Not every high-level language gives you byte-level access to the representation of memory objects.
But it is also wrong to reduce a language to what is in the spec.
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Many do, contrary to what many C advocates talk about.
Apparently reducing the language to what is in the spec is only a thing when talking about C and to some extent C++.
When other languages have compiler specific extensions beyond the spec, it is a failure in their design.
Yet when C and C++ devs have to reach out to compiler specific extensions, it is not a design failure like it is pointed out to others, rather an advantage.
It is also wrong to not apply the same measure when it doesn't suit the message.
You comment this almost everyone it comes up. The hardware also isn’t x86! That’s an abstraction too.
The point is in C you have greater control of execution and resources, not that it matches the hardware exactly. It’s a spectrum and C is closer on that spectrum than JavaScript.
Because just like your comment proves the point, many think only C can do this.
So I keep re-educating folks that isn't the case.
Every thread has different people reading it, so there is always a first time for many of them.
You are again misreading even the most clearly put statement. Compared to e.g. Javascript, C is "closer" to the hardware, gives you "more control" of it. It would be completely ridiculous to deny this fact.
And if you move to e.g. C# / Java or similar, if you squint, and you try to be a smart-arse, then you could deny that C is closer to the hardware than C#, because C# probably has everything you need to control it, to the same degree that C allows you to. But if you work in these languages for a while, and look at the code that you ended up producing, then again you will absolutely find that it would be ridiculous to not admit that C gives you better control.
And you could even extend this to Rust, because the language encourages you to use high-level prefabricated components. It discourages you from doing low-level things, at least a little bit I think (I'm not a Rust user).
I think what you are doing all the time, is you are being a smart-arse, nothing else. What interesting low-level performant things have you actually programmed lately?
> But if you work in these languages for a while, and look at the code that you ended up producing, then again you will absolutely find that it would be ridiculous to not admit that C gives you better control.
I disagree somewhat. C gives you better control, and you have to accept that gift to get anything done. The likes of (modern) C# give you better control, but you can reject the gift if you want, and program in higher abstractions. You can also accept it in some places and reject it in others.
With C, you can reject the control, too, but then, you have to use third party libraries (or write them yourselves), and using those, your code looks less nice because it cannot escape C’s syntax (yes, macros help a bit there, but having real syntax beats it)
Mind you, the "you can use this other way as you see fit" idea often isn't practical (like combining GC'ed and non-GC'ed parts). You generally want a whole codebase to be structured according to shared idioms. Otherwise the interfacing cost becomes too high.
I have doubts that you can program easily in a C-style way in C# without adding lots of annotations everywhere in many places. But don't know, maybe I'm wrong, I did a search for a simple C-style arena allocator in C#, and it looked acceptable, it was quite close. The most annoying thing was maybe keyword boilerplate.
Smart-arse is comparing C versus JavaScript, instead of C vs C++, for example.
And then coming with such lengthy ad hominem.
Let make a fun exercise for the audience, given your performance remark.
Paste a random C code that I should replicate in whatever language I feel like.
There is one rule.
If the sample code is pure ISO C, then I will only use what is in the standard of whatever language I pick up.
If the sample code makes use of single language extension not part of ISO C, then I will have the freedom to also pick whatever language extensions I feel like.
So do you want to "rewrite" some C code in C++ to think you made a point? I think you should do C# or Java.
What about you do xxHash? Should be quite basic, not a lot of complicated structures. https://github.com/Cyan4973/xxHash/blob/dev/xxhash.h
Or what about you do an audio or video codec? Or an operating system?
Not going to paste any of my own code, because any non-trivial stuff is hundreds to thousands of lines. But one more example (that I recently did myself): Create a block allocator (power of two blocks) with bookkeeping in shadow memory (administered in individually committed zones representing virtual memory regions of 64 MB (2^26)). Any used memory has bookkeeping support for being sub-allocated at any and all levels up from 64 KB (2^16) to 64 MB (2^26), and even higher (by joining committed regions). Individual blocks are collected (using intrinsic linking, because no memory allocation) in a hierarchy of pools of same-sized chunks that have the same parent, and can be recursively sub-allocated on any smaller chosen power-of-2 level, and finally be consumed in linear fashion (arenas). Blocks are pooled with a moderate retain policy (watermark system) to allow subsystems to almost completely avoid any system calls and avoid inter-thread synchronisation. The memory overhead must be below 1% even though it's totally flexible (as said has metadata for all levels from 64 KB up).
The bookkeeping should function on 32-bit systems (small virtual space, occupancy range from megabytes to 3 GB) as well 64-bit systems (2^48-2^57 bytes of virtual address space, occupancy range from megabytes to hundreds of gigabytes) with reasonable overhead compared to actual usage.
