is it possible for xdm to ask for window manager?

in /usr/X11R6/lib/X11/xdm/Xsession i found things like this showing that
windows manager option can be sent as first parameter.



if [ -s "$startup" ]; then
        if [ -x "$startup" ]; then
                exec "$startup"
        else
                exec /bin/sh "$startup"
        fi
else
        if [ -r "$resources" ]; then
                xrdb -load "$resources"
        fi

        case $# in
        1)
                case $1 in
                kde)
                        exec $SHELL -c startkde
                        ;;
                esac
        esac
        exec xsm
fi
(E