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Tell HN: C Experts Panel – Ask us anything about C

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Re: Tell HN: C Experts Panel – Ask us anything about C

#81

Post by nicoburns »

Are there any plans to "clean up C"? A lot of effort has been put into alternative languages, which are great, but there is still a lot of momentum with C, and it seems that a lot of improvements that could be done in a backwards compatible way and without introducing much in the way of complexity. For example:

- Locking down some categories of "undefined behaviour" to be "implementation defined" instead.

- Proper array support (which passes around the length along with the data pointer).

- Some kind of module system, that allows code to be imported with the possibility of name collisions.

Re: Tell HN: C Experts Panel – Ask us anything about C

#83

Post by jhallenworld »

nickysielicki wrote: post #75
ux wrote: post #66

Is there any plan to deal with the locale fiasco at some point? Some hints on what I'm referring to can be found here: https://github.com/mpv-player/mpv/commit/1e70e82baa9193f6f02... Unrelated, but I also miss a binary constant notation (such as 0b10101)

In the same vein, I really like being able to use underscores in binary and hex literals to denote subfields in hardware registers. 0xDEADB_EEF 0b1_010_110111001001 etc.

Should take Verilog binary construction syntax, like { 12'd12, 16'hffee, 3'b101 } (or something similar that would fit with C's syntax).

Re: Tell HN: C Experts Panel – Ask us anything about C

#84

Post by pascal_cuoq »

ux wrote: post #66

Is there any plan to deal with the locale fiasco at some point? Some hints on what I'm referring to can be found here: https://github.com/mpv-player/mpv/commit/1e70e82baa9193f6f02... Unrelated, but I also miss a binary constant notation (such as 0b10101)

Many C compilers offer, as an extension, the very binary constant notation that you miss, as anyone who has worked on the front-end of a C static analyzer would tell you.

Re: Tell HN: C Experts Panel – Ask us anything about C

#85

Post by shawnz »

stephencanon wrote: post #59
rbultje wrote: post #38

I'd love your opinion on the abundance of "undefined behaviour" (as opposed to implementation-defined, or some new incantation such as "unknown result in variable but system is safe") for relatively trivial things such as signed (but not unsigned) integer overflows. I've heard that this is to allow for non-twos-complement implementations. However, in practice, you notice that most people use ugly workarounds which le…

> (because of e.g. casting to unsigned and allowing the same overflow to happen anyway) only work correctly on twos-complement anyway Unsigned arithmetic never overflows, and guarantees two's-complement behavior, because unsigned arithmetic is always carried out modulo 2^n: > A computation involving unsigned operands can never overflow, because a result that cannot be represented by the resulting unsigned integer typ…

Wrapping around the modulus to me is an "overflow", although maybe the spec doesn't use the word that way

Re: Tell HN: C Experts Panel – Ask us anything about C

#86

Post by jfkebwjsbx »

DougGwyn wrote: post #62
billfruit wrote: post #32

I do find that C is difficult use for large programs. It there any thoughts that introducing features like namespaces. Another thing very cumbersome is to do in C is object creation; creating instantiable objects is possible very cumbersome. Is there some feature in the thoughy process to deal with it. To make it clear, in C we can create a data structure like a Stack or a queue easily. But if the program needs 10 st…

In BRL's MUVES project, we used a 2-character prefix indicating category. E.g., all the external identifiers for our fancy memory allocator began with "Mm", where Mm.h documented the interface for the Mm package only. To minimize the external identifiers, one could make just the name of a container structure the sole entry access handle, with structure members pointing to the functions. Then use it like: #include if…

Tip: you can use four leading spaces to write code.

    Like this

Re: Tell HN: C Experts Panel – Ask us anything about C

#87

Post by pantalaimon »

orsenthil wrote: post #68

Why is still the learning curve for C so high? * Why can't the learning curve be solved using tools? * Why don't we actively promote more higher level languages which are implemented in C (by fewer people)?

Do you find the learning curve for C to be high? I find it quite the opposite. It's a simple language with only a few concepts to learn, once you got those, that's it. There might be some preprocessor tricks you'll pick up later, but the base language and library is pretty comprehensive IMHO.

Re: Tell HN: C Experts Panel – Ask us anything about C

#89

Post by OnACoffeeBreak »

ux wrote: post #66

Is there any plan to deal with the locale fiasco at some point? Some hints on what I'm referring to can be found here: https://github.com/mpv-player/mpv/commit/1e70e82baa9193f6f02... Unrelated, but I also miss a binary constant notation (such as 0b10101)

I know that we're not voting, but I miss a binary literal very much. I would also like a literal digit separator to improve readability. Verilog Hardware Description Language does that with an underscore [1]. For example, 0xad_beef to improve readability of a hex literal, and 0b011_1010 to improve readability of a binary literal.

1: http://verilog.renerta.com/mobile/source/vrg00020.htm

Re: Tell HN: C Experts Panel – Ask us anything about C

#90

Post by eqvinox »

What's the best way to deal with "transitive const-ness", i.e. utility functions that operate on pointers and where the return type should technically get const from the argument?

(strchr is the most obvious, but in general most search/lookup type functions are like this...)

Add to clarify: the current prototype for strchr is

  char *strchr(const char *s, int c);
Which just drops the "const", so you might end up writing to read-only memory without any warning. Ideally there'd be something like:

  maybe_const_out char *strchr(maybe_const_in char *s, int c);
So the return value gets const from the input argument. Maybe this can be done with _Generic? That kinda seems like the "cannonball at sparrows" approach though :/ (Also you'd need to change the official strchr() definition...)
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