I don’t speak C, but isn’t this an extreme simplification of the issue? I thought memory could be abused in an almost infinite number of subtle ways outside of allocating it wrong. For example, improperly sanitized string inputs. I feel like if it were this easy, it would have been done decades ago.

In my opinion, the article is flawed in several ways:

Many want to solve this by hard-forking the world’s system code, either by changing C/C++ into something that’s memory-safe, or rewriting everything in Rust.

We are building a convenient strawman here. The foolish unnamed “many” who wish to rewrite everything in rust shall remain unnamed. But rest assured there are many. In any case, a false dichotomy is presented: rewrite all, or enhance C/C++. In fact a reasonable compromise is possible: rust is perfectly capable of interoperating with the C languages. Large C and C++ projects such as the Linux kernel and Firefox have successfully incorporated rust into their codebase. In this way codebases may be slowly refactored, incorporating safety piecewise.

The core principle of computer-science is that we need to live with legacy, not abandon it.

Citation needed. Not abandoning working code is clearly a Good Idea™, but calling it the core principle of all computer science? I would require some further justification.

This specific feature isn’t in compilers. But gcc and clang already have other similar features. They’ve only been halfway implemented. This feature would be relatively easy to add. I’m currently studying the code to see how I can add it myself. I could just mostly copy what’s done for the alloc_size attribute. But there’s a considerable learning curve, I’d rather just persuade an existing developer of gcc or clang to add the new attributes for me.

“It would be pretty easy to make. In fact I’m already doing it. But it’s actually quite hard, so I’d rather get someone else to do it” is quite the argument.

With such features, the gap is relative small, mostly just changing function parameter lists and data structures to link a pointer with its memory-bounds. The refactoring effort would be small, rather than a major rewrite.

The argument, such as I understand it, goes like this: bounds checking is an aspect of memory safety. We can add automatic bounds checking easily to C. Once it’s there, existing C programs only require minor modifications to compile again. All other memory safety features can be added in a similar way.

It seems to me that the author underestimates the problem.

Firstly, bounds checking is indeed only one aspect. Achieving memory safety as exists in rust requires many such features to be added to C. Secondly, it is not necessarily the case that once the compiler detects unsafe code, the fix is always small. Bounds checking is a convenient case for this argument: simply add bounds checks. Refactoring code to remove e.g. data races may not be so simple. Especially so because “crash when an unsafe access is detected” is often not a desirable solution. One must refactor the code such that the unsafe conditions (and the crash) cannot occur.

Indeed, code written in rust often entirely avoids patterns that are common in C, for the simple fact that they are hard/impossible to write such that they can be proven safe by the compiler. Just because you can add the checks to the compiler doesn’t mean the rest is “easy” or “minor.”

Lastly, I’m greatly in favor of enabling C programmers to write safer code. That’s a good thing! C code is not going away soon, and they need all the help they can get. However, I believe that the idea that one can gain all the benefits rust offers with a few additions to the C compiler and some refactoring is not likely to be true. And as stated before, a language that offers the features you need is already available and can be integrated into your C project! You could consider using it for your refactoring.

The core principle of computer-science is that we need to live with legacy, not abandon it.

The problem isn’t a principle of a computer science, but one of just safety. Also, who said this is a principle of computer science?

C compilers can’t tell you if your code has data races. That is one of the major selling points of Rust. How can the author claim that these features already exist in C compilers when they simply don’t?

Forking is a foolish idea. The core principle of computer-science is that we need to live with legacy, not abandon it.

what a crazy thing to say. The core principle of computer-science is to continue moving forward with tech, and to leave behind the stuff that doesn’t work. You don’t see people still using fortran by choice, you see them living with it because they’re completely unable to move off of it. If you’re able to abandon bad tech then the proper decision is to do so. OP keeps linking Joel, but Joel doesn’t say to not rewrite stuff, he says to not rewrite stuff for large scale commercial applications that currently work. C clearly isn’t working for a lot of memory safe applications. The logic doesn’t apply there. It also clearly doesn’t apply when you can write stuff in a memory safe language alongside existing C code without rewriting any C code at all.

And there’s no need. Modern C compilers already have the ability to be memory-safe, we just need to make minor – and compatible – changes to turn it on. Instead of a hard-fork that abandons legacy system, this would be a soft-fork that enables memory-safety for new systems.

this has nothing to do with the compiler, this has to do with writing ‘better’ code, which has proved impossible over and over again. The problem is the programmers and that’s never going to change. Using a language that doesn’t need this knowledge is the better choice 100% of the time.

C devs have been claiming ‘the language can do this, we just need to implement it’ for decades now. At this point it’s literally easier to slowly port to a better language than it is to try and ‘fix’ C/C++.

The C dev doth protest too much, methinks.

Humans can be immortal

Don’t believe me? I went to my local old folks home and found some who are older than 50!!