this post was submitted on 13 Apr 2024
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Supreme leader mad (sh.itjust.works)
submitted 5 months ago by 0x4E4F@sh.itjust.works to c/linuxmemes@lemmy.world
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[–] tubbadu@lemmy.kde.social 92 points 5 months ago (10 children)

Is there some lore about this I don't know?

[–] BartyDeCanter@lemmy.sdf.org 137 points 5 months ago (2 children)

There is no C++ allowed in the Linux kernel and Linus has gone on several major rants about how terrible a language it is.

[–] VubDapple@lemmy.world 53 points 5 months ago (4 children)

Is it all C?

[–] ozymandias117@lemmy.world 86 points 5 months ago (1 children)

There’s assembly and makefiles too

Less of a joke answer, there has been work to allow Rust bindings for drivers.

[–] Vilian@lemmy.ca 26 points 5 months ago

rust too

[–] BartyDeCanter@lemmy.sdf.org 85 points 5 months ago (2 children)

According to the github analysis, the kernel repository is:

  • C 98.3%
  • Assembly 0.7%
  • Shell 0.4%
  • Makefile 0.2%
  • Python 0.2%
  • Perl 0.1%
  • Other 0.1%

So yeah, its basically all C, plus a tiny bit of assembly for very low level bootstrapping and some helper scripts.

[–] rambling_lunatic@sh.itjust.works 30 points 5 months ago (1 children)

Yeah but a lot of that C code has inline assembly so it's more like 5-10% asm.

[–] riodoro1@lemmy.world 13 points 5 months ago (1 children)

Inline assembly is such a shit practice. But c++ bad.

[–] Mananasi@feddit.nl 11 points 5 months ago (1 children)

Sometimes you can't get around it though.

[–] riodoro1@lemmy.world 1 points 5 months ago

Afaik MSVC forbids it and it’s one of the very few nice things about c++ on windows.

If you need to write assembly don’t fucking do it in a cpp file. Create a header, an assembly file, assemble it and link to it.

[–] Blackmist@feddit.uk 1 points 5 months ago (2 children)

Wot no Delphi?

[–] FlorianSimon@sh.itjust.works 3 points 5 months ago

No VB6 either 🤷‍♂️

How can one write a kernel without using VB6 at all?

[–] 0x4E4F@sh.itjust.works 1 points 5 months ago

Yeah, indeed, why not 🤔...

[–] jabjoe@feddit.uk 17 points 5 months ago (1 children)

Lots of core UNIX and Linux projects are. C++ is not liked by a lot of low level FOSS community. I think Rust is going to get further into these areas. I know C++ well but prefer C. I know plenty of others who feel the same.

[–] doriancodes@infosec.pub 3 points 5 months ago (1 children)

I've read that they are writing parts of the kernel in Rust

[–] jabjoe@feddit.uk 4 points 5 months ago (2 children)

Yes, I think Rust is a better C++ and will replace it in many places. Though all three will be around for ever to be honest.

[–] 0x4E4F@sh.itjust.works 2 points 5 months ago (1 children)

Yes, first Rust code was released in 6.6 I think and MS also started implementing Rust code in the Windows kernel.

[–] jabjoe@feddit.uk 3 points 5 months ago (1 children)

Rust is certainly interesting. I think it's the C++ we need.

[–] 0x4E4F@sh.itjust.works 1 points 5 months ago

Exactly my thoughts 👍.

[–] refalo@programming.dev 1 points 4 months ago

Personally I find the syntax unreadable.

[–] VitabytesDev@feddit.nl 1 points 5 months ago (1 children)

Always has been

[–] VubDapple@lemmy.world 4 points 5 months ago

Why do I suddenly feel a meme coming on? 😅

[–] Rossphorus@lemm.ee 76 points 5 months ago (3 children)

Torvalds just really dislikes C++. He's gone on the record saying that he thinks it's just not a good language. In his own words "C++ is just a waste, there is no design at all, just adding some scum on top of C."

[–] Vilian@lemmy.ca 55 points 5 months ago (1 children)

he's not wrong

[–] acockworkorange@mander.xyz 33 points 5 months ago (2 children)

In the specific use case of kernel programming, maybe. But the Standard Template Library is awesome.

[–] Vilian@lemmy.ca 5 points 5 months ago

they dumped everything in the languaga, at least samething they needed to have right, it's otherwise statistically impossible

[–] magic_lobster_party@kbin.run 2 points 5 months ago* (last edited 5 months ago) (1 children)

The STD is maybe the only good thing C++ has over C, and even that is awful compared to other language’s standard libraries.

I can’t name another good thing C++ has. Maybe templates. C++’s reliance on inheritance for polymorphism is awful (should’ve gone with interfaces/traits).

Not to mention the mess with all the different types of constructors that must always be implemented.

It’s just a bunch of bad design choices added on top of an old outdated language.

[–] acockworkorange@mander.xyz 2 points 5 months ago

The STD is maybe the only good thing C++ has over C, […]. I can’t name another good thing C++ has. Maybe templates.

Are you high? I was praising the STL, you know, the template library?

