sure its return value is meaningful.
;; Fill prefix used for filling the paragraph.
fill-pfx)
(save-excursion
+ ;; To make sure the return value of forward-paragraph is meaningful,
+ ;; we have to start from the beginning of line, otherwise skipping
+ ;; past the last few chars of a paragraph-separator would count as
+ ;; a paragraph (and not skipping any chars at EOB would not count
+ ;; as a paragraph even if it is).
+ (move-to-left-margin)
(if (not (zerop (forward-paragraph)))
;; There's no paragraph at or after point: give up.
(setq fill-pfx "")