Cleaning up after the Close button is pressed

Colin Hume lightwing15 at
Thu Jan 20 06:27:13 CET 2011

Hi everyone,

I posted previously on haskell-beginners about an issue which would have been better directed to this list. Since then, I have revisited the issue and am now even less certain of its cause.

I have to perform cleanup when my application terminates. GHC.ConsoleHandler handles cleanup from Ctrl-C and Ctrl-Break very nicely under Windows. My sample handler and main function are shown at [1].

When I press Ctrl-C and Ctrl-Break during threadDelay, messages are written to console_event.log as I expected. When I press the Close button during threadDelay, no message is written to console_event.log. Am I missing something fundamental about handling the Close button or installing handlers?

In case it makes a difference, I'm using GHC 6.12.3 under Windows XP.


module Main where

import Control.Concurrent (threadDelay)
import GHC.ConsoleHandler
import System.IO

onConsoleEventReceived :: ConsoleEvent -> IO ()
onConsoleEventReceived event = withFile "console_event.log" AppendMode $ \ file -> do
  hPutStrLn file $ case event of
    ControlC  -> "Received Ctrl-C event"
    Break     -> "Received Ctrl-Break event"
    Close     -> "Received X button event"
    _         -> "Received other console event"
  hFlush file
main :: IO ()
main = installHandler (Catch onConsoleEventReceived) >> threadDelay (20*1000000)
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