@end deftypefn
@cindex strings, searching backwards
-@deftypefn {Function} {} RINDEX (@var{string}, @var{format})
+@deftypefn {Function} {} RINDEX (@var{haystack}, @var{needle})
Returns a positive integer indicating the position of the last
occurrence of @var{needle} in @var{haystack}. Returns 0 if
@var{haystack} does not contain @var{needle}. Returns system-missing if
returns the largest value. Returns 0 if @var{haystack} does not contain
any part in @var{needle}. It is an error if @var{needle_len} does not
evenly divide the length of @var{needle}. Returns system-missing
-if @var{needle} is an empty string.
+if @var{needle} is an empty string or if needle_len is less than 1.
@end deftypefn
@cindex padding strings