Is u64 atomic on wasm?

Quoting AtomicU64 in std::sync::atomic - Rust :

Note: This method is only available on platforms that support atomic operations on u64.

Is Rust/u64 atomic on wasm ?

Considering that WASM is single-threaded, it should exist and be equivalent to a Cell<u64>.


If nothing changed, by default standard library is not compiled with wasm atomics so I think it is not available there instead you get regular ops.

Follow it up Tracking issue for WebAssembly atomics · Issue #77839 · rust-lang/rust (
For now it is behind feature +atomics

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