Get string field content without return std::string copy

[zmwangcode]

I am dealing with json with a lot of string fields, I checked the souce code , seems there is no way to get the underlying string of string field without a std::string copy?

auto content = j.get<char*>()

Something likes this will be very helpful.

[zmwangcode]

I am fully aware of the fact that the returned char* may be invalidate when the json object is altered later. It's the client's responsbility to use the returned raw string properly, is ther any way to get it ?

[AraHaan]

just take the std::string return and to .to_cstr() or something like that.

[zmwangcode]

just take the std::string return and to .to_cstr() or something like that.

this required a std::string copy as well. I want the content without any copy..

[nlohmann]

This works:

json j = "Hello";
auto s = j.get_ref<std::string&>().c_str();

[zmwangcode]

due to compatbility reason, I need to use version 2.1.1, and seems this version does not support such operation.

how to achieve this in version 2.1.?

[nlohmann]

According to the Release Notes, get_ref() was introduced in version 1.1.0.

[zmwangcode]

Cool, I got build error and though it was caused by no such definition.

I checked the code, my issue was not provide const before std::string reference, because my input json j is a const object.

[nlohmann]

Cool! (But you really should update to the recent version...)

[AraHaan]

This is why I use submodules makes update just a git submodule foreach "git pull" away.

[nlohmann]

This depends on your policies of how updates are made. But yes, this may be a convenient method.

[zmwangcode]

This is why I use submodules makes update just a git submodule foreach "git pull" away.

this is not quite a safe way for large project, since it may introduce new features automatically that may break existing functionality.

I prefer to test intensively before mannually upgrade to new version.

[zmwangcode]

Cool! (But you really should update to the recent version...)

Will check and upgarade. :-)

[AraHaan]

@zmwangcode I mean if it did not work out you can always git reset the submodule updates away.