- * SORT_INPUT_FB fastbuf stream
- * SORT_INPUT_PRESORT custom presorter: call function PREFIX_presorter (see below)
- * to get successive batches of pre-sorted data as temporary
- * fastbuf streams or NULL if no more data is available.
+ * SORT_INPUT_FB seekable fastbuf stream
+ * SORT_INPUT_PIPE non-seekable fastbuf stream
+ * SORT_INPUT_PRESORT custom presorter. Calls function
+ * int PREFIX_presort(struct fastbuf *dest, void *buf, size_t bufsize);
+ * to get successive batches of pre-sorted data.