// std::unique_ptr<Foo> pf1 = pf; // compile error// 按值传参,会有拷贝问题,同上// auto p = change_a(pf); //compile errorautop=change_a(std::move(pf));std::cout<<"get_a = "<get_a()<<std::endl;if(!pf){std::cout<<"pf is nullptr"<<std::endl;}//owner transfer fr...