Rust is still fringe even at FAANG level companies. I work at one such and we have a service or two written in Rust. I like Rust as a C++ replacement in the right context, but for 99.999% of applications it’s not better in any qualitative or quantitative way than C++. Or Java. Or Go.
> Rust is still fringe even at FAANG level companies.
Yes, everyone knows that, except for HN users! While I'm sure there are managers at large companies who let some employees play with Rust, it's not used.
I mean, I'm a HN user who just left one FAANG for another and I'm pretty confident this is changing a lot faster than you think.
The thing that obscures this, I think, is that at most of them the surface area that the intersection of C, C++, and Rust that is high availability, security critical software, makes up a relatively small portion of what they do no matter what language it's in.
So while there's a lot of C++ at say, Google and Facebook (but relatively little at Apple IME), very little of it needs to be in c++ let alone Rust.
But where it matters? You better believe big companies are shifting towards "if you're starting new you should seriously consider Rust" (if not a mandate). And once you let one other language into your mix, the question becomes: why's all the high level stuff written in c++? May as well start new projects in Go.
Some are farther along than others but it's a thing.
There is a lot of C++ at Apple. It's of course possible to work there and never touch it, but it's also possible to work there and do almost all your work in C++. Many significant parts of iOS and macOS are written in C++, for example WebKit, the implementations of ObjC and Swift, clang/llvm, dyld, CoreAudio, CoreAnimation, WindowServer, Dock, Finder, etc.
I enjoy this[1] annual series of blog posts on Apple's usage of Swift in iOS. I just did a quick and dirty, but similar analysis of Apple's usage of C++ of the macOS 12.5.1 install on my computer. I extracted my dyld_shared_cache, and then used find and nm to count up binaries containing unstripped C++ symbols. This undercounts the usage of C++, since sometimes it's used only internally in stripped binaries, and I also think the number of binaries metric probably undercounts the importance of C++ because the ones that do use C++ tend to be more significant binaries, but even still it gives some idea of the scope of C++'s use at Apple.
About 25% (559 / 2292) of the libraries in the dyld_shared_cache contain unstripped C++ symbols. About 15% (22 / 154) of executables in /System/Applications (so 1st party apps / helpers that ship with the system) do.
That said, I think you're probably right that things are changing. Probably there are lots of people at Apple thinking of how they can replace C++ with Swift in their code. But on the other hand, I would not be surprised if we can still find significant uses of C++ in whatever macOS release we have 10 years from now.
To clarify: Relative to Google and Facebook, which have built up immense c++ codebases that span the entire companies.
I spent 8 years at Apple, mostly working in C and then rust, both even smaller pieces of the Apple language pie.
But I also did a little c++. I have commits in swift for eg (though I wasn't on the team and they were pre-oss, so you'd have to dig real deep to find them now).
Most of the services side of the company, which is where I was, was java ime. A lot of shift to Go in the last few years though. And that's a very quickly growing part of the company where you can't do a local check to find out language use. It's also the only part where rust is viable, because the product side of the company has much stricter limitations on what they'll build for distribution and as of when I'd left, adding rust to that mix was not even on the radar there.
But the places where rust was gaining were small but important, which is the main thrust of what I was saying.
But anyways, with how siloed apple is experiences can differ a lot, even beyond normal for bigcorps. :/
The number of teams at these companies where “you should seriously consider Rust” is a thing is approximately (not exactly) zero. Its adoption is still a novelty, and most of the impetus behind it is engineers looking to scratch an itch without any legitimate analysis of the benefits or trade-offs involved.
It may be changing, but certainly not faster than I’ve observed (it’s not a matter of speculation, for me).
