C++单继承、多继承情况下的虚函数表分析
- 2019 年 10 月 3 日
- 笔记
C++??????????????????????????????????????????????VTAB???????????????????VTAB??????VPTR??????????????????????????????????VPTR??VTAB???????????????????
?????1.http://blog.lucode.net/programming-language/cpp-vtab-and-call-convention.html
??2.https://blog.csdn.net/tangaowen/article/details/5830803
??3.?????C++?????
?????
1 #include<iostream> 2 #include <stdio.h> 3 using namespace std; 4 class A { 5 public: 6 void func() { 7 cout << "A::func()" << endl; 8 } 9 virtual void func1() { 10 cout << "A::func1(): " << endl; 11 } 12 13 virtual void func3() { 14 cout << "A::func3(): " << endl; 15 } 16 }; 17 18 class B: public A { 19 public: 20 virtual void func() { 21 cout << "B::func()" << endl; 22 } 23 virtual void vfunc() { 24 cout << "B::vfunc()" << endl; 25 } 26 void func1() { 27 cout << "B::func1(): " << endl; 28 } 29 }; 30 int main() { 31 typedef void (*Fun)(void); 32 B a; 33 34 Fun *fun = NULL; 35 fun = (Fun*) ((int *) *(int *) &a); 36 // fun = *(Fun **) &a; 37 fun[0](); 38 fun[1](); 39 fun[2](); 40 fun[3](); 41 42 return 0; 43 }
?????
B::func1():
A::func3():
B::func()
B::vfunc()
??????
1 #include<iostream> 2 #include <stdio.h> 3 using namespace std; 4 class B1 { 5 public: 6 virtual void barB1() {cout << "B1::bar" << endl;} 7 virtual void fooB1() {cout << "B1::foo" << endl;} 8 }; 9 10 class B2 { 11 public: 12 virtual void barB2() {cout << "B2::bar" << endl;} 13 virtual void fooB2() {cout << "B2::foo" << endl;} 14 }; 15 16 class D : public B1, B2 { 17 public: 18 void fooB1() {cout << "D::foo" << endl;} 19 void barB2() {cout << "D::bar" << endl;} 20 }; 21 22 typedef void (*Func)(); 23 int main() { 24 D tt; 25 Func* vptr1 = *(Func**)&tt; 26 Func* vptr2 = *((Func**)&tt + 1); 27 28 vptr1[0](); 29 vptr1[1](); 30 vptr1[2](); 31 cout<<"\\\"<<endl; 32 vptr2[0](); 33 vptr2[1](); 34 35 return 0; 36 }
?????
B1::bar
D::foo
D::bar
\
D::bar
B2::foo
???
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?? ?C++???????????????????virtual???????????????virtual????????????????????????????????????????????
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