GHC.Event

This module provides scalable event notification for file descriptors and timeouts.

This module should be considered GHC internal.

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Types

data EventManager

The event manager state.

data TimerManager

The event manager state.

Creation

getSystemEventManager :: IO (Maybe EventManager)

Retrieve the system event manager for the capability on which the calling thread is running.

This function always returns Just the current thread's event manager when using the threaded RTS and Nothing otherwise.

new :: IO EventManager

Create a new event manager.

getSystemTimerManager :: IO TimerManager

Registering interest in I/O events

data Event

An I/O event.

Instances

Eq Event

Methods

(==) :: Event -> Event -> Bool

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

Show Event

Since: 4.3.1.0

Methods

showsPrec :: Int -> Event -> ShowS

show :: Event -> String

showList :: [Event] -> ShowS

Semigroup Event

Since: 4.10.0.0

Methods

(<>) :: Event -> Event -> Event

sconcat :: NonEmpty Event -> Event

stimes :: Integral b => b -> Event -> Event

Monoid Event

Since: 4.3.1.0

Methods

mempty :: Event

mappend :: Event -> Event -> Event

mconcat :: [Event] -> Event

evtRead :: Event

Data is available to be read.

evtWrite :: Event

The file descriptor is ready to accept a write.

type IOCallback = FdKey -> Event -> IO ()

Callback invoked on I/O events.

data FdKey

A file descriptor registration cookie.

Instances

Eq FdKey

Methods

(==) :: FdKey -> FdKey -> Bool

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

Show FdKey

Methods

showsPrec :: Int -> FdKey -> ShowS

show :: FdKey -> String

showList :: [FdKey] -> ShowS

data Lifetime

The lifetime of an event registration.

Since: 4.8.1.0

Constructors

OneShot

the registration will be active for only one event

MultiShot

the registration will trigger multiple times

Instances

Eq Lifetime

Methods

(==) :: Lifetime -> Lifetime -> Bool

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

Show Lifetime

Methods

showsPrec :: Int -> Lifetime -> ShowS

show :: Lifetime -> String

showList :: [Lifetime] -> ShowS

Semigroup Lifetime

Since: 4.10.0.0

Methods

(<>) :: Lifetime -> Lifetime -> Lifetime

sconcat :: NonEmpty Lifetime -> Lifetime

stimes :: Integral b => b -> Lifetime -> Lifetime

Monoid Lifetime

mappend takes the longer of two lifetimes.

Since: 4.8.0.0

Methods

mempty :: Lifetime

mappend :: Lifetime -> Lifetime -> Lifetime

mconcat :: [Lifetime] -> Lifetime

registerFd :: EventManager -> IOCallback -> Fd -> Event -> Lifetime -> IO FdKey

registerFd mgr cb fd evs lt registers interest in the events evs on the file descriptor fd for lifetime lt. cb is called for each event that occurs. Returns a cookie that can be handed to unregisterFd.

unregisterFd :: EventManager -> FdKey -> IO ()

Drop a previous file descriptor registration.

unregisterFd_ :: EventManager -> FdKey -> IO Bool

Drop a previous file descriptor registration, without waking the event manager thread. The return value indicates whether the event manager ought to be woken.

closeFd :: EventManager -> (Fd -> IO ()) -> Fd -> IO ()

Close a file descriptor in a race-safe way.

Registering interest in timeout events

type TimeoutCallback = IO ()

Callback invoked on timeout events.

data TimeoutKey

A timeout registration cookie.

Instances

Eq TimeoutKey

Methods

(==) :: TimeoutKey -> TimeoutKey -> Bool

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

registerTimeout :: TimerManager -> Int -> TimeoutCallback -> IO TimeoutKey

Register a timeout in the given number of microseconds. The returned TimeoutKey can be used to later unregister or update the timeout. The timeout is automatically unregistered after the given time has passed.

updateTimeout :: TimerManager -> TimeoutKey -> Int -> IO ()

Update an active timeout to fire in the given number of microseconds.

unregisterTimeout :: TimerManager -> TimeoutKey -> IO ()

Unregister an active timeout.