显式选择复制分配

在C++ 11中,如果复制和移动赋值都可用,则编译器自动选择复制赋值,如果参数是LValk,则如果赋值为rValk,则移动赋值。使用 std::move 可以明确地为左值选择移动分配。但是,如何能够明确地选择右值的复制分配呢?

代码示例:

#include <iostream>

class testClass
{
public:
    testClass &operator=(const int &other) {
        std::cout << "Copy assignment chosen." << std::endl;
        return *this;
    }

    testClass &operator=(int &&other) {
        std::cout << "Move assignment chosen." << std::endl;
        return *this;
    }   
};  

int main(int argc, char *argv[])
{
    int a = 4;
    testClass test;

    test = a; // Selects copy assignment
    test = 3; // Selects move assignment

    test = std::move(a); // Selects move assignment
//  test = std::copy(3); // <--- This does not work

    return 0;
}