[–] nandeEbisu@lemmy.world 34 points 5 months ago

Never before have I been so offended by something I 100% agree with.

[–] blind3rdeye@lemm.ee 12 points 5 months ago

I would have agreed with that before C++11. But since then, C++ has improved a lot. Its like the vision of what C++ suddenly became more clear. So I wonder if Linus would still say that today. (Unfortunately, there have been a lot of missteps in the development of C++ though, and so there is a lot of cruft that everyone wishes was not there...)

[–] jalkasieni@sopuli.xyz 53 points 5 months ago

”C++ is a horrible language. It's made more horrible by the fact that a lot of substandard programmers use it, to the point where it's much much easier to generate total and utter crap with it. Quite frankly, even if the choice of C were to do nothing but keep the C++ programmers out, that in itself would be a huge reason to use C.”

http://harmful.cat-v.org/software/c++/linus

[–] raoul@lemmy.sdf.org 41 points 5 months ago (1 children)

I don't know about Linus, but the last time Reiser's wife was seen, she was writing a c++ hello world

[–] ikidd@lemmy.world 21 points 5 months ago

Too soon.

[–] vox@sopuli.xyz 25 points 5 months ago (1 children)

”C++ is a horrible language. It's made more horrible by the fact that a lot of substandard programmers use it, to the point where it's much much easier to generate total and utter crap with it. Quite frankly, even if the choice of C were to do nothing but keep the C++ programmers out, that in itself would be a huge reason to use C.”

http://harmful.cat-v.org/software/c++/linus

[–] MashedTech@lemmy.world 18 points 5 months ago (1 children)

Literally apply that train of thought to JavaScript and JavaScript is in an even worse position than C++

[–] CancerMancer@sh.itjust.works 9 points 5 months ago

JavaScript has the Node.js community in it and that just says it all really.

[–] ozymandias117@lemmy.world 25 points 5 months ago (2 children)

For an example from the other poster’s explanation:

https://lwn.net/Articles/249460/

This was pre c++11 - not sure if he’s changed his mind at all with more modern c++

[–] 5C5C5C@programming.dev 11 points 5 months ago (1 children)

He absolutely has not.

[–] ozymandias117@lemmy.world 4 points 5 months ago* (last edited 5 months ago) (1 children)

That’s my guess, but there was a conversation on the mailing list a few months ago that wasn’t just immediately shut down, even by other prolific developers

Ts’o seems skeptical, but is at least asking whether c++ has improved

https://lore.kernel.org/lkml/20240110175755.GC1006537@mit.edu/

[–] BartyDeCanter@lemmy.sdf.org 12 points 5 months ago* (last edited 5 months ago) (2 children)

Take a look at what even the proposer is saying wouldn't be allowed in:

 (1) new and delete.  There's no way to pass GFP_* flags in.

 (2) Constructors and destructors.  Nests of implicit code makes the code less
     obvious, and the replacement of static initialisation with constructor
     calls would make the code size larger.

 (3) Exceptions and RTTI.  RTTI would bulk the kernel up too much and
     exception handling is limited without it, and since destructors are not
     allowed, you still have to manually clean up after an error.

 (4) Operator overloading (except in special cases).

 (5) Function overloading (except in special inline cases).

 (6) STL (though some type trait bits are needed to replace __builtins that
     don't exist in g++).

 (7) 'class', 'private', 'namespace'.

 (8) 'virtual'.  Don't want virtual base classes, though virtual function
     tables might make operations tables more efficient.

C++ without class, constructors, destructors, most overloading and the STL? Wow.

[–] ozymandias117@lemmy.world 10 points 5 months ago (2 children)

That doesn’t really surprise me, as most of those are the same requirements from any embedded development use case using c++ that I’ve worked on

4 and 5 are the only ones stricter than I’m used to

[–] BartyDeCanter@lemmy.sdf.org 5 points 5 months ago

I've only worked on a few embedded systems where C++ was even an option, but they allowed 2, 4, 5, and 7. Though, for the most part most classes were simple interfaces to some sort of SPI/I2C/CAN/EtherCAT device, most of which were singletons.

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[–] nandeEbisu@lemmy.world 3 points 5 months ago (1 children)

I don't think its the ergonomics of the language he has an issue with. If anything C++1x probably just made the original critiques of bloat worse.

[–] ozymandias117@lemmy.world 13 points 5 months ago (3 children)

In that post, his critiques were around the problems with the STL and everyone using Boost. The STL has improved significantly since then, and it would be a limited subset of c++ if it was ever allowed

There have been mailing list conversations earlier this year, citing that clang/gcc now allowing c++ in their own code might mean they’ve taken care of the issues that made it unusable for kernel code

https://lore.kernel.org/lkml/e5949a27-999d-4b6e-8c49-3dbed32a00bc@zytor.com/

I’m not saying it will happen, but it’s not being shot down as an absolute insanity anymore, and I wouldn’t have expected Rust to be allowed in the kernel, either

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[–] Titou@sh.itjust.works 1 points 4 months ago

Linus is a C advocate btw, which make him even more goated

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