base-4.17.0.0: Basic libraries
Safe HaskellTrustworthy
LanguageHaskell2010

GHC.Event

Description

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

This module should be considered GHC internal.

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Synopsis

Types

data EventManager Source #

The event manager state.

data TimerManager Source #

The event manager state.

Creation

getSystemEventManager :: IO (Maybe EventManager) Source #

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 Source #

Create a new event manager.

Registering interest in I/O events

data Event Source #

An I/O event.

Instances

Instances details
Monoid Event Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Internal.Types

Semigroup Event Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Event.Internal.Types

Show Event Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Internal.Types

Eq Event Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Internal.Types

Methods

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

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

evtRead :: Event Source #

Data is available to be read.

evtWrite :: Event Source #

The file descriptor is ready to accept a write.

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

Callback invoked on I/O events.

data FdKey Source #

A file descriptor registration cookie.

Instances

Instances details
Show FdKey Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Manager

Eq FdKey Source #

Since: base-4.4.0.0

Instance details

Defined in GHC.Event.Manager

Methods

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

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

data Lifetime Source #

The lifetime of an event registration.

Since: base-4.8.1.0

Constructors

OneShot

the registration will be active for only one event

MultiShot

the registration will trigger multiple times

Instances

Instances details
Monoid Lifetime Source #

mappend takes the longer of two lifetimes.

Since: base-4.8.0.0

Instance details

Defined in GHC.Event.Internal.Types

Semigroup Lifetime Source #

Since: base-4.10.0.0

Instance details

Defined in GHC.Event.Internal.Types

Show Lifetime Source #

Since: base-4.8.1.0

Instance details

Defined in GHC.Event.Internal.Types

Eq Lifetime Source #

Since: base-4.8.1.0

Instance details

Defined in GHC.Event.Internal.Types

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

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 () Source #

Drop a previous file descriptor registration.

unregisterFd_ :: EventManager -> FdKey -> IO Bool Source #

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 () Source #

Close a file descriptor in a race-safe way. It might block, although for a very short time; and thus it is interruptible by asynchronous exceptions.

Registering interest in timeout events

type TimeoutCallback = IO () Source #

Warning: since the TimeoutCallback is called from the I/O manager, it must not throw an exception or block for a long period of time. In particular, be wary of throwTo and killThread: if the target thread is making a foreign call, these functions will block until the call completes.

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

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.

Be careful not to exceed maxBound :: Int, which on 32-bit machines is only 2147483647 μs, less than 36 minutes.

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

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

Be careful not to exceed maxBound :: Int, which on 32-bit machines is only 2147483647 μs, less than 36 minutes.

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

Unregister an active timeout.