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Comment by mrich | Hacker News Reader

C is a subset of C++. The key point is that both languages suffer from the same problems, e.g. memory safety issues, undefined behavior, data races.

The software industry has been dealing with the fallout of these issues for the past three decades. It's about time we moved the bar higher.

By the way, the main data structure of my first large Rust program was simply a vector of a custom struct, optimized for memory footprint. Just like in C, with the same low overhead serialization.

With C, you always have to be careful to not overrun a buffer. The recent NSS vulnerability is a great example of this:

https://googleprojectzero.blogspot.com/2021/12/this-shouldnt...

Even though this code was heavily fuzzed and tested, the problem slipped through. Not possible in Rust. Also, with Rust you can throw away all your sanitizer infrastructure and save all the associated costs.

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> C is a subset of C++

It is not, they diverged since decades now.

Still, even if this was the case, the programming styles are so different that there’s nothing to gain considering them as any more similar as any two other languages.

> It is not, they diverged since decades now.

AFAIK you always had to cast `void *` in C++ (like the return value of `malloc`).

Why on Earth would one use malloc in C++? Instead of using ’new’ if explicit allocation is desired.

We are talking about the question if C is a subset of C++. `new` certainly isn't a part of C, so also not an element of the intersection of C and C++.

Idiomatic C code doesn't explicitly cast the return value of malloc

    foo *bar = malloc(sizeof *bar);

C++ did AFAIK never (certainly not with C++98, the question is if it had been allowed sometime before the standardization, but I think it never did) allow this, so you always had to do

    foo *bar = (foo *)malloc(sizeof *bar);

Therefore, C is not a subset of C++. But a (non-empty ;) intersection of C and C++ exists.

If you need to change the buffer size afterwards.

My understanding is that most implementations of new call malloc under the hood (this may or may not be outdated at this point, I haven't kept up with C++ implementation) and both of these systems introduce a layer of record keeping, so if you're in an extremely memory constrained environment, you may want to use malloc directly.

If you want your code to be noexcept, you need to call malloc and handle the case where it returns null as new can throw (this is UB in theory, but in practice I'm pretty sure everything just aborts) to strip out all the stack-unwinding code.

If you want to avoid the constructor call (for whatever reason).

> Why on Earth would one use malloc in C++? Instead of using ’new’ if explicit allocation is desired.

That was the point of my original comment that C++ and C are not the same language :)

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