GCC doesn't catch this when optimization is enabled and the result is discarded:
https://godbolt.org/g/4b0BQC I think that means a type wrapper approach is needed, which probably necessitates option 1. - Zach On Mon, Jan 9, 2017 at 9:17 AM, Jim Apple <[email protected]> wrote: > My vote, as I mentioned on the patch, is option 1. I see MUST_USE(T) > as a property of T, like const T or volatile T. I think it is dual to > move semantics or to Rust's ability to temporarily or permanently > consume values so that /only/ one copy is in use rather than > MUST_USE's /at least one/. > > https://en.wikipedia.org/wiki/Substructural_type_system > > On Fri, Jan 6, 2017 at 4:05 PM, Taras Bobrovytsky > <[email protected]> wrote: > > I'd vote for #2. I think it's better to have less important information > > (such as qualifiers) towards the end of lines. (I think it would be nice > if > > modifiers such as public and private were at the end of method > declarations > > in Java, for example: void myMethod() private static {...}) > > > > On Fri, Jan 6, 2017 at 3:38 PM, Daniel Hecht <[email protected]> > wrote: > > > >> As I indicated in the original review, my preference is #2 but I don't > feel > >> too strongly. > >> > >> On Fri, Jan 6, 2017 at 2:59 PM, Tim Armstrong <[email protected]> > >> wrote: > >> > >> > Hi All, > >> > I wanted to poll the Impala community for opinions about style for > >> > declaring functions where the caller is expected to do something with > the > >> > return value. > >> > > >> > Ideally we'd be able to declare Status with an attribute that made > this > >> > take effect globally, but unfortunately that's not available until > C++17. > >> > > >> > So we need to annotate each Status-returning function. The two > >> alternatives > >> > we discussed on this CR (https://gerrit.cloudera.org/#/c/4878/) were: > >> > > >> > #1 - a special macro wrapping Status > >> > > >> > MUST_USE(Status) DoSomethingThatCanFail(int64_t foo, Bar* bar); > >> > > >> > Pros: > >> > * Closely connected to the return type that it affects > >> > * It's easier to search/replace Status with MUST_USE(Status) > >> > > >> > Cons: > >> > * Could get visually noisy if we use it everywhere > >> > > >> > #2 - a macro that gets appended to the declaration: > >> > > >> > Status DoSomethingThatCanFail(int64_t foo, Bar* bar) > WARN_UNUSED_RESULT; > >> > > >> > Pros: > >> > * Macro is slightly > >> > * Less visually noisy since it's at the end of the declaration > >> > > >> > What do people think? > >> > > >> >
