Mailing-List: contact cygwin-help AT sourceware DOT cygnus DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe AT sources DOT redhat DOT com>
List-Archive: <http://sources.redhat.com/ml/cygwin/>
List-Post: <mailto:cygwin AT sources DOT redhat DOT com>
List-Help: <mailto:cygwin-help AT sources DOT redhat DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender: cygwin-owner AT sources DOT redhat DOT com
Delivered-To: mailing list cygwin AT sources DOT redhat DOT com
Message-ID: <001f01c178c0$5b315c20$4a5f37c1@isima.fr>
Reply-To: "Bruno Bachelet" <bachelet AT ifrance DOT com>
From: "Bruno Bachelet" <bachelet AT ifrance DOT com>
To: <cygwin AT cygwin DOT com>
Subject: Problem with virtual inheritance and destruction of arrays
Date: Thu, 29 Nov 2001 11:26:49 +0100
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2600.0000
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000

I apologize in advance if the bug has already been reported. Normally when
calling the destructor of an object, the destructors of all the classes in
the hierarchy of inheritance are executed. Imagine you have a virtual
inheritance at some place in the hierarchy, the destruction works well with
a single object, but it doesn't work with an array of objects.

Here is an example I compiled with Cygwin 1.3.2 and Cygwin 1.3.5 using no
particular optimization flag.

#include <iostream.h>

class A {
 protected: int i;
 public: A(int x=5) : i(x) {}
 public: virtual ~A(void) { cout << "A: i=" << i << endl; }
};

class B : public A {
 protected: int j;
 public: B(int x=5) : A(10),j(x) {}
 public: virtual ~B(void) { cout << "B: j=" << j << endl; }
};

class C : public virtual A {
 protected: int k;
 public: C(int x=5) : A(20),k(x) {}
 public: virtual ~C(void) { cout << "C: k=" << k << endl; }
};

int main(void) {
 A * a = new A;
 B * b = new B;
 C * c = new C;

 A * ta = new A[3];
 B * tb = new B[3];
 C * tc = new C[3];

 cout << "destruction object class A" << endl;
 delete a;
 cout << "destruction array class A" << endl;
 delete [] ta;

 cout << "destruction object class B : public A" << endl;
 delete b;
 cout << "destruction array class B : public A" << endl;
 delete [] tb;

 cout << "destruction object class C : public virtual A" << endl;
 delete c;
 cout << "destruction array class C : public virtual A" << endl;
 delete [] tc;

 return (0);
}

Here is the result that illustrates the point. Destruction of the array of
objects of class C didn't execute correctly.

destruction object class A
A: i=5
destruction array class A
A: i=5
A: i=5
A: i=5
destruction object class B : public A
B: j=5
A: i=10
destruction array class B : public A
B: j=5
A: i=10
B: j=5
A: i=10
B: j=5
A: i=10
destruction object class C : public virtual A
C: k=5
A: i=20
destruction array class C : public virtual A
C: k=5
C: k=5
C: k=5

Good luck and "bravo" for the excellent work.


<><><><><><><><><><><><><><><><><><><><>
 Bruno Bachelet (PhD Student)

 LIMOS Laboratory
 ISIMA (Door B112)
 Complexe des Cezeaux
 BP 10125 - 63173 Aubiere Cedex
 France

 Phone: (33).4.73.40.50.44
 Fax: (33).4.73.40.50.01
 Cellular: (33).6.71.94.81.31

 E-mail: bachelet AT ifrance DOT com
 Web: http://bruno.bachelet.net
<><><><><><><><><><><><><><><><><><><><>



--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/