Need some help with serialization & deserialization

[Manohar-Penta]

@nlohmann
I am trying to deserialize(json -> string) my json to a file with json.dump(). I also want to pick up the data from this file and serialize(string->json) this into json to use further.

But I am having issues while picking up the data. the string returned by the json.dump() is following:

{"profile":{"data":{"age":21,"graduation":"1956","institute":"X-men","name":"Wolverine"},"expiry":1739613272}}

But json::parse() is throwing when i pass the above string. my guess is that since this is not a raw string, the " is ending the string.

please help me with this. I am fairly new to all this, so give me as much advice as possible. I am doing this for a job assignment, so quick responses would be greatly appreciated.

[nlohmann]

Please provide code.

[Manohar-Penta]

My Code:

deserilazation(){
        std::string data = j.dump();
        ftruncate(fd, 0);
        write(fd, data.c_str(), data.size());
}

serialization(){
            std::ifstream initFile(filename);
            std::string content;
            getline(initFile, content);
            std::cout << content << std::endl;
            j = json::parse(content);
}

[Manohar-Penta]

Yeah i have went through the documentation, and tried passing the stream directly to the parse. same problem with it. I will try to debug and get some more context.

[Manohar-Penta]

I am implementing a file lock, which doesn't allow me to use fstream's after I lock the file. I am locking the file after I am done reading from the file. After that I am writing using the write().
Is that can be a problem here??

[nlohmann]

Please check in your debugger.

[Manohar-Penta]

Hey @nlohmann , Thanks for helping me. I have mostly wrote code in Codeforces or Leetcode, So don't have much idea about developing with c++. The debugger gave me context to solve the problem.

The problem was with ftruncate() which removes the data but have to use the lseek() to move the position where the data should be appended in file.

thanks again, this project really helped me complete this assignment.

[nlohmann]

Thanks for checking back! Sorry that I couldn't be of more help.