"segment fault" when using mysql++

[wangxu]

below is my code;these code works very fine until, the length of the 
field "content"  exceeds 300000,
then  "segment fault" happened.
how can I avoid this?

                mysqlpp::Query query = conn.query();
                query << "select content from pages where id="<<id;
                mysqlpp::ResUse res = query.use();
                if (!res) {
                        std::cerr << "Result set is empty!" << std::endl;
                        return 1;
                }
                mysqlpp::Row r;
                while (r = res.fetch_row()) {
                        printf (r["content"]);
              }