标签:itblog test 技术 code alt 内存 efi [] entry
Smart pointer
line 58之后smart pointer里的计数已经是0,所以会真正释放它引用的对象,调用被引用对象的析构函数。如果继续用指针访问,会出现如下图的内存访问异常。所以说如果选择了用智能指针,就不要再试图用其他方式再去访问对象了。
1 // sharedTest.cpp : Defines the entry point for the console application. 2 // 3 4 #include "stdafx.h" 5 #include <boost/make_shared.hpp> 6 #include <vector> 7 //using namespace std; 8 using namespace boost; 9 10 #define SMART_PTR shared_ptr 11 12 class Based 13 { 14 protected: 15 int a; 16 char* pa; 17 18 public: 19 Based():a(0) 20 { 21 pa = new char[10]; 22 } 23 24 void Func(){ std::cout<<"Func "<<a<<std::endl; } 25 virtual ~Based() 26 { 27 delete[] pa; 28 std::cout<<"deconstrctor"<<std::endl; 29 } 30 }; 31 32 33 34 class Foo : public Based 35 { 36 private: 37 int b; 38 39 public: 40 void Test() 41 { 42 this->b = 100; 43 this->pa[0] = ‘b‘; 44 std::cout<<"Test(), b = "<<this->b<<"this->pa[0] = "<<this->pa[0]<<std::endl; 45 } 46 47 ~Foo(){ std::cout<<"~Foo()"<<std::endl;} 48 }; 49 50 int main (int argc, const char * argv[]) 51 { 52 Foo * pfoo = new Foo; 53 54 std::cout<<"{"<<std::endl; 55 { 56 SMART_PTR<Foo> smart_foo(pfoo); 57 smart_foo->Test(); 58 } 59 std::cout<<"}"<<std::endl; 60 61 pfoo->Test(); 62 63 return 1; 64 }
标签:itblog test 技术 code alt 内存 efi [] entry
原文地址:http://www.cnblogs.com/dirichlet/p/3227692.html