More MDB_node doc

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 57c6e4cde1b623b98e5ad4eb8b74e2c391cbf351..7a181d45f69226073384d21414735a0392f6360f 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -879,6 +879,11 @@ typedef struct MDB_page {
         * pgno on branch nodes.  On 64 bit platforms, #mn_flags is also used
         * for pgno.  (Branch nodes have no flags).  Lo and hi are in host byte
         * order in case some accesses can be optimized to 32-bit word access.
+        *
+        * Leaf node flags describe node contents.  #F_BIGDATA says the node's
+        * data part is the page number of an overflow page with actual data.
+        * #F_DUPDATA and #F_SUBDATA can be combined giving duplicate data in
+        * a sub-page/sub-database, and named databases (just #F_SUBDATA).
         */
 typedef struct MDB_node {
        /** part of data size or pgno