FUNCTION  NetFilLock([<nSeconds>])

     NetFilLock() will attempt to lock the current database to prevent
access from other users.  This is generally used for a database opened
in SHARED mode.  If a problem arises, NetFilLock() will attempt to
retry locking the file for nSeconds.

     If the SetShowStatus() function call was set to True, the status
of retrying will automatically appear on the application screen as
required.

Parameter:
     nSeconds  Time to keep retrying to lock the file
               (Defaults to 10 seconds)
Returns:
     True if the database is locked successfully, False if not.