scanf question

[John Salmon]

I have an old (March 87) draft of the standard which says
in Sec. 4.9.6.2 The fscanf function, paragraph 8:

"...A white-space directive fails if no white-space can be found."

K&R 2nd edition says that "white-space directives are ignored"

Which is correct?  Is count set to 0 or 1 by:
   count = sscanf("10", " %d", &i);

Thanks,
John Salmon
johns at wega.caltech.edu