Rust is less safe because it has a feature for turning off safety, called `unsafe`. Fil-C does not have a way to turn off safety, and it enforces safety checks at runtime. That's the reasoning anyways. If you define another language Rust-Without-Any-Unsafe, then maybe that one is safer than Fil-C.

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MaulingMonkey an hour ago | parent | next [-]

> If you define another language Rust-Without-Any-Unsafe, then maybe that one is safer than Fil-C.

Just write `#![forbid(unsafe_code)]` at the top of your src/lib.rs, and track crates not using it with `cargo geiger`. You don't need a whole new language, it already provides the tools to wield that hatch shut.

> Rust is less safe because it has a feature for turning off safety

Can I write Fil-C's mmap wrapper in Fil-C?

If no, fair enough, but it's worth noting I can write a safe Rust mmap wrapper in Rust, and I absolutely and frequently need to do that kind of "syscall wrapping" in arenas Fil-C explicitly hasn't handled, by virtue of being explicitly a Linux project.

If yes, that sounds like an escape hatch to Fil-C's memory safety, undermining the claim that Fil-C is fundamentally safer, and you're now at best arguing it's safer as tends to be used.

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Cyph0n an hour ago | parent | prev [-]

But the runtime cost of Fil-C means that - in most cases - your actual production application will be compiled with a standard C compiler. This applies not just to your code, but to all dependencies (due to ABI).

So I don’t see how Rust is at a huge disadvantage here when Fil-C is typically not going to be enforcing safety in production. I suppose the testing/fuzzing story becomes all the more important because you need to exercise runtime behavior for Fil-C to detect unsafe faults.

Don’t get me wrong: I think Fil-C is a smart idea and an excellent way to introduce memory safety to existing C codebases. But I don’t get this whole (usually implied) idea that Fil-C somehow makes Rust look bad or renders it obsolete.

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baranul 21 minutes ago | parent | next [-]

I think it's not so much that Fil-C renders Rust completely useless, but rather it reduces the supposed validity and wild arguments to frivolously rewrite anything and everything in Rust.

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modeless an hour ago | parent | prev [-]

The whole point of Fil-C is that it is fast enough to consider using in production for some applications while still guaranteeing memory safety. We already have ASAN and Valgrind and other tools for development purposes, that's not what Fil-C is targeting.

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josephg an hour ago | parent | next [-]

So Fil-C is competing with Go, C#, typescript and Python. If I’m writing a greenfield project where “bare metal” performance isn’t needed, why would anyone choose Fil-C over a more mature GC language?

C is more verbose and more error prone than Go and C#. It has worse tooling. It’s missing decades of language features. C isn’t properly cross platform. There’s no package manager. The “standard library” isn’t fully standard. It’s full of sharp edges and bad decisions.

I can imagine using Fil-C to run legacy code. But for new projects, it just seems worse in every way compared to Go, C#, typescript and friends. It’s worse, slow, and inconvenient.

	▲	baranul 8 minutes ago \| parent [-]
		Of the group of languages presented, your argument has more merit for Go. With C# and others, there is an additional OOP argument in there, that splits into different factions. But what is being overlooked, is the massive numerical dominance of C programmers and projects, along with legacy and embedded code. There is going to be a preference for writing and using C, that could arguably fuel Fil-C for a very long time.

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Cyph0n an hour ago | parent | prev [-]

I am assuming that Fil-C introduces orders of magnitude less overhead than ASAN or Valgrind.

Also, it’s probably fast enough for apps to be deployed in something like a staging environment for integration tests to run against them. Production deploy/release can then happen using a tagged version that gets compiled using vanilla GCC/Clang.

	▲	modeless an hour ago \| parent [-]
		I'm not sure about the speed of ASAN, it may be comparable but doesn't guarantee memory safety. It's only for catching mistakes and not secure against an adversary. Valgrind is dramatically slower.