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Automotive embedded C developer here. Most of the code in this industry is implemented in a subset of ANSI C90. The reason is not header files, libraries or lin

Automotive embedded C developer here. Most of the code in this industry is implemented in a subset of ANSI C90. The reason is not header files, libraries or linker scripts. The reason is as the grandparent post points out: compiler availability. For rare targets, there's just no money in making a compiler work for more than this small subset of C. My favorite example is the compiler for a really strange architecture where everything is 24 bits. Char is short is long is a pointer. Bigger controllers tend to be ARM-based, so it's getting better. Also Tricore has a big share, but their compiler support is getting better. There was even a rust compiler being announced recently, though I doubt it's using LLVM backend, so it's likely to be behind in terms of features.

l33t233372 4y ago
> Char is short is long is a pointer. I thought char was required by the C standard to be 8 bits. If everything is 24 bits, how do you cover 24 bit address space with 8 bit pointers?
- detaro 4y ago
  > I thought char was required by the C standard to be 8 bits It's not. (EDIT: it is required to be at least 8 bits though)
  - pclmulqdq 4y ago
    Welcome to C! The guns are free, but you can only point them at your foot. The C standard specifies so much less than everyone thinks.
    - userbinator 4y ago
      It specifies so much less, precisely to allow it to be usable on such weird architectures.
    - detaro 4y ago
      I wouldn't really qualify this as a foot gun, but rather appropriate flexibility. 98% of people never encounter it, and the 2% that do are happy that it is that way, and I don't think alternative approaches like having the compiler hide it are appropriate for C.
  - kjs3 4y ago
    I thought char was required by the C standard to be 8 bits Common misconception. to be at least 8 bits though At least 8 bits for the latter-day compilers for which the 'standard' was the guide. I have seen C compilers where char was 6-bit or 7-bits matching the underlying hardware. However, those probably never implemented more than K&R or some pre-standardization perversion of it. Also...as noted a char can be more than 8 bits, pre- and post-standardization. I've heard tell of (at least) 9-, 16-, 24- and 32-bit chars on more or less weird platforms. At some point I'm sure the standards bodies will do some variation of depreciating 8-ish-bit char's for 32-bit Unicode as the standard representation for text.
userbinator 4y ago
My favorite example is the compiler for a really strange architecture where everything is 24 bits DSP? That's the one example I can think of where 24-bit architectures are in active use (and many of them are not Von Neumann, but Harvard with separate data/program memory.)
chii 4y ago
> The reason is as the grandparent post points out: compiler availability. is there no appetite to self-write a compiler for the architecture being used?

l33t233372 4y ago

> Char is short is long is a pointer. I thought char was required by the C standard to be 8 bits. If everything is 24 bits, how do you cover 24 bit address space with 8 bit pointers?

detaro 4y ago
> I thought char was required by the C standard to be 8 bits It's not. (EDIT: it is required to be at least 8 bits though)
- pclmulqdq 4y ago
  Welcome to C! The guns are free, but you can only point them at your foot. The C standard specifies so much less than everyone thinks.
  - userbinator 4y ago
    It specifies so much less, precisely to allow it to be usable on such weird architectures.
  - detaro 4y ago
    I wouldn't really qualify this as a foot gun, but rather appropriate flexibility. 98% of people never encounter it, and the 2% that do are happy that it is that way, and I don't think alternative approaches like having the compiler hide it are appropriate for C.
- kjs3 4y ago
  I thought char was required by the C standard to be 8 bits Common misconception. to be at least 8 bits though At least 8 bits for the latter-day compilers for which the 'standard' was the guide. I have seen C compilers where char was 6-bit or 7-bits matching the underlying hardware. However, those probably never implemented more than K&R or some pre-standardization perversion of it. Also...as noted a char can be more than 8 bits, pre- and post-standardization. I've heard tell of (at least) 9-, 16-, 24- and 32-bit chars on more or less weird platforms. At some point I'm sure the standards bodies will do some variation of depreciating 8-ish-bit char's for 32-bit Unicode as the standard representation for text.

userbinator 4y ago

My favorite example is the compiler for a really strange architecture where everything is 24 bits DSP? That's the one example I can think of where 24-bit architectures are in active use (and many of them are not Von Neumann, but Harvard with separate data/program memory.)

chii 4y ago

> The reason is as the grandparent post points out: compiler availability. is there no appetite to self-write a compiler for the architecture being used?