There have also been repeated statements from NSA & CISA that they recommend all development should be done in memory safe languages.
It's abundantly clear that there is a strong headwind towards memory safety, whether that's Rust or GC'd languages.
There have also been repeated statements from NSA & CISA that they recommend all development should be done in memory safe languages.
It's abundantly clear that there is a strong headwind towards memory safety, whether that's Rust or GC'd languages.
A headwind makes it harder to advance in the direction you're going. I think you might have meant to say "there is a strong tailwind towards memory safety".
You're right, I better do a 360 on my comment ;)
A 180 might be more useful :)
oh boy, maybe geometry intuitions and spatial reasoning are what's really needed.
Or maybe a nice sabbatical aboard a sailboat expedition.
Or maybe not, because that's where confusing 180 and 360 degrees or headwind and tailwing will REALLY bite you.
Sure, but if you come back, you'll have really learned that stuff!
Do it twice to be sure
That was obviously a joke...
[dead]
> A headwind makes it harder to advance in the direction you're going
nit: except in aviation
Also in aviation, but with caveats; you want to take off and land with a headwind, because the headwind gives a greater airspeed which means greater lift.
This is true for takeoffs but not for landings. You want to land with a headwind because this means that for the same airspeed you have a lower groundspeed, i.e. when you actually touch down you're going slower on the runway than if you touched down at the same airspeed but with a tailwind.
In other words, it's because of the greater lift.
No. Your calculated landing speed doesn't change depending on the winds, so you'll always be touching down at roughly the same airspeed for the same aircraft type, weight, and flap setting. Touching down with a headwind just means you don't need to use the brakes as hard.
It's beneficial on takeoff because headwind already factors into your airspeed before you even start rolling, which gives you more lift for the same groundspeed yes, enabling you to rotate sooner than you otherwise would.
Ah
Surely a headwind makes an aircraft travel slower over the ground so it takes longer to reach the destination?
Correct. See e.g.:
https://www.businessinsider.com/3-aircraft-fly-new-york-to-l...
The recommendation is qualified for typical apps that do not have extreme performance or scale requirements. They use Java for many, many things.
C++ is still indicated for systems that are optimizing for performance and scalability characteristics, since it intrinsically requires a lot of "unsafe" constructs.
> C++ is still indicated for systems that are optimizing for performance
The only evidence I've seen for this is that people with a vested interest in my believing this keep saying it is true. That's the exact same evidence I have for Trump having triumphed in Iran. Do better if you want me to believe you.
> since it intrinsically requires a lot of "unsafe" constructs.
This is an excellent reason to choose Rust. The whole point of Rust's technology is to enable you to encapsulate the tricky difficult part of the problem so that people don't blow their foot off working on the mundane parts of the software. And the truth is there are always mundane parts of the software.
I'm feeling generous so I'll add more here: Vec<T> illustrates how this works. This is a growable array type, C++ has std::vector<T> for much the same concept. But inside Vec<T> this encapsulation is used heavily so that there's a RawVec<T>, which doesn't care about knowing how many things are in the growable array, only about its capacity, then a RawVecInner which doesn't even care what things we're keeping in the array, it's just an appropriately large container for whatever it is, that RawVec<T> remembers what T is if that becomes important - and then a Cap which doesn't even contain things, it's just in charge of being able to represent the capacity correctly while having the same shape as "just" an integer but not always necessarily working like one.
Vec<T> is entirely safe to use, very pleasant, no danger. But internally it's extremely sophisticated, hence the layers of different types encapsulating different pieces of the problem to make a growable array type with excellent performance.
Tangent: your comment would have been stronger without the politics.
Btw, Rust ain't the only vector here. With an LLM at your side, you can also write your performance and safety critical parts in Lean and prove them correct.
Lean can compile to some pretty fast code. (Though it needs a bit more engineering work around eg SIMD to get really fast.)
I do think though, it is in the best interests for all compiled languages to eventually bootstrap themselves, instead of depending on either C or C++ for their implementation.
Either that, or we really need to keep improving C and C++ safety story, if they are to stay around on those language runtimes, or compiler backends.
I heard that unsafe rust is then unsafer than c++. I haven't learned rust yet, and I get that it's a tradeoff because the rest of the system can still be relied on. But how true is that first statement?
Rust allows much more aggressive optimization of the reference types than C++. If you have a &T, the compiler can assume that it will not change over the entire lifetime of the reference, and reorder things even past things that a C++ compiler would never reorder across. This can easily bite you badly if you have the mental model of C/C++ pointers and step into unsafe land. There is a separate warning for:
in the compiler because this is something that a lot of people think might be safe (I'm running single-threaded, everything would be so much simpler if I just mutated this bit while no-one's looking), but is in fact pretty much always UB of the nasal demons type. But there are more ways to step on this problem than the most apparent way, and the compiler is not able to protect you from all of them.To be clear, just declaring a block to be unsafe does not immediately do anything in Rust, it just allows a set of primitives that are not normally available, so it is possible to use unsafe judiciously without immediately stepping into a million landmines. You just have to be careful and ideally read the docs and the nomicon page for the operations you do, especially if they are very long.
