cppreference std::memory_order # Explanation

Constants

memory_order_acq_rel

A read-modify-write operation with this memory order is both an acquire operation and a release operation.

NOTE: 只能怪用于 read-modify-write operation 。

No memory reads or writes in the current thread can be reordered before or after this store.

NOTE: 显然，同时施加 acquire operation 和 release operation:

1、acquire operation: reads can not be reordered before

2、release operation: writes can not be reordered after

All writes in other threads that release the same atomic variable are visible before the modification and the modification is visible in other threads that acquire the same atomic variable.

NOTE: 这描述的是实现的效果

NOTE:

1、Relaxed ordering

2、Release-Acquire ordering

3、Release-Acquire ordering

4、Sequentially-consistent ordering

Relaxed ordering

NOTE: 参见 Relaxed-ordering 章节

Release-Acquire ordering

NOTE: 参见 Release-Acquire-ordering 章节

Release-Consume ordering

NOTE: 参见 Release-Consume-ordering 章节

Sequentially-consistent ordering

NOTE: 参见 Sequentially-consistent-ordering 章节

Relationship with volatile

TODO