[xmonad] xmobar

[Norbert Zeh]

Marco Guidetti [2011.11.16 1028 +0100]:
> Hi all,
> 
> I have started using xmonad very recently but so far so good, almost
> everything works exactly as it should.
> One of the biggest issue I am dealing with right now is xmobar.
> 
> I mean:
> I use two different xmobar instances in xmonad (one at the top and one
> at the bottom of the screen): the top one has time/battery/xmonad
> stuff (as in windows, workspace and layout info), the bottom some
> weather stuff/cpu and so on.
> I start them in this way:
>       xmproc <- spawnPipe "xmobar ~/.xmobaruprc" (for the top one,
> which uses DynamicLog)
> and
>       spawn "xmobar ~/.xmobarrc" (for the bottom one)
> 
> Obviously this leads to having multiple instances of xmobar running
> each time i press mod4Mask+q to restart xmonad (which happens quite
> frequently since I am still configuring all the stuff I need and
> playing around with xmonad to understand it better).
> 
> I have seen that in XMonad.Hooks.DynamicLog (xmobar) there is a way to
> do this (even if I still don't fully comprehend how to use it for the
> DynamicLog, for example).
> It's not clear to me how to use for multiple xmobar instances (as in my case).
> 
> Can someone point to relevant examples (I have found the doc/wiki
> page, but I don't get it)?

I ran into the same problem.  The way I see it, the problem is that xmonad does
not keep track of the processes it spawns.  Thus, when restarting, these
processes stay around.  The reason why I think this does not happen with the
xmobar spawned as a pipe to receive xmonad's log output is that the xmobar
instance dies the moment the pipe gets closed by xmonad.

The way I work around this (I'm running 4 xmobar instances ;) and some other
things in my X11 session) is to wrap the invocation of xmonad into a session
script that starts all the things I want.  Then restarting xmonad does not
trigger rerunning the session script and all is well.  The only situation where
I'm not happy with this solution is when I reconfigure the xmobar instances
themselves because they still won't restart when restarting xmonad.  In this
case, I kill them and restart them by hand.

Cheers,
Norbert