C++ storing custom object as blob in Mysql -

i need store c++ object mysql database blob. following code,

int mysqldb::save(string name, trackerfeatures features) {   ofstream ofs("features.ros", ios::binary);   ofs.write((char*)&features, sizeof(features));    try{     sql::preparedstatement *pstmt = con->preparestatement("insert faces(name,features) values(?,?)");     istream stream(ofs.rdbuf());     pstmt->setstring(1, name);     pstmt->setblob(2, &stream);      pstmt->executeupdate();   } catch (sql::sqlexception &e) {     cout << "# err: sqlexception in " << __file__;     cout << "(" << __function__ << ") on line " << __line__ << endl;     cout << "# err: " << e.what();     cout << " (mysql error code: " << e.geterrorcode();     cout << ", sqlstate: " << e.getsqlstate() << " )" << endl;   }    return exit_success; } 

when pass data function, see features.ros file being created binary data. also, there row created in table "features" column empty. not sure getting wrong.

the raw buffer of std::ofstream instance (named ofs) empty when constructing std::istream object using raw buffer.

however, it's not idea store actual memory representation of given object, reason... instead, consider creating proper persisting methods, gives valid , portable representation, desired classes.