# atomicCasWeak

`import { atomicCasWeak } from "destack:sync";`

Atomic compare-and-swap (weak).

Like `atomicCas`, but may fail spuriously even if the comparison succeeds.

```ds title="atomicCasWeak"
export declare function atomicCasWeak<T>(ptr: *T, expected: T, desired: T, order: MemoryOrdering, scope: AtomicScope, memoryScope: MemoryScope, regions: MemoryRegionSet, isVolatile: boolean, isMakeAvailable: boolean, isMakeVisible: boolean): (T, boolean)
```

[language/library/src/sync/atomic.ds:253:264](https://github.com/destack-sh/destack/blob/main/language/library/src/sync/atomic.ds#L253-L264)