Ref-qualified member functions serve the purpose of allowing a member function to be called on an rvalue reference. This enables the function to modify the object it is called on, even if the object itself is an rvalue. By using the ref-qualifier syntax, the function can be overloaded to have different behavior depending on whether it is called on an lvalue or an rvalue. This provides flexibility and efficiency in handling object references, enhancing the overall functionality and performance of the code.

Question

Ref-qualified member functions serve the purpose of allowing a member function to be called on an rvalue reference. This enables the function to modify the object it is called on, even if the object itself is an rvalue. By using the ref-qualifier syntax, the function can be overloaded to have different behavior depending on whether it is called on an lvalue or an rvalue. This provides flexibility and efficiency in handling object references, enhancing the overall functionality and performance of the code.

32

在阅读http://en.cppreference.com/w/cpp/language/member_functions时，我遇到了一些我以前没有见过的东西：lvalue/rvalue Ref-qualified member functions。它们的目的是什么？

- newprint

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- FKaria · Accepted Answer

请看下面的内容：

在重载决议时，对于类X的非静态cv限定成员函数，如果它没有ref-qualifiers或者有左值引用限定符，那么它被视为一个接受隐式参数类型为cv限定的X的左值引用的函数。否则（如果它具有右值引用限定符），它被视为一个接受隐式参数类型为cv限定的X的右值引用的函数。

示例

#include <iostream>
struct S {
    void f() & { std::cout << "lvalue\n"; }
    void f() &&{ std::cout << "rvalue\n"; }
};
 
int main(){
    S s;
    s.f();            // prints "lvalue"
    std::move(s).f(); // prints "rvalue"
    S().f();          // prints "rvalue"
}

因此，在重载决议期间，如果调用程序对象是 lvalue，则编译器会查找带有 & 限定符的函数，如果调用程序对象是 rvalue，则编译器会查找带有 && 限定符的函数。