Control.Concurrent.Lifted

This is a wrapped version of Control.Concurrent with types generalized from IO to all monads in either MonadBase or MonadBaseControl.

Concurrent Haskell

data ThreadId :: *

A ThreadId is an abstract type representing a handle to a thread. ThreadId is an instance of Eq, Ord and Show, where the Ord instance implements an arbitrary total ordering over ThreadIds. The Show instance lets you convert an arbitrary-valued ThreadId to string form; showing a ThreadId value is occasionally useful when debugging or diagnosing the behaviour of a concurrent program.

Note: in GHC, if you have a ThreadId, you essentially have a pointer to the thread itself. This means the thread itself can't be garbage collected until you drop the ThreadId. This misfeature will hopefully be corrected at a later date.

Instances

Eq ThreadId

Methods

(==) :: ThreadId -> ThreadId -> Bool

(/=) :: ThreadId -> ThreadId -> Bool

Ord ThreadId

Methods

compare :: ThreadId -> ThreadId -> Ordering

(<) :: ThreadId -> ThreadId -> Bool

(<=) :: ThreadId -> ThreadId -> Bool

(>) :: ThreadId -> ThreadId -> Bool

(>=) :: ThreadId -> ThreadId -> Bool

max :: ThreadId -> ThreadId -> ThreadId

min :: ThreadId -> ThreadId -> ThreadId

Show ThreadId

Methods

showsPrec :: Int -> ThreadId -> ShowS

show :: ThreadId -> String

showList :: [ThreadId] -> ShowS

Basic concurrency operations

myThreadId :: MonadBase IO m => m ThreadId

Generalized version of myThreadId.

fork :: MonadBaseControl IO m => m () -> m ThreadId

Generalized version of forkIO.

Note that, while the forked computation m () has access to the captured state, all its side-effects in m are discarded. It is run only for its side-effects in IO.

forkWithUnmask :: MonadBaseControl IO m => ((forall a. m a -> m a) -> m ()) -> m ThreadId

Generalized version of forkIOWithUnmask.

Note that, while the forked computation m () has access to the captured state, all its side-effects in m are discarded. It is run only for its side-effects in IO.

forkFinally :: MonadBaseControl IO m => m a -> (Either SomeException a -> m ()) -> m ThreadId

Generalized version of forkFinally.

Note that in forkFinally action and_then, while the forked action and the and_then function have access to the captured state, all their side-effects in m are discarded. They're run only for their side-effects in IO.

killThread :: MonadBase IO m => ThreadId -> m ()

Generalized version of killThread.

throwTo :: (MonadBase IO m, Exception e) => ThreadId -> e -> m ()

Generalized version of throwTo.

Threads with affinity

forkOn :: MonadBaseControl IO m => Int -> m () -> m ThreadId

Generalized version of forkOn.

Note that, while the forked computation m () has access to the captured state, all its side-effects in m are discarded. It is run only for its side-effects in IO.

forkOnWithUnmask :: MonadBaseControl IO m => Int -> ((forall a. m a -> m a) -> m ()) -> m ThreadId

Generalized version of forkOnWithUnmask.

Note that, while the forked computation m () has access to the captured state, all its side-effects in m are discarded. It is run only for its side-effects in IO.

getNumCapabilities :: MonadBase IO m => m Int

Generalized version of getNumCapabilities.

setNumCapabilities :: MonadBase IO m => Int -> m ()

Generalized version of setNumCapabilities.

threadCapability :: MonadBase IO m => ThreadId -> m (Int, Bool)

Generalized version of threadCapability.

Scheduling

yield :: MonadBase IO m => m ()

Generalized version of yield.

Blocking

Waiting

threadDelay :: MonadBase IO m => Int -> m ()

Generalized version of threadDelay.

threadWaitRead :: MonadBase IO m => Fd -> m ()

Generalized version of threadWaitRead.

threadWaitWrite :: MonadBase IO m => Fd -> m ()

Generalized version of threadWaitWrite.

Communication abstractions

module Control.Concurrent.MVar.Lifted

module Control.Concurrent.Chan.Lifted

module Control.Concurrent.QSem.Lifted

module Control.Concurrent.QSemN.Lifted

Bound Threads

rtsSupportsBoundThreads :: Bool

True if bound threads are supported. If rtsSupportsBoundThreads is False, isCurrentThreadBound will always return False and both forkOS and runInBoundThread will fail.

forkOS :: MonadBaseControl IO m => m () -> m ThreadId

Generalized version of forkOS.

Note that, while the forked computation m () has access to the captured state, all its side-effects in m are discarded. It is run only for its side-effects in IO.

isCurrentThreadBound :: MonadBase IO m => m Bool

Generalized version of isCurrentThreadBound.

runInBoundThread :: MonadBaseControl IO m => m a -> m a

Generalized version of runInBoundThread.

runInUnboundThread :: MonadBaseControl IO m => m a -> m a

Generalized version of runInUnboundThread.

Weak references to ThreadIds

mkWeakThreadId :: MonadBase IO m => ThreadId -> m (Weak ThreadId)

Generalized versio of mkWeakThreadId.