Exit script when no command line parameter is given

[Chetwood 0]

Apparently I can't see the forest for the trees so maybe someone of you can help me out. I have a little script that among other things opens the cd tray when a drive letter is given as a command-line parameter. "myscript.au3 e" would open drive e. But how do I make the script exit immediately when it is started without any parameter?

If $CmdLine[0] Then 
Exit
Else
do fancy stuff
EndIf
Exit

does still execute "do fancy stuff" instad of stopping immediately. TIA.

[funkey 104]

If $CmdLine[0] = 0 Then
 MsgBox(16, "Error", "No commandline parameter given!")
 Exit
EndIf

[Chetwood 0]

D'uh. Thanks.