std::unique_ptr<>
初始化：直接初始化、右值赋值、std::move
作为函数返回值
作为函数形参
#include <iostream>
using namespace std;
class Base{
public:
Base(int val=0) : val_(val){
cout << "Base ctor " << val_ << "\n";
}
~Base()
{
cout << "------------------------Base dctor " << val_ << "\n";
}
void GetVal()
{
cout << "val is " << val_;
cout << "\n\n";
}
private:
int val_;
};
std::unique_ptr<Base> GetBase(int n){
std::unique_ptr<Base> base;
base.reset(new Base(n));
return std::move(base);
}
int main(){
//std::unique_ptr<Base> pBase(std::move(GetBase()));
//auto pBase = GetBase();
//unique_ptr初始化：直接初始化、右值赋值、std::move
std::unique_ptr<Base> pBase1(new Base(1));
std::unique_ptr<Base> pBase2(new Base(2));
//unique_ptr是返回值
std::unique_ptr<Base> pBase3;
pBase3 = GetBase(44);
pBase1 = GetBase(55);
//pBase3 = std::unique_ptr<Base>(new Base(3)); //rvalue
std::unique_ptr<Base> pBase4;
pBase4 = std::move(pBase1); //std::move
Base* base = pBase1.get();
//unique_ptr作为形参，一般是通过std::move移交转移权
//unique_ptr release()：释放指针独占权，返回指向对象的指针，并将内部指针设为null
//unique_ptr reset()：释放指针独占权，回收对象内存，无返回值
base = pBase2.release();
delete base;
Base *base2 = pBase2.get();
//pBase2 = std::move(pBase1);
//pBase1.reset(pBase2.get());
}
