Safe Haskell	Safe
Language	Haskell2010

Control.Event

Description

This module can execute events at specified time. It uses a two thread system that allows the STM adding and deleting of new threads without requiring later IO actions. For a simpler system that uses relative times see Control.Event.Relative

Synopsis

data EventId
data EventSystem
noEvent :: EventId
initEventSystem :: IO EventSystem
addEvent :: EventSystem -> UTCTime -> IO () -> IO EventId
addEventSTM :: EventSystem -> UTCTime -> IO () -> STM EventId
cancelEvent :: EventSystem -> EventId -> IO Bool
cancelEventSTM :: EventSystem -> EventId -> STM Bool
evtSystemSize :: EventSystem -> STM Int

Documentation

data EventId Source #

IDs useful for canceling previously scheduled events.

Instances

Eq EventId Source #
Instance details Defined in Control.Event Methods (==) :: EventId -> EventId -> Bool # (/=) :: EventId -> EventId -> Bool #
Ord EventId Source #
Instance details Defined in Control.Event Methods compare :: EventId -> EventId -> Ordering # (<) :: EventId -> EventId -> Bool # (<=) :: EventId -> EventId -> Bool # (>) :: EventId -> EventId -> Bool # (>=) :: EventId -> EventId -> Bool # max :: EventId -> EventId -> EventId # min :: EventId -> EventId -> EventId #
Show EventId Source #
Instance details Defined in Control.Event Methods showsPrec :: Int -> EventId -> ShowS # show :: EventId -> String # showList :: [EventId] -> ShowS #

data EventSystem Source #

The event system must be initilized using initEventSystem. More than one event system can be instantiated at once (eg. for non-interference).

noEvent :: EventId Source #

A value indicating there is no such event. Canceling this event returns True and has no other effect.

initEventSystem :: IO EventSystem Source #

The only way to get an event system is to initilize one

addEvent :: EventSystem -> UTCTime -> IO () -> IO EventId Source #

Add an *action* to be performed at *time* by *system*. Returns a unique ID.

addEventSTM :: EventSystem -> UTCTime -> IO () -> STM EventId Source #

Atomic version of addEvent

cancelEvent :: EventSystem -> EventId -> IO Bool Source #

Cancel an event from the system, returning True on success.

cancelEventSTM :: EventSystem -> EventId -> STM Bool Source #

Atomic version of cancelEvent

evtSystemSize :: EventSystem -> STM Int Source #

Returns the number of pending events.