I would add on top of brabel's post that C is surprisingly difficult to parse correctly (C++ notoriously so).
Zoom out a little: C is a lot like Unix: simple probably isn't the right word; `underengineered` comes to mind. Which leads to complexity, as you need to make things work in the real world. And so Unix syscalls being designed in the early 1970's for a PDP-11 don't really map to modern needs. And so every unanalyzed complex C app has memory leaks.
To be clear, I like C, I like C++, I like Objective-C, I like Swift; I'm comfortable in all of them. But, in 2026, I don't see why for native code everyone shouldn't be programming in Rust / Swift / other modern memory-safe flavor for any new production use. Zig if you want faster compile times, I guess.
> But, in 2026, I don't see why for native code everyone shouldn't be programming in Rust / Swift / other modern memory-safe flavor for any new production use. Zig if you want faster compile times, I guess.
Because C is very simple (unlike Rust) and works everywhere. Zig is not yet stable. Go and Swift are under the governance of tech companies.
The true appeal of C for me is the standard and how it applies only to the language. You can easily take a project from 2 decades ago and port it to a current platform. Lot of current ecosystem is way too fussy about tooling to do this.
> Because C is very simple (unlike Rust) and works everywhere
That's definitely true. C is a "Worse is better" language and as such it's everywhere. You can knock together a halfway usable C for some crap hardware in a few weeks and then the hardware is saleable because there's a C implementation.
> You can easily take a project from 2 decades ago and port it to a current platform.
Much of the software I wrote two decades ago in C won't even build today. Good luck figuring out why, periodically I try to figure out which weird 2000s era Mac OS hacks don't like a 2026 Linux system and eventually I give up and write modern software instead.
In theory C written in 2006 definitely "just works" on a 2026 Linux machine but in practice real world C is broken and even though I (co)wrote it I don't know why. Also in practice the first serious Rust project I wrote in 2021 I just found it, checked out the oldest working version ("first rough working code" says the log) from git, cargo run, works as expected.
Maybe it's because the C was four times older, but I think it's because in the real world you don't end up writing that mythical portable C code too often.
I have 'C' code that was written in 1985 that runs today, mostly after moving function parameters from inside the function to inside the argument list.
'C' seems to be a language that makes it easy to write incomprehensible statements, but it's not that hard (or it was not that hard) to write code that is trivial bring up to date. Perhaps it was easier for me because I started with Fortran.
> Maybe it's because the C was four times older, but I think it's because in the real world you don't end up writing that mythical portable C code too often.
It's because C, over time, went from a bunch of almost compatible implementations, to a standard that differed a little from every existing implementation, to a standard that is updated every decade or so, which is then implemented by a bunch of different products, with enough ambiguity in the standard (UB) that there will be differences between compilers and versions of compilers.
Rust is a single implementation. Always has been.
It's a single product, so you code to the product. The product has no external forcing function, like a language standard, that produces changes every decade. When you write Rust, you aren't thinking "Wait, lets make sure this works on the Watcom compiler too".
If Rust code cannot compile 30 years later, that's a failure on the language, because the single implementation is in full control of compatibility. If C code cannot compile 30 years later, that's not a failure of the language, because the implementation in 30 years has had external pressure forcing changes.
People often forget that Rust is a product, C is a specification.
In practice the cadence is exactly half that of WG21's breakneck C++ pace. Every six years. C11, C17, C23 so far and C2y is expected to land before the end of this decade.
But anyway, all I can do is report the observable fact. If you want to say it's because GCC 15 is a different product from GCC 4 whereas rustc 1.99 is the same product as rustc 1.49 then I guess you can re-phrase my position as "In C you will keep needing new products and that sucks" if you like.
In theory, in practice many C developers only know "My C Compiler standard", and are usually surprised that some of their expectations aren't even part of ISO C PDF specification.
Then they get irritated that not all C compiler vendors have the same language extensions or implementation defined behaviours they got used to rely on.
True. In C, it's hard to know what's defined where and what dependencies one is even using unknowingly. The only help is to build on multiple platforms from early on, this will reduce the pain of porting to new platforms later.
It's _very_ easy to write C that is impossible to port to other platforms or other compilers. The reason is that more than for most other ecosystems, there are many different implementations with their own implementations and quirks.
