Shared_ptr 相互引用问题

class parent
{
public:
~parent() { std::cout <<"destroying parent\n"; }

public:
children_ptr children;
};

class children
{
public:
~children() { std::cout <<"destroying children\n"; }

public:
parent_ptr parent;
};

void test()
{
parent_ptr father(new parent());
children_ptr son(new children);

father->children = son;
son->parent = father;
}

在函数 test() 中，father->children = son, 使得 father 的计数器加至 2， son 同理，以至于析构 father(或son)时，仅仅是计数器减一，指针指向的资源并没有被析构。

参考

[1] http://blog.csdn.net/liuzhi1218/article/details/6993135