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.
Two notes: GCC has its "access" attributes which can give you similar bounds safety as clang.
Please see also my experimental library. https://codeberg.org/uecker/noplate/ While I do not had enough time to polish it yet, I think it provides some very nice interfaces with improve type and bounds safety, and are also rather convenient.
Also I wonder what parts are redundant if you have FORTIFY_SOURCE ?
(And thank you for working in this topic. If you continue, please reach out to us)
I think I had seen noplate before -- looks like you're taking advantage of the anonymous struct compatibility changes in C23? Those are going to open up a lot of possibilities. Regardless I'd love to stay in touch -- by "us" do you mean the working group?
I use c23 features but also vm-types for bounds checking which are older (i need the statement expression extension though): https://godbolt.org/z/T96T89Yhc
yes, with us I mean wg14 (or just me).
What do you think C would need in order to reach the user experience of those languages?
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.
Doesn't Apple have a nice `defer { }` block for cleanup? Did you include that in lib0xc? I didn't see in on your README.
Why Must C be safe, rather than people writing safer code in it or transfering to other languages if they cannot be bothered?
The C committee at least seems to get it now. The C++ committee still doesn't, led in large part by Bjarne.
(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)
C++ is something else. Heck, it's often far more bound to a Windows domain (and for a while Be/Haiku) than Unix itself by a huge stretch.
Still looking forward to the day C supports something like std::string, std::string_view, std::span, std:;array.
Which starting with C++26 finally have a standards compliant story about having bounds checks enabled by default.
Having said that, some of it may be due to "it's from Microsoft, we can't ever use it". I'm actually surprised not to have seen any anti-MS diatribes in the discussion so far.
Anything needs to be demonstrated and used in practice before being included in the standard. The standard is only meant to codify existing practices, not introduce new ideas.
It's up to compiler developers to ship first, standardize later.
So the best hope is probably for a third party library that has safet APIs to get popular enough that it becomes a de facto standard.
I don't have any clue how to patch clang's front end. I'm not a language or compiler person. I just want to make stuff better. There needs to be a playground for people like me, and hopefully lib0xc can be that playground.
Not all of the APIs were brain-dead. They just ignored all previous developments and in the proposal they didn't even remove the C++-related language.
To the best of my fallible knowledge, the notion was first popularized via <http://esr.ibiblio.org/?p=8764>.
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.
I do NOT want a package manager in my c code. I'm perfectly content with cloning a git repo from my cmake script.
And there is plenty to choose from if you don't like one or another build system.
Like it or not, having a little bit of friction prevents pulling in packages with thousands of transitive dependencies.
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).
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.
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++.
Practical. Useful. Not sexy. (I am only one of those.)
Bravo!
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.
I personally struggle with often being stuck on c99, not even c11.