vmcontainer VS libcxx

Some game engine developers have certainly used this idea, to prevent any reallocations when the dynamic array needs to be resized. Such as:

https://ruby0x1.github.io/machinery_blog_archive/post/virtua...

Some ECS implementations use this to reduce the overhead of dynamic arrays, as well as ensuring pointer stability of the items stored. For example entt:

https://skypjack.github.io/2021-06-12-ecs-baf-part-11/

And here's a library implementing a resizable, pointer-stable vector using virtual memory functionality from the OS:

https://github.com/mknejp/vmcontainer

We have also released in the meantime our code on GitHub (https://github.com/mknejp/vmcontainer)

If you are comparing hoops that library authors need to jump through in both languages, you can easily make the real-world comparison in the other direction, by comparing Rust's Option with C++'s std::optional (an exercise left for the reader): Rust std: https://github.com/rust-lang/rust/blob/master/library/core/src/option.rs libcxx: https://github.com/llvm-mirror/libcxx/blob/master/include/optional

My favorite prime number generator is the undocumented __next_prime():

https://github.com/llvm-mirror/libcxx/blob/78d6a7767ed57b501...

There is no good reason to use this one except in a code golf environment that includes all headers by default, which is where I learned about it.

I once read a Strousroup quote amounting to "If you understand std::vector, then you understand C++". I thought surely he couldn't have meant the interface but the implentation, googled that llvm's implementation is considered nice and clean, had a look, and noped straight out of there.

C++'s STL linked list for comparison (libcxx).

https://github.com/llvm-mirror/libcxx/blob/master/include/li...

> For example, accessing a std::span or a std::vector outside of its bounds would abort the program, and so would accessing an empty std::optional.

I don't really understand the difference with libc++, libstdc++ and msvc stl's respective debug modes, they already do exactly these checks :

- https://github.com/llvm-mirror/libcxx/blob/78d6a7767ed57b501...

- https://github.com/gcc-mirror/gcc/blob/966010b2eb4a4c52f139b...

I mean it's not hard to read the source for your platform. On Linux/x86_64/libc++ it's roughly:

- https://github.com/llvm-mirror/libcxx/blob/master/include/__...

- https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=nptl/...

I don't particularly care to comb through it to see if anything has changed, but historically it was a a little spin-CAS to make the non-contended path fast and then dropping into a https://en.wikipedia.org/wiki/Futex, which is about as good as it gets for staying mostly in userspace but still letting it be scheduler aware so you're not burning up a core busy-polling, which is what often happens when people try to roll their own shit.

Google wants a bit more latitude on the heuristics and degrees of freedom around read/write ownership, so they did it like this: https://github.com/abseil/abseil-cpp/blob/master/absl/synchr... which is quite a bit better commented/legible.

If anyone reading this can do better than the `abseil-cpp` folks, not only would Google take their PR, they'd probably offer them a job.