C++11--move/forward

Std::move

Std::move () is provided in c++11 to convert the Lvalue to the right value, making it easy to use move semantics. Move is to transfer the state or ownership of an object from one object to another, only to transfer, without a memory copy.
All containers in C + + implement the move semantics, allowing us to optimize performance. Move simply shifts the control of the resource, essentially casting the lvalue to an rvalue reference to use the move semantics to avoid a meaningless copy of the object containing the resource. Move is valid for objects that have the shape of a member of a resource such as memory, file handle, and so on. If there are some basic types, such as an int or char[10] array, if you use Move, the copy will still occur (because there is no corresponding move constructor), so move is more meaningful for objects with resources.

    Std::list<std::string> tokens;    std::list<std::string> t = std::move (tokens); A move construct has occurred. When the list is implemented, it assigns the resource handle of the destination object to the resource handle of the source object, and the resource handle of the source object is emptied.

Std::forward

An rvalue reference type is independent of the value, an rvalue reference parameter acts as a formal parameter of the function, and when the parameter is forwarded inside the function it becomes an lvalue, not his original type.

If we need a way to forward to another function according to the original type of the parameter, this type of forwarding is called perfect forwarding .

Template<typename t>void Print (t& T) {    cout << "Lvalue" << Endl;} Template<typename t>void Print (t&& T) {    cout << "rvalue" << Endl;} Template<typename t>void Testforward (T && v) {    print (v);    Print (std::forward<t> (v));    Print (Std::move (v));} int main () {    testforward (1);    int x = 1;    Testforward (x);    Testforward (std::forward<int> (x));    return 0;}

C++11--move/forward