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I cannot consistently write safe C/C++ code

robert.ocallahan.org

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Re: I cannot consistently write safe C/C++ code

#81

Post by catdog »

ccommsxx wrote: post #27

The worst thing about these kinds of articles is the troves of junior programmers that never touched systems programming with a stick before but will read this on hackernews today and sit in the office tomorrow lecturing seasoned coders how they´re dumb for not having seen the light and using an unsafe language. This is how stupid cargo cult gets made, guys. It's easy to repeat some talking points that you found on t…

> Do c/c++ for 10 years, like the author, and then you're qualified to comment about the topic. If you're new to this, try to put your time into actually learning about these topics and not just blindly repeating other peoples opinions. Please don't say things like "c/c++ is unsafe and should not be used" without understanding it first.

I don't think you need 10 years to understand enough to be qualified to comment. Like it or not people make mistakes, even the most seasoned coders do. C does its best to turn every little oversight into a potential entry in the CVE database.

> And try to consider for a moment that a humongous part of the critical software in the world is written in it. It is the industry standard for all things embedded and low level.

That is a valid excuse to use it but it doesn't mean that shouldn't be changed. What you see quite often is people defending using C less because of leveraging the existing ecosystem but because "it's so beautifully simple" and this "experienced coder can do it right" elitism.

> This is how stupid cargo cult gets made, guys. It's easy to repeat some talking points that you found on the rust homepage or another internet forum, but doing that does not make you an enlightened programmer!

> The thing is, I'm not even saying the author is wrong (I don't think he is). I'm just saying that circulating these kinds of opinion posts here and then applauding each other for being such brilliant rust fanboys is not helpful.

Nobody talks specifically about rust here, it's just a new promising language which is designed to fit inside the territories where C/C++ are prevalent and seems to have some traction. Rust is simply a non-theoretical opportunity to shift to something better.

Re: I cannot consistently write safe C/C++ code

#82

Post by alfiedotwtf »

ccommsxx wrote: post #80
alfiedotwtf wrote: post #77

Earlier quoted context omitted.

Another scenario: Option 1. Spends 5 years learning the ins and outs of systems programming, whilst using C++. Still writes unsafe code. Option 2. Spends 5 years learning the ins and outs of systems programming, whilst using Rust. Zero unsafe code has ever been written.

Again, the assertion that all code written in rust is automatically "safe" (let alone correct) is false unless you say what precisely you mean with "safe" in very specific terms. While there are some ways in which rust is "safe" while c-family languages are not, these cases are _subtle_ and you _will_ have to understand modern C++ first to see what they are. But yes, rust could turn out to become a new widely accepte…

I'm talking safe as in Rust's memory safety guarantees.

Re: I cannot consistently write safe C/C++ code

#83

Post by ccommsxx »

catdog wrote: post #81
ccommsxx wrote: post #27

The worst thing about these kinds of articles is the troves of junior programmers that never touched systems programming with a stick before but will read this on hackernews today and sit in the office tomorrow lecturing seasoned coders how they´re dumb for not having seen the light and using an unsafe language. This is how stupid cargo cult gets made, guys. It's easy to repeat some talking points that you found on t…

> Do c/c++ for 10 years, like the author, and then you're qualified to comment about the topic. If you're new to this, try to put your time into actually learning about these topics and not just blindly repeating other peoples opinions. Please don't say things like "c/c++ is unsafe and should not be used" without understanding it first. I don't think you need 10 years to understand enough to be qualified to comment.…

You took my post as saying "all systems code should be written in C and that should always stay that way because people don't make mistakes". However, that is not at all what I said (also see other replies).

What I said was that one should not blindly make the opposite (false) reverse assumptions, which are that "code should not be written in C/C++ because they are 'unsafe'" or "all code written in 'safe' languages is 'safe'" (both for a hand-wavy definition of safe). The point that I tried to make was that if you do not have a good understanding of C++, you're probably not qualified to comment on the matter of some alternative being safer/better than it or not. And also that just blindly repeating other's opinions is not a path to understanding in this case.

I realize that the linked article didn't say or do that, but my comment was clearly not directed at the author of the post, but at the community of this forum (just look around in this thread to find some of the group-think I'm referring to).

Re: I cannot consistently write safe C/C++ code

#84

Post by ccommsxx »

alfiedotwtf wrote: post #82
ccommsxx wrote: post #80

Earlier quoted context omitted.

Again, the assertion that all code written in rust is automatically "safe" (let alone correct) is false unless you say what precisely you mean with "safe" in very specific terms. While there are some ways in which rust is "safe" while c-family languages are not, these cases are _subtle_ and you _will_ have to understand modern C++ first to see what they are. But yes, rust could turn out to become a new widely accepte…

I'm talking safe as in Rust's memory safety guarantees.

As far as I understand, there is no accepted formal specification or even single source of truth for what the rust community thinks are the "rust memory safety guarantees". Only a large number of people that have completely convinced each other that "it's better than C++" with little proof and without even clearly defining their own semantics. Please correct me if I'm wrong here (a blog post does not qualify as a specification).

Relevant: https://github.com/rust-lang/rfcs/issues/1447

Re: I cannot consistently write safe C/C++ code

#85

Post by clarry »

simias wrote: post #63
millstone wrote: post #25

> I cannot consistently write safe C/C++ code. I'm not ashamed of that; I don't know anyone else who can. With respect, two mistaken beliefs: 1: Only a few programmers can write safe code. 2: One will naturally encounter such programmers in the course of a prestigious career working for a high-profile web browser company. But mediocre programmers consistently write safe C/C++ code, every day. They do it in the contex…

It's true but I'd argue that they're not really "coding" in C or C++ in the way it's commonly accepted in those critical environments. It's more like a "fill the blanks" exercise where everything is split in tiny functions that are thoroughly specified and tested. Effectively 90% of the dev work is done higher level by the various specification and constraint tools. All that's left to the C coder is the most menial o…

  > int test(void) {
  >      int i[3] = {0};
  >
  >      return i[8];
  >    }
clang will warn. gcc will warn with -Wall -O2.

