CGAL users discussion list

[Panagiotis Foteinos <>]

Taking the low level details out, the following code is compiled
successfully, but throws a segmentation fault (see the dashed arrow below):

*********************************************************************************************************************************************************************
typedef CGAL::Triangulation_hierarchy_3<Dt>  Dh;
typedef Dh::Finite_cells_iterator Finite_cells_iterator;
std::list<Cell_handle*> red_elements;

main()
{
    Dh T;
    //Insert some vertices into T.

    for(Finite_cells_iterator c = T.finite_cells_begin(); i !=
T.finite_cells_end(); i++)
       if(c->info().color == red)
       {
          Cell_handle* cell_handle_pointer = new Cell_handle();
          *cell_handle_pointer = c;
          red_elements.push_back(cell_handle_pointer);
       }

    //Do stuff with T by removing, inserting, changing the color of some
elements...
    //red_elements list is not touched, however.

    for(std::list<Cell_handle*>::iterator i = red_elements.begin(); i !=
red_elements.end(); i++)
    {
       Cell_handle c = **i;
       if(T.is_cell(c) == false || c->info().color != red)
         
red_elements.erase(i);                                                
---------------------------------> segmentation fault the first time
this line is executed.
    }
   
}
*********************************************************************************************************************************************************************

Let me know if the problem is still unclear.

Thanks,
Panagiotis


Sylvain Pion wrote:
> Panagiotis Foteinos a écrit :
>> Hello all.
>>
>> I have a list of Cell_handle pointers: std::list<Cell_handle*> my_list.
>> This list (i.e., my_list) contains pointers of specific Cell_handles.
>> For example, it may contain pointers that point to Cell_handles of color
>> red.
>>
>> After processing  the ith  element of my_list, I erase this element by
>> doing my_list.erase(i). Of course, the destructor of the ith pointer is
>> called, which is no-op, while the destructor of the pointed Cell_handle
>> is not.
>>
>> Unfortunately, I am not able to erase elements without a segmentation
>> fault and I do not understand why: the elements of my_list are pointers
>> to objects and not objects (Cell_handle is not exactly a pointer...).
>>
>>
>> How could I resolve this problem?
>
> I fear that there is not enough information in your mail to determine
> the cause of your problem.
>