System.Glib.MainLoop

main event loop, and events

Documentation

type HandlerId = CUInt

timeoutAdd :: IO Bool -> Int -> IO HandlerId

Sets a function to be called at regular intervals, with the default priority priorityDefault. The function is called repeatedly until it returns False, after which point the timeout function will not be called again. The first call to the function will be at the end of the first interval.

Note that timeout functions may be delayed, due to the processing of other event sources. Thus they should not be relied on for precise timing. After each call to the timeout function, the time of the next timeout is recalculated based on the current time and the given interval (it does not try to 'catch up' time lost in delays).

timeoutAddFull :: IO Bool -> Priority -> Int -> IO HandlerId

Sets a function to be called at regular intervals, with the given priority. The function is called repeatedly until it returns False, after which point the timeout function will not be called again. The first call to the function will be at the end of the first interval.

Note that timeout functions may be delayed, due to the processing of other event sources. Thus they should not be relied on for precise timing. After each call to the timeout function, the time of the next timeout is recalculated based on the current time and the given interval (it does not try to 'catch up' time lost in delays).

timeoutRemove :: HandlerId -> IO ()

Remove a previously added timeout handler by its HandlerId.

idleAdd :: IO Bool -> Priority -> IO HandlerId

Add a callback that is called whenever the system is idle.

• A priority can be specified via an integer. This should usually be priorityDefaultIdle.
• If the function returns False it will be removed.

idleRemove :: HandlerId -> IO ()

Remove a previously added idle handler by its HandlerId.

data IOCondition

Flags representing a condition to watch for on a file descriptor.

IOIn

There is data to read. [IOOut] Data can be written (without blocking). [IOPri] There is urgent data to read. [IOErr] Error condition. [IOHup] Hung up (the connection has been broken, usually for pipes and sockets). [IOInvalid] Invalid request. The file descriptor is not open.

Constructors

IOIn

IOOut

IOPri

IOErr

IOHup

IOInvalid

Instances

Bounded IOCondition

Enum IOCondition

Eq IOCondition

Flags IOCondition

inputAdd

Arguments

:: FD

a file descriptor

-> [IOCondition]

the condition to watch for

-> Priority

the priority of the event source

-> IO Bool

the function to call when the condition is satisfied. The function should return False if the event source should be removed.

-> IO HandlerId

the event source id

Adds the file descriptor into the main event loop with the given priority.

inputRemove :: HandlerId -> IO ()

type Priority = Int

Priorities for installing callbacks.

priorityLow :: Int

priorityDefaultIdle :: Int

priorityHighIdle :: Int

priorityDefault :: Int

priorityHigh :: Int

data MainLoop

A main event loop abstraction.

mainLoopNew

Arguments

:: Maybe MainContext

context - the context to use, or Nothing to use the default context

-> Bool

isRunning - True to indicate that the loop is running; False otherwise

-> IO MainLoop

the new MainLoop

Create a new MainLoop.

mainLoopRun :: MainLoop -> IO ()

Runs a main loop until mainLoopQuit is called on the loop. If this is called for the thread of the loop's MainContext, it will process events from the loop, otherwise it will simply wait.

mainLoopQuit :: MainLoop -> IO ()

Stops a MainLoop from running. Any calls to mainLoopRun for the loop will return.

mainLoopIsRunning :: MainLoop -> IO Bool

Checks to see if the main loop is currently being run via mainLoopRun.

data MainContext

An opaque datatype representing a set of sources to be handled in a main loop.

mainContextNew :: IO MainContext

Creates a new MainContext.

mainContextDefault :: MainContext

The default MainContext. This is the main context used for main loop functions when a main loop is not explicitly specified.

mainContextIteration :: MainContext -> Bool -> IO Bool

Runs a single iteration for the given main loop. This involves checking to see if any event sources are ready to be processed, then if no events sources are ready and mayBlock is True, waiting for a source to become ready, then dispatching the highest priority events sources that are ready. Note that even when mayBlock is True, it is still possible for mainContextIteration to return (0), since the the wait may be interrupted for other reasons than an event source becoming ready.

mainContextFindSourceById :: MainContext -> HandlerId -> IO Source

newtype Source

Constructors

Source (ForeignPtr Source)

sourceAttach :: Source -> MainContext -> IO HandlerId

sourceSetPriority :: Source -> Priority -> IO ()

sourceGetPriority :: Source -> IO Priority

sourceDestroy :: Source -> IO ()

sourceIsDestroyed :: Source -> IO Bool