Check LPARAMETERS statement in VFP Help.

>In my function I got the message missing parameters
>
>Then I looked into another function I saw the parameters:
>
>*****************************************************************
>LPARAMETERS tcSource, tcDestination, tcAction, tlUserCanceled
>*****************************************************************
>
>What are parameters ?
>Are they variables ?
>
>Could anybody explain ? because I never used them before
>
>Moises