It's basically everyone learning from everyone else on what works and what doesn't work.
C++ 11 wants to model two non-trivial orderings, Acquire-Release and Consume-Release, but only Acquire-Release is actually usable. So yes, C and Rust both also choose to offer Acquire-Release ordering like C++ but it's also clear that the universe of possibilities is actually smaller than WG21 realised when C++ 11 was developed.
If on your first random stab you guess 65537 is prime, you're correct and you might foolishly assume all those Fermat Numbers are prime and then try say, 4294967297. Nope, that's divisible by 641 for some reason. There are only Five of these Fermat Primes so far as we know, they weren't common after all.
I sometimes wonder how difficult it would be for a compiler that was designed from the outset to implement Consume correctly.
I've sketched what I think an ideal "language of today" would look like, and one of the core tenets is making concurrent code explicit and part of the design surface.
You might imagine a webserver with main code like:
spawn(on_core: 0) {
await receive_packet(input)
}
The vast, vast majority of software, and software developers, simply do not care about core affinity, NUMA, noisy neighbors, etc.
Even on systems or situations where this matters (massive number of cores and memory, multiple sockets, thousands of threads, etc.) the juice is rarely worth the squeeze.
Doubly so when you end up being I/O bound anyways.
Nearly every software developers wants their software to work across multiple deployment targets. Maybe you just target x86-64, and you don't care about the number of CPUs because you'll be upgrading your servers every couple of years.
No one wants to deal with difficult-to-reproduce issues related to scheduling in niche configurations. It's much more efficient for runtime or compiler engineers to solve these problems for us, leveraging the vast amount of resources of corporations to develop and test these features. Then you have a place your code can live happily ignorant of its runtime constraints.
And that, my friend, is the beauty of our industry.
The effects can be subtle and lurk for years until a seemingly unrelated change exposes them. It starts with optimizations like instead of spawning a thread, you use a thread pool, possibly abstracted as some kind of executor service. Other code might use different thread pools to isolate them because each pool has its own limits on the number of threads. Some might grow but usually they won't.
Until one day you end up with thread starvation and a deadlock through a series of benign seeming optimizations. There are threads around but not in the right pools and the entire thing grinds to a halt.
Cooperative async/await on a single thread is the ideal solution for most use cases, particularly with complete environment teardown between requests. Yes, this is basically the PHP model.
In my opinion, that's really the best place for it. From what I understand, that's always been FORTRAN's secret sauce.
I've been doing threaded code since Day One (Machine Code), and have gotten it wrong, quite often. There are a million things that can cause concurrent code to actually perform worse than single-thread code.
These days, I usually just let the platform pick the threads, and generally write code that will play along.
Anything else heavily uses concurrency in all kinds of ways.
I remain unconvinced as why this is a necessary feature over the already existing `assert` statements.
It seems like part of the concern is that the feature needs to be shipped right the first time because it'll live forever. Perhaps allowing features to be deprecated and then removed could help?
But idk, I haven't written anything that lasted 36 years, so maybe the current approach is for the best!
C++ definitely has complexity, but I'm surprised by the two examples specifically chosen. Which pointer? C++ only has 2: unique_ptr and shared_ptr (or 2.5 if you want to include weak_ptr but that necessarily means you already chose strong_ptr first). While this might be a complicated choice if you're just comparing to Python, but it shouldn't be if you're familiar with Rust since Rust has you make the same choice.
And then "how should I iterate" is similarly the same as any other language? Either a for or a for-each loop?
There's definitely baggage from 38 years of lessons learned, to be sure, just those examples are odd choices
for (ignoring do and while) and foreach loops, std::for_each, ranges for_each at the very least
https://en.cppreference.com/cpp/language/pointer
When I started C++ nearly 15 years ago this was already a huge problem. I bought some books and looked up online references and after a while I discovered that both were already out of date.
C++ is a chimera. And it hasn't improved since.
Other languages are far more stable, conceptually. New features rarely undermine or reinvent the older ones.
C++ is unique in the way it keeps modifying its own core. There is no formal deprecation or EOL process, so the language is more like an archaeological dig than a living standard.
Yes there is or we'd have been talking about std::auto_ptr as well.
> New features rarely undermine or reinvent the older ones.
Many languages have mistakes they've later tried to sweep under the rug. JavaScript arrow functions trying to convince everyone that bind(this) wasn't ever a thing, for example.
