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

[Brandon Allbery]

On Thu, Jun 21, 2012 at 9:31 AM, Lara Michaels
<laramichaels1978 at yahoo.com>wrote:

> thank you for this, now I no longer get the error message upon starting
> xmonad. However, still nothing gets read by 'tail -f .xmonad-fifo'.
>

Sorry for the delay on this, things have been "interesting" here of late.

It belatedly occurred to me that this *is* a FIFO, and as such the reader
has to open it first, with O_RDWR (or what Haskell calls ReadWriteMode) or
it won't get hooked up properly.  (This is a POSIXism, and Linux at least
is very strict about it; depending on the kernel version, you may see
ENXDEV ("No such device or address") or what gets "opened" is a dummy node
that will never successfully read or write data.)


> Is there some other way to the dynamicLogXinerama information so that I
> can display it on an applet/appindicator?
>

dynamicLogXinerama is not very flexible; the documentation notes this, and
suggests an alternative which provides most of the same information while
giving you flexibility
(dynamicLogXinerama<http://xmonad.org/xmonad-docs/xmonad-contrib/XMonad-Hooks-DynamicLog.html#v:dynamicLogXinerama>
).

All in all, POSIX FIFOs are remarkably useless (and I'm still amazed POSIX
found a way to make them even less useful than they were originally) and
should probably be avoided.

-- 
brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
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