Comment by mbrock

6 days ago

I don't understand the need to hammer in the point that Fil-C is only valuable for this tiny, teeny, irrelevant microscopic niche, while not even talking about what the niche is? To be clear, the niche is rebuilding your entire GNU/Linux userland with full memory safety and completely acceptable performance, tomorrow, without rewriting anything, right? Is this such a silly little idiosyncratic hobby?

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mbrock

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simonask  6 days ago

So I don’t want to come off as dismissive of the effort - it’s certainly impressive!

The reason I’m not super excited is based on the widely publicized findings from Google and Microsoft (IIRC) about memory safety issues in their code: The vast majority is in new code.

As such, the returns on running the entire userspace with Fil-C may be quite diminished from the get-go. Those who need to guard against UB bugs in seriously battle-hardened C software in production are definitely a small niche.

But that doesn’t mean it isn’t also very useful as a tool during development.

  • mbrock  6 days ago

    Hmm, so if they're writing new memory unsafe code in C/C++, presumably to remain within their already established and entrenched C/C++ ecosystems, why isn't Fil-C interesting as a way to thwart memory safety issues in that new code?

    • simonask  6 days ago

      Because every problem detected by Fil-C is already a serious problem in the existing code.

      As a mitigation strategy, that becomes less interesting as the quality of that code increases, but you still pay the full cost regardless of whether there are actually any bugs.

      That can certainly be valuable to you, but as a developer, the more interesting proposition is about how not to ship bugs in the first place.

      1 reply →

  • jitl  6 days ago

    It seems like there are constant updates for 20 year old packages on my Ubuntu systems. Ubuntu 20.04 Focal Fossa (first released April 2020) glibc had an update on 2025-05-28. Current stable updated glibc 2025-09-22. To say nothing about the rest of the packages in that operating system.

  • brucehoult  6 days ago

    > The reason I’m not super excited is based on the widely publicized findings from Google and Microsoft (IIRC) about memory safety issues in their code: The vast majority is in new code

    This makes perfect sense to me.

    Which is why I don't at all understand the current fetish with rewriting things that have been working well for decades in Rust. Such as coreutils. Or apt.

    It feels like an almost deliberate crippling of progress by diverting top talent into useless avenues, much like string theory in physics, or SLS/Artemis.

    • tempaccount420  6 days ago

      > It feels like an almost deliberate crippling of progress by diverting top talent into useless avenues, much like string theory in physics, or SLS/Artemis.

      You don't have to be a "top talent" to rewrite old unix utilities. The hard part is writing it safely, which in Rust can be done without "top talent."

      1 reply →

vorador  6 days ago

There's a contingent of rust fans that show up on every story about C – their premise is that C code is unsafe and most safety-critical C code should be rewritten in rust.

Fil-C is new and is a viable competitor to rust, that's why you're hearing all asides about tiny niches, unacceptable performance degradation, etc.

  • vacuity  6 days ago

    Hacker News is not a place where any one group brigrades a thread. There are people who prefer C who don't want a GC, people who prefer Rust who don't want C, people who prefer Rust who agree with Fil-C for legacy C, people who don't prefer C or Rust and may use languages with GC.... We all have interests and face people who denigrate them in bad faith. If you have specific objections to inaccurate statements in this thread, then state them. I'll do the same for any technology if I'm qualified to make statements on it.

  • petesergeant  6 days ago

    > Fil-C is new and is a viable competitor to rust

    I’ve no horse in the race here, but the Fil-C page talks about a 4x overhead from using it, which feels like it would make it less competitive

  • testdelacc1  6 days ago

    There’s no Rust fans here, only GC skeptics. GC skeptics existed long before anyone dreamed of Rust and will survive Rust as well.

    It’s a pretty reasonable objection too (though I personally don’t agree). C has always been chosen when performance is paramount. For people who prioritise performance it must feel a bit weird to leave performance on the table in this way.

    And Jesus Christ, give it a rest with this “Rust fans must be thinking” stuff. It sounds deranged.

    • vorador  6 days ago

      No, back in the day C was used for everything. Vim was not written in C because it needed to wring every last bit of performance out of text editing.

      Rewriting everything in rust "for memory-safety" is a false tradeoff given the millions of lines of C code out there and the fact that rewrites always introduce new bugs.

      3 replies →