C++, for whatever reason, is consistently the only language where people are determined to always dig up the skeletons and pretend they are at all still relevant. It's not unique in having skeletons. It's not unique in having language spec mistakes that can't realistically be changed, just ammended with a newer, better alternative.
But like the saying goes, there are only two kinds of languages: the ones people complain about and the ones nobody uses
C++ does have many ways to do anything. Most of that is historical, or due to features and library facilities with overlapping capabilities, or inherent to multi-paradigm programming languages.
Every C++ project is written in its own language. Its own "house flavor." This is true of all languages, but is particularly stark for a language as old, complicated, and powerful as C++.
> pre-LLM, so maybe it's better now?
I came back to the toy tool some time later and used GLM 4.x to implement it further. I had a good experience with it and I understood the code it generated. From my experience, in general, LLM is a good mentor, if you are willing to ingest the content step by step. For me, it is no different from when I used StackOverflow (and other forums) to try and ask how a thing is done.
what should be conclude from this? this is like saying you tried to become a professional trapeze artist for a couple of days. C++ is complex and deep. what did you seriously hope to accomplish in a "few weeks"?
i started writing C++ professionally 4 years ago, i.e., i write it every single day at $JOB. there are still large parts of the language i'm not familiar with.
Yes, that's the point. Much of this complexity would not be necessary to achieve the same things, given the ability to redesign from scratch.
- it shines for some tasks where Rust isn't capable enough
- it's impossible to get rid of because of all the code so we may as well modernize it
- there's an active community of people who built a career of being C++ experts and have no interest to see the language disappears.
Even in the LLM era, I find it's difficult to code in C++. The language has so many corner cases that LLMs make mistakes. My experience 6 months ago was that the code written by my agent had tons of complex linter warning (exceptions, lambda leaking references, futures whatever... that I just can't avoid because the codebase mixes all of this). Whenever possible, it's probably time to either modernize it or port it to Rust, component by component, until the C++ part is small or inexistant.
1. C++ is unsafe. Bjarne keeps giving talks that effectively say "use it perfectly and don't make any mistakes and it's safe". That's not useful anymore. In a world where LLMs can find every mistake to exploit it, all the C++ projects are struggling to keep up and keeping them in C++ is basically guaranteeing there will be more exploits in the future. Yes, not every bug gets solved by switching to a safer language but reducing the attack surface in the new reality is no longer something that can be put off.
2. LLMs can re-write. The previous arguments used to be "there are C++ legacy code bases so C++ will never die". That was a valid argument before an LLM would just rewrite it all. I get people will say they aren't perfect, neither are humans though. Further they get better all the time, and we see their progress. People pointing an LLM at some project and it magically making it work on some other platform etc... It's clear it's happening.
Bjarne’s opposition to contracts might have tipped the scale but there is definitely growing weariness (and wariness) about large half-baked features that are left as exercises to the implementors (looking at you modules).
Ignoring that historical context when analysing this vote seems like a mistake.
It also lists 6 possible paths forward for C++26 with pros and cons. I think they are roughly:
A. Skip an official C++26 standard but roll these features into C++29.
B. Remove contracts from C++26 and pass it.
C. Say "please" and vote again.
D. Tweak contracts regarding virtual functions and vote again.
E. Pass C++26 as many different countries' national standards rather than an international standard.
F. Do E and also consider leaving ISO and moving to ANSI/INCITS instead.
If, on the other hand, you mean only that, regardless of the status of a contract, if the compiler can detect that it would be violated, it must have failed to compile, I guess that would be all for that. On the other hand, the state of theorem provers that are able to prove things will and won't work is ... evolving. There will a lot of people be frustrated when they upgrade their compiler to a minor point release and suddenly a lot of code fails to compile because it always was broken but likely in an obscure situation that never happens in the real world.
Or you do the BDFL model like Python, D, Zig, Odin, etc.
I think it works better. A language that reflects the vision of an individual deeply thinking about the interactions of language features, and being able to say "no" to anyone/everyone has many benefits.
Committees make me think of the Web, C++, Swift, etc., and they have a lot of "odd" decisions that have had a heavy cost. Swift has https://www.swift.org/swift-evolution/, but a lot of ideas with minority support were pushed through by Apple (for SwiftUI mainly), against overwhelming community feedback.
And the Web has had a lot of "duds" when you think of WebGPU, WASM (not saying it's bad, but people clearly want to stop writing TS/JS and they haven't made that a reality yet, at least in a way I'd call "successful"), etc.. Oh and DRM in the browser sucks. I forget the details but I was goofing around with FreeBSD Desktop and couldn't get various things to work due to some browser DRM bullshit. https://en.wikipedia.org/wiki/Widevine if curious.
Well I mean you're just wrong, you can look at any of those languages (or https://en.wikipedia.org/wiki/Benevolent_dictator_for_life). Python is over 30 years old and it's going fine. You don't see people ragging on Guido everywhere. But everyone pokes fun at the C++ committee and the wacky shit they cook up.
Design by committee just sucks. Coordinating and working with people is expensive, and a drag. If you have to, you have to, but for many projects you don't and shouldn't. An individual's design is always going to be more cohesive, and we can see it clearly looking at PL history IMO.
Guido stepped down from that role 8 years ago. It now has a 5-member steering council along with the core developers as the primary maintainers and decision makers.
That said, I'd agree with GP that design by committee does suck and I'm not impressed with several of the decisions the SC has made since.
Python doesn't have a BDFL[1] and the others are toys.
1: Guido stepped down in 2018 and stopped involvement entirely in 2020 after an extended conflict with the community at large over PEP 572
Thanks, I relinquish that point and accept it as a success story for BDFL succession instead.
The implementations are the language.
One learns this when their standards-compliant code fails to compile.
You will find, though, that every major compiler considers those features that don't work either. Don't work because of bugs or they're not implemented yet. But either way, it's something they plan to implement.
Your objection reads like 1995. Of course, the C++ standard didn't exist until 1998, which is my point. Compilers have generally considered it a bug to not have all features implemented - the exception that proves the rule is export, which was removed from C++11 because all compilers agreed they weren't going to implement it.
With Rust, only the unsafe blocks are in scope. The point of Rust is not to eliminate unsafe code, but to make it not scale with the size of your program. There is no good reason for those to be coupled.
We’ve sent rockets into space running C/C++ and assembly. And that was long before C++11 rolled around.
I’m wondering because: man Rust is an ugly language. C is not perfect either, but it’s still pretty close to what it was FIFTY YEARS AGO.
Fast forward to now, and all we’ve come to is Rust? I just wonder why don’t we just keep using C, C#, and Java? I mean the former two are memory safe, and they can do “unsafe” just like Rust.
Another thing: why do we write pseudocode and not design languages to look like pseudocode? With Rust and modern C++ compile times you’d think the machine is parsing prose and turning it into assembly…
many of those who ended up as Rust developers came from C and C++, seeing improvement from what they were using.
languages have been designed more and more to allow for higher level behaviours, in Rust's case, although not pursuing psuedocode, generally allows for very high level abstractions. regardless the computer still has to run things, languages are typically deterministic in their handling and psuedocode leaves much undetermined, unfully specified.
Just playing devils advocate it seems higher level behaviours don’t belong in a low level language.
I think that period has arguably already come and gone. C and C++ have been the most popular systems languages for decades. I think it's clear that mere popularity is not sufficient to produce memory-safe software with those languages. If anything, those languages are experiencing somewhat of a renaissance these days and it's these more recent developments that end up producing improvements with regard to memory safety.
> I just wonder why don’t we just keep using C, C#, and Java? I mean the former two are memory safe, and they can do “unsafe” just like Rust.
Bit of a nitpick, but I think you meant "latter" instead of "former".
That aside, there's more to picking a language to use than just memory safety and the ability to perform "unsafe" operations. Take your pick from more technical reasons (zero-overhead FFI to C, low-level control over data structures/operations/runtime, etc.) and more "soft" reasons (language affordances/features, ecosystem, etc.).
> Another thing: why do we write pseudocode and not design languages to look like pseudocode?
Perhaps COBOL might be what you're looking for? :P
As with many things, language design is full of tradeoffs, particularly when you want to produce something that is not too unfamiliar to a certain audience. IIRC another factor is that languages that want to work well for "experts" will tend to favor different points on the design spectrum. Consider APL-family languages - those are completely incomprehensible to anyone not familiar with them, but that same terseness is highly valued by proficient practitioners and is something pseudocode-like (or even "regular" code-like!) could never replicate.
It’s just interesting that ALL of these languages have a C compatible interface built into the language. That’s an interesting fact and says something about C that no other language can really claim. Nor will any other language claim that any time soon.
I’m not looking for anything in particular. It’s just that I’ve seen and used a lot of languages over the years, and I’m not wholly sold on the “memory safety” of Rust when something like Python can just put the performance sensitive parts in C and have safety for everything else.
Most languages are memory safe.