Object operation and special member function/magic function and concept

1、object operation、magic function、concept之间有着对应关系，本文对此进行总结。

2、其实在cppreference Named Requirements中，已经对此进行了总结，参见 Named-requirements 章节。

Object operation and magic function

在 Object-operation 章节做了如下总结:

object lifetime	operation
create
	refer to
	access
	stored in arrays
	copy
	assign
	move
	swap
	serialization-deserialization
	......
destroy

1、copy、swap是基础操作，能够用于实现assign

2、move的实现很多都依赖于swap

Create

1、对应的magic function是constructor

参见如下章节:

1、Constructor

Copy

1、copy: 可以copy from lvalue、copy from rvalue

2、对应的magic function是: copy constructor、assignment operator

3、对应的magic function是: lvalue copy constructor、rvalue copy constructor; lvalue assignment operator、rvalue assignment operator;

因此包含四个 magic function。

参见如下章节:

1、Copy 章节

Swap

交换两个object的value。

Move

1、C++ 并不直接move

2、C++ move很多是基于swap而实现的

参见如下章节:

1、Move章节

Destroy

1、对应的magic function是destructor

参见如下章节:

1、在Destructor章节

cppreference Special member functions

NOTE:

下面是 cppreference 中总结的special member function

Special member functions
Default constructor
Copy constructor
Move constructor (C++11)
Copy assignment operator
Move assignment operator (C++11)
Destructor

Concepts

可以看到，上述每种operation

cppreference Named Requirements

Basic
DefaultConstructible	specifies that an object of the type can be default constructed (named requirement)
MoveConstructible(C++11)	specifies that an object of the type can be constructed from rvalue (named requirement)
CopyConstructible	specifies that an object of the type can be constructed from lvalue (named requirement)
MoveAssignable(C++11)	specifies that an object of the type can be assigned from rvalue (named requirement)
CopyAssignable	specifies that an object of the type can be assigned from lvalue (named requirement)
Destructible	specifies that an object of the type can be destroyed

关于 named requirement，参见 Named-requirements 章节。