#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(atomic_try_update)]
use std::sync::atomic::{AtomicPtr, Ordering};
fn main() {
    let ptr: *mut _ = &mut 5;
    let some_ptr = AtomicPtr::new(ptr);
    let new: *mut _ = &mut 10;
    assert_eq!(
        some_ptr.try_update(Ordering::SeqCst, Ordering::SeqCst, | _ | None), Err(ptr)
    );
    let result = some_ptr
        .try_update(
            Ordering::SeqCst,
            Ordering::SeqCst,
            |x| { if x == ptr { Some(new) } else { None } },
        );
    assert_eq!(result, Ok(ptr));
    assert_eq!(some_ptr.load(Ordering::SeqCst), new);
}