It's not helpful to think of it as "unsafer" but I think the way I'd explain this goes as follows:
Rust has some stricter and more complicated rules even than a language like C++. Just as in C++ you absolutely must obey these rules at all times. However, in Safe Rust the tooling will ensure that following those rules is never your problem. You don't even need to know what the rules are, just like you don't need to know why a plane works let alone how to fly it to get on a jetliner and fly across the country for $$$.
In unsafe Rust, it is your job as programmer to understand and obey these rules because the "unsafe super powers" you can use only in these blocks cannot be checked by the tooling, it can help sometimes but you can't rely on it. Writing ten lines of correct unsafe Rust is thus probably significantly harder than writing ten lines of C++. But the Rust programmer knows when they need to be at their sharpest, they need proper review by somebody paying attention, they need to slow down and think it through, versus the rest of the safe Rust where it's less scary, in C++ every line you write might be a fatal problem.
Basically, walking a tight rope is harder than everyday walking, but you know when you're on a tight rope, you've trained for it, everybody is focused on your safety - so actually maybe that's not a problem, lot of people get injured just walking about every day.
That statement is incorrect.
It's harder to write unsafe code in Rust. That doesn't make it "unsafer". What I mean is this, if you want to write unsafe code in Rust the C++ way, your entire program has to have unsafe markers everywhere. It's just as unsafe as C++ at that point.
But if you want to write unsafe code in Rust the Rust way, you run into a requirement that didn't exist in C or C++: The abstraction around the unsafe code must be safe for you to drop the unsafe marker. This created a unique category of abstractions that no other language has, so if you are working on unsafe code in Rust you are often a pioneer doing something never done before.
> This is an excellent reason to choose Rust. The whole point of Rust's technology is to enable you to encapsulate the tricky difficult part of the problem so that people don't blow their foot off working on the mundane parts of the software. And the truth is there are always mundane parts of the software.
The problem is that it actually sucks for dealing with the encapsulated parts. The reason everyone loves Rust is because they can just import a package where somebody else did the hard part for them and not worry their pretty little brains about a thing, getting high performance with minimal concern. That is a valid advantage, and that does make more mundane usage of the language safer. But it does not make the unsafe parts safer. There is every reason for having unsafe-oriented languages with ergonomics that actually make working with unsafe code more reliable too. The annoying thing about Rust is that 90% of its users are religious dogmatists who insist that Rust is the only valid language rather than accepting different languages can have different advantages, and moreover that 90% is basically the 90% who are benefitting from Rust while not being the ones who have to write unsafe code themselves.
The autovectorizer works quite well in llvm with all the aliasing guarantees rust gives it. Especially now fastmath hit so wide types aren't necessary anymore. I don't need unsafe or crates that use unsafe to beat the performance of c++. If you are doing something very specific with niche intrinsics llvm can't use, then maybe I'd have to use unsafe. But I don't run into that. Rust is faster for the same reasons it avoids UB. Also the Kool aid comes in multiple flavors!
In real world systems, Java can beat programs in compiled languages like C++ and Rust when it comes to throughput and even latency.
This is so untrue I still don't know how anyone can even claim this. When I run tests in Rust, the biggest portion of the time is spent compiling the test (lets say 3-4 seconds), then the tests conclude practically instantly, in less than half a second.
Meanwhile when I run tests on my JVM projects it can take 30 seconds just to start and the test execution is extremely slow too.
Even if you do manage to match the performance after warmup, you still have the issue that keeping the class files in RAM plus the JIT compilation state will cost more memory than simply running AOT compiled code. You simply cannot write processes that use a single digit MiB amount of memory on a JVM and getting down to 2 digits is theoretically possible but requires significant effort.
Once you get into the micro optimizations like the lack of mutable aliasing in Rust, there is significantly more potential for auto vectorization.
What you mean by "real world systems" is probably defined in such a narrow way that all the weaknesses of Java programs don't count anymore.
> This is so untrue I still don't know how anyone can even claim this.
Because it's referring to long running processes, AKA the kind of things where hot paths can be JITted into faster native code than is possible from static compilation because the JIT has information about the real-world usage patterns.
> Meanwhile when I run tests on my JVM projects it can take 30 seconds just to start
That strongly implies you're using some sort of framework that's doing a _lot_ of initialization. That's not JVM startup time, don't be intellectually dishonest here.
> You simply cannot write processes that use a single digit MiB amount of memory on a JVM and getting down to 2 digits is theoretically possible but requires significant effort.
Again, the main use case for Java is long running server processes. No one cares if the binary is 1, 10, or 100MB or if it consumes 2, 3, or 4x the memory as long as the throughput is there. And Java has a long track record of delivering very good performance in those contexts, coupled with an extremely rich and mature library/tooling ecosystem.
> or if it consumes 2, 3, or 4x the memory
I think this used to be true more than it is now. Memory has been relatively expensive in cloud environments for a while (often 2x the price of an ec2 node for an equivalent with 2x RAM) and DRAM shortages aren't helping.
Yeah it's more of a concern but not "rewrite a ten year old application in Rust to save on the cost of several gigabytes of RAM" bad.
For the most part yeah but does depend on scale. For Java there are lower cost migration pathways like native compilation anyway if that does become your concern