ISO/IEC 14882:2020 C++ Standard Published | Hacker News Reader

ISO/IEC 14882:2020 C++ Standard Published

iso.org

26 pointsapaprocki16 comments

Impressive how C++ always attracts a naive and uninformed toxicity on HN. C++20 is amazing, there has been so much incredible work put in my some many amazing engineers.

Yes there are competitors to C++, and we all love an underdog story, but I personally find it to be the only language with this level of expressiveness, without sacrificing complete control. You can write JS-style, with auto and other zero-runtime-cost abstractions, or you can write plain C with function overloading and templates.

C++20 is an incredibly exciting milestone, and I congratulate the standards commitee on every little milestone. Great work, guys!

I just pray that modules will one day let developers speed up compile times.

Toolchain complexity, size and slowness are the only things that make me use python.

clang and MSVC both already (partially) support modules! other than that, gcc is the most c++20-feature-complete compiler

My C++ coding on Windows with VC++ is usually faster than Rust coding, because of incremental compiler, incremental linking and using binary libraries for 3rd party dependencies (DLL/COM).

I think when modules mature, it can eventually reach Delphi/.NET like compile speeds.

> I just pray that modules will one day let developers speed up compile times.

Compiles times are not a problem if you use adequate tools. I have a codebase that heavily uses some large libs such as boost and Qt, here's a video of the edit-compile-run cycle:

https://streamable.com/o2g765

compilation when editing a file takes one-two seconds (measured it at 101 frames in the video in this case, so a bit less than 2 seconds).

If anyone's wondering how it's done:

- Clang & lld instead of GCC & bfd/gold

- Ninja instead of Make (or anything else really)

- CMake target_precompile_headers

- Code split in dynamic libraries for dev builds

There aren't even advanced tricks such as incremental linking mentioned by other comments.

1853 pages. Oof.

And somehow still insufficient. They can't find words in all that to define some undefined behavior?

Undefined behavior isn't undefined because somebody didn't have enough words to nail down a definition. It's undefined by definition.

And some of them does a "sane" defined thing on some of the platforms, but enforcing them for all of the platforms would mean a lot of burden to the implementors working on those.

They found them, because UB cases are documented actually.

It's a cultural problem. The standards committee cares about security than micro-benchmarks on legacy hardware.

some behaviors are defined to be undefined because there is no sane way to universally define them in a way that doesnt cripple the range of supported hardware & OSs.

It includes the standard library, still way smaller than Java, C#/VB/F#/.NET or Python standards.

For a language like C, add the POSIX standards, which is like C's extended library.

C# standard has 550ish pages https://www.ecma-international.org/publications/standards/Ec...

Are you making the numbers up?

No, I explicitly mentioned "standard library", you are missing these ones as well.

https://www.ecma-international.org/publications/standards/Ec...

C# standard doesn't define the standard library, it only gives you the class prototypes (from pages 463-473 from what I can see) while the C++ standard does give you preconditions and postconditions for every function, complexity bounds for algorithms, etc. (from pages 458 to 1609, so by far the majority of the thing). C# also does not define threads, linq, etc... which if it was C++ would all have to be defined in the standard.

If you compare only the language definition itself, C++ is actually shorter by a couple pages than C#: it ends at page 457 on the pdf:

https://isocpp.org/files/papers/N4860.pdf

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