Effective C++ .14 智能指针的拷贝与deleter函数

#include <iostream>

#include <cstdlib>

#include <memory>

using namespace std;



class Kiwi {

private:

    int weight;

public:

    Kiwi(int w) : weight(w) {}

    ~Kiwi() {

        cout<<"~Kiwi"<<endl;

    }

    int getWeight() {return weight;}

};



void deleter(Kiwi* x) {

    cout<<"deleting"<<endl;

    // if remove below line object will not be delete by smart pointer

    delete x;

}



void driven() {

    shared_ptr<Kiwi> p(new Kiwi(100), deleter);

    cout<<p->getWeight()<<endl;

    cout<<p.use_count()<<endl;



    shared_ptr<Kiwi> q = p;

    cout<<p->getWeight()<<endl;

    cout<<q->getWeight()<<endl;

    cout<<p.use_count()<<endl;

    cout<<q.use_count()<<endl;

}



int main() {

    cout<<"test start"<<endl;

    driven();

    cout<<"test end"<<endl;

    return 0;

}

智能可以定义deleter函数，即在其认为资源应该释放时调用该函数来代替默认的delete操作