"Пропускаю все присвоения и настройки таблиц виртуальных методов"

http://www.bugtraq.ru/cgi-bin/forum.cgi?type=sb&b=2&m=13325&id=31&cp=azPOqy9BYBYZc

http://www.bugtraq.ru/cgi-bin/forum.cgi?type=sb&b=2&m=13571&id=31&cp=azPOqy9BYBYZc

public:
    virtual void foo()
    {    printf("Function called successful.\n");}

    void Magic()
    {
        this->~Child(); 

        PrintMsg();
        foo(); // если детруктор ни хрена не изменил, этот код пройдет. так ли это, сам посмотри.

        new (this) Parrent();
    }

#include <stdio.h>
#include <new.h>

class Parent
{
public:
    Parent() { ;}
    virtual ~Parent() { ;}
public:
    virtual void PrintMsg() { printf("This function called from class Parent.\n"); }
};
 
class Child: public Parent
{
public:
    Child() { ;}
    virtual ~Child() { ;}
public:
    virtual void PrintMsg() {	printf("This function called from class Child.\n"); }
    void Magic()
    {
        // важная строка !!!! разрушаем "старую" virtual table
        this->~Child();
        // создаем "новый" РОДИТЕЛЬСКИЙ virtual table 
        new (this) Parent;
        printf("Leave Magic.\n");
    }
};

int main()
{
    Child child;
    Child* pChild = &child;
    Child& rChild = child;
 
    child.PrintMsg();
    pChild->PrintMsg();
    rChild.PrintMsg();
  
    printf("\n");
    child.Magic();
    printf("\n");

    child.PrintMsg();
    pChild->PrintMsg();
    rChild.PrintMsg();
 
    return 0;
}

В результате имеем 
This function called from class Child. 
This function called from class Child. 
This function called from class Child. 

Leave Magic. 

This function called from class Child. 
This function called from class Parent. 
This function called from class Parent. 

> #include <iostream>
> using namespace std;
> 
> class Base {
> public:
>   virtual int f() const { return 1; }
> };
> 
> class Derived : public Base {
> public:
>   int f() const { return 2; }
     void foo()
     {
          this->~Derived();
          new (this)Base;
          f(); // is here late or early binding ???
          // according your words, here must by early binding. right? look at the results
     }
> };
> 
> int main() {
>   Derived d;
>   Base* b1 = &d;
>   Base& b2 = d;
>   Base b3;
>   // Late binding for both:
>   cout << "b1->f() = " << b1->f()
> << endl;
>   cout << "b2.f() = " << b2.f() << endl;
>   // Early binding (probably):
^^^^^^^^^^^^^ good words. you can only suppose, but I gues you are not sure.
>   cout << "b3.f() = " << b3.f() << endl;
> } ///:~ 

> > #include <iostream>
> > using namespace std;
> > 
> > class Base {
> > public:
> >   virtual int f() const { return 1; }
> > };
> > 
> > class Derived : public Base {
> > public:
> >   int f() const { return 2; }
>      void foo()
>      {
> 	  this->~Derived();
> 	  new (this)Base;
> 	  f(); // is here late or early binding ???
> 	  // according your words, here must by early
> binding. right? look at the results
Read my first post again and read this:
foo()
{
	f();
//is equal to
	this->f();//address is used, which
//means  the information is incomplete. Now you see it. Late binding.
//if you don’t believe me look at this assembler code generated by VC compiler.

