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Lib0xc: A set of C standard library-adjacent APIs for safer systems programming
- platinumrad 5mo agoI truly hope something like this catches on. There is so much low hanging fruit in both the C and C++ standard libraries. Spatial memory could be 90% solved in both languages by mandating the use of safe interfaces.
- matheusmoreira 5mo agoInteresting. I'll be studying this later tonight so I can apply it to my C projects. Especially clang's -fbounds-safety.
- atilimcetin 5mo agoThe title looks very promising. I’ve added this library to my to-do list to take a deeper look at it. Using this standart library within restricted safe subset of C++ can be a strong opponent for Zig (at least for myself).
- EPWN3D 5mo agoHaven't really verified that it works with C++, but I tried my best to guard the stuff I knew would be problematic with #if __cplusplus. Happy to have a PR that makes C++ happier with it.
- atilimcetin 5mo agoThanks for the reply. Noted :)
- aDyslecticCrow 5mo agoAt the very least, It's a treasure trove of more advanced c design patterns that are worth knowing. As the readme describes it as basically established industry patterns passed down through word of mouth. I find It's difficult to find deeper level C programming techniques like these normally.
- raggi 5mo agothere are no good reasons we don't do this in the standards themselves, C, C++, and POSIX should all be working on editions that add safer APIs and mark unsafe APIs as deprecated, to start a long term migration. we know how to do this, we've had a lot of success with this. there are real engineering concerns, sure, but they're not reasons to not do it. compilers and library chains can retain support for less safe variants for plenty of time.
- zbentley 5mo agoThere are only two kinds of standards: ones that prioritize stability and backwards compatibility over usefulness and security, and ones nobody uses.
- AlotOfReading 5mo agoThe reason this wasn't done by the standards committees is that they spent decades refusing to admit there was even a problem they could help fix. And if there was a problem, it was easily avoided by just writing better code. And if writing better code wasn't enough, well it was certainly too expensive to provide as a debug option. And if it wasn't too expensive to provide as a debug option, the implementors should really lead the way first. And on and on. The C committee at least seems to get it now. The C++ committee still doesn't, led in large part by Bjarne.
- uecker 5mo agoThis is a misrepresentation based on a misunderstanding on how standardization works. The C standard committee has long recognized the need for better safety and carefully made it possible so that C could be implemented safely. But the process is that vendors implement something and then come together during standardization so that it is compatible, not that the standardization is the government that prescribes top-down what everybody has to do. Vendors did not bother to provide safer C implementations and safety features (such as bounds checking) did not get much attention from users in the past. So I am happy to see that there is now more interest in safety, because as soon as there solutions we can start putting them into the standard. (We can do some stuff before this, but this is always a bit of a fight with the vendors, because they do not like it at all if we tell them what to do, especially clang folks)
- nxobject 5mo agoI'm curious – is MSFT using this in production, or is this a "20% time" project? I'm not sure MSVC could compile the GNU extensions used.
- EPWN3D 5mo agoAuthor here. It is not currently in production, but it is part of a project in Azure which will go to production at some point. I'm actually leaving Microsoft next week and fully intend to keep working on it if I can reach an agreement to do so with my new employer.
- ofek 5mo agoIf an agreement can't be reached with your new employer are you certain that folks at Microsoft will continue maintaining this library? I'd like to experiment with it but have trepidation regarding future development.
- EPWN3D 5mo agoThere are people on my team who are interested in stewarding, so I think it'll be covered.
- sgbeal 5mo ago> I'm not sure MSVC could compile the GNU extensions used. The supported platforms only list Linux and Mac. Notably missing from that list is any of the BSDs (not counting what may or may not remain of BSD under the Mac hood).
- EPWN3D 5mo agoI just haven't tried it on a BSD. No reason it wouldn't work though. Might require a couple of fixes here and there, but generally the library sticks to standard C stuff and uncontroversial POSIX (in the POSIX target).
