the first call tofpasses a local variable (an lvalue) as its argument. The second call tofpasses a temporary object as its argument. Because the temporary object can't be referenced elsewhere in the program, the call binds to the overloaded version offthat takes an rvalue reference, which ...
且morden c++又为reference增加了一条规则:rvalue reference只能绑定到rvalue上,甚至rvalue reference to const也只能绑定到rvalue上: intgem=7030;int&&r=gem;//error: cannot bind rvalue reference of type ‘int&&’ to lvalue of type ‘int’constint&&rr=gem;//error: cannot bind rvalue reference of...
the first call tofpasses a local variable (an lvalue) as its argument. The second call tofpasses a temporary object as its argument. Because the temporary object can't be referenced elsewhere in the program, the call binds to the overloaded version offthat takes an rvalue reference, which ...
the name of a variable or a function in scope, regardless of type, such as std::cin or std::endl. Even if the variable's type is rvalue reference, the expression consisting of its name is an lvalue expression; (变量,函数都是左值) a function call or an overloaded operator expression o...
为此C++11 引入 rvalue reference 这样一个语法,但是它表达仅仅匹配 rvalue 的 reference。我们知道原有的语法中通过 int& 可以匹配 lvalue,但是无法匹配 rvalue,如果使用 const int& 可以匹配 rvalue,却只能将 rvalue 作为输入但却无法修改其内容,在 C++11 里面可以写 int&& 匹配 rvalue 的引用,这样与 const...
// The named rvalue reference str acts like an lvalue std::swap(_capacity, str._capacity); std::swap(_length, str._length); // char* _str points to a character array and is a // member variable of the string class std::swap(_str, str._str); ...
A rvalue reference is a guarantee from the compiler that the object referenced by the variable was a temporary object. This means that you are free to cannibalize the object so that you can implement a copy operation faster than if the ...
2) What is the expected value of the global variableglobalIntafter foo returns (undefined may be an acceptable answer)? 667. The reference returned bystatic_cast<int&&>(*__i)binds directly to*__i- i.e.,globalInt. No temporary should be created. The applicable rule, in [expr.static.ca...
On Artima article about C++ rvalue reference (http://www.artima.com/cppsource/rvalue.html) there is words: That's why it is necessary to say move(x) instead of just x when passing down to the base class. This is a key safety feature of move semantics designed to prevent accidently ...
如果是右值的话，你正好又是用值捕获，那rethrow出去的就是个无效对象=_=