How to write content of an object into a file in c++

Question

I have a code in this format:

        srcSAXController control(input_filename.c_str());

        std::string output_filename = input_filename;
        output_filename = "c-" + output_filename.erase(input_filename.rfind(XML_STR));

        std:: ofstream myfile(output_filename.c_str());                                    

        coverage_handler handler(i == MAIN_POS ? true : false, output_filename);

        control.parse(&handler);

        myfile.write((char *)&control, sizeof(control));

        myfile.close();

I want the content of object 'control' to be written into my file. How to fix the code above, so that content of the control object is written to the file.

Answer 1

In general you need much more than just writing the bytes of the object to be able to save and reload it.

The problem is named "serialization" and depending on a lot of factors there are several strategies.

For example it's important to know if you need to save and reload the object on the same system or if you may need to reload it on a different system; it's also fundamental to know if the object contains links to other objects, if the link graph is a simple tree or if there are possibly loops, if you need to support versioning etc. etc.

Writing the bytes to disk like the code is doing is not going to work even for something as simple as an object containing an std::string.