保证参数原来的属性(用在template的参数是引用的时候):左值引用在被转发之后仍然保持左值属性,右值引用在被转发之后依然保持右值属性
void show(std::string& str) {
std::cout<<"lvalue:"<<str<<std::endl;
}
void show(std::string&& str) {
std::cout<<"rvalue:"<<str<<std::endl;
}
template<typename T>
void ShowWrapper(T&& t) {
show(std::forward<T>(t));
}
void TestForward() {
std::string str("left");
ShowWrapper(str);//lvalue:left
ShowWrapper("right"); //rvalue:right
}
将左值转化为右值
void TestMove() {
std::string str("move");
ShowWrapper(str);//rvalue:move
}
原文:https://www.cnblogs.com/smallredness/p/11085369.html