This requires intrusively linked lists, occupancy bitmasks, bit-counting and bit-prefix counting, OS syscall access (virtual memory), pointer arithmetic (alignment needed to address shadow bookkeeping memory) and thread synchronisation. The reference code is >> 95% pure ISO C++11 (could be C99 with few changes), with a little platform code glued in. It works on Windows but it could be ported to Linux in a few hours. It supports a mostly-immediate-mode GUI with hundreds of thousands (maybe millions?) of small variable-sized allocations per second. Allocation has almost completely disappeared from the CPU profile, well below 1% of CPU usage.
I said any systems programming language, and stated the rules, so I gather you don't want to play this game after all.
> Or what about you do an audio or video codec? Or an operating system?
There are already plenty of examples out there, Claude can probably help you there regarding history of such products not written in C, or where C required help from Assembly code.
You can start by researching IBM i, z/OS, OS 2200, Xerox Alto, DirectX and Metal (C++ for the most part, and Objective-C++ on the 2nd)
> This requires intrusively linked lists,....
And the C99 version is impossible to be written in Ada95 because?
> Smart-arse is comparing C versus JavaScript, instead of C vs C++, for example.
Using C++ as your other comparison point when arguing that C isn't low level is by far the most smartass idea in this thread.
Not at all, because for C heads, C++ can't do what C does, for whatever imaginary reasons.
Requesting a block of system memory, by address, and writing to it.
This is common with C, when interfacing with hardware.
Define how you want to write to that system memory without OS syscall.
What exact C code did you had in mind?
So that the counter example is close enough to it in exposing the same semantics.
> If the sample code makes use of single language extension not part of ISO C
What are you even arguing right now? (Btw -ansi compiler flag)
> Smart-arse is comparing C versus JavaScript
I chose JavaScript to make the idea of a spectrum clearer using extremes. I can do C++ if you like. The machine doesn’t care about destructors, move, concepts, initializer lists, virtual methods, launder, or inheritance. You are programming against an abstract model further divorced from how x86 CPUs work.
That many features are not ISO, and any language can have extensions just like C, nothing special there.
To me choosing JavaScript as example against C, feels like the Tiger Beetle guy that initially chose JavaScript and then went to Zig because JavaScript did not deliver, go figure.
So many systems languages to chose from since 1958.
_You_ do that. All the time. And then you fight these strawmans.
And you reply to that all the time with the C bias as well, oh well.
"When other languages have compiler specific extensions beyond the spec, it is a failure in their design."
This one of the failures of Linus T. with the linux kernel: he was not able to keep the assembly source code with plain and simple C code you can compile with a small and alternative C compiler (same failure for the glibc devs I think).
I don't blame him, he is already keeping the linux ABI stable, and pulling that off is something.
Many other languages only have one compiler available to start with.
Each additional compiler supported by a project means variance in functionality and thus additional work for the project. That work could make the codebase more robust. Or it could be a ton of useless work. Or anything in between. Depends on the context of the project.
> assembly source code with plain and simple C code you can compile with a small and alternative C compiler
Which part of that big clause is the part that failed? Because I thought you could still compile Linux with TCC.
As far as I know, that was for x86(32bits) linux, that decades ago.
With those assembly source files (which do not abuse any pre-processor) and plain and simple C, I could build a modern x86_64 linux kernel with cproc/qbe (which gets 70% of gcc speed in my CPU intensive benchmarks... for a few % of gcc code and in plain and simple C, not brain damaged c++).
But I kind of don't mind since the future is assembly coding on non-IP-locked standard like RISC-V, and the main issue for that future is the abuse of pre-processors (ffmpeg was bitten by it) or code generators which would not be written in assembly themselves (or with a simple high level language with an assembly written interpreter, asmpython?).
I had checked that the project was touched more recently but apparently the kernel version wasn't updated at all. So yes, decades ago, oh well.
Indeed, Linus T. is not superman, he cannot preserve linux of all the danger around.
Lot of stawman arguments.
Wouldn't be a authentic pjmlp comment unless they shit on C/C++ and/or praise Java/.NET with a bunch of straw-men :)
How wrong you are, C++ isn't in the same league as C, Microsoft was right not wanting to keep updating their C support.
It was already outdated by the time Borland released Turbo C++ 1.0 for MS-DOS, and only got new wind thanks to GNU FOSS and their manifest to prefer C as the main compiled language for GNU projects.
Everywhere else outside UNIX, was going with a mix of C++ for OS frameworks, Apple, Microsoft, IBM, Be, Nokia, Epoch,....
Naturally given the option, between C, C++ and something else I might prefer that something else, however I managed a few interesting positions exactly due to my C++ skills, and interests.
So don't mix my preferences for C and C++ on the same basket.
