[xmonad] how to redirect dynamicLogXinerama output to a FIFO/named pipe?

[wagnerdm at seas.upenn.edu]

You can use liftIO to turn an IO action into an X action: liftIO  
(hSetBuffering stdout LineBuffering).
~d

Quoting Lara Michaels <laramichaels1978 at yahoo.com>:

> Hi Brandon
>
> thank you for this. I tried changing xmonad.hs to read
> main =  do
>     xmonad $ gnomeConfig { modMask = mod4Mask
>                        , startupHook = hSetBuffering stdout LineBuffering
>                        , manageHook = manageDocks <+> myManageHook  
> <+> manageHook defaultConfig
>                        , workspaces = myWorkspaces
>                        , normalBorderColor  = "#cccccc"
>                        , focusedBorderColor = "#cd8b00"
>                        , borderWidth = 3
>                        , layoutHook = showWName myLayout
>                        , logHook =  dynamicLogXinerama
>                        -- , logHook =  ewmhDesktopsLogHook <+>  
> dynamicLogXinerama
>                        , handleEventHook = ewmhDesktopsEventHook
>                        } `additionalKeysP` myKeys
>
> but now xmonad shows me an error message:
>
> Couldn't match expected type 'X ()' with actual type 'IO ()'
> In the return type of a call of 'hsetBuffering'
> In the 'startupHook' field of a record
> In the first argument of 'addditionalKeysP', [...]
>
> Do you know why this is happening?
>
> thank you for any help
> ~l
>
>
>
> ________________________________
>  From: Brandon Allbery <allbery.b at gmail.com>
> To: Lara Michaels <laramichaels1978 at yahoo.com>
> Cc: "xmonad at haskell.org" <xmonad at haskell.org>
> Sent: Wednesday, June 20, 2012 3:33 AM
> Subject: Re: [xmonad] how to redirect dynamicLogXinerama output to a  
> FIFO/named pipe?
>
>
> On Tue, Jun 19, 2012 at 9:57 PM, Lara Michaels  
> <laramichaels1978 at yahoo.com> wrote:
>
> but to my surprise running 'tail -f /tmp/xmonad-fifo' shows no
> output, while if I simply start xmonad in a terminal I can see it
> printing information about the workspaces being used to the terminal:
>
> At a guess, you've just demonstrated that nobody has been using  
> dynamicLogXinerama.  It isn't flushing its output, and I can't find  
> anywhere where xmonad sets its stdout to unbuffered or line buffered  
> output.  Output to a terminal is automatically line buffered, so in  
> that case it works as expected; block buffering means it'd only get  
> flushed to the FIFO every 4Kbytes or so.
>
> You could try importing System.IO and adding
>
>     hSetBuffering stdout LineBuffering
>
> to the startupHook.
> --
> brandon s allbery                                      allbery.b at gmail.com
> wandering unix systems administrator (available)     (412) 475-9364 vm/sms