- * indicates how large your structure is. If your size is larger than
- * that known about by this version of tdb, the size will be reduced to
- * the known structure size. Thus you can detect older versions, and
- * thus know that newer stats will not be updated.
+ * indicates how large your structure is: it must be filled in before
+ * calling tdb_get_attribute(), which will overwrite it with the size
+ * tdb knows about.