https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425
--- Comment #48 from Andrew Church <achurch+gcc at achurch dot org> --- (In reply to rusty from comment #47) > Civility please. I have no intention of trying to start a fight :) Like you, I'm just trying to improve the situation, and knowing that in my own open-source work I'm always happier when a user offers a patch instead of just a "please fix this", I've done the same here. That said, since I _am_ trying to improve the situation, I won't step back from debating the utility of the change if the developer disagrees. (And I freely admit that I can be tempted into a bit of snark from time to time...) > But accept that the > conversation on this issue is only a weak indication of consensus. I agree, which is why I gave other examples such as Clang's behavior and especially the C++/C2x standards. While I grant that even standards committees are small subsets of the total user community and are not immune to poor decision-making, I'd consider the facts that (1) the C++17 description of [[nodiscard]] called out void casts as a case which should not be diagnosed, (2) C++20 expanded on that with an explicit example of a cast-to-void call not being diagnosed, and (3) C2x, as of the current draft, also includes the call-out of void casts from C++17 (though not the explicit example from C++20), to collectively be a much stronger indicator of that consensus. > As Andrew Pinski says "people are mis-using this attribute", and Jakub > Jelinek makes a similar point. The use of _wur has changed from "ignoring > the result is criminally wrong" to "possibly wrong". I think "mis-using" is a bit harsh; the core concept (warning about a discarded return value) is a useful one, as evidenced by the feature's adoption into C++ and subsequently C2x. I grant that it's being used for a wider variety of purposes than originally intended, but since there was no other option until the relatively recent addition of [[nodiscard]], that's what people went with. I was thinking about adding a suggestion for multiple levels of warning, such as "ignoring this is almost certainly wrong" (e.g. realloc()) vs "ignoring this could be dangerous, you might want to doublecheck" (e.g. system()); in fact, [[nodiscard]] is effectively that since void casts do silence [[nodiscard]] warnings in GCC, though I don't know if the difference in behavior from _wur is intentional. But that ultimately wouldn't do anything about the present problem, which is API developers and users disagreeing on whether a return value is safe to discard - it might morph into something like "why is this function marked with the stricter _wur when it should just be [[nodiscard]]", and we're back to wanting to selectively silence _wur warnings again.