It's also easy to write C that won't build on the system it was originally developed on, a few years down the line. But that is true for almost every other language ecosystem. I would say, C makes it _possible_ to write code in such a way that it works on many different platforms and compilers, and/or can continue to work in decades to come with relatively little maintenance.
The latter isn't true for most other ecosystems, because to get anything done in them, you need to rely more on that language and its ecosystem -- specific language features, specific libraries. C isn't a glue code language. It's very good at letting you create your own thing.
To do it well though, requires a lot of care and expertise.
> more than for most other ecosystems, there are many different implementations with their own implementations and quirks.
Is that the reason? I thought it was primarily because C stupidly* makes a ton of platform-specific things more convenient than the platform-independent equivalent - the width of integer types, locales, etc., all vary by platform, and it's easy to accidentally depend on them.
* Maybe it wasn't stupid at the time when C was developed, but it's a bad choice now.
Integer widths are a problem, but hardly the biggest headache (unless it's a decade old preexisting project that was never designed with portability in mind). Fixed width integer types like int32_t have existed for decades. Even Rust has usize which is machine dependent, and pointers as well have to be machine dependent of course.
Much bigger problem is understanding the scope of dependencies. Dependencies can go bad and you need to update. A dependency might not be available on some new platform so you might have to replace with something else on that platform. To make the software portable, good modularity is required. This is to a large extent an aspect of software architecture. Even Rust can't magically make this happen, if you depend on 300 crates that's probably not a great place to be in either if you want to be portable and maintainable.
There is probably a point that C's flat namespace is a major contributor to badly designed software, because people aren't aware of the dependencies they're mixing all the time. Also C encourages transitive includes, leaking implementation details to the user instead of just to the compiler. (But btw. I find C++ and Rust namespace to be unergonomic syntax-wise, and what's needed is not actually namespaces but control over visibility).
It is "underengineered" perhaps if you believe it is the job of the language to prevent memory leaks (which Rust also doesn't). IMHO it is just fine - and in fact better - if the language is small and analysis is done by a separate tool.
I also do not see why the simplicity of C should lead to complexity. I have build complex systems in C. I did this using C++ in the past, but switched to C because I found out that all the complexity of C++ was a huge distraction and not something that helps me design better systems. C++ also came with a lot of claims that all the features are absolutely needed to build good abstractions and that this is not possible in C, something I found to be completely false. (And then, a lot of complex and still extremely reliable software I use daily is build in C. My practical experience completely contradicts the myth propagated nowadays by some that all C is inherently bad and unreliable . In my experience it is the exact opposite: The C software I use is in fact the most reliable.)
My view is that Linux and free software is still going strong, because it managed to largely keep out the unnecessary complexity out of the core infrastructure. With Rust and AI, I worry that now get a lot of overly complex infrastructure and that it will be hard to ever get this complexity under control again.
> But, in 2026, I don't see why for native code everyone shouldn't be programming in Rust / Swift / other modern memory-safe flavor for any new production use.
The lack of OpenMP for Rust etc. seems like the most obvious reason for "why use C instead of Rust in 2026" to me.
Zoom out a little: C is a lot like Unix: simple probably isn't the right word; `underengineered` comes to mind. Which leads to complexity, as you need to make things work in the real world. And so Unix syscalls being designed in the early 1970's for a PDP-11 don't really map to modern needs. And so every unanalyzed complex C app has memory leaks.
To be clear, I like C, I like C++, I like Objective-C, I like Swift; I'm comfortable in all of them. But, in 2026, I don't see why for native code everyone shouldn't be programming in Rust / Swift / other modern memory-safe flavor for any new production use. Zig if you want faster compile times, I guess.
Because C is very simple (unlike Rust) and works everywhere. Zig is not yet stable. Go and Swift are under the governance of tech companies.
The true appeal of C for me is the standard and how it applies only to the language. You can easily take a project from 2 decades ago and port it to a current platform. Lot of current ecosystem is way too fussy about tooling to do this.
That's definitely true. C is a "Worse is better" language and as such it's everywhere. You can knock together a halfway usable C for some crap hardware in a few weeks and then the hardware is saleable because there's a C implementation.
> You can easily take a project from 2 decades ago and port it to a current platform.
Much of the software I wrote two decades ago in C won't even build today. Good luck figuring out why, periodically I try to figure out which weird 2000s era Mac OS hacks don't like a 2026 Linux system and eventually I give up and write modern software instead.
