5 ms·

C still represents the closest approximation of what is happening on a chip, quasi-atomic operations acting on finite resources like registers, memory, and I/O.

C still represents the closest approximation of what is happening on a chip, quasi-atomic operations acting on finite resources like registers, memory, and I/O. Even if you don't know assembly, you can reasonably understand what various chips will do with your C code, especially low level C code that occasionally dips into assembly (e.g., handling interrupts or chip-level atomic operations). Rust, Go, and Java, with their memory management and cross-platform portability, and general non-determinism may eat away at the edge of C, but can never replace it. I could see them fully replacing C if features like garbage collection and byte-code interpretation were handled at the chip-level, so languages would not have to necessarily deal with them. Could also see it happening if a chip's out-of-order execution was exposed at the language level. That would not necessarily make C worse, but Java may be more adept at handling it.

blub 8y ago
You've made several points... 1. C is no closer than C++, or Rust (including unsafe) and they're all surprisingly pretty far from the hardware these days... this is visible the most in multi-threading, where high-level C statements are re-ordered by the compiler and even simple C statements like an integer assignment can be split into multiple instructions. Inlining and register allocation is also quite opaque and perhaps best left to the compiler, unless one uses non-standard code to force specific behaviour. 2. Well put: Go and Java were/are eating at the edge of C. Java took serious bites in the past, nowadays they're not really competing much. Today, what might have been a small Linux C program could be a Go program, especially if the performance constraints aren't too tight. Technically speaking, Rust can replace C almost everywhere, it's just that it's a significantly more complex language.
- pjmlp 8y ago
  Regarding 2. I am fully convinced that if Java and .NET had a proper AOT toolchain from day 1, meaning beyond dynamic linking (NGEN) or commercial offerings from 3rd party JDKs, C's influence on FOSS world would have been much less than it achieved to be. And we would already have achieved an UNIX like stack closer to what Inferno/Limbo was all about.
- speedplane 8y ago
  Regarding #1, disagree. In C, a function call is just a request to send the instruction pointer to another point in the memory space. In C, code is treated as data, which is how it's treated in hardware. C++ introduces virtual functions, and when you make a function call, you're no longer going to a single place in memory, you go to where the class's virtual function table tells you to go, effectively jumping to a memory pointer. This is pretty helpful, but it's an incredibly different way to think about code. A function is no longer a set of instructions in memory, it's a logical representation of functionality. And yes, I know in C, you can set a variable to a function location, and then jump there, but it's painful to do and you have to do it explicitly, so it doesn't really create an abstraction.

blub 8y ago

You've made several points... 1. C is no closer than C++, or Rust (including unsafe) and they're all surprisingly pretty far from the hardware these days... this is visible the most in multi-threading, where high-level C statements are re-ordered by the compiler and even simple C statements like an integer assignment can be split into multiple instructions. Inlining and register allocation is also quite opaque and perhaps best left to the compiler, unless one uses non-standard code to force specific behaviour. 2. Well put: Go and Java were/are eating at the edge of C. Java took serious bites in the past, nowadays they're not really competing much. Today, what might have been a small Linux C program could be a Go program, especially if the performance constraints aren't too tight. Technically speaking, Rust can replace C almost everywhere, it's just that it's a significantly more complex language.

pjmlp 8y ago
Regarding 2. I am fully convinced that if Java and .NET had a proper AOT toolchain from day 1, meaning beyond dynamic linking (NGEN) or commercial offerings from 3rd party JDKs, C's influence on FOSS world would have been much less than it achieved to be. And we would already have achieved an UNIX like stack closer to what Inferno/Limbo was all about.
speedplane 8y ago
Regarding #1, disagree. In C, a function call is just a request to send the instruction pointer to another point in the memory space. In C, code is treated as data, which is how it's treated in hardware. C++ introduces virtual functions, and when you make a function call, you're no longer going to a single place in memory, you go to where the class's virtual function table tells you to go, effectively jumping to a memory pointer. This is pretty helpful, but it's an incredibly different way to think about code. A function is no longer a set of instructions in memory, it's a logical representation of functionality. And yes, I know in C, you can set a variable to a function location, and then jump there, but it's painful to do and you have to do it explicitly, so it doesn't really create an abstraction.