std::wstring to rapidJson [duplicate]

Try this for parse std:: string

std::string str = "{ \"hello\" : \"world\" }";
copiedDocument.Parse<0>(str.c_str());

if contentString is std::string, just try

document.Parse<0>(contentString.c_str()).HasParseError()

if contentString is char *, just try

document.Parse<0>(contentString).HasParseError()

and you'd better post your original code snippet

Have you tried

if (document.Parse<0>(contentString.c_str()).HasParseError())
    return 1;

?

Because, from the documentation, I fail to see why you want anything "writable"...

Seems to me there is an error with the string you send json, You are using it correctly, I suggest you try sending it:

const char json[] = "{ \"hello\" : \"world\" }";

And see if it works, if so obviously it's a buffer problem.. you can continue from there I am sure