Comment by alfiedotwtf | Hacker News Reader

Comment by alfiedotwtf | Hacker News Reader

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Let's say you're a fresh grad and looking at options for you future dev career:

Option 1. Spend the next 5 years learning the ins and outs of C++, where it can bite you, where it can go wrong, all the intricate edge cases, etc... and you'll come out a better C++ programmer. Hopefully after 5 years of hard concentration, you may be able to write safe code (I still haven't met a C++ programmer that hasn't been burned by segfaults in production).

Option 2. Spend a single month learning Rust. Play with it for another month or even two just to be sure. Hopefully after the 3rd month, they'll be 100% certain that their code won't break because of errors that are above their pay grade.

I've done programming for over 12 years. x86 assembly and C for the earlier years. Then I realised that higher level languages gave me the power to code confidently without causing the errors that I was constantly seeing without explanation.

After many years of HLL I wanted to go back down to the metal... after everything that I knew, "C or C++, not even once".

Rust gives me the confidence to "compile once, run safe everywhere".

>> Spend the next 5 years learning the ins and outs of C++, [..,] Spend a single month learning Rust. Play with it for another month or even two just to be sure. Hopefully after the 3rd month, they'll be 100% certain that their code won't break [...] Rust gives me the confidence to "compile once, run safe everywhere".

See, this is exactly the fallacy that I am criticizing. I think the belief that "C++ is too hard to learn but one could become a good systems programmer in rust in a few months" is - frankly - misguided. I think that in order to become a good systems programmer in rust, you _will_ have to know all of your systems basics (i.e. you should already be able to code in C for starters) and then some more. But sadly this seems to be the spin that their marketing is pushing also.

Personally, I found practical rust (that interfaces with actual system libraries - think openssl) to be more or less on par with good C++11 with RAII memory and ressource management in terms of practical memory safety. Having somebody writing rust code without a basic understanding of things like ressource management and threading is just as bad as having them writing "unsafe" C(++) code.

I hope I'm not feeding the trolls here.

Another scenario:

Option 1. Spends 5 years learning the ins and outs of systems programming, whilst using C++. Still writes unsafe code.

Option 2. Spends 5 years learning the ins and outs of systems programming, whilst using Rust. Zero unsafe code has ever been written.

If you are writing systems code, you will be writing unsafe code; it's just how it works when you are working with the underlying kernel and hardware.

The best you can do is attempt to contain it within "unsafe" blocks, but as has been proven by others in the rust community already this will not save the rest of your "safe" code from crashing if you write a bug.

There have been memory safe languages for longer than c has existed; rust is just the latest.

Again, the assertion that all code written in rust is automatically "safe" (let alone correct) is false unless you say what precisely you mean with "safe" in very specific terms. While there are some ways in which rust is "safe" while c-family languages are not, these cases are _subtle_ and you _will_ have to understand modern C++ first to see what they are.

But yes, rust could turn out to become a new widely accepted standard for systems programming some day and depending on whether you believe that or not, it might make sense to "invest" your time into it.

These cases are not subtle at all. You can understand a good number of them with barely the knowledge from an Intro to Java class- iterator invalidation, data races, etc.

There is no need to understand the particulars of C or C++ to do or appreciate safe systems programming.

I'm talking safe as in Rust's memory safety guarantees.

As far as I understand, there is no accepted formal specification or even single source of truth for what the rust community thinks are the "rust memory safety guarantees". Only a large number of people that have completely convinced each other that "it's better than C++" with little proof and without even clearly defining their own semantics. Please correct me if I'm wrong here (a blog post does not qualify as a specification).

Relevant: https://github.com/rust-lang/rfcs/issues/1447

It's a little more subtle than that: It's "safe code must be memory safe" and "unsafe code infects the whole module". The stuff you're talking about is "what exact invariants are unsafe code supposed to uphold". Because unsafe Rust is a superset of safe Rust, that being an open question does not mean that what's meant by "Safe Rust" inside of safe Rust is up for questioning.

Work on exactly what unsafe code is expected to do is ongoing.

It's nowhere near that uncertain. "Memory safety" is hardly a subtle property and it's been well-understood since we figured out how to enforce it in garbage collected languages.

The only uncertain part is which rules unsafe code has to follow to maintain it- it currently comes down to "whatever LLVM optimizations won't break," which is in practice what C and C++ programmers deal with already. Things like your link are work to improve the situation beyond C and C++.

That assumes there will be no errors in the Rust compiler or runtime environment to deal with. If there are then those would definitely be above their pay grade.

I'd take a bug within LLVM over my own any day

Rust has basically the same amount of runtime as C; I'd say "standard libraries" here instead, personally.

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