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### 864. Defect in atomic wording

Section: 31.8.2 [atomics.types.operations] Status: NAD Editorial Submitter: Anthony Williams Opened: 2008-07-10 Last modified: 2016-01-28

Priority: Not Prioritized

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Discussion:

There's an error in 31.8.2 [atomics.types.operations]/p9:

>     C atomic_load(const volatile A * object);
>     C atomic_load_explicit(const volatile A * object, memory_order);
>     C A ::load(memory_order order = memory_order_seq_cst) const volatile;

> > Requires: The `order` argument shall not be `memory_order_acquire` nor `memory_order_acq_rel`.

I believe that this should state

> shall not be `memory_order_release`.

There's also an error in 31.8.2 [atomics.types.operations]/p17:

> ... When only one `memory_order` argument is supplied, the value of success is `order`, and the value of failure is `order` except that a value of `memory_order_acq_rel` shall be replaced by the value `memory_order_require` ...

I believe this should state

> shall be replaced by the value `memory_order_acquire` ...

Proposed resolution:

Change 31.8.2 [atomics.types.operations]/p9:

>     C atomic_load(const volatile A * object);
>     C atomic_load_explicit(const volatile A * object, memory_order);
>     C A ::load(memory_order order = memory_order_seq_cst) const volatile;

> > Requires: The `order` argument shall not be `memory_order_acquire` `memory_order_release` nor `memory_order_acq_rel`.

Change 31.8.2 [atomics.types.operations]/p17:

> ... When only one `memory_order` argument is supplied, the value of success is `order`, and the value of failure is `order` except that a value of `memory_order_acq_rel` shall be replaced by the value `memory_order_require` `memory_order_acquire` ...

Rationale:

Already fixed by the time the LWG processed it.