modern-cpp-features VS draft

Just go through this https://github.com/AnthonyCalandra/modern-cpp-features and you should be fine.

If you also like thorough explanations and graphs, there's https://hackingcpp.com/ that could answer many questions you might have.

By the way, just in case, bookmark this online C++ reference https://eel.is/c++draft/ for diving in deep waters.

Good luck!

I'm a little 10 years out from writing C++ professionally and I found this cheat sheet[0] useful. Basically if you have an inkling of the concept you're looking for, just search on that cheat sheet to find the relevant new C++ thing. Specifically for me, we used Boost for smart pointers which are now part of the stdlib, and threads are now part of the stdlib as well.

[0] https://github.com/AnthonyCalandra/modern-cpp-features

A more productive way to go about it would be to ask "What are the features in each version of C++ past C++11 that I should care about the most?" instead. In that case you could take a look at things like https://github.com/AnthonyCalandra/modern-cpp-features and https://github.com/mortennobel/cpp-cheatsheet, see what appeals to you, ignore what does not.

Looks like there's a version history here

As someone suggested cppcon and c++ talks, also I would reccomend reading this: https://github.com/AnthonyCalandra/modern-cpp-features and all things in the papers section in this: https://en.cppreference.com/w/cpp/compiler_support

I've already done a bit of research which has led me to the The Definitive C++ Book Guide & List. From that, I've decided to go over The C++ Programming Language (4th Edition) to learn C++11 and then this GitHub repo to learn the remaining C++14/17/20 features.

clickable:

"Welcome back to C++ - Modern C++" https://learn.microsoft.com/en-us/cpp/cpp/welcome-back-to-cp...

"21 New Features of Modern C++ to Use in Your Project" http://www.vishalchovatiya.com/21-new-features-of-modern-cpp...

"What is modern C++"? https://www.reddit.com/r/cpp_questions/comments/tgs6ir/what_...

"C++ is the next C++" https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p26...

"modern c++ features" https://github.com/AnthonyCalandra/modern-cpp-features

C++ 23 to introduce module support "https://www.infoworld.com/article/3662808/c-plus-plus-23-to-..."

"C++ 2023" https://en.wikipedia.org/wiki/C%2B%2B23

I should have said the "latest standard", not "spec", if we're being technical. But EVERY bit of official material is very clear about asserting that C++23 is still a preview/in-progress, not a standard. Saying otherwise is, strictly speaking, incorrect.

https://isocpp.org/std/the-standard

https://www.iso.org/standard/79358.html

https://github.com/cplusplus/draft/blob/main/papers/n4951.md

[3] https://github.com/cplusplus/draft/releases/tag/n4917

*This is a joke, but only barely so.

pdf

I'm currently going through Annex A of C++20, but I can't find the definition of "designator brace-or-equal-initializer", and couldn't find much formal information on it in an obvious way. The newest source on [decl] (https://github.com/cplusplus/draft/blob/main/source/declarations.tex) also doesn't seem to have it. Am I missing anything, or is this a missing definition in the standard grammar?

> I don't have a copy of the standard at hand, can anyone quote the relevant section?

The C++ (draft) standard is on GitHub! [0] Compiling it needs Perl and some LaTeX packages, but is reasonably straightforwards otherwise. In addition, links to specific draft standards can be found on cppreference [1].

But anyways, in the first C++20 post-publication draft (N4868), the wording you're interested in is in multiple sections. Section 22.2.3 Sequence Containers [sequence.reqmts] has Table 78: Optional sequence container operations [tab:container.seq.opt] (starting on page 815), which states that a precondition of pop_back() is that empty() returns false. Section 16.3.2.4 Detailed Specifications [structure.specifications] (page 481) states:

> Preconditions: the conditions that the function assumes to hold whenever it is called; violation of any preconditions results in undefined behavior.

Therefore, calling pop_back() on an empty vector results in undefined behavior.

> Is this something that in practice is implemented in different (exception-throwing) ways?

Based on a quick glance at the major implementations (libc++ 15.0.7 at [2], MSVC at [3], libstdc++ at [4]), it looks like asserts are used. Whether those result in exceptions probably depends on whether the asserts are compiled in in the first place and how they are implemented, but it's definitely not a guaranteed exception.

[0]: https://github.com/cplusplus/draft

[1]: https://en.cppreference.com/w/cpp/links

[2]: https://github.com/llvm/llvm-project/blob/llvmorg-15.0.7/lib...

[3]: https://github.com/llvm/llvm-project/blob/8dfdcc7b7bf66834a7...

[4]: https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libstdc%2B%2B-v3...

Which standard specifically are you quoting there? I checked an old and a new C++ draft in https://github.com/cplusplus/draft/tree/main/papers, and in neither one did 6.3 have anything like that.

https://github.com/cplusplus/draft/releases/download/n4917/n4917.pdf (page 1, chapter 1 scope):

PRs for C++ are at https://github.com/cplusplus/draft But the discussion for a PR is via https://isocpp.org/std/submit-a-proposal

C/C++

By the way, https://github.com/cplusplus/draft/releases/tag/n4910 , says