How to allocate JSON object on heap space?

[himanshusahu06]

How do I allocate json in stack space? Current implementation json j = json::parse(raw_string) creates object in stack space which gets destroyed as soon as it leaves the context.

We can't use shared_ptr because underlying library doesn't support it.

I tried json *j = new json() but not sure how do I parse a json string and store it in j?

Below code works, but again it this will first create object on stack and then copy it to the j which is inefficient.

jsoncons::json *j = new jsoncons::json();
*j = jsoncons::json::parse(raw_string);

[himanshusahu06]

Hi @danielaparker! Could you please help answering this question? Thanks!

[jsonconsorg]

Apologies, just got back from a long trek in the Pyrenees. You can do it as follows (without a copy)

#include <jsoncons/json.hpp>

int main()
{
    jsoncons::json doc = jsoncons::json::parse(R"({"foo" : "bar"})");

    jsoncons::json* pdoc = new jsoncons::json(std::move(doc));
}

[himanshusahu06]

Thanks @jsonconsorg! I hope you enjoyed the trek!

This worked but I'm curious to know that still calls destructor of doc. Does that mean it's not O(1) operation?

[jsonconsorg]

In the move constructor, pdoc acquires the resources previously held by doc, and doc becomes a JSON null value. So when the destructor of doc gets called, it has nothing to do, no resources to release.

[himanshusahu06]

Thanks! It helped!