xprop can’t set STRING array properties. As I needed that capability to set
_XKB_RULES_NAMES on the root window I wrote xproperty.
Without editing of the source code it can get and set STRING properties and does so on the root window.
# get property (just give the name)
$ ./xproperty.py _XKB_RULES_NAMES
_XKB_RULES_NAMES evdev pc104 us altgr-intl ''
Judging from the strings I have seen on my root window I can’t tell for sure if strings are supposed to be null-terminated or not. I guess it doesn’t really matter as long as the user of that string is written halfway sensible.
To be able to see and set any string with xproperty.py, string arrays are set
with null-byte as separator only. If you want to have the whole array null-
terminated, add an empty argument.
# set property to STRING array (first argument is the name, the rest are
# the strings to set it to (one or more)
$ ./xproperty.py _XKB_RULES_NAMES evdev pc104 us altgr-intl
$ ./xproperty.py _XKB_RULES_NAMES evdev pc104 us altgr-intl ''
The latter has an additional null-byte at the end
(to separate the following empty string). You can distinguish those with
xproperty.py. For xprop both look the same:
$ xprop -root _XKB_RULES_NAMES
_XKB_RULES_NAMES(STRING) = "evdev", "pc104", "us", "altgr-intl"