CGAL 5.5.2  2D and 3D Linear Geometry Kernel

#include <CGAL/Kernel_traits.h>
The class Kernel_traits
provides access to the kernel model to which the argument type T
belongs.
(Provided T
belongs to some kernel model.) The default implementation assumes there is a local type T::R
referring to the kernel model of T
. If this type does not exist, a specialization of Kernel_traits
can be used to provide the desired information.
This class is, for example, useful in the following context. Assume you want to write a generic function that accepts two points p
and q
as argument and constructs the line segment between p
and q
. In order to specify the return type of this function, you need to know what is the segment type corresponding to the Point type representing p
and q
. Using Kernel_traits
, this can be done as follows.
Types  
typedef T::R  Kernel 
If T is a type K::Point_2 of some kernel model K , then Kernel is equal to K .  