CGAL users discussion list

[Sylvain Pion <>]

Le 05/08/10 13:30, mparusinski a écrit :
> Hi everyone,
>
> I am having some trouble with CGAL circulators. I am stuck with an akward
> segmentation fault. The gdb debugger informs that * operator fails to work.
> But it doesn't happen systematically. The code usually manages to perform a
> few iterations. Any ideas on what could be wrong or any advice on how to use
> circulators? (I am using CGAL 3.6)
>
>   if (circ == 0) {
>      cerr<<  "ERROR: Unexpected error empty circulator"<<  endl;
>      exit(-1);
>    }
>    Orientation minimun = none;
>    Facet_circulator origin(circ);
>    do {
>      // operator * fails
>      // Valgrind ->  "Invalid read of size 8" Compact_container.h:808 
> operator*() const

Do you see this problem when running under valgrind ?
As mentioned recently in another mail, valgrind does not work
with (most of) CGAL.  Namely it kills some numerical computations
(because it does not support rounding modes), so the triangulation
computed can be severely buggy, and then circulators can go wrong.

Otherwise, I don't see anything wrong with your piece of code,
but you don't show much anyway.

>      if (circ == 0) {
>        cerr<<  "ERROR: Unexpected empty circulator"<<  endl;
>        exit(-1);
>      }
>      Facet adj_facet = *circ;
>      // Make sure adjacent facet is a surface facet
>      map<Facet, int>::iterator iter = f_map.find(adj_facet);
>      if (iter != f_map.end()){
>        int adj_facet_pos = iter->second;
>        Orientation dir = orientations[adj_facet_pos];
>        minimun =  dir<  minimun ? dir : minimun;
>      }
>    } while (++circ != origin);
>
> Michal Parusinski


--
Sylvain