Annex C (informative) Compatibility [diff]

C.5 C++ and ISO C++ 2017 [diff.cpp17]

C.5.2 [basic]: basics [diff.cpp17.basic]

Affected subclause: [intro.races]
Change: Except for the initial release operation, a release sequence consists solely of atomic read-modify-write operations.

Rationale: Removal of rarely used and confusing feature.

Effect on original feature: If a memory_­order_­release atomic store is followed by a memory_­order_­relaxed store to the same variable by the same thread, then reading the latter value with a memory_­order_­acquire load no longer provides any “happens before” guarantees, even in the absence of intervening stores by another thread.