Comment by wsve | Hacker News Reader

Comment by wsve | Hacker News Reader

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"Kernel C" is the name given to the subset of C (read, Linux's flavor of C) that was formed by deciding which language features/compiler extensions they would/wouldn't use. Hardly a new or unsolvable problem.

Benefits of C++ over Rust: - Far easier and nicer to integrate with an enormous existing C codebase - C semantics are much more similar to C++ than to Rust, so no need to do huge pattern redesigns - No need to suddenly fight a borrow checker and prove lifetimes for a code base that isn't aware of them at all - Interfacing with existing C code will require unsafe interop, which greatly reduces the benefit of Rust's primary selling point - Transitions to C++ code will counterintuitively almost certainly introduce less bugs than rewriting in Rust, because you can do it in a much more piecemeal manner, and only do so in very disciplined way

Why should they rewrite it in Rust?

Rust gives you useful and important properties that C++ doesn't. For example, you can look at a piece of rust code and by following very simple rules verify that there's no UB in that code. You can't do the same in C++.

Also, the interop story with rust is equal or better than C++ in many areas at this point. Aside from tools like bindgen eliminating entire families of footguns, try doing something like registering a member function to a c callback, the way virtually every driver works. The rust equivalent in the extremely immature kernel dev trees are a bit ugly, but already much simpler than the idiomatic C++ equivalents. For additional fun, try and do it safely with a custom allocator or closures in a modern version.

>No need to suddenly fight a borrow checker

This isn't a bad thing. Failing to compile when there is a memory error is better than leaving it in to later manifest as a mysterious crash or be found by a fuzzer or an attacker. When programming without a borrow checker you have to be the borrow checker yourself. People being their own borrow checker does not scale.

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