Moduleunliftio-0.2.25.1Haskell2010

UnliftIO.QSem

1 type
4 values

Packageunliftio-0.2.25.1
Exports5
LanguageHaskell2010
LicenceMIT
SourceQSem.hs

newtypenewtype QSem

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_ waitQSem signalQSem (...)

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

valuenewQSem :: MonadIO m => Int -> m QSem

Lifted newQSem.

valuewaitQSem :: MonadIO m => QSem -> m ()

Lifted waitQSem.

valuesignalQSem :: MonadIO m => QSem -> m ()

Lifted signalQSem.

valuewithQSem :: MonadUnliftIO m => QSem -> m a -> m a

withQSem is an exception-safe wrapper for performing the provided operation while holding a unit of value from the semaphore. It ensures the semaphore cannot be leaked if there are exceptions.