diff --git a/src/rcldb/rcldb.h b/src/rcldb/rcldb.h
index 00f26101..1962c3b4 100644
--- a/src/rcldb/rcldb.h
+++ b/src/rcldb/rcldb.h
@@ -358,11 +358,12 @@ class Db {
     /** Get document for given udi
      *
      * Used by the 'history' feature, and to retrieve ancestor documents.
-     * @param udi the unique document identifier
-     * @param idxdoc used when there are several index as an opaque way to pass
-     *   the index id. Use a doc from the same index 
-     *   (e.g.: when looking for parent), 
-     * @param doc the output doc
+     * @param udi The unique document identifier.
+     * @param idxdoc A document from the same database as an opaque way to pass
+     *   the database id (e.g.: when looking for parent in a multi-database 
+     *   context).
+     * @param[out] doc The output Recoll document.
+     * @return True for success.
      */
     bool getDoc(const string &udi, const Doc& idxdoc, Doc &doc);
 
diff --git a/src/rcldb/rcldb_p.h b/src/rcldb/rcldb_p.h
index 4ba7b693..65dceee8 100644
--- a/src/rcldb/rcldb_p.h
+++ b/src/rcldb/rcldb_p.h
@@ -124,7 +124,11 @@ class Db::Native {
 
     /** Retrieve Xapian::docid, given unique document identifier, 
      * using the posting list for the derived term.
-     *
+     * 
+     * @param udi the unique document identifier (opaque hashed path+ipath).
+     * @param idxi the database index, at query time, when using external
+     *     databases.
+     * @param[out] xdoc the xapian document.
      * @return 0 if not found
      */
     Xapian::docid getDoc(const string& udi, int idxi, Xapian::Document& xdoc);