Function core::arch::wasm::memory_atomic_wait64

pub unsafe fn memory_atomic_wait64(
    ptr: *mut i64, 
    expression: i64, 
    timeout_ns: i64
) -> i32

🔬 This is a nightly-only experimental API. (stdsimd #48556)

Available on target_family="wasm" and target feature atomics only.

Corresponding intrinsic to wasm’s memory.atomic.wait64 instruction

This function, when called, will block the current thread if the memory pointed to by ptr is equal to expression (performing this action atomically).

The argument timeout_ns is a maximum number of nanoseconds the calling thread will be blocked for, if it blocks. If the timeout is negative then the calling thread will be blocked forever.

The calling thread can only be woken up with a call to the wake intrinsic once it has been blocked. Changing the memory behind ptr will not wake the thread once it’s blocked.

Return value

• 0 - indicates that the thread blocked and then was woken up
• 1 - the loaded value from ptr didn’t match expression, the thread didn’t block
• 2 - the thread blocked, but the timeout expired.