Re: [boost] Outcome v2

Subject: Re: [boost] Outcome v2
From: Groke, Paul (paul.groke_at_[hidden])
Date: 2017-07-15 21:23:06

> From: Emil DotchevskiSent: Freitag, 14. Juli 2017 18:37
> To: boost_at_[hidden]
>
> Ah, now I get it, thanks for the explanation. There *might* even be a
> way to get this to work even without memory allocation in the end
> (without exception_ptr), but I think this is perhaps missing the point
> of returning an error object, which is to be able to interact with it.
> Also, reasonably if you could fit the things you need to create the
> object into a "small object optimized" buffer, you can probably fit the
> object itself into the same buffer. Noexcept already has that, it's the
> result<T> object, however it might be too heavy to return up the call
> chain one level at a time (it is instead designed for capturing the TLS-
> stored object to postpone its handling, perhaps after moving it to
> another thread).

The question is: how do you interact with a return value of unknown type?
For exceptions it's much easier. There is at least the common practice to derive your exception from std::exception, so if nothing else, you can at least get an error message. And you can catch base classes, which can also come in quite handy.