CGAL 5.2.2  2D Regularized Boolean SetOperations

#include <CGAL/Boolean_set_operations_2/Gps_default_dcel.h>
The default Dcel class template used by the General_polygon_set_2
and General_polygon_with_holes_2
class templates.
This template is parameterized by a traits class, which is a model of the GeneralPolygonSetTraits_2
concept. It uses the types Traits::Point_2
and Traits::X_monotone_curve_2
nested in the traits class to instantiate the base vertex, halfedge, and face types, respectively. Recall, that the Dcel stores the incidence relations between the arrangement calls and the geometric data attached to vertices and edges. This Dcel also stores data used to determine whether a face is interior and exterior of the general polygon set, and additional data used for optimizations.
You need to override this default and use a different Dcel only if you intend to obtain the underlying arrangement of the general polygon set and process it further.
Arr_dcel_base<V,H,F>
Gps_halfedge_base<X_monotone_curve_2>
Gps_face_base<Point_2, X_monotone_curve_2>