A variation on Allen's example:
 Code:
Global $X
$X=3.1514
Func($X)

Function Func($_V)

  'X=' $X ?	; X is a global, value displays
  'V=' $_V ?

  Dim $X	; define a local var called X

  'X=' $X ?	; X is now local, Dim'd but unset - nothing to see here!
  'V=' $_V ?
  
  Exit 0

EndFunction
Note that once you declare X locally, the value in the function is empty. Try replacing the DIM with GLOBAL. \:\)

Glenn
_________________________
Actually I am a Rocket Scientist! \:D