Wouldn't trade it for anything <3 Enjoy your Tuesday mate :)
> So don't mix my preferences for C and C++ on the same basket.
That mistake is mine indeed, I'll remember. Thanks, and I hope "no harm meant" was implicit :)
> Wouldn't be a authentic pjmlp comment unless...
> and I hope "no harm meant" was implicit :)
Ad hominen then an apology, mixed signals here or I'm missing something. Maybe sarcasm?
Yeah, original/parent comment I wrote with a twinkle in my eye (hard to communicate though), hoping that the smiley at the end conveyed it, but I might have replaced ; with : mistakenly.
I think many of us throughout the years been reading pjmlp's comments which fits a certain "theme". I don't mind though, it's just text after all, but was hard to keep myself from entering the meta-conversation when the opportunity just sat there. I still don't mean no harm by it, we all have our less agreeable ways of writing our comments, I'm surely guilty of it in some way too.
> Ad hominen then an apology, mixed signals here or I'm missing something. Maybe sarcasm?
You can express annoyance at someone's pattern of behavior without it being personal. embedding-shape isn't the only person annoyed by pjmlp's repeated disdain and snark towards people who use C (or Zig or WebAssembly or Rust or...).
Really?! That is how many in C circles, including your regular comments to my comments happen to be like.
Two measures two weights, in C versus other systems languages.
Maybe provide a concrete example instead of making vague accusations. Or rather, please not, it is not a useful discourse. A productive response to my comment would be an insightful explanation of how byte-level access to memory objects is done in other languages.
> explanation of how byte-level access to memory objects is done in other languages.
I'm not pjmlp but I can explain this for the case of Rust, where this works a bit like C but with a few interesting differences.
Mainly, in Rust there is not a concept of a "memory object" per se in the runtime semantics. Memory is made of allocations and allocations are made of bytes. Unlike C, bytes are guaranteed to be 8 bits in size. Every byte of memory can hold integer values (0x00 to 0xff), pieces of a pointer or be uninitialized. That means there is nothing like strict aliasing, and therefore no need to have special rules for byte-level access. You can alias any type as any other type, so long as you avoid all the other sources of UB (out-of-bounds access, uninitialized memory access etc.).
The way to practically access this is much the same as in C. You can do things like cast pointers between different types and project a pointer to a struct to a pointer to one of its fields. It should be noted that, unlike with major C implementations, structs do not have a stable, well-defined layout, so if you do manual pointer math you need to put #[repr(C)] on the struct to get C layout rules (which might still yield platform-dependent field offsets, e.g. size_t is not the same size everywhere).
Note also that these are the dynamic rules of Rust, you need to follow these when writing unsafe code to avoid UB. The static rules of safe Rust are much more restrictive and don't allow much at all. It is possible to write unsafe code that exposes safe abstractions for this, one example is the "bytemuck" crate. It provides macros that can parse a type definition to check certain properties (e.g. well-defined layout, no padding) and then provide you with safe functions for byte-level access. Since there is no strict aliasing, for certain types you can also get safe functions for access at other granularities. For example:
#[repr(C)] struct Foo {
x: u32,
y: u16,
z: u16
}
#[repr(C)] struct Bar {
x1: u16,
x2: u16,
y: u16,
z: u16
}
Yes, Rust copied many good ideas from C (and added many new).
BTW: If you use character-pointers, you also do not need to worry about strict-aliasing in C.
Easy accessible in a NEWP, Mesa, PL/I, Modula-2 or Ada manual, on how to map structs into byte arrays.
Or for something more modern either D or C++ will do.
Examples omitted on request.
> That is how many in C circles
Being able to find someone who's made the argument you're rebutting doesn't make it not a straw man. What matters is whether the person you're arguing with is making the argument.
Specifically this:
> When other languages have compiler specific extensions beyond the spec, it is a failure in their design.
Is not a point I've seen anyone here make.
> Not every high-level language gives you byte-level access to the representation of memory objects.
Any code that ventures anywhere near that territory is 99% Undefined Behavior. It's almost impossible to write proper C/C++ code that isn't UB while touching byte-level representations.
This is certainly not true. Accessing bytes of objects is well-defined in C.
Just look at this: https://blog.habets.se/2026/05/Everything-in-C-is-undefined-...
This is undefined behavior!
const int* magic_intp = (const int*)bytes;
Heck even something trivial like this is UB:
bool bar(char ch) { return isxdigit(ch); }
The only safe thing to do is memcpy, but that's super useless. As soon as you try to interpret or manipulate the byte-level data in any way, there are UB traps everywhere you go.
Yes, using an arbitrary type that is different from the one of the object is UB. But any access of a representation byte using a character pointer is well defined, not just memcpy and I would also not call memcpy useless.