/**
* Return the database format version of the given database.
+ *
+ * @retval 0 on error
*/
unsigned int
notmuch_database_get_version (notmuch_database_t *database);
* fail with NOTMUCH_STATUS_UPGRADE_REQUIRED. This always returns
* FALSE for a read-only database because there's no way to upgrade a
* read-only database.
+ *
+ * Also returns FALSE if an error occurs accessing the database.
+ *
*/
notmuch_bool_t
notmuch_database_needs_upgrade (notmuch_database_t *database);
* notmuch_message_destroy on 'message' or until a query from which it
* derived is destroyed).
*
- * This function will not return NULL since Notmuch ensures that every
- * message belongs to a single thread.
+ * This function will return NULL if triggers an unhandled Xapian
+ * exception.
*/
const char *
notmuch_message_get_thread_id (notmuch_message_t *message);