pointers - If I want to code in Rust securely, should I code without using pointer arithmetic?

Question

I've read that pointer arithmetic in Rust can be done through the pointer.offset() function, but it always has to be implemented in unsafe code:

fn main() {
    let buf: [u32; 5] = [1, 2, 3, 4, 5];
    let mut ptr1: *const u32 = buf.as_ptr();
    unsafe {
        let ptr2: *const u32 = buf.as_ptr().offset(buf.len() as isize);
        while ptr1 < ptr2 {
            println!("Address {:?} | Value {}", ptr1, *ptr1);
            ptr1 = ptr1.offset(1);
        }
    }
}

If I want to code in Rust securely, should I code without using pointer arithmetic and just using the corresponding index of an array for example? Or is there any other way?

标签： pointersrustpointer-arithmetic

Answer 1

If I want to code in Rust securely

Then you should not use unsafe. There are a few legit reasons for unsafe (e.g. accessing memory locations that are known and safe to use, e.g. on microcontrollers several registers), but generally you should not use it.

should I code without using pointer arithmetic and just using the corresponding index of an array for example

Yes. There is no reason (in this specific case) to use unsafe at all. Just use

for i in 0..buf.len() {
    println!("Value {}", buf[i]);
}

This code however is not considered as "rusty", instead use a for-loop

for i in &buf {
    println!("Value {}", i);
}