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Ordering::AcqRel implementation contradicts the docs #49127
Description
Documentation on Ordering::AcqRel states:
AcqRel
When coupled with a load, uses `Acquire` ordering, and with a store `Release` ordering.
However, this code
use std::sync::atomic::{AtomicBool, Ordering};
fn main() {
let b = AtomicBool::new(false);
b.store(true, Ordering::AcqRel);
b.load(Ordering::AcqRel);
}
panics on both store and load (if the call to store() is commented out)
thread 'main' panicked at 'there is no such thing as an acquire/release store', /checkout/src/libcore/sync/atomic.rs:1482:19
note: Run with `RUST_BACKTRACE=1` for a backtrace.
Either documentation should be updated to describe why this is not relevant to store/load, or implementation should be fixed to actually deliver on the promise.
Activity
hanna-kruppe commentedon Mar 18, 2018
The implementation is correct. AcquireRelease is an ordering for operations that both load and store. If you just have a load or a store, you can and should simply use acquire or release respectively.
imp commentedon Mar 18, 2018
Ok, makes sense. Then the documentation should reflect that more clearly.
Rollup merge of rust-lang#49170 - steveklabnik:gh49127, r=nagisa
Rollup merge of rust-lang#49170 - steveklabnik:gh49127, r=nagisa