Git's list of banned C functions

Post by 1f60c » Fri, Mar 05, 2021, 12:05 AM UTC

unbalancedevh wrote: post #249

frob wrote: post #138

Earlier quoted context omitted.

As someone who learned C as their first language, strings in every single language after that have felt like cheating. "What? You mean I can type an arbitrary string and it works? I don't need to worry about terminators or the amount of memory I've allocated? You can concatenate two strings with +?!? What is this magic?"

It always makes me wonder if there's some hidden overhead that I'm absorbing. When I program in C I feel like I know a lot better what the generated instructions will be. Using higher-level languages for embedded programming where resources are tight makes me uncomfortable.

Post by xxpor » Fri, Mar 05, 2021, 12:06 AM UTC

Gibbon1 wrote: post #110

anyfoo wrote: post #55

Earlier quoted context omitted.

That's however relatively easy to verify programmatically, and indeed any recent compiler will complain about that. I'd say the usual trap is rather the size of the target buffer, because that requires bigger static analysis guns. (I'm ignoring things like "%n", because then you're playing with fire already.)

I think the big three C compilers have pragma's that you can tag printf/scanf with that will cause the compiler to verify the argument list.

Post by IgorPartola » Fri, Mar 05, 2021, 12:08 AM UTC

orwin wrote: post #196

viklove wrote: post #100

Earlier quoted context omitted.

It amuses me that HN hates JS so much, that even a topic about problems with C turns into a JS-bashing thread. Also, I just want to remind you that JS isn't just React. There are plenty of libraries written in C that introduce breaking changes over the course of 3 years. Nothing will stop people from finding ways to complain about JS though, I know. The hate-boner is very real.

I think most people on HN like Javascript, or at least its idea? I mean, its a very C-like functionnal language, especially since ES6 put Js on the right road (for me at least)?

Post by david2ndaccount » Fri, Mar 05, 2021, 12:09 AM UTC

kiwidrew wrote: post #265

munchbunny wrote: post #143

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The decision to make C strings null terminated with implied length instead of length + blob continues to trip us up, 30+ years later. There's a good reason the "safe" versions of those functions all take length parameters. But way back when this approach was chosen, I don't think the state of the art could fully predict this outcome. But also, "strings" and "time" are actually very complex concepts, and these functio…

I would argue that C's fundamental mistake (well, more like limitation due to hardware of the time) was allowing arrays to decay to pointers; arrays hold valuable type information (the length!) that is lost once converted to a pointer. C99 came so very very close with VLAs. You can declare a function like: int main(int argc, char *argv[argc]) { ... } But C99 requires the compiler to discard the type annotations and t…

    #include 
    
    void foo(int len, const char (*str)[len]){
        printf("%zu\n", sizeof(*str));
        printf("%.*s", len, *str);
    }
    
    int main(void){
        // note: not nul-terminated
        const char text[] = {'h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd', '!', '\n'};
        // prints 13, then 'hello world!'
        foo(sizeof(text), &text);
        return 0;
    }

Post by 1f60c » Fri, Mar 05, 2021, 12:11 AM UTC

UncleMeat wrote: post #280

ggregoire wrote: post #142

Earlier quoted context omitted.

> in JavaScript you have footguns like the with statement I've been coding in JS on a daily basis for more than 10 years and today I learned there is a `with` statement in JS. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... Edit: well, seems like it's been deprecated/forbidden since ES5 (2009), so it makes sense I've never seen it.

An old grad school connection of mine wrote a formal semantics for ES5 and couldn't explain what "with" did in words.

  with (Math) with (console) log(PI)