How do you work with unsafe Rust?

Question

Accepted Answer

**unsafe** — bypass safety checks.

**Unsafe operations:**
```rust
unsafe {
    // Dereference raw pointer
    let mut num = 5;
    let r1 = &mut num as *mut i32;
    *r1 = 10;

// Call unsafe function
    dangerous_function();

// Access mutable static
    COUNTER += 1;

// Implement unsafe trait
    // impl UnsafeTrait for Type {}
}
```

**Safe abstraction:**
```rust
pub fn split_at_mut(slice: &mut [i32], mid: usize)
    -> (&mut [i32], &mut [i32])
{
    let len = slice.len();
    let ptr = slice.as_mut_ptr();

assert!(mid <= len);

unsafe {
        (
            std::slice::from_raw_parts_mut(ptr, mid),
            std::slice::from_raw_parts_mut(ptr.add(mid), len - mid),
        )
    }
}
```

**Key:** Minimize unsafe blocks, document invariants.

Rust: How do you work with unsafe Rust?