result_id is a valid result id returned by ifx_query() or ifx_prepare().
Returns the number of rows affected by a query associated with result_id.
For inserts, updates and deletes the number is the real number (sqlerrd[2]) of affected rows. For selects it is an estimate (sqlerrd[0]). Don't rely on it. The database server can never return the actual number of rows that will be returned by a SELECT because it has not even begun fetching them at this stage (just after the "PREPARE" when the optimizer has determined the query plan).
Useful after ifx_prepare() to limit queries to reasonable result sets.
See also ifx_num_rows().