[kde-solaris] Crash in kmail (kdepim-3.1.93)

[James F. Hranicky]

On Mon, 24 Nov 2003 02:22:34 -0400
Stefan Teleman <steleman at nyc.rr.com> wrote:

> Should _never_ use C-style casts, but dynamic_cast<>(), and check for 
> returning 0.

When I try changing the line to this:

    const QListViewItem* c = dynamic_cast<QListViewItem * const>(this);

I get this compilation error:

   widgets/qlistview.cpp:3815: error: cannot dynamic_cast `this' (of type `const 
   class QListViewItem* const') to type `class QListViewItem* const' (
   conversion casts away constness)

Do you know how this should be done? My C++ is *very* rusty.

Jim

> On Sunday 23 November 2003 22:21, James F.Hranicky wrote:
> > Platform: Solaris 8
> > Compiler: gcc/g++ 3.3.2 -g (debug enabled for qt and kde)
> > IMAP Server: courier 1.6.2/freebsd
> >
> > When running kmail, I can read some of my folders without any
> > problems, but when I go to read my INBOX, and kmail is retrieving
> > the header list, I get a sefgault (shortened gdb output):
> >
> >   Program received signal SIGSEGV, Segmentation fault.
> >   0xfc9535cc in QListViewItem::listView() const (this=0x33be70)
> >       at widgets/qlistview.cpp:3815
> >   (gdb) where
> >   #0  0xfc9535cc in QListViewItem::listView() const (this=0x33be70)
> >       at widgets/qlistview.cpp:3815
> >   #1  0xff065a90 in KMHeaderItem::irefresh() (this=0x33be70) at
> > kmheaders.cpp:207 #2  0xfedf2dcc in
> > KMHeaders::msgHeaderChanged(KMFolder*, int) (this=0x33be70,
> > msgId=996088) at kmheaders.cpp:1363
> >   (gdb) p this
> >   $1 = (const QListViewItem * const) 0x33be70
> >   (gdb) p c
> >   $2 = (const QListViewItem *) 0x6c626f78
> >   (gdb) p *c
> >   Cannot access memory at address 0x6c626f78
> >   (gdb)
> >
> >   ----:**-F1  *gud-kmail*      
> > (Debugger:run)--L235--Bot-----------------------------------
> >
> >   QListView * QListViewItem::listView() const
> >   {
> >       const QListViewItem* c = this;
> >   =>  while ( c && !c->is_root )
> >           c = c->parentItem;
> >       if ( !c )
> >           return 0;
> >       return ((QListViewPrivate::Root*)c)->theListView();
> >   }
> >
> > Other times, c is a different invalid value:
> >
> >   [Switching to Thread 1 (LWP 1)]
> >   0xfbc1d34c in _poll () from /usr/lib/libc.so.1
> >   (gdb) c
> >   Continuing.
> >
> >   Program received signal SIGSEGV, Segmentation fault.
> >   0xfc9535cc in QListViewItem::listView() const (this=0x570da8)
> >     at widgets/qlistview.cpp:3815
> >   (gdb) p this
> >   $1 = (const QListViewItem * const) 0x570da8
> >   (gdb) p c
> >   $2 = (const QListViewItem *) 0x149
> >   (gdb)
> >
> > The cast seems to have problems, I guess due to a pointer bug
> > somewhere. Anyone have any suggestions?
> >
> > -------------------------------------------------------------------
> >---
> >
> > | Jim Hranicky, Senior SysAdmin                   UF/CISE
> > | Department | E314D CSE Building                            Phone
> > | (352) 392-1499 | jfh at cise.ufl.edu                     
> > | http://www.cise.ufl.edu/~jfh |
> >
> > -------------------------------------------------------------------
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> 
> -- 
> Stefan Teleman          'Nobody Expects the Spanish Inquisition'
> steleman at nyc.rr.com                          -Monty Python
> 
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