System.Glib.Signals

Documentation

newtype Signal object handler

Constructors

Signal (Bool -> object -> handler -> IO (ConnectId object))

on :: object -> Signal object callback -> callback -> IO (ConnectId object)

Perform an action in response to a signal.

Use it like this:

on obj sig $ do
...

or if the signal handler takes any arguments:

on obj sig $ \args -> do
...

after :: object -> Signal object callback -> callback -> IO (ConnectId object)

Perform an action in response to a signal.

• Like on but the signal is executed after Gtk's default handler has run.

type SignalName = String

type ConnectAfter = Bool

data GObjectClass o => ConnectId o

The type of signal handler ids. If you ever need to disconnect a signal handler then you will need to retain the ConnectId you got when you registered it.

Constructors

ConnectId CULong o

signalDisconnect :: GObjectClass obj => ConnectId obj -> IO ()

Disconnect a signal handler. After disconnecting the handler will no longer be invoked when the event occurs.

signalBlock :: GObjectClass obj => ConnectId obj -> IO ()

Block a specific signal handler.

• Blocks a handler of an instance so it will not be called during any signal emissions unless it is unblocked again. Thus "blocking" a signal handler means to temporarily deactive it, a signal handler has to be unblocked exactly the same amount of times it has been blocked before to become active again.

signalUnblock :: GObjectClass obj => ConnectId obj -> IO ()

Unblock a specific signal handler.

• Undoes the effect of a previous signalBlock call. A blocked handler is skipped during signal emissions and will not be invoked, unblocking it (for exactly the amount of times it has been blocked before) reverts its "blocked" state, so the handler will be recognized by the signal system and is called upon future or currently ongoing signal emissions (since the order in which handlers are called during signal emissions is deterministic, whether the unblocked handler in question is called as part of a currently ongoing emission depends on how far that emission has proceeded yet).

signalStopEmission :: GObjectClass obj => obj -> SignalName -> IO ()

Stops a signal's current emission.

• This will prevent the default method from running. The sequence in which handlers are run is "first", "on", "last" then "after" where Gtk-internal signals are connected either at "first" or at "last". Hence this function can only stop the signal processing if it is called from within a handler that is connected with an "on" signal and if the Gtk-internal handler is connected as "last". Gtk prints a warning if this function is used on a signal which isn't being emitted.

disconnect :: GObjectClass obj => ConnectId obj -> IO ()

Deprecated: use signalDisconnect instead

data GClosure

connectGeneric :: GObjectClass obj => SignalName -> ConnectAfter -> obj -> handler -> IO (ConnectId obj)