1 #include <string> 2 #include <iostream> 3 #include <boost/shared_ptr.hpp> 4 #include <boost/weak_ptr.hpp> 5 6 class parent; 7 class children; 8 9 typedef boost::shared_ptr<parent> parent_ptr; 10 typedef boost::shared_ptr<children> children_ptr; 11 12 class parent 13 { 14 public: 15 ~parent() { std::cout <<"destroying parent\n"; } 16 17 public: 18 children_ptr children; 19 }; 20 21 class children 22 { 23 public: 24 ~children() { std::cout <<"destroying children\n"; } 25 26 public: 27 parent_ptr parent; 28 }; 29 30 31 void test() 32 { 33 parent_ptr father(new parent()); 34 children_ptr son(new children); 35 36 father->children = son; 37 son->parent = father; 38 } 39 40 void main() 41 { 42 std::cout<<"begin test...\n"; 43 test(); 44 std::cin.get(); 45 std::cout<<"end test.\n"; 46 }
输出 begin test...
递归析构, 不停
解决: weak_ptr 化 两个强引用为 其中之一为弱引用
weak_ptr是为配合shared_ptr而引入的一种智能指针来协助shared_ptr工作，它可以从一个shared_ptr或另一个weak_ptr对象构造，它的构造和析构不会引起引用记数的增加或减少。没有重载*和->但可以使用lock获得一个可用的shared_ptr对象
weak_ptr的一个重要用途是通过lock获得this指针的shared_ptr,使对象自己能够生产shared_ptr来管理自己，但助手类enable_shared_from_this的shared_from_this会返回this的shared_ptr，只需要让想被shared_ptr管理的类从它继承即可
#include <string> #include <iostream> #include <boost/shared_ptr.hpp> #include <boost/weak_ptr.hpp> class parent; class children; typedef boost::shared_ptr<parent> parent_ptr; typedef boost::shared_ptr<children> children_ptr; class parent { public: ~parent() { std::cout <<"destroying parent\n"; } public: children_ptr children; }; class children { public: ~children() { std::cout <<"destroying children\n"; } public: boost::weak_ptr<parent> parent; }; void test() { parent_ptr father(new parent()); children_ptr son(new children); father->children = son; son->parent = father; } void main() { std::cout<<"begin test...\n"; test(); std::cin.get(); std::cout<<"end test.\n"; }