[arp242]

> I doubt it would compile currently!

It compiles (and runs!) fine with just "gcc a.c"; nothing more needed. clang does throw some fatal errors, but there's probably some combination of flags to make it work; I couldn't be bothered to look further.

I've compiled plenty of code from the 80s; I can't recall a single example where it didn't work that wasn't due to OS-specific stuff. Tons of warnings and maybe some special-flags? Sure. But it works.

There's even some modern (well, "modern") code around today that uses K&R style function parameters.

[Cockbrand]

TIL that on macOS, both `gcc` and `clang` are present, but `/usr/bin/gcc` is in fact just a hard link to `/usr/bin/clang`. So I couldn't compile it with gcc (which is clang) on the Mac, but it compiles just fine with gcc on Linux.

It's really astonishing that we can compile 35 years old code with our current tooling. I somehow doubt that we'll be able to compile 35 years old Java/Go/Rust/... code without changes in the futue.

[epcoa]

Java is in that age ballpark and code with a similar level of dependencies as this of that vintage works just fine. Java has a solid backward compatibility story. The Java standard runtime also comes with much more than the C library so I’d say it’s better.

[arp242]

That's surprising! But I kind of get why they do that, as so many tools hard-code "gcc" rather than using "cc" or "$CC".

I'm not all that familiar with Java or Rust, but Go is very compatible; it's hard to predict the future, but it's already a third on its way to "35 years of compatibility".

JavaScript is pretty compatible as well; crummy JS from the 90s typically still works today (arguably it's compatible to a fault, with things like arr[-1] not being fixed).

[DeathArrow]

C was designed to be portable.

[throwawaymobule]

I'm sure a few compiler maintainers take pride in making sure certain 'famous' code snippets still compile as time goes on.

[hnfong]

IOCCC is "test cases for free", so if C compilers haven't added these code to their testing suite they really should.

[HeckFeck]

I tried -std=c89 with clang; no luck. If anyone gets further do let us know.

[Narishma]

This is K&R C, which predates the 89 standard.

[creatonez]

> It compiles

That's really unfortunate! The category this entry competed in is "Least likely to compile successfully"

[orf]

What modern code are you referencing?

[arp242]

Most if not all of bash.

zlib changed it just a few months ago (1.3 release from August): https://github.com/madler/zlib/issues/633

I've also seen it in some FreeBSD code, but that was quite a few years ago and I don't know to what degree that's been cleaned up – not so easy to grep for, but a quick check in git log shows e.g. https://github.com/freebsd/freebsd-src/commit/e5d0d1c5fbbc and some other things, so it seems there's still some K&R around.

Probably others as well, this is what I happen to know from the top of my head.