Compiling Error

[wxh158849067wxh]

Issue Details

when using CGAL::IO::write_polygon_mesh(), it will cause no suitable operator / for this expression:

 Vector_3
    operator()(const Point_3& p,const Point_3& q, const Point_3& r) const
    {
      CGAL_kernel_precondition(! K().collinear_3_object()(p,q,r) );
      Vector_3 res = CGAL::cross_product(q-p, r-p);
      res = res / CGAL::sqrt(res.squared_length());//   this where goes wrong
      return res;
        }
  };

above funtion is member function of class Construct_unit_normal_3, in E:\CGAL\CGAL-5.4.2\include\CGAL\Kernel\function_objects.h,

Source Code

#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Nef_polyhedron_3.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/draw_nef_3.h>
#include <fstream>
#include <iostream>
#include<list>
#include<string>
#include<CGAL\OFF_to_nef_3.h>
#include<CGAL\IO\Nef_polyhedron_iostream_3.h>
#include<CGAL\draw_polyhedron.h>
#include<CGAL\IO\Nef_polyhedron_iostream_3.h>
#include <CGAL/boost/graph/convert_nef_polyhedron_to_polygon_mesh.h>
#include<CGAL\Nef_nary_union_3.h>
#include <CGAL/Polygon_mesh_processing/IO/polygon_mesh_io.h>
#include <CGAL/boost/graph/IO/polygon_mesh_io.h>
typedef CGAL::Exact_predicates_exact_constructions_kernel   Kernel;
typedef Kernel::Aff_transformation_3 Aff;

typedef CGAL::Polyhedron_3<Kernel>                          Polyhedron;
typedef CGAL::Nef_polyhedron_3<Kernel>                      Nef_polyhedron;
typedef Kernel::Vector_3 Vector;
typedef Kernel::Point_3 Point;
typedef Kernel::Segment_3 Segment;
typedef Kernel::Plane_3 Plane;
typedef Point* point_iterator;
typedef std::pair<point_iterator, point_iterator> point_range;
typedef std::list<point_range> polyline;
typedef Nef_polyhedron::Volume_const_iterator Volume_const_iterator;
typedef Kernel::Aff_transformation_3 Aff_3;

int main(int argc, char *argv[])
{

	Polyhedron P1, P2;
	Nef_polyhedron N2, N3, N4, N5;
	CGAL::Polygon_mesh_processing::IO::read_polygon_mesh("C:\\Users\\CSU\\Desktop\\buliding\\7-1024-1008-1.3\\7-1024-1008-1.3.obj", P1);
	CGAL::IO::write_polygon_mesh("C:\\Users\\CSU\\Desktop\\buliding\\7-1024-1008-1.3\\7-1024-1008.off", P1);//this line will cause above compiling error, but when using CGAL5.5.1 will not cause same error 
// maybe it is version error
}

Environment

• Operating system (Windows/Mac/Linux, 32/64 bits): windows 64
• Compiler:MSVC
• Release or debug mode:debug
• Specific flags used (if any):
• CGAL version:5.4.2
• Boost version:1.78
• Other libraries versions if used (Eigen, TBB, etc.):

[MaelRL]

What type is Kernel::FT for both versions, please? You can get this using std::cout << typeid(Kernel::FT).name() << std::endl;.

[wxh158849067wxh]

What type is Kernel::FT for both versions, please? You can get this using std::cout << typeid(Kernel::FT).name() << std::endl;.

5.4.2 and 5.5.1 both are class CGAL::Lazy_exact_nt<class boost::multiprecision::number<struct boost::multiprecision::backends::gmp_rational,1> >

[sloriot]

What is you compiler version? Did you do anything special ? Did you use cmake?

[wxh158849067wxh]

cl is 19.16.27048 ,is it right?
I do not think I did something special .i just change "#include ui_ImageInterface.h" