STM Bool
Core
A monad supporting atomic memory transactions.
Instances
Alternative STM | Since: base-4.8.0.0 |
Applicative STM | Since: base-4.8.0.0 |
Functor STM | Since: base-4.3.0.0 |
Monad STM | Since: base-4.3.0.0 |
MonadPlus STM | Since: base-4.3.0.0 |
MonadCatch STM | |
MonadThrow STM | |
Defined in Control.Monad.Catch | |
MArray TArray e STM | |
Defined in Control.Concurrent.STM.TArray getBounds :: Ix i => TArray i e -> STM (i, i) # getNumElements :: Ix i => TArray i e -> STM Int newArray :: Ix i => (i, i) -> e -> STM (TArray i e) # newArray_ :: Ix i => (i, i) -> STM (TArray i e) # unsafeNewArray_ :: Ix i => (i, i) -> STM (TArray i e) unsafeRead :: Ix i => TArray i e -> Int -> STM e unsafeWrite :: Ix i => TArray i e -> Int -> e -> STM () |
atomically :: MonadIO m => STM a -> m a Source #
Lifted version of atomically
Since: 0.2.1.0
TVar
Shared memory locations that support atomic memory transactions.
readTVarIO :: MonadIO m => TVar a -> m a Source #
Lifted version of readTVarIO
Since: 0.2.1.0
modifyTVar :: TVar a -> (a -> a) -> STM () #
Mutate the contents of a TVar
. N.B., this version is
non-strict.
Since: stm-2.3
modifyTVar' :: TVar a -> (a -> a) -> STM () #
Strict version of modifyTVar
.
Since: stm-2.3
stateTVar :: TVar s -> (s -> (a, s)) -> STM a #
Like modifyTVar'
but the function is a simple state transition that can
return a side value which is passed on as the result of the STM
.
Since: stm-2.5.0
registerDelay :: MonadIO m => Int -> m (TVar Bool) Source #
Lifted version of registerDelay
Since: 0.2.1.0
mkWeakTVar :: MonadUnliftIO m => TVar a -> m () -> m (Weak (TVar a)) Source #
Lifted version of mkWeakTVar
Since: 0.2.1.0
TMVar
A TMVar
is a synchronising variable, used
for communication between concurrent threads. It can be thought of
as a box, which may be empty or full.
newEmptyTMVar :: STM (TMVar a) #
Create a TMVar
which is initially empty.
newTMVarIO :: MonadIO m => a -> m (TMVar a) Source #
Lifted version of newTMVarIO
Since: 0.2.1.0
newEmptyTMVarIO :: MonadIO m => m (TMVar a) Source #
Lifted version of newEmptyTMVarIO
Since: 0.2.1.0
tryReadTMVar :: TMVar a -> STM (Maybe a) #
A version of readTMVar
which does not retry. Instead it
returns Nothing
if no value is available.
Since: stm-2.3
tryTakeTMVar :: TMVar a -> STM (Maybe a) #
A version of takeTMVar
that does not retry
. The tryTakeTMVar
function returns Nothing
if the TMVar
was empty, or
if
the Just
aTMVar
was full with contents a
. After tryTakeTMVar
, the
TMVar
is left empty.
tryPutTMVar :: TMVar a -> a -> STM Bool #
mkWeakTMVar :: MonadUnliftIO m => TMVar a -> m () -> m (Weak (TMVar a)) Source #
Lifted version of mkWeakTMVar
Since: 0.2.1.0
TChan
TChan
is an abstract type representing an unbounded FIFO channel.
newTChanIO :: MonadIO m => m (TChan a) Source #
Lifted version of newTChanIO
Since: 0.2.1.0
newBroadcastTChan :: STM (TChan a) #
Create a write-only TChan
. More precisely, readTChan
will retry
even after items have been written to the channel. The only way to read
a broadcast channel is to duplicate it with dupTChan
.
Consider a server that broadcasts messages to clients:
serve :: TChan Message -> Client -> IO loop serve broadcastChan client = do myChan <- dupTChan broadcastChan forever $ do message <- readTChan myChan send client message
The problem with using newTChan
to create the broadcast channel is that if
it is only written to and never read, items will pile up in memory. By
using newBroadcastTChan
to create the broadcast channel, items can be
garbage collected after clients have seen them.
Since: stm-2.4
newBroadcastTChanIO :: MonadIO m => m (TChan a) Source #
Lifted version of newBroadcastTChanIO
Since: 0.2.1.0
dupTChan :: TChan a -> STM (TChan a) #
Duplicate a TChan
: 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.
cloneTChan :: TChan a -> STM (TChan a) #
Clone a TChan
: similar to dupTChan, but the cloned channel starts with the
same content available as the original channel.
Since: stm-2.4
tryReadTChan :: TChan a -> STM (Maybe a) #
A version of readTChan
which does not retry. Instead it
returns Nothing
if no value is available.
Since: stm-2.3
peekTChan :: TChan a -> STM a #
Get the next value from the TChan
without removing it,
retrying if the channel is empty.
Since: stm-2.3
tryPeekTChan :: TChan a -> STM (Maybe a) #
A version of peekTChan
which does not retry. Instead it
returns Nothing
if no value is available.
Since: stm-2.3
writeTChan :: TChan a -> a -> STM () #
Write a value to a TChan
.
unGetTChan :: TChan a -> a -> STM () #
Put a data item back onto a channel, where it will be the next item read.
TQueue
TQueue
is an abstract type representing an unbounded FIFO channel.
Since: stm-2.4
newTQueueIO :: MonadIO m => m (TQueue a) Source #
Lifted version of newTQueueIO
Since: 0.2.1.0
readTQueue :: TQueue a -> STM a #
Read the next value from the TQueue
.
tryReadTQueue :: TQueue a -> STM (Maybe a) #
A version of readTQueue
which does not retry. Instead it
returns Nothing
if no value is available.
peekTQueue :: TQueue a -> STM a #
Get the next value from the TQueue
without removing it,
retrying if the channel is empty.
tryPeekTQueue :: TQueue a -> STM (Maybe a) #
A version of peekTQueue
which does not retry. Instead it
returns Nothing
if no value is available.
writeTQueue :: TQueue a -> a -> STM () #
Write a value to a TQueue
.
unGetTQueue :: TQueue a -> a -> STM () #
Put a data item back onto a channel, where it will be the next item read.
TBQueue
TBQueue
is an abstract type representing a bounded FIFO channel.
Since: stm-2.4
Builds and returns a new instance of TBQueue
.
newTBQueueIO :: MonadIO m => Natural -> m (TBQueue a) Source #
Lifted version of newTBQueueIO
Since: 0.2.1.0
readTBQueue :: TBQueue a -> STM a #
Read the next value from the TBQueue
.
tryReadTBQueue :: TBQueue a -> STM (Maybe a) #
A version of readTBQueue
which does not retry. Instead it
returns Nothing
if no value is available.
flushTBQueue :: TBQueue a -> STM [a] #
Efficiently read the entire contents of a TBQueue
into a list. This
function never retries.
Since: stm-2.4.5
peekTBQueue :: TBQueue a -> STM a #
Get the next value from the TBQueue
without removing it,
retrying if the channel is empty.
tryPeekTBQueue :: TBQueue a -> STM (Maybe a) #
A version of peekTBQueue
which does not retry. Instead it
returns Nothing
if no value is available.
writeTBQueue :: TBQueue a -> a -> STM () #
Write a value to a TBQueue
; blocks if the queue is full.
unGetTBQueue :: TBQueue a -> a -> STM () #
Put a data item back onto a channel, where it will be the next item read. Blocks if the queue is full.