  > int *test(void) {
  >      int i;
  >
  >      return &i;
  >    }
You are free to use -Werror.

I encourage people to learn to use their tools first. Instead of whining about the language when it is their tools that do not do what you want by default.

Re: I cannot consistently write safe C/C++ code

#86

Post by clarry »

danieltillett wrote: post #59
pjmlp wrote: post #14

Earlier quoted context omitted.

Of course every programming language is not perfect, including its library and related implementations. In all of them is possible to introduce logical bugs. The problem with C and its derived languages is that not only one has the logical bugs common to all programming languages, there are the memory corruption and UB introduced bugs to worry about as well. While one can think as being super competent, make use of a…

The good thing about C is there is an amazing tool support that can make it as safe as any other language. The bad thing about C is that most developers don’t know about (or don’t use) all the tools.

They don't even use their compiler.. case in point: https://news.ycombinator.com/item?id=14787072

Of course they always just blame the language. Like the language needs to be responsible for the implementation and its proper use.

Re: I cannot consistently write safe C/C++ code

#87

Post by alfiedotwtf »

ccommsxx wrote: post #84
alfiedotwtf wrote: post #82

Earlier quoted context omitted.

I'm talking safe as in Rust's memory safety guarantees.

As far as I understand, there is no accepted formal specification or even single source of truth for what the rust community thinks are the "rust memory safety guarantees". Only a large number of people that have completely convinced each other that "it's better than C++" with little proof and without even clearly defining their own semantics. Please correct me if I'm wrong here (a blog post does not qualify as a spe…

Trolling you? Go fuck yourself

Re: I cannot consistently write safe C/C++ code

#88

Post by pjmlp »

fnl wrote: post #67
pjmlp wrote: post #35

Earlier quoted context omitted.

Fact 1, the article doesn't mention Rust a single time. Fact 2, mostly safe systems programming languages exist since ESPOL (1961), 10 years older than C, and with a great linage of attempts of safe systems programming outside AT&T walls, so plenty of alternatives are available So as someone with more than 10 years of C and C++ experience, among other programming languages, before focusing on Java and .NET, I find th…

There is a big difference between modern C++ (C++11 ff.) and even the most current iteration of C. The two languages might have been quite similar back in the day when "C with classes" was created, but they have diverged significantly since then. Therefore, I think it is wrong to consider C a "proper subset" of C++, as often is claimed, or even to treat them as equals. In other words, the real fallacy of the original…

I kind of agree with you, back in the day during the C vs C++ flamewars, I was always in the C++ side, and still am if you follow my comment history.

However a big part of the problem, which you kind of refer to, when talking about lack of understanding between C and C++ differences is that, at least on enterprise space, many use C++ compilers for writing what is mostly C-like code.

Do you know why most MFC classes have an Afx prefix?

Microsoft created a C++ framework similar to OWL in abstraction capabilities, but the test group of early adopters said it was too high level and they just wanted a thin wrapper around Win32, hence Afx was reborn as MFC. [0]

I like modern C++ very much, and it is true that many of the "modern C++" concepts were already available on C++98, the problem is getting developers to actually use it, specially old school devs when working in companies where CI builds, static analyzers or sanitizers aren't part of the culture.

Which is the situation I see most of the time across many enterprise customers.

[0] http://cs.sookmyung.ac.kr/class/00891/C++/mfc-faq/

Re: I cannot consistently write safe C/C++ code

#89

Post by pjmlp »

nec4b wrote: post #55

I wonder how can anyone even use computers these days, since C and C++ are so unsafe. My OS is written in C and C++, also my browser and my word processor, my shell and most of the applications that I daily use. The firmware in my phone, my set-up box and my car is also written in those two languages. Also all the major web servers are written in those to languages. Maybe Rust programmers are an exception, but I pers…

Before 1990, other than UNIX related software, that was hardly the case.

Re: I cannot consistently write safe C/C++ code

#90

Post by fnl »

pjmlp wrote: post #88
fnl wrote: post #67

Earlier quoted context omitted.

There is a big difference between modern C++ (C++11 ff.) and even the most current iteration of C. The two languages might have been quite similar back in the day when "C with classes" was created, but they have diverged significantly since then. Therefore, I think it is wrong to consider C a "proper subset" of C++, as often is claimed, or even to treat them as equals. In other words, the real fallacy of the original…

I kind of agree with you, back in the day during the C vs C++ flamewars, I was always in the C++ side, and still am if you follow my comment history. However a big part of the problem, which you kind of refer to, when talking about lack of understanding between C and C++ differences is that, at least on enterprise space, many use C++ compilers for writing what is mostly C-like code. Do you know why most MFC classes h…

I completely agree with you on that take.

However, if you accept that take, I see little chances of convincing management in such a company to switch to a new, fledgling language - even if it were much safer to use. If anything, your hopes might be that you can teach their teams to use modern C++ and accordingly and slowly massage their code-bases into a more up-to-date state...

Ie., (not the least due to those vast code-bases) C++ (and Java) is (are) quite certainly going to stick around for the foreseeable future, like it or not. I don't really see any great migrations coming our way as long as those languages keep updating themselves to reflect the more significant insights from programming language research, even if those updates lag behind by years.

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