62:           this->f();
00401589   mov         eax,dword ptr [ebp-4]
0040158C   mov         edx,dword ptr [eax]
0040158E   mov         esi,esp
00401590   mov         ecx,dword ptr [ebp-4]
00401593   call        dword ptr [edx+4]
00401596   cmp         esi,esp
00401598   call        __chkesp (00401c50)
63:           f();
0040159D   mov         eax,dword ptr [ebp-4]
004015A0   mov         edx,dword ptr [eax]
004015A2   mov         esi,esp
004015A4   mov         ecx,dword ptr [ebp-4]
004015A7   call        dword ptr [edx+4]
004015AA   cmp         esi,esp
004015AC   call        __chkesp (00401c50)

}
>      }
> > };
> > 
> > int main() {
> >   Derived d;
> >   Base* b1 = &d;
> >   Base& b2 = d;
> >   Base b3;
> >   // Late binding for both:
> >   cout << "b1->f() = " << b1->f()
> > << endl;
> >   cout << "b2.f() = " << b2.f() <<
> endl;
> >   // Early binding (probably):
> ^^^^^^^^^^^^^ good words. you can only suppose, but I gues
> you are not sure.
Yes, I am not sure. But many compilers were constructed to do “early binding” there.
> >   cout << "b3.f() = " << b3.f() <<
> endl;
> > } ///:~ 
> 

> > > #include <iostream>
> > > using namespace std;
> > > 
> > > class Base {
> > > public:
> > >   virtual int f() const { return 1; }
> > > };
> > > 
> > > class Derived : public Base {
> > > public:
> > >   int f() const { return 2; }
> >	  void foo()
> >	  {
> >	  this->~Derived();
> >	  new (this)Base;
> >	  f(); // is here late or early binding ???
> >	  // according your words, here must by early
> > binding. right? look at the results
> Read my first post again and read this:
> foo()
> {
> 	f();
> //is equal to
> 	this->f();//address is used, which
> //means  the information is incomplete. Now you see it.
> Late binding.
> //if you don’t believe me look at this assembler code
> generated by VC compiler.
> 
> 62:	      this->f();
> 00401589   mov	       eax,dword ptr [ebp-4]
> 0040158C   mov	       edx,dword ptr [eax]
> 0040158E   mov	       esi,esp
> 00401590   mov	       ecx,dword ptr [ebp-4]
> 00401593   call        dword ptr [edx+4]
> 00401596   cmp	       esi,esp
> 00401598   call        __chkesp (00401c50)
> 63:	      f();
> 0040159D   mov	       eax,dword ptr [ebp-4]
> 004015A0   mov	       edx,dword ptr [eax]
> 004015A2   mov	       esi,esp
> 004015A4   mov	       ecx,dword ptr [ebp-4]
> 004015A7   call        dword ptr [edx+4]
> 004015AA   cmp	       esi,esp
> 004015AC   call        __chkesp (00401c50)

right !!! I meant exactly this. in this case it is always called via vtbl. here are your words :
The compiler knows the exact type and that it’s an object, so it can’t possibly be an object derived from Base — it’s exactly a Base. Thus early binding is probably used.
class A
{
    void foo()
    {
        ; // Do I know who am I ???
    }
};

---



> 
> }
> >	  }
> > > };
> > > 
> > > int main() {
> > >   Derived d;
> > >   Base* b1 = &d;
> > >   Base& b2 = d;
> > >   Base b3;
> > >   // Late binding for both:
> > >   cout << "b1->f() = " <<
> b1->f()
> > > << endl;
> > >   cout << "b2.f() = " << b2.f()
> <<
> > endl;
> > >   // Early binding (probably):
> > ^^^^^^^^^^^^^ good words. you can only suppose, but I
> gues
> > you are not sure.
> Yes, I am not sure. But many compilers were constructed to
> do “early binding” there.
> > >   cout << "b3.f() = " << b3.f()
> <<
> > endl;
> > > } ///:~ 
> > 

#inclide <windows.h>
class Ellipse
{
public:
    void foo()
    {}
};

int main()
{
    Ellipse* p = new Ellipse;
    p->foo();
    return 0;
}

> class A
> {
>     void foo()
>     {
> 	; // Do I know who am I ???
>     }
> };
B:
Kak obect znaet o member funkcii?
O:
obect hranit pointer na etu foo.
B:
Kak funkcia znaet kto ee "hoziain"?
O:
Foo imeet implicit argument kotoryi postavliaet "this" pointer.

