Re: Cppcheck Dangerous iterator usage after erase()-method

On 16/09/2012 12:26, Noel Grandin wrote:
> On Sat, Sep 15, 2012 at 9:13 PM, Markus Mohrhard
> <markus.mohrhard@googlemail.com>  wrote:
> > Hey,
> >
> >
> > > Here are the lines:
> > >      178 void SwBlink::FrmDelete( const SwRootFrm* pRoot )
> > >      179 {
> > >      180     for( SwBlinkList::iterator it = aList.begin(); it !=
> > > aList.end(); )
> > >      181     {
> > >      182         if( pRoot == (*it).GetRootFrm() )
> > >      183             aList.erase( it );
> > >      184         else
> > >      185             ++it;
> > >      186     }
> > >      187 }
> > >
> > > I must recognize, I don't understand how can it work above all if we go  in
> > > the "if" since there's no increment.
> > >
> > > Any idea?
> > It can't. Line 183 is supposed to be:
> >
> > aList.erase(it++);
> No, it should be
>     it = aList.erase(it);
>
> Once you have called erase(), the iterator becomes invalid, so it must
> be replaced by the iterator returned by erase(), which returns the
> next valid position,
Except that SwBlinkList inherits from boost::ptr_set, I don't know how 
iterator works with this class.
Some container returns an iterator when you call erase method, some not. 
Sometimes it depends on if you use C++11
Moreover what kind of things can invalidate iterator still seem hard to 
remember (see 
http://cb.nowan.net/blog/2004/12/30/what-will-invalidate-your-iterators/).
So I let experts decide :)

Julien