[CyberDildonics]

Keep in mind that when you have a dll you are unloading instructions, not data.

Also C++ has unique_ptr that also tracks lifetimes, I don't think Rust would really give you anything you don't already have and I think you are overestimating the fragility. I've done hot reloading of .dll and it isn't really all that fragile. If you have the c runtime as a dynamic .dll the heap won't be tied to the .dll either.

[steveklabnik]

uniqe_ptr does not "track lifetimes".

For example, this Rust program:

  fn main() {
       let r: &i32;

      {
          let b = Box::new(i32);
          r = &*b;
      }

      // r is dangling here, this would be bad:
      println!("{}", r);
  }

Is caught at compile time. Rust keeps track of the lifetime of both b and r, and knows that r will be dangling.

The C++ version:

  #include<iostream>
  #include<memory>

  using namespace std:

  int main() {
      int *r;

      {
          uniq_ptr<int> b(new int(5));
 
          r = &*b;
      }

      // r is dangling here
      cout << r << endl
  }

This compiles with no warnings under -Wall -Wextra with no warnings, and happily does whatever you ask with r, even though it's dangling.

Yes, this specific example is a bit contrived, but such is the way of examples. My point is just that C++'s smart pointers are a great thing, but that doesn't mean they do everything that Rust's do.

[pcwalton]

unique_ptr does not track lifetimes in any way. Nothing in C++ does.