>>SYS(2015) is not safe either, SUBSTR(SYS(2015)3) is safe AFAIK.
>
>Why?

Because the help says so <g>

SYS(3) may return a non-unique name when issued successionally on a fast computer. Use SUBSTR(SYS(2015), 3, 10) to create unique, legal eight character file name.

Hey, it is also supposed to be in Sergey.chm we are dependent on it. <vbg>

My compliments.