- EPWN3D 5mo agoAuthor here, I posted this in Show HN but someone clearly beat me to it. So I'll repost my blurb from there. Various patterns for safer C programming have been cargo-culting around the industry for decades. Because the language evolves intentionally slowly, these patterns rarely get folded into the language as first-class constructs and are passed down through the generations in a sort of oral tradition of programming. lib0xc leverages GNUC extensions and C11 features to codify safer C practices and patterns into real APIs with real documentation and real testing. Reduce your casts to and from `void *` with the `context_t` tagged pointer type. Enable type-checked, deferred function invocation with `call_t`. Interrogate structure descriptors with `struct_field_t`. Stop ignoring `-Wint-conversion` and praying you won't regret it when you assign a signed integer to an unsigned integer and use `__cast_signed_unsigned`. These are just a few of lib0xc's standard-library-adjacent offerings. lib0xc also provides a basic systems programming toolkit that includes logging, unit tests, a buffer object designed to deal with types, a unified Mach-O and ELF linker set, and more. Everything in lib0xc works with clang's bounds-safety extensions if they are enabled. Both gcc and clang are supported. Porting to another environment is a relatively trivial effort. It's not Rust, and it's not type safety, but it's not supposed to be. It's supposed to help you make your existing C codebase significantly safer than it was yesterday. My employer holds the copyright and has permitted its release under the MIT license.
- valorzard 5mo agoThis might be a dumb question, but using this + clang bounds-safety, whats the difference between this and something like Zig or Odin. What do you think C would need in order to reach the user experience of those languages?
- EPWN3D 5mo ago> This might be a dumb question, but using this + clang bounds-safety, whats the difference between this and something like Zig or Odin. I really need to learn more about Zig, but from what I know, there are still worlds of possibilities that a modern, well-designed language offers over something like lib0xc. Zig's ability to evaluate any expression at compile-time is one such example. But generally, lib0xc gives you bounds-safety everywhere it can. Languages like Zig and Rust give you type-safety to their own degrees, which I think is a superset. > What do you think C would need in order to reach the user experience of those languages? Not really having direct user experience, it's hard for me to say. But if I what I can give you is a list of features that would make large parts of lib0xc irrelevant: 1. Protocols/traits 2. Allocating from a caller's stack frame (think, returning the result of `alloca` to the caller) 3. printf format specifiers for stdint.h types and for octet strings 4. Ability to express function parameter lists as structures 5. New sprintf family that returns a value which is always less than or equal to the size passed (no negative values) Basically, I think that the C standard should be working aggressively to cut down on the use cases for heap allocation and `void *`. And I think that the bounds safety annotations should become first-class language features.
- jabl 5mo agoUnfortunate naming. I thought this was about https://libxc.gitlab.io/ https://libxc.gitlab.io/ but there's an extra '0' in the name here.
- bananaboy 5mo agoThis is very cool!
- andrefelipeafos 5mo agoQuick question for those who've tried it — does this play with existing C codebases incrementally, or is it more of a "new project only" situation? The README didn't make that obvious to me.
- EPWN3D 5mo agoIt's designed to be incremental. For example, you can do a search for `sprintf` and replace it with `ssprintf`. The function signature is the same. Any instance of printing to a character array just works. Think of the APIs as "the stuff you usually do by hand, but safer". If you get compiler errors, it means you were printing to a heap-allocated buffer (or a buffer whose bounds you did not know), and you should be propagating bounds and using `snprintf`. Integer conversion is the same way. If you have something like int v1; uint64_t v2; <stuff happens> v2 = (uint64_t)v1; Then you can replace it with v2 = __cast_signed_unsigned(uint64_t, v1); and you'll get a runtime trap when v1 is a negative value, meaning you can both enable -Wint-conversion and have defined behavior for when the value in a certain integer type is not representable in another.
- thayne 5mo agoInteresting that a project from Microsoft doesn't support MSVC or Windows.
- queuebert 5mo agoI suspect in 20 years Windows will be a Linux distribution with a compatibility layer.
- kristianp 5mo agoPeople say that kind of thing on HN every now and then. I have no idea why this idea is around, it's a complete fantasy in my opinion. I say this as someone who mostly uses Linux.
- sgbeal 5mo ago> I have no idea why this idea is around, To the best of my fallible knowledge, the notion was first popularized via <http://esr.ibiblio.org/?p=8764 http://esr.ibiblio.org/?p=8764>.
- kristianp 5mo agoThanks for the link, interesting that it was written in 2020. It doesn't take into account the fact that Office has never been ported to Linux. Many versions can be run on Wine of course.
