+/* Convert a rate back to a value_t. When converting to a derive_t, counter_t
+ * or absoltue_t, take fractional residuals into account. This is important
+ * when scaling counters, for example.
+ * Returns zero on success. Returns EAGAIN when called for the first time; in
+ * this case the value_t is invalid and the next call should succeed. Other
+ * return values indicate an error. */
+int rate_to_value (value_t *ret_value, gauge_t rate,
+ rate_to_value_state_t *state, int ds_type, cdtime_t t);
+