关于本章

本章回答"why need memory model"，下面这几篇，从高角度来进行的阐述，阐述了为什么需要memory model、着重讲的是memory model的意义:

1、Bjarne-Stroustrup

2、stackoverflow-C++Memory-model

下面是总结:

为什么C++11引入memory model？

1、时代背景: parallel computing

对于single thread，其实memory model并没有什么意义；但是对于multi-thread，它有着非常重要的意义，参考:

1、C++11 introduced a standardized memory model. What does it mean? And how is it going to affect C++ programming? # A 的如下comment:

@Nawaz: Yes! Memory accesses can get reordered by the compiler or CPU. Think about (e.g.) caches and speculative loads. The order in which system memory gets hit can be nothing like what you coded. The compiler and CPU will ensure such reorderings do not break single-threaded code. For multi-threaded code, the "memory model" characterizes the possible re-orderings, and what happens if two threads read/write the same location at the same time, and how you excert control over both. For single-threaded code, the memory model is irrelevant. – Nemo Jun 12 '11 at 17:08

2、portable

3、充分发挥hardware power

参考:

1、stackoverflow C++11 introduced a standardized memory model. What does it mean? And how is it going to affect C++ programming?