[libcxx-commits] [PATCH] D126249: [libc++] Remove _LIBCPP_ALIGNOF

Louis Dionne via Phabricator via libcxx-commits libcxx-commits at lists.llvm.org
Thu Jun 9 10:07:25 PDT 2022

ldionne added a comment.

In D126249#3561099 <https://reviews.llvm.org/D126249#3561099>, @philnik wrote:

> Can you tell me/do you know what problems there were changing the default to something newer than C++03 and when you tried it? I wasn't aware AppleClang still defaults to C++03.

I don't know the details because it was before my time, unfortunately.

> It's absolutely possible that I'm underestimating how many people still compile in C++03 mode. Do you know of any statistics which language mode get used?

We unfortunately don't have great data around that, but it would be useful for the LLVM community as a whole.

> Is the main reason we still support C++03 that AppleClang still defaults to it?

Even if AppleClang switched to C++14 by default, I don't think we'd remove C++03 support unless Clang (so the LLVM community as a whole) decided to also remove support for `-std=c++03`.

The more I think about this change, the less certain I am about it. If we want to do this, why not pursue providing `alignof` as an extension in C++03 mode in Clang itself? It seems to me that the better place to bridge language gaps is in the compiler itself.

  rG LLVM Github Monorepo



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