record Sighandler : TypeS : IORef SignalST -> Sighandler.ref : Sighandler -> IORef SignalSTsighandler : IO1 Sighandlerawait : Sighandler -> List Signal -> (Siginfo -> IO1 ()) -> IO1 (IO1 ())Await a signal and carry out the given action once it is
fired.
This returns an action for cancelling the signal handler
checkSignals : Sighandler -> IO1 ()Checks for pending signals and runs the corresponding
signal handlers (if any).