[Bug c++/36964] New: reintrepret_cast corrupts data / does not work as expected

[shyam_77_2000 at yahoo dot com]

Hello the following program does not work in gcc 4.1.1 compiler
//tried to analyse it and found vptr is laid out in front and so its shifting 4
bytes and data gets c

#include<iostream>
#include<stdio.h>
using namespace std;
typedef struct c
{
int a;
int b;
char bb[0];
};
class d: public c
{
public:
virtual ~d() {;}
string x;
short y;
}d1;

main()
{
c c1; // c object
c1.a=5;
c1.b=6;

d1.x="abc"; //d object
d1.y=4;

d *ptr = reinterpret_cast<d*>(&c1);

cout<<ptr->a<<endl<<ptr->b<<endl;
}
<*************************************************>
Compile
g++ test.cpp
OUTPUT:
6
-1074749676
****************************************************
wheras the expected answer is 5 and 6.
****************************************************

where is the vptr laid out in binary layout of object? and why it skips 4 bytes
always.


-- 
           Summary: reintrepret_cast  corrupts data / does not work as
                    expected
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: shyam_77_2000 at yahoo dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36964