Add BTOPTIONS_PROC comments to nbtree.h.

Add comments explaining the purpose of B-Tree support function 5 to
nbtree.h for consistency (all other support functions were already
described by nearby comments).

This fixes what was arguably an oversight in commit 911e702077, or in
follow-up doc commit 15cb2bd2 (which documented support function 5 in
btree.sgml, but neglected to add anything to nbtree.h).

diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index 8dcfe5674c68e490b4956cc6905b5b371d35a0e7..6a501537e1eb3f8c86d415ec20e52b5c97bac932 100644 (file)
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -702,6 +702,11 @@ BTreeTupleGetMaxHeapTID(IndexTuple itup)
  * To facilitate B-Tree deduplication, an operator class may choose to
  * offer a forth amproc procedure (BTEQUALIMAGE_PROC).  For full details,
  * see doc/src/sgml/btree.sgml.
+ *
+ * An operator class may choose to offer a fifth amproc procedure
+ * (BTOPTIONS_PROC).  These procedures define a set of user-visible
+ * parameters that can be used to control operator class behavior.  None of
+ * the built-in B-Tree operator classes currently register an "options" proc.
  */
 
 #define BTORDER_PROC       1