-/* Return true if the text immediately before POS in BUF is known, for
- the purposes of CACHE. If NEXT is non-zero, set *NEXT to the nearest
- position before POS where the knownness changes. */
-int region_cache_backward (struct buffer *buf, struct region_cache *c,
- ptrdiff_t pos, ptrdiff_t *next)
+/* Return the value for the text immediately before POS in BUF if the
+ value is known, for the purposes of CACHE, and return zero
+ otherwise. If NEXT is non-zero, set *NEXT to the nearest
+ position before POS where the knowledge changes. */
+int
+region_cache_backward (struct buffer *buf, struct region_cache *c,
+ ptrdiff_t pos, ptrdiff_t *next)