问题描述
最近我在阅读，并遇到了以下几行：
Recently I was reading through the API of boost::optional and came across the lines:
T const& operator *() const& ;
T& operator *() & ;
T&& operator *() && ;
我也写了我自己的程序定义成员函数const&和&& （注意，我不是说的返回类型，而是分号之前的分号），他们似乎工作正常。
I also wrote my own program that defines member functions as const&, & and && (Note that I am not speaking about the return type, but the specifiers just before the semi-colons) and they seems to work fine.
我知道声明一个成员函数const的意思，但是任何人都可以解释它声明它的意义const&和&&< / p>
I know what it means to declare a member function const, but can anyone explain what it means to declare it const&, & and &&.
推荐答案
const& 重载将仅用于const，非const和rvalue对象。
const& means, that this overload will be used only for const, non-const and rvalue object.
const A a = A();
*a;
& 只能用于非const对象。
& means, that this overload will be used only for non-const object.
A a;
*a;
&&& 重载将仅用于右值对象。
&& means, that this overload will be used only for rvalue object.
*A();
有关C ++ 11标准的此功能的更多信息，您可以阅读此帖
for more information about this feature of C++11 standard you can read this post What is "rvalue reference for *this"?
这篇关于常数& ，&和&& C ++中成员函数的说明符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！