- thayne 5mo agoIs there anything in here for something like a "slice" or dynamically sized array that carries its length along with it?
- Panzerschrek 5mo agoJust use compiler option -std=c++20 and use std::span. Don't try reinventing it in C.
- lelanthran 5mo agoIf someone needs more than C provides, why on earth would they choose C++? No rational person is going to want to have to deal with 10x the number of foot guns. Literally anything when moving from C is better than C++.
- Panzerschrek 5mo agoSwitching to C++ is relatively easy in an existing codebase. It's in many cases as simple as renaming a file from .c to .cpp. But for writing something from scratch it's better to use Rust.
- uecker 5mo agoRenaming c. to .cpp may work with ancient c89 code, but not with anything remotely modern. But while the code then is technically C++, it is not better. I still prefer C for new projects to any other language, because I value short compilation time and reduced complexity. For me, this translates in higher productivity and more fun. With modern tooling, also most C issues are detected early.
- Panzerschrek 5mo agoSlightly tweaking C code to allow it working in C++ is still much easier compared to full rewrite in some other language.
- akoboldfrying 5mo agoHow things change. Imagine Microsoft circa 2000 publishing an MIT-licensed source code library targeting "the competition"'s compilers, and including some light humour ("Embiggen C's Pit of Success") in the docs.
- fudgeonastick 5mo agoThis stuff is amongst my favourite type of engineering. Practical. Useful. Not sexy. (I am only one of those.) Bravo!
- worthless-trash 5mo agoHell, I aim to be all of those.
- pseudohadamard 5mo agoNot sexy? Yeah, I can manage that one too.
- ww520 5mo agoThis is great. Other things needed for a great C development environment are a standardized build process plus build tools and a standardized packaging system.
- FuckButtons 5mo agoI think most people who are into c that I’ve met quite like header only libraries. Copy paste as a package manager does have its benefits.
- uecker 5mo agoI mostly just install a -dev package on Linux and I am done.
- deleted 5mo ago[deleted]
- EPWN3D 5mo agoThanks! I agree, a better build story for C projects is desperately needed.
- skydhash 5mo agoWhat most people forget is that software is meant to be used as part of the system. The rush to adopt packaging tools like npm and cargo prevent standardization of system tools. On debian, installing tools should be as simple as ‘apt install’, but now you have to check what toolchain version you install then download GB of stuff from the internet. And that for each software. Easy deps donwload for devs means maintenance nightmare for admins and users.
- DeathArrow 5mo agoI thought Microsoft adopted Rust. Are they back pedaling?
- EPWN3D 5mo agoMicrosoft supports memory safety. Rust is 100% the direction for new projects. But there are existing C codebases that are unlikely to be entirely rewritten in a memory-safe language for various reasons. Such projects can significantly benefit from incremental improvements in memory safety.
- Panzerschrek 5mo agoIt's just an excuse not to use safe languages. And adopting it isn't that easy - one need to learn how the new library works or even rewrite old working and tested code with it.
- aDyslecticCrow 5mo agoIf i cannot use GCC i cannot compile to half the embedded platforms i work with on a daily basis. C remains widespread for unique reasons that not many other languages actually quite grasp. Using C for a destop application should probably stop being done in light of many more languages more suited for the domain. But there is no replacement for C in hard embedded systems. And there is no replacement for C in the massive domain of legacy c systems.
- xigoi 5mo agoGood thing there are safe languages that compile to C, such as Nim.
- aDyslecticCrow 5mo agoThese kind of effort have potential in my eyes. I've seen some others, and been tempted to write some tools of my own of this type. I personally struggle with often being stuck on c99, not even c11.
- Panzerschrek 5mo agoIt's not an excuse to write C forever, only because some embedded platforms have poor support in compilers other than GCC. Embedded developers should do something to force embedded vendors providing something better than a GCC fork or even something more obscure.
- aDyslecticCrow 5mo agoI really wish i could at the very least force them to use a modern GCC fork. Please no more c99!
- AnaSpelunker 5mo agoLook, C is so simple, you can implement a compiler in under 10K lines of code on a new platform. And then spend the your life dodging bugs and come up with a zoo of bizarre macros to keep you safe.
- xigoi 5mo agoYou forgot the part where you have to read an 800-page document that costs 250€ to access.