- * In case of any failure, this function returns NULL, (after printing
- * an error message on stderr).
+ * In case of any failure, this function returns an error status and
+ * sets *database to NULL (after printing an error message on stderr).
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Successfully opened the database.
+ *
+ * NOTMUCH_STATUS_NULL_POINTER: The given 'path' argument is NULL.
+ *
+ * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory.
+ *
+ * NOTMUCH_STATUS_FILE_ERROR: An error occurred trying to open the
+ * database file (such as permission denied, or file not found,
+ * etc.), or the database version is unknown.
+ *
+ * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred.