triple-buffer VS jakt

Great write up! I believe the colloquial name for this algorithm is a "lock-free triple buffer". Here's an implementation in Rust (I couldn't find any c/c++ examples) that has extremely thorough comments that might help completely wrap your head around the synchronization ordering. Rust uses the same semantics for atomic primitives as C11, so it should be pretty easy to match up with your implementation. I came to the same conclusion as you to solve an issue I had with passing arbitrarily large data between two threads in an RTOS system I was working with at my day job. It was an extremely satisfying moment, realizing the index variable was sufficient to communicate all the needed information between the two threads.

Rust marks cross-thread shared memory as immutable in the general case, and allows you to define your own shared mutability constructs out of primitives like mutexes, atomics, and UnsafeCell. As a result you don't get rope to hang yourself with by default, but atomic orderings are more than enough rope to devise incorrect synchronizations (especially with more than 2 threads or memory locations). To quote an earlier post of mine:

In terms of shared-memory threading concurrency, Send and Sync, and the distinction between &T and &Mutex and &mut T, were a revelation when I first learned them. It was a principled approach to shared-memory threading, with Send/Sync banning nearly all of the confusing and buggy entangled-state codebases I've seen and continue to see in C++ (much to my frustration and exasperation), and &Mutex providing a cleaner alternative design (there's an excellent article on its design at http://cliffle.com/blog/rust-mutexes/).

My favorite simple concurrent data structure is https://docs.rs/triple_buffer/latest/triple_buffer/struct.Tr.... It beautifully demonstrates how you can achieve principled shared mutability, by defining two "handle" types (living on different threads), each carrying thread-local state (not TLS) and a pointer to shared memory, and only allowing each handle to access shared memory in a particular way. This statically prevents one thread from calling a method intended to run on another thread, or accessing fields local to another thread (since the methods and fields now live on the other handle). It also demonstrates the complexity of reasoning about lock-free algorithms (https://github.com/HadrienG2/triple-buffer/issues/14).

I find that writing C++ code the Rust way eliminates data races practically as effectively as writing Rust code upfront, but C++ makes the Rust way of thread-safe code extra work (no Mutex unless you make one yourself, and you have to simulate &(T: Sync) yourself using T const* coupled with mutable atomic/mutex fields), whereas the happy path of threaded C++ (raw non-Arc pointers to shared mutable memory) leads to pervasive data races caused by missing or incorrect mutex locking or atomic synchronization.

In terms of shared-memory threading concurrency, Send and Sync, and the distinction between &T and &Mutex and &mut T, were a revelation when I first learned them. It was a principled approach to shared-memory threading, with Send/Sync banning nearly all of the confusing and buggy entangled-state codebases I've seen and continue to see in C++ (much to my frustration and exasperation), and &Mutex providing a cleaner alternative design (there's an excellent article on its design at http://cliffle.com/blog/rust-mutexes/).

My favorite simple concurrent data structure is https://docs.rs/triple_buffer/latest/triple_buffer/struct.Tr.... It beautifully demonstrates how you can achieve principled shared mutability, by defining two "handle" types (living on different threads), each carrying thread-local state (not TLS) and a pointer to shared memory, and only allowing each handle to access shared memory in a particular way. This statically prevents one thread from calling a method intended to run on another thread, or accessing fields local to another thread (since the methods and fields now live on the other handle). It also demonstrates the complexity of reasoning about lock-free algorithms (https://github.com/HadrienG2/triple-buffer/issues/14).

I suppose &/&mut is also a safeguard against event-loop and reentrancy bugs (like https://github.com/quotient-im/Quaternion/issues/702). I don't think Rust solves the general problem of preventing deadlocks within and between processes (which often cross organizational boundaries between projects and distinct codebases, with no clear contract on allowed behavior and which party in a deadlock is at fault), and non-atomicity between processes on a single machine (see my PipeWire criticism at https://news.ycombinator.com/item?id=31519951). File saving is also difficult (https://danluu.com/file-consistency/), though I find that fsync-then-rename works well enough if you don't need to preserve metadata or write through file (not folder) symlinks.

SerenityOS is doing exactly that:

https://github.com/SerenityOS/serenity/tree/master/Ladybird

I also like their Jakt programming language:

https://github.com/SerenityOS/jakt

Though I'm more enthusiastic about Redox (doing it in Rust):

https://gitlab.redox-os.org/redox-os/redox/

It's very opinionated and SerenityOS-focused, but the language Jakt ( https://github.com/SerenityOS/jakt ) transpiles to C++, has memory safety and some very neat ideas for readability.

I love Rust, but its model and specifics would make it difficult to learn how to write code in other languages.

For low-level code, I think Carbon may fill that niche in the future. If it doesn't, C++ may be a good candidate once up-to-date books have been written and compilers actually support the modern spec. Classrooms/guides would need to move away from the still-lingering "C++ is C with classes" approach and use the standard library before that can be a reality, but this book[0] by Bjarne Stroustrup himself demonstrates the future C++ _could_ have if all the modern language features become usable.

In business, C++ will still be the domain of ancient clusterfucks compiled by MSVC++ 6 in many areas, similar to how most Java code is still built around Java 8 because that was the most recent stable version for many projects' lifecycle (and Oracle's decision to only ship JRE 8 to consumers doesn't help) and how .NET 4 is still taught in schools because the new and scary dotnet tool doesn't map 1-to-1 with the old way of working. I can't imagine microcontroller toolkits supporting a modern version of _any_ language in the first place.

However, if more people would learn modern C++ (or a replacement, like Carbon), I think this class of programming languages can have the same growth and hype Rust has enjoyed for the past years.

I'm keeping my eye on Carbon and Zig. Google's influence has managed to push Go to the forefront despite its many quirks, and Zig seems to be focused on doing "C, but right" rather than "C++, but right" which so far is looking pretty promising.

It's also fun to see Jakt[1] being developed in real time; I don't think it's a language that will be useful for production software any time soon, but on the other hand it's a language that actually produces binaries reliably (unlike pre-alpha Carbon or pre-release Zig, the latter exposing many problems after switching to a self-hosted compiler).

[0]: https://www.stroustrup.com/tour3.html

[1]: https://github.com/SerenityOS/jakt

About php, I have no problem of rewriting whole game for performance reasons once it is done and popular in low level language like https://github.com/SerenityOS/jakt but I think for now php is good and sufficient.

Jakt, pretty well designed (lots of ideas stolen from ML/Rust), but very immature

I think this thread might be interesting to the people here. The guy eventually started working on his own safe language, Jakt: https://github.com/SerenityOS/jakt