HaskellWorks.Polysemy.Control.Concurrent.QSem

Documentation

data 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.

newQSem :: MonadIO m => Member (Embed m) r => Int -> Sem r QSem

waitQSem :: MonadIO m => Member (Embed m) r => QSem -> Sem r ()

signalQSem :: MonadIO m => Member (Embed m) r => QSem -> Sem r ()

bracketQSem :: MonadIO m => Member (Embed m) r => Member Resource r => QSem -> Sem r a -> Sem r a