Re: [boost] Outcome v2

Emil Dotchevski via Boost Sent: Donnerstag, 13. Juli 2017 00:27

To clarify the clarification of the clarification, I _am_ interested in finding a way to express the equivalent of the Noexcept return throw_() without using TLS, and I don't insist on it being a free function; for example it would be sufficient if somehow I could just return r in case of an error, as long as it works regardless of what error type r might contain, and of course it should be reasonably efficient.

Have you thought about using a type-erased factory - like function - as the error type? Assuming that a) the function class implementation is small-object-optimized and b) that small-object buffer is large enough and c) the actual function object is very cheap to construct/copy/destruct... I think the speed could be acceptable. Still slower than copying some 2-3 ints, but probably faster than exception_ptr. This is purely a (somewhat) educated guess though, I haven't run any benchmarks. Regards, Paul