|+ operators in getops of ksh

Question

What is difference when we use |+ operator in getopts of ksh ?

Examples of code are

while getopts d: o
do  case "$o" in
    d|+d)   seplist="$OPTARG";;
    esac
done

echo $seplist

and

while getopts d: o
do  case "$o" in
    d)  seplist="$OPTARG";;
    esac
done

echo $seplist

Answer 1

The operator | means or, so d|+d) means d or +d.