Teper` kogda ty ( ili I ) vyzyvaesh(u) drugui non static foo etogo obecta, chto proishodit? To chto my i videli v tom primere (f(); this->f()).
. . . 

> > It is not correct. It is just an optimization, because
> > nobody tries to “TPAX” an object such way as you do.
> look, it is ever possible to avoid bug. We do not discuss
> about sexual orientations. The code which I wrote is
> correct.

No doubt. 

> in VC++ try this
> 
> #inclide <windows.h>
> class Ellipse
> {
> public:
>     void foo()
>     {}
> };
> 
> int main()
> {
>     Ellipse* p = new Ellipse;
>     p->foo();
>     return 0;
> }
> 

---

> is anything incorrect? But try to compile this. Is it bug?
> but of course we can avoid this, just declare Ellipse as
> XEllipse. So, should we pay attention on it or keep
> silence?


Yep, compiler must give us a warning about redefinition.



> 
> > > 
> > > > 
> > > > P.S. tema zakryta.
> > > З.Ы. давно пора.
> > Chto takoe "З.Ы." ?   :-}
> З.Ы. => very terrible words
> 
> Армянскому радио спрашивают - можно ли трахаться на Красной
> площади.
> ответ - можно, но не советуем. Будут слишком много
> советчиков.
> 
> мораль - то что происходит в коде даже моя бабушка со
> зрением -10 увидеть сможет. вопрос стоит является это багом
> или так и должно быть. совет - не ленись, почитай все


Po moemu BUG eto ne namerennoe upuchenie v programme resultat kotorogo nepravilnaia rabota etoi programmy. To chot bylo zalozheno v kompiler ne Iavlialos` bugom, eto bylo sdelano s celu optimizacii koda. S teoreticheskoi tochki zrenia eto ne pravilno, no my zivem v realnom mire i ochen chasto delaem uprocheniia (okruglenie, zamenu, i.t.d ).Chto i bylo sdelanno.



> мессаги. понимаю что связь плохая. попроси у XR-a может он
> разрешит попользоваться его прокси.


Ne zhelannyi I gost`. (dazhe dl ne mozhet(ne  hochet, net vremeni . . .) login otremontirovat`)



> 
> могу себе позволить подумать, что у тебя хреновый опыт
> работы с узерами. т.к. узер очень хитрыми комбинациями


Dumai chto hochesh.



> действий крашнет твою прогу. да еще так, что ты никогда не
> догодаешься как такое возможно. так что же из этого?


Chto I tupee usera chto li? A Krashanut` mozhno tolko tu progu v kotoroi eto zalozheno. Estestvenno chem slozhnee proga, tem bolshe veroiatnost` etogo. I ni kto ot etogo ne zastrahovan. Dlia etogo QA dengi poluchaet, chto by vse eto vylovit`. I kstati lublu kogda izmyvautsia nad moei programmoi, sam lubli nad nei ismyvatsia (chto mazohistkoe v etom est`, uff). 



> показать узеру красную карточку и удалить из поля словами -
> нехер было изнываться над программой.
> 
> regards
take care . . . 

> > #inclide <windows.h>
> > class Ellipse
> > {
> > public:
> >	 void foo()
> >	 {}
> > };
> > 
> > int main()
> > {
> >	 Ellipse* p = new Ellipse;
> >	 p->foo();
> >	 return 0;
> > }
> > 

> > #inclide <windows.h>
> > class Ellipse
> > {
> > public:
> >	 void foo()
> >	 {}
> > };
> > 
> > int main()
> > {
> >	 Ellipse* p = new Ellipse;
> >	 p->foo();
> >	 return 0;
> > }
> > 

bool  Ellipse(int, int, int, int, int);
class Ellipse {};

void main()
{
  Ellipse *p;
}