AaronBallman wrote: > > FWIW, I did verify that it's very unlikely the changes in this PR will > > break existing code: > > https://sourcegraph.com/search?q=context:global+__need_unreachable+-file:.*clang.*&patternType=keyword&sm=0, > > so that's a good thing. > > > I do wonder if we could have the broader builtin headers discussion > > > independent of this patch? Is everyone happy with this patch? We can keep > > > talking about the builtin headers in here independent of merging right? > > > > > > I guess I don't see these as independent topics; if we decide that C++ mode > > should not have observable differences in C headers, then the changes here > > are incorrect. I think we should have this discussion in a broader context > > (like Discourse) before moving forward with these changes. > > Also, I'd still like an explanation for [this > > question](https://github.com/llvm/llvm-project/pull/86748#issuecomment-2023145043): > > > I don't understand why this is making into C++ builds at all: > > > > > > because it may turn out we don't need these changes in the first place > > because the issue is elsewhere. > > Right now I just noticed that in a C++ test I was writing that stddef.h alone > doesn't give me unreachable, but __needs_unreachable does. And that's > probably wrong because unreachable belongs to <utility> in C++ and _not_ > stddef.h. The C++ standard has some frustrating divergence with the C > standard as to what the c stdlib headers declare...
I don't yet agree that it's wrong -- you define the macro saying you want `unreachable` from `stddef.h`, so you get `unreachable` from `stddef.h`. Morally, it's very similar to: ``` #define unreachable "I am doing something which causes myself pain" #include <utility> ``` https://github.com/llvm/llvm-project/pull/86748 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
