* \param fdr FDR matcher engine.
* \param buf Buffer to scan.
* \param len Length of buffer to scan.
- * \param start First offset in buf at which a match may end.
+ * \param start First offset in buf at which a match may start.
* \param cb Callback to call when a match is found.
* \param scratch Scratch supplied to callback on match.
* \param groups Initial groups mask.
* \param hlen Length of history buffer (hbuf).
* \param buf Buffer to scan.
* \param len Length of buffer to scan (buf).
- * \param start First offset in buf at which a match may end.
+ * \param start First offset in buf at which a match may start.
* \param cb Callback to call when a match is found.
* \param scratch Scratch supplied to callback on match.
* \param groups Initial groups mask.
* Returns \ref HWLM_TERMINATED if scanning is cancelled due to the callback
* returning \ref HWLM_TERMINATE_MATCHING.
*
- * \p start is the first offset at which a match may start.
+ * \p start is the first offset at which a match may start. Note: match
+ * starts may include masks overhanging the main literal.
*
* The underlying engine may choose not to report any match which starts before
* the first possible match of a literal which is in the initial group mask.
* \p len is the length of the main buffer to be scanned.
*
* \p start is an advisory hint representing the first offset at which a match
- * may start. Some underlying literal matches may not respect it.
+ * may start. Some underlying literal matches may not respect it. Note: match
+ * starts may include masks overhanging the main literal.
*
* \p scratch is used to access the history buffer, history length and
* the main buffer.