Re: 64b Windows - crashes not detected

From:

phil oakleaf <news@oakleafsoftware.co.uk>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 20 Aug 2009 17:41:17 +0100

Message-ID:

<eJg8dUbIKHA.1684@TK2MSFTNGP04.phx.gbl>

David Lowndes wrote:

Phil,

Can you give us a simple self-contained console application that will
compile and illustrate the differences you're experiencing?

Dave

I am working with MFC so here is an example in that

Drop this into the main 'view' cpp file of a new MFC application (just
before 'OnDraw'

- on the 64bit machine this compiles and runs straight past the
NULL->testMe() part

- on the 32bit machine - Unhandled exception which is what I would expect

I'd be really interested to know if this happens on other machines -
becuase it definately happens on my two.

Many thanks
Phil

// couple of very simple classes

class MTest
{
public:
     float m_aVal;
     float m_bVal;
     MTest():m_aVal(0),m_bVal(0) {}

};

class RoomTest
{
public:
     MTest *m_mat;

     RoomTest():m_mat(NULL) {}

     virtual MTest *getMaterial() {return m_mat;}

     virtual void testMe()
     {
         MTest *tt=getMaterial();
         tt->m_bVal=45;
         tt->m_aVal=46;
     }
};

void CcrashTestView::OnDraw(CDC* /*pDC*/)
{
     CcrashTestDoc* pDoc = GetDocument();
     ASSERT_VALID(pDoc);
     if (!pDoc)
         return;

     // just create a real one
     RoomTest testRoom;

     // NULL pointer
     RoomTest *room=NULL;

     // call testMe on the NULL Pointer
     room->testMe();

     // TODO: add draw code for native data here
}