Moving the kernel to modern C

Posted Feb 25, 2022 11:28 UTC (Fri) by jem (subscriber, #24231)
In reply to: Moving the kernel to modern C by wtarreau
Parent article: Moving the kernel to modern C

You can add this to the list of things you hate about Rust, too. In Rust you can even do this:

fn main() {
    let i = 0;
    println!("{}", i);    // Prints 0.
    
    let i = i+1;
    println!("{}", i);    // Prints 1.
}

Note that the i variables are immutable ("const") and there are two of them. The second let introduces a new variable which is initialized with the value i+1, where i refers to the first variable.

Moving the kernel to modern C

Posted Feb 28, 2022 8:09 UTC (Mon) by geert (subscriber, #98403) [Link] (3 responses)

So is this really any safer in the end?
I still cannot rely on the constant i being constant over the full range of the block, as anyone can have inserted one or more redefinitions in the middle of the block.

Moving the kernel to modern C

Posted Feb 28, 2022 9:38 UTC (Mon) by marcH (subscriber, #57642) [Link] (1 responses)

I believe every compiler for pretty much every language can detect shadowing and warn about it. C included.

Moving the kernel to modern C

Posted Feb 28, 2022 10:09 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link]

Go is a notable exception.

Moving the kernel to modern C

Posted Feb 28, 2022 11:26 UTC (Mon) by taladar (subscriber, #68407) [Link]

It is quite idiomatic in Rust to check a Result<T, E> value and reuse the same name for the content of type T after checking.

The alternative isn't really any better, coming up with extra names for what is logically the same value.