>Use sys(2015) to create temp files.
>If you need absolutely 8 in lenght, thinking a temp file's lifecyle is not long, you could use :
>
>'_'+substr(sys(2015),4)
>
>or make 2 chars part of extension :
>
>stuff(sys(2015),9,0,'.')

FYI:

If you want to know how SYS(2015) works and how to convert it to Datetime and vise versa, see FILE#9704

For instance substr(sys(2015),4) will be unique for 36 days.

hth,