In theory C written in 2006 definitely "just works" on a 2026 Linux machine but in practice real world C is broken and even though I (co)wrote it I don't know why. Also in practice the first serious Rust project I wrote in 2021 I just found it, checked out the oldest working version ("first rough working code" says the log) from git, cargo run, works as expected.
Maybe it's because the C was four times older, but I think it's because in the real world you don't end up writing that mythical portable C code too often.
'C' seems to be a language that makes it easy to write incomprehensible statements, but it's not that hard (or it was not that hard) to write code that is trivial bring up to date. Perhaps it was easier for me because I started with Fortran.
Do you also put Java in quotes? Rust?
I am quite sure my MS-DOS C code is going to have some hard time being compiled on GCC 16.
It's because C, over time, went from a bunch of almost compatible implementations, to a standard that differed a little from every existing implementation, to a standard that is updated every decade or so, which is then implemented by a bunch of different products, with enough ambiguity in the standard (UB) that there will be differences between compilers and versions of compilers.
Rust is a single implementation. Always has been.
It's a single product, so you code to the product. The product has no external forcing function, like a language standard, that produces changes every decade. When you write Rust, you aren't thinking "Wait, lets make sure this works on the Watcom compiler too".
If Rust code cannot compile 30 years later, that's a failure on the language, because the single implementation is in full control of compatibility. If C code cannot compile 30 years later, that's not a failure of the language, because the implementation in 30 years has had external pressure forcing changes.
People often forget that Rust is a product, C is a specification.
In practice the cadence is exactly half that of WG21's breakneck C++ pace. Every six years. C11, C17, C23 so far and C2y is expected to land before the end of this decade.
But anyway, all I can do is report the observable fact. If you want to say it's because GCC 15 is a different product from GCC 4 whereas rustc 1.99 is the same product as rustc 1.49 then I guess you can re-phrase my position as "In C you will keep needing new products and that sucks" if you like.
Then they get irritated that not all C compiler vendors have the same language extensions or implementation defined behaviours they got used to rely on.
It's also easy to write C that won't build on the system it was originally developed on, a few years down the line. But that is true for almost every other language ecosystem. I would say, C makes it _possible_ to write code in such a way that it works on many different platforms and compilers, and/or can continue to work in decades to come with relatively little maintenance.
The latter isn't true for most other ecosystems, because to get anything done in them, you need to rely more on that language and its ecosystem -- specific language features, specific libraries. C isn't a glue code language. It's very good at letting you create your own thing.
To do it well though, requires a lot of care and expertise.
Is that the reason? I thought it was primarily because C stupidly* makes a ton of platform-specific things more convenient than the platform-independent equivalent - the width of integer types, locales, etc., all vary by platform, and it's easy to accidentally depend on them.
* Maybe it wasn't stupid at the time when C was developed, but it's a bad choice now.
Much bigger problem is understanding the scope of dependencies. Dependencies can go bad and you need to update. A dependency might not be available on some new platform so you might have to replace with something else on that platform. To make the software portable, good modularity is required. This is to a large extent an aspect of software architecture. Even Rust can't magically make this happen, if you depend on 300 crates that's probably not a great place to be in either if you want to be portable and maintainable.
There is probably a point that C's flat namespace is a major contributor to badly designed software, because people aren't aware of the dependencies they're mixing all the time. Also C encourages transitive includes, leaking implementation details to the user instead of just to the compiler. (But btw. I find C++ and Rust namespace to be unergonomic syntax-wise, and what's needed is not actually namespaces but control over visibility).
I also do not see why the simplicity of C should lead to complexity. I have build complex systems in C. I did this using C++ in the past, but switched to C because I found out that all the complexity of C++ was a huge distraction and not something that helps me design better systems. C++ also came with a lot of claims that all the features are absolutely needed to build good abstractions and that this is not possible in C, something I found to be completely false. (And then, a lot of complex and still extremely reliable software I use daily is build in C. My practical experience completely contradicts the myth propagated nowadays by some that all C is inherently bad and unreliable . In my experience it is the exact opposite: The C software I use is in fact the most reliable.)
My view is that Linux and free software is still going strong, because it managed to largely keep out the unnecessary complexity out of the core infrastructure. With Rust and AI, I worry that now get a lot of overly complex infrastructure and that it will be hard to ever get this complexity under control again.
The lack of OpenMP for Rust etc. seems like the most obvious reason for "why use C instead of Rust in 2026" to me.