This module implements a proper way of finding out whether the window is remote or local.

Just checking for a hostname and WM_CLIENT_MACHINE being equal is often not enough because the hostname is a changing subject (without any established notification mechanisms), and thus WM_CLIENT_MACHINE and the hostname can diverge even for a local window.

This module solves the problem. As soon as there is a new window created, we check the hostname and WM_CLIENT_MACHINE, and then we cache the result into the XMONAD_REMOTE property.

Notice that XMonad itself does not know anything about hostnames, nor does it have any dependency on Network.* modules. For this module it is not a problem: you can provide a mean to get the hostname through your config file (see usage). Or, if you don't like the hassle of handling dynamic hostnames (suppose your hostname never changes), it is also fine: this module will fallback to using environment variables.

You can use this module with the following in your xmonad.hs:

import XMonad
import XMonad.Util.RemoteWindows
import Network.BSD

main = xmonad def
   { manageHook = manageRemote =<< io getHostName }