MYSQL_RES * mysql_use_result(MYSQL * mysql);
Used to initiate the retrieval of a result set from the last query executed using the mysql_real_query() function on the database connection. Either this or the mysql_store_result() function must be called before the results of a query can be retrieved, and one or the other must be called to prevent the next query on that database connection from failing.
Returns an unbuffered result set or NULL if an error occurred.
The mysql_use_result() function does not transfer the entire result set. Hence several functions like mysql_num_rows() or mysql_data_seek() cannot be used. mysql_use_result() will block the current connection until all result sets are retrieved or result set was released by mysql_free_result().