my_ulonglong mysql_stmt_insert_id(MYSQL_STMT * stmt);
stmt- a statement handle, which was previously allocated by mysql_stmt_init().
The mysql_stmt_insert_id() function returns the ID generated by a prepared statement on a table with a column having the AUTO_INCREMENT attribute. If the last query wasn't an INSERT or UPDATE statement or if the modified table does not have a column with the AUTO_INCREMENT attribute, this function will return zero.
When performing a multi insert prepared statement, mysql_stmt_insert_id() will return the value of the first row.