System.Linux.Epoll.Base

Low level interface to Linux' epoll, a high performance polling mechanism which handles high numbers of file descriptors efficiently. See man epoll(7) for details.

Documentation

data EventType

EventType corresponds to epoll's event type defines, e.g. EPOLLIN, EPOLLOUT, EPOLLET, etc.

Instances

Eq EventType

Ord EventType

Show EventType

data Size

Unsigned type used for length specifications.

Instances

Eq Size

Ord Size

Show Size

toSize :: Int -> Maybe Size

data Duration

Unsigned type used for timeout specifications.

Instances

Eq Duration

Ord Duration

Show Duration

toDuration :: Int -> Maybe Duration

data Descriptor a

Event descriptor. Will be returned from add and must be passed to delete exactly once.

data Device

Abstract epoll device. Holds internal data. Returned from create and used in almost every other API function. Must be closed explicitely with close.

Instances

Eq Device

Show Device

data Event a

A single event ocurrence.

(=~) :: EventType -> EventType -> Bool

Match operator. Useful to test whether an EventType returned from wait contains one of the defined event types because EventTypes returned by wait might be the bitwise OR of several EventTypes.

create :: Size -> IO Device

Creates an epoll device. Must be closed with close. The parameter Size specifies the number of events that can be reported by a single call to wait.

close :: Device -> IO ()

Closes epoll device.

wait :: Duration -> Device -> IO [Event a]

Waits for the specified duration on all event descriptors. Returns the list of events that occured.

add :: Device -> a -> [EventType] -> Fd -> IO (Descriptor a)

Adds a filedescriptor to the epoll watch set using the specified EventTypes. User data might be passed in as well which will be returned on event occurence as part of the Event type. Returns an event descriptor which must be deleted from the watch set with delete and passed to freeDesc exactly once.

modify :: Device -> [EventType] -> Descriptor a -> IO ()

Modified the event types of the event descriptor.

delete :: Device -> Descriptor a -> IO ()

Removes the event descriptor from the epoll watch set. and frees descriptor which must not be used afterwards.

freeDesc :: Descriptor a -> IO ()

Frees the resources associated with this descriptor. Must be called exactly once.

inEvent :: EventType

outEvent :: EventType

peerCloseEvent :: EventType

urgentEvent :: EventType

errorEvent :: EventType

hangupEvent :: EventType

edgeTriggeredEvent :: EventType

oneShotEvent :: EventType

combineEvents :: [EventType] -> EventType

Bitwise OR of the list of EventTypes.