Dimitris,
I think you have to setup an error trap:

lcOnError = ON("ERROR")
ON ERROR STORE .t. TO llError
xx = "20011101"
ldDate = date(val(left(xx, 4)), val(substr(xx,5,2)), val(right(xx,2)))
ON ERROR &lcOnError

RETURN NOT llError

HTH
>You mean
>xx = "20011101"
>?date(val(left(xx, 4)), val(substr(xx,5,2)), val(right(xx,2)))
>aerror(ff) e.t.c. ?
>
>dim
>
>>>Hello friends,
>>>
>>>I would like to ask whether there is a way (function or something) which can determine that a specific string contains a valid date for instance :
>>>isvaliddate("20011101") would return .t.
>>>
>>>Thank you
>>>Dimitris
>>
>>Convert to a date with the date(year, month, day) function. Before VFP6, you have to use dtoc() instead.
>>
>>Trap for errors.
>>
>>HTH, Hilmar.