[Cyph0n]

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.

[modeless]

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.

[josephg]

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]

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.

[josephg]

> But what is being overlooked, is the massive numerical dominance of C programmers

I roll to doubt. I haven’t seen C topping programming language popularity charts for a long, long time.

I used to interview software engineering candidates professionally. Candidates could pick any language they wanted for the interview. Python was chosen by about 70% of our interviewees. C was under 5%. (N=400 or so)

[baranul]

> I haven’t seen C topping programming language popularity charts

C is still highly ranked on many charts. C (as of July 2026) is ranked #2 on the TIOBE index. PYPL has C and C++ weirdly merged, the annoying C/C++, and that comes in as #3. The IEEE and Redmonk have C firmly in the top 10, using different methodologies. We also have to consider how many years back that C's run in the top 10 goes.

We have to also use context, as popularity can be a measure beyond simply job demand, relative to usage by students, hobbyists, open-source, and legacy. Furthermore, demand can be relative to location and country. Because it is less in your specific area or company, doesn't mean that's so in other areas or countries.

[Jach]

A job market specific survey: https://www.devjobsscanner.com/blog/top-8-most-demanded-prog... They combine C and C++ together and it slides in at number 6. But together they only account for 5% of the job market. Totaling all such non-managed languages together is roughly 10% and that figure hasn't changed in decades. I'd bet that figure matches up with what consultancy firms that take on a wide variety of projects see. Needless to say, "massive numerical dominance" in relation to C is something that needs many qualifications to become true. Certainly there's a lot of C code out there, and C jobs, and in some niche domains it's very dominant. But there's just such a vast amount more of JavaScript, Java, and Python across more domains.

[dminik]

I'm sorry, but just mentioning TIOBE has killed any credibility you might have had. I mean, seriously, look at the list.

JavaScript at #6, when it should be at #1? Trailed by Visual Basic at #7? SQL (not a programming language) at #8 and R (have you ever seen an R job?) at #9. Then you have Rust just barely squeezing past Delphi? Followed by scratch???

Come on, this is not a serious source. Neither are the the rest really. Any popularity/usage list that doesn't have JS at first place is not serious.

[pjmlp]

Speaking for myself, I am never hired because I know C or C++, rather specific managed languages, however if there is the need to look under the runtime hood, or have bindings, like most Python libraries actually are, then suddenly it is welcome that I know C and C++ versus most folks on the team.

[josephg]

> suddenly it is welcome that I know C and C++ versus most folks on the team.

Yeah I know the feeling. But you don’t need Fil-C to learn C.

That said, with a GC, you could make some great tools & visualisations for learning C and understanding the memory layout of a running C program. That would be cool to see

[rcxdude]

to be fair, most programmers are at least a little bit polyglot, and if you know python and C and you're trying to solve an interview problem, python is gonna be the easier option 99% of the time, even if you're not that great at python compared to C.

[josephg]

> python is gonna be the easier option 99% of the time

If python/go/C# is easier to write, why choose C? Fil-C removes C’s performance and interoperability advantages.

[cma]

You could use raw C in environments with effective sandboxes, Fil-C in environments without a sandbox.

Or you could write a library that works for Fil-C and C without writing the library twice.

[Cyph0n]

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]

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.

[baranul]

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.