CGAL users discussion list

[Winnie <>]

> I want to know if a particular vertex was inserted inside
> a constrained inserted before.
Ok, then what about combining ct.locate( Point query, Locate_type& lt, 
int& li) with ct.is_constrained( Edge e) ?

https://www.cgal.org/Manual/latest/doc_html/cgal_manual/Triangulation_2_ref/Class_Triangulation_2.html#Function_Face_handle_locate6const_Point__query+_Locate_type__lt+_int__li+_Face_handle_h_=Face_handle69_9_const;

https://www.cgal.org/Manual/latest/doc_html/cgal_manual/Triangulation_2_ref/Class_Constrained_triangulation_2.html#Function_bool_is_constrained6Edge_e9;

You can check if Locate_type == EDGE and if not, the point is not on a 
constraint. Using the Face_handle and li returned by locate you can 
check if an edge is a constraint.