I read the article as saying that there's no official C library but unofficial ones do exist. Quote below, emphasis mine.
> A official c library doesn’t exist yet unfortunately, but there’s several out there you can try.
Also, it looks like there is more than zero support for C programs calling Landlock APIs. Even without a 3rd-party library you're not just calling syscall() with a magic number:
I don't understand what you mean. There's no "official" Rust, Haskell and Go APIs for this thing either. All libraries available seem to be just what some third party made available. There's also several C libraries, just none that have been officially endorsed by the Linux kernel team.
Go is famous for not needing libc and talking to the kernel. Rust and Haskell have communities that are very interested in safety and security, so they are earlier adopters.
For C, unofficial support apparently sufficed for now.
