startxfce4 and ck-launch

[Paul Menzel]

Dear Xfce folks,


In chapter 35 *Xfce Desktop* from the book *Linux from Scratch* [1], for 
xfce4-session-4.12.1 the following line is suggested for `~/.xinitrc`

```
ck-launch-session dbus-launch --exit-with-session startxfce4
```

Now looking at the help text of `startxfce4`, it has a similar switch.

```
$ startxfce4 --help
[…]
   --with-ck-launch         Start xfce4-session inside a
                            ConsoleKit session

```

Adding that switch, sets the the environment variable 
`XFCE4_SESSION_WITH_CK` to 1.

```
$ more /usr/bin/startxfce4
[…]
       XFCE4_SESSION_WITH_CK="1"
       export XFCE4_SESSION_WITH_CK
[…]
```

Is there a difference between the two? Is one recommended?

Does the same apply for desktop files?

The upstream `/usr/share/xsessions.available/xfce.desktop` only contains 
the execution command below.

```
Exec=startxfce4
```


Kind regards,

Paul


[1] http://www.linuxfromscratch.org/blfs/view/cvs/xfce/xfce4-session.html