Virtual Destructors

[NeerajVaidya]

This is a strange difference I noted between Borland 5.5 compiler and the VC++ 7.0 compiler.

The following program crashes when compiled and executed using a VC++ 7.0 compiler , but DOES NOT crash when using the Borland C++ 5.5 compiler.

ANYBODY ANY CLUES ?

#include <iostream.h>

class A
{
public:
A() { cout << "A::A()" << endl; }
~A() { cout << "~A::A()" << endl; }
};

class B : public A
{
public:
B() { cout << "B::B()" << endl; }
virtual ~B() { cout << "~B::B()" << endl; }
};

void main()
{
A* a = new B;
delete a;
}

[weaknessforcats]

Virtual destructors must be virtual in the base class.

You need a virtual destructor in A because you are deleting a pointer to A.

If you don't have this, results are indeterminate.

[weaknessforcats]

Oh, by the way:

iostream.h?

That's the pre-ANSI C++ that went obsolete in Sep 1998.

[Banfa]

void main()

Main needs to be declared as returning int otherwise you are invoking undefined behaviour, anything may happen.

[NeerajVaidya]

Oh, by the way:

iostream.h?

That's the pre-ANSI C++ that went obsolete in Sep 1998.

Sorry about that. Actually , this was copied and pasted from the Editplus window in which I used the Borland compiler.
But , why does this program not CRASH on Borland 5.5 ? That is the strange part.
If it is to be indeterminate , then shouldn't it be a behaviour seen across all C++ Compilers ?
I think there is something strange happening with the vtable layout in this case. Will examine more.