struct VirtualTest1
{
	~VirtualTest1(){ cout<<"VirtualTest1 Dtor\n"; }
};

struct VirtualTest2 : public VirtualTest1
{
	virtual ~VirtualTest2(){ cout<<"VirtualTest2 Dtor\n"; }
};

struct VirtualTest3 : public VirtualTest2
{
	~VirtualTest3(){ cout<<"VirtualTest3 Dtor\n"; }
};

struct VirtualTest4 : public VirtualTest3
{
	~VirtualTest4(){ cout<<"VirtualTest4 Dtor\n"; }
};

//somewhere
VirtualTest1* pDerive1 = new VirtualTest4;
delete pDerive1;

Quote:Original post by alvaro
The destructor should be virtual in the base class. That way the correct destructor can be called. Calling the destructor for base class on an instance of a derived class is probably undefined behavior, so crashing is normal.

Quote:Original post by rip-off
I couldn't reproduce the crash on either MSVC or GCC, using a minimal program wrapped around your code.

#include <iostream>struct VirtualTest1{	~Base(){std::cout << __FUNCTION__ << "\n";}};struct VirtualTest2 : public VirtualTest1{	virtual ~Derived1(){std::cout << __FUNCTION__ "\n";}};struct VirtualTest3 : public VirtualTest2{	~Derived2(){std::cout << __FUNCTION__ "\n";}};struct VirtualTest4 : public VirtualTest3{	~Derived3(){std::cout << __FUNCTION__ "\n";}};int main(){	VirtualTest1* ptr = new VirtualTest4;	delete ptr;}

Quote:Original post by Daave
VS2008 and 2003 on 2 different machines. The behavior I would expect is VirtualTest1 dtor being called, and that's it, however something is happening with the virtual method table to complicate the case.

Quote:Original post by alvaro
Trying to understand why two similar programs that invoke undefined behavior have different behavior in practice is not a very interesting thing to do. Just don't invoke undefined behavior.

In your case, it probably has something to do with the presence of the virtual table. You can try to define a different virtual method in VirtualTest2, leave the destructors as non-virtual and see if you can still get the crash.

Anyway, you invoked undefined behavior and your program crashed. Or didn't. Yawn.

Quote:Original post by Daave
Go back a step, how did you determine this invoked an undefined behavior?