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Relax a memory order in once_box #131746

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Merged
merged 1 commit into from
Oct 16, 2024
Merged

Relax a memory order in once_box #131746

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4 changes: 2 additions & 2 deletions library/std/src/sys/sync/once_box.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@
use crate::mem::replace;
use crate::ptr::null_mut;
use crate::sync::atomic::AtomicPtr;
use crate::sync::atomic::Ordering::{AcqRel, Acquire, Relaxed};
use crate::sync::atomic::Ordering::{Acquire, Relaxed, Release};

pub(crate) struct OnceBox<T> {
ptr: AtomicPtr<T>,
Expand Down Expand Up @@ -60,7 +60,7 @@ impl<T> OnceBox<T> {
#[cold]
fn initialize(&self, f: impl FnOnce() -> Box<T>) -> &T {
let new_ptr = Box::into_raw(f());
match self.ptr.compare_exchange(null_mut(), new_ptr, AcqRel, Acquire) {
match self.ptr.compare_exchange(null_mut(), new_ptr, Release, Acquire) {
Ok(_) => unsafe { &*new_ptr },
Err(ptr) => {
// Lost the race to another thread.
Expand Down
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