1 #ifndef TEST_CLASS_H
 2 #define TEST_CLASS_H
 3 
 4 #include <iostream>
 5 using std::cout;
 6 using std::endl;
 7 
 8 class TestClass
 9 {
10 public:
11     TestClass()
12     {
13         cout << "TestClass constructor call" << endl;
14         data = new int(3);
15     }
16     TestClass(const TestClass& test_class)
17     {
18         cout << "TestClass copy constructor call. copy data:"
19             << *(test_class.data) << endl;
20         data = new int;
21         *data = *(test_class.data) * 2;
22     }
23     ~TestClass()
24     {
25         cout << "TestClass destructor call. delete the data:" << *data << endl;
26         delete data;
27     }
28 private:
29     int *data;
30 };
31 
32 #endif

 1 // my_type_traits.h开始
 2 #ifndef MY_TYPE_TRAITS_H
 3 #define MY_TYPE_TRAITS_H
 4 
 5 //#include "test_class.h"
 6 
 7 struct my_true_type {
 8 };
 9 
10 struct my_false_type {
11 };
12 
13 template <class T>
14 struct my_type_traits
15 {
16     typedef my_false_type has_trivial_destructor;
17 };
18 
19 template<> struct my_type_traits<int>
20 {
21     typedef my_true_type has_trivial_destructor;
22 };
23 
24 //template<> struct my_type_traits<TestClass>
25 //{
26 //    typedef my_true_type has_trivial_destructor;
27 //}; //若删除对TestClass的注释，则TestClass将会被定义成没有特性的析构的类
28 
29 #endif
30 // my_type_traits.h结束

 1 // my_destruct.h开始
 2 #ifndef MY_DESTRUCT_H
 3 #define MY_DESTRUCT_H
 4 #include <iostream>
 5 
 6 #include "my_type_traits.h"
 7 
 8 using std::cout;
 9 using std::endl;
10 
11 template <class T1, class T2>
12 inline void myconstruct(T1 *p, const T2& value)
13 {
14     new (p) T1(value);
15 }
16 
17 template <class T>
18 inline void mydestroy(T *p)
19 {
20     typedef typename my_type_traits<T>::has_trivial_destructor trivial_destructor; //此处获得类型T是否没有特性析构
21     _mydestroy(p, trivial_destructor()); 
22 }
23 
24 template <class T>
25 inline void _mydestroy(T *p, my_true_type)
26 {
27     cout << " do the trivial destructor " << endl;
28 }
29 
30 template <class T>
31 inline void _mydestroy(T *p, my_false_type)
32 {
33     cout << " do the real destructor " << endl;
34     p->~T();
35 }
36 
37 #endif
38 // my_destruct.h结束

 1 #include "test_class.h"
 2 #include "my_destruct.h"
 3 
 4 int main(void)
 5 {
 6     {
 7         TestClass *test_class_buf;
 8         TestClass test_class;
 9 
10         test_class_buf = (TestClass *)malloc(sizeof(TestClass));
11         myconstruct(test_class_buf, test_class);
12         mydestroy(test_class_buf);
13         free(test_class_buf);
14     }
15 
16     {
17         int *int_p;
18         int_p = new int;
19         mydestroy(int_p);
20         free(int_p);
21     }
22 }