`=default` 移动构造函数是否等同于成员移动构造函数?

这是吗

struct Example { 
    string a, b; 

    Example(Example&& mE) : a{move(mE.a)}, b{move(mE.b)} { }
    Example& operator=(Example&& mE) { a = move(mE.a); b = move(mE.b); return *this; } 
}

相当于这个

struct Example { 
    string a, b;

    Example(Example&& mE)            = default;
    Example& operator=(Example&& mE) = default;
}

?

推荐答案

是的,两者是一样的.

但是

struct Example { 
    string a, b; 

    Example(Example&& mE)            = default;
    Example& operator=(Example&& mE) = default;
}

此版本将允许您跳过正文定义.

This version will permits you to skip the body definition.

但是,在声明explicitly-defaulted-functions时必须遵循一些规则:

However, you have to follow some rules when you declare explicitly-defaulted-functions :

8.4.2 显式默认函数 [dcl.fct.def.default]

表单的一个函数定义:

  attribute-speci?er-seqopt decl-speci?er-seqopt declarator virt-speci?er-seqopt = default ;

被称为 明确默认 定义.一个明确默认的函数应该

is called an explicitly-defaulted definition. A function that is explicitly defaulted shall

  • 成为一个特殊的成员函数,

  • be a special member function,

具有相同的声明函数类型(除了可能不同的ref-qualifiers,并且除了在复制构造函数或复制赋值运算符的情况下,参数类型可能是引用到非常量 T",其中 T 是成员函数的类的名称),就像它已经被隐式声明一样,

have the same declared function type (except for possibly differing ref-qualifiers and except that in the case of a copy constructor or copy assignment operator, the parameter type may be "reference to non-const T", where T is the name of the member function’s class) as if it had been implicitly declared,

没有默认参数.

相关文章