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Comment by delta_p_delta_x | Hacker News Reader

A big improvement in compile times with modern C++ can be had with C++20 standard modules.

This requires extremely bleeding-edge toolchains, though: VS 2022 17.10, Clang 18, and GCC 14.

I'm under the impression "big" here might mean a 10-20% improvement if you're lucky. Good to back this claim up with hard data.

I'm still waiting for clangd support, e.g. [0] before trying modules. But maybe I should just try it, as at least one person reports that it already works [1].

[0] https://github.com/clangd/clangd/issues/1293 [1] https://github.com/snu-sf-class/swpp202401/issues/21

You know you are talking about C++ when "bleeding edge" is compilers from 3 years ago which implement the version before the current standard from 4 years ago....

Clang 18 came out in March and GCC 14 isn't even out. So those are bleeding edge by just about any metric

Well, ISO C++ is a standard, and the standard being finished does not mean the implementation being finished.

Also, modules is probably one of the biggest changes in terms of work required in build systems, compilers and tooling since at least C++11.

Clang 18 was released this March, barely two months ago[1]; VS 2022 17.10 is still in preview[2], and GCC 14 isn't even out yet. This can't be nearer the bleeding edge.

[1]: https://github.com/llvm/llvm-project/releases/tag/llvmorg-18...

[2]: https://learn.microsoft.com/en-us/visualstudio/releases/2022...

I'm still waiting for CMake support to mature.

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