set -- -a bb
readonly OPTARG
getopts :x x

echo OPTARG = $OPTARG x = $x

getopts x x
echo ${OPTARG-unset} x = $x

typeset -r RO=foo
typeset -n OPTARG=RO

getopts :x x
typeset -p RO

getopts x x
typeset -p RO
