Copyright	(c) 2016 Michael Walker
License	MIT
Maintainer	Michael Walker <mike@barrucadu.co.uk>
Stability	stable
Portability	portable
Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Concurrent.Classy.QSem

Contents

Simple Quantity Semaphores

Description

Simple quantity semaphores.

Synopsis

data QSem m
newQSem :: (MonadConc m, MonadFail m) => Int -> m (QSem m)
waitQSem :: MonadConc m => QSem m -> m ()
signalQSem :: MonadConc m => QSem m -> m ()

Simple Quantity Semaphores

data QSem m Source #

QSem is a quantity semaphore in which the resource is acquired and released in units of one. It provides guaranteed FIFO ordering for satisfying blocked waitQSem calls.

The pattern

bracket_ qaitQSem signalSSem (...)

is safe; it never loses a unit of the resource.

Since: 1.0.0.0

newQSem :: (MonadConc m, MonadFail m) => Int -> m (QSem m) Source #

Build a new QSem with a supplied initial quantity. The initial quantity must be at least 0.

Since: 1.0.0.0

waitQSem :: MonadConc m => QSem m -> m () Source #

Wait for a unit to become available.

Since: 1.0.0.0

signalQSem :: MonadConc m => QSem m -> m () Source #

Signal that a unit of the QSem is available.

Since: 1.0.0.0