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// You are responsible for releasing the structure in the end arrow_array.release(&arrow_array); This doesn't look like RAII. How is this idiomatic for C++20
by levzettelin 1y ago
// You are responsible for releasing the structure in the end
arrow_array.release(&arrow_array);
This doesn't look like RAII. How is this idiomatic for C++20? Why do you have to pass a pointer to "this" again as an explicit argument.
- rfoo 1y agoThis is the extracted Arrow C data interfaces as documented in https://arrow.apache.org/docs/format/CDataInterface.html https://arrow.apache.org/docs/format/CDataInterface.html It's not how you interact with the data in your own C++ code, it's for passing this data to other in-process consumers (libraries etc). While in the example it calls the release function, this is usually just passed to a downstream consumer and it's their responsibility to call it. I agree that having such an example as the first one is confusing. Given that a large part of the point of Apache Arrow is passing data columnar data between libraries in different languages in memory, it makes some sense.
- CyberDildonics 1y agoIt's not how you interact with the data in your own C++ code, it's for passing this data to other in-process consumers (libraries etc). While in the example it calls the release function, this is usually just passed to a downstream consumer and it's their responsibility to call it. This seems like a strange rationalizations when you don't need to have explicit release to be able to pass it to something else.
- pjmlp 1y agoRAII predates C++98, I was already used to it in Turbo C++ for MS-DOS, and is pity we need to keep advocating for it as something extraordinary.
- CyberDildonics 1y agoThis doesn't have anything to do with what they said, they didn't say RAII was new.
- pjmlp 1y agoMight be misunderstood by others not skilled in C++ when reading, > This doesn't look like RAII. How is this idiomatic for C++20?
- CyberDildonics 1y agoYou can try to be insulting if you want but if you could explain the connection I think you would have already.
- pjmlp 1y agoI wasn't.
- CyberDildonics 1y agoYou weren't what? Who are you saying "isn't skilled in C++" here and why would that matter?
- pjmlp 1y agoThose that by reading that sentence think RAII is something new in C++20.
- CyberDildonics 1y agoWhy would someone who knows what RAII and C++20 are end up thinking that?
- ender341341 1y agoI think you're partly making the point for them, RAII has been idiomatic C++ since before c++ was standardized. It wasn't even idiomatic c++98 to be missing it, so to be missing it in c++20 library definitely still isn't.
- pjmlp 1y agoIndeed, that is the point.