综述C++ multiple level memory model

本节标题的含义是: 多层次的memory model，它能够帮助我们建立对C++ memory model高屋建瓴的认识。

关于各种memory model的描述；

本章概述C++ memory model，主要参考:

1、sciencedirect Victor Alessandrini, in Shared Memory Application Programming, 2016

2、zhihu 如何理解 C++11 的六种 memory order？

3、modernescpp C++ Memory Model

三种还是四种还是六种?

可以看到:

一、sciencedirect Victor Alessandrini, in Shared Memory Application Programming, 2016

有如下三种memory model:

1 Sequential consistency

2 Acquire-release

3 Relaxed

NOTE: 由强到弱

二、zhihu 如何理解 C++11 的六种 memory order？ # A

有如下四种memory model:

\1. Relaxed ordering

\2. Release -- acquire

\3. Release -- consume

\4. Sequential consistency

NOTE: 有弱到强

三、modernescpp C++ Memory Model

有如下三种:

1 Sequential consistency

2 Acquire-release

3 Relaxed

NOTE: 由强到弱

四、cppreference std::memory_order

在 Explanation 段中给出了四种:

1、Relaxed ordering

2、Release-Consume ordering

3、Release-Acquire ordering

4、Sequentially-consistent ordering

在 Constants中给出了六种:

1、memory_order_relaxed

2、memory_order_consume

3、memory_order_acquire

4、memory_order_release

5、memory_order_acq_rel

6、memory_order_seq_cst