Re: [Texmacs-dev] [PATCH] solves GCC 3.2 auto_save segfault for me...

[Joris van der Hoeven]

> > +//void destroy_tree_rep (tree_rep* rep);
> >   inline tree::tree (const tree& x): rep (x.rep) { rep->ref_count++; }
> > -inline tree::~tree () {
> > -  if ((--rep->ref_count)==0) destroy_tree_rep (rep); }
> > +
> > +inline tree::~tree ()
> > +{
> > +    if ((--rep->ref_count)==0) {
> > +        //destroy_tree_rep (rep);
> > +        delete rep;
> > +        rep = NULL;
> > +    }
> > +}
> 
> I am a bit confused by this. Is this necessary?
> We should recursively delete the tree,
> so it does not suffice to just delete the pointer...

I see now; that is the purpose of the virtual destructor...

But now I am again confused, because the old routine
destroy_tree_rep should precisely do the same thing
as the virtual destructor. Apparently, a string is sometimes
not a string or a compound not a compound...

By the way, what is the effect of "rep = NULL" ?
This is the only real change I can see,
but I do not see why this should stabilize the code.

Maybe some destructor is called twice,
like it has been the case with g++-3.0,
and that the effect of your changes is to
make this less disastrous. What happens if
a virtual destructor is called for the NULL pointer?
Is that just ignored?