[Question] how to use nlohmann/json in c++?

[boddumanohar]

I am working on an application where two process exchange data through shared memory. So instead of using structs to pack the data, I choose to use JSON so that I won't face any issues due to compilers.

My sender side is written in C++14 and the receiver side is written in C

On the reciver side, which is C, how do I read the json data?

I really appreciate the help.

[nlohmann]

You want to know how to access a C++ data structure in C?

[boddumanohar]

Yes. Also which header file should I use?

[nlohmann]

The library heavily relies on C++11 features and the STL. I have no idea how C should be able to make sense out of a basic_json value...

[boddumanohar]

Do you know of any other library that can fulfil my need?

[nlohmann]

Sorry, I do not. Maybe check on http://json.org which C libraries are suitable.

[boddumanohar]

Thanks a ton @nlohmann

[pboettch]

You could, theoretically, write a C-wrapper around this library. Losing basically every flexibility gained by using modern C++. But, with the advantage, that you could share the data-structure (and the same allocated memory) between C and C++ without reparsing JSON several times within the same application.

[boddumanohar]

My idea is, JSON is plain text based serialized data. So the serialisation will be preserved somewhere within the data structures. I just need to pass the pointer to this location of serialised data. But I still trying to figure out how.

Could please help me understand how nlohmann/json preserves this serialisation?

[nlohmann]

The library has a function dump() that serializes to a std::string. That string is returned and note stored in the library (if this is what you mean with "preserves the serialization").

[boddumanohar]

So serialisation means putting all the data in the form of plain old string? So that it can be transmitted easily?

…

On Wed, 16 May 2018 at 1:21 PM, Niels Lohmann ***@***.***> wrote: The library has a function dump() that serializes to a std::string. That string is returned and note stored in the library (if this is what you mean with "preserves the serialization"). — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#1088 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AIuXdddidgq8tsabvpLRknzUHTiFv3xHks5ty9qJgaJpZM4T9QyN> .

[nlohmann]

I guess so.