>>yes ! you are right..!
>>
>>but naomi give a solution with more security...
>
>Yes, less unstable than a few others, because there's no stable one.
>
>You may only look for a certain string within your expression, depending on the Set Date, and here's your worst enemy:
>
>

SET DATE LONG
>?DATE()
>15. januar 2011
>?DTOC(DATETIME())
>15. januar 2011; 1:07:54
>

>In a case like this, counting characters gets you nowhere, because we have months from 3 to 8 characters long, plus a space around the month. In other date formats it may look different. The semicolon after the year is not guaranteed in all locales etc etc. So any solution like those offered may work only if you know exactly what your Set Date will be for the date or datetime string you are checking. If you don't, all bets are off.
>
>Are you sure you have irretrievably lost the variable which was transformed into this string? If you didn't, that variable knew what it was, a D or a T.

There is extra parameter in dtoc or ttoc functions that guarantee the same string everytime.