You can use TRY...ENDTRY to build such UDF. See sample code in Re: Check to see if a table on a network drive is in use Message #798413.

>I would like to do the following:

>If IsThisFileUsedExclusive(MyAlias) = .T.
>    Do Nothing
>Else
>    Select MyAlias
>    Set Exclu On
>    Pack
>    Set Exclu Off
>Endif

>Is there any command in VFP8 which does a IsThisFileUsedExclusive ?
>
>Regards,
>
>Gerard