draft VS cppreference-doc

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

Rather than looking at good examples (which you should by all means do), add cppreference.com to you bookmarks and use it as your reference. By far the best C++ reference on the net. (from a C programmer who was thrown into C++ a decade ago -- slowly digesting C++20 now) Both StackOverflow.com and electronic.stackexchange.com are two additional QA sites that can help.

Sadly, not much. My method of learning is to get my hands dirty and waste a lot of time doing things wrong before I do them right. The only resource (outside of Google and StackOverflow) that I always had open was https://en.cppreference.com

In general, https://en.cppreference.com is your friend.

> As a C++ language reference I highly recommend https://en.cppreference.com

I'd be careful about such re-formulations of the Standard. When I was adding printf format checking to the D compiler, I discovered there were subtle discrepancies in the description of exactly how printf behaves. I went back to using the Standard.

Modern C++ code now looks very different to even C++11 code which is considered to be the start of modern C++.

"A Tour of C++" which has already been recommended is probably a good start to get back in the game. I think there was a new version coming out, but not sure what the current status about this is.

[https://en.cppreference.com](cppreference.com) is a good resource for me. It has documentation regarding the new standards as well and up to C++20 the examples are mostly complete, at least for the relevant things.

I can also recommend watching the "Back to Basics" talks on the CppCon youtube channel and once you are more familiar also the regular talks. They are great resources about practical topics.

Jason Turner's C++ Weekly videos are also a great resource. They are usually 10-15 minutes long videos that give you a good start to think about. Great way to learn something new every week.

At Google, at least, the style guide says to use snake case for variable names in C++ (but camel case for classes). As far as I can tell, this is also the convention in the C++ standard library.

Lets say that there's a file at https://en.cppreference.com/ called preferences.c. The command to download it would be wget https://en.cppreference.com/preferences.c

I would start with a direction of where to apply C++. Updating legacy code, working on embedded systems, creating financial application and creating high performant games are a few common option. Also sites like cppreference and Compiler Explorer/Godbolt are your friends in learning. CPlusPlus.com might help with legacy support as it stops with C++11.

Keep in mind that most YouTube C++ tutorials are garbage. Use www.learncpp.com instead as a tutorial, and https://en.cppreference.com as a language reference. Once you familiarize yourself with the language, you can learn the best practices using the C++ Core Guidelines.

The important thing to remember is that a concept exist and roughly what it's called, so you can look it up when you need to. You don't need to keep all the details in your head, that's what we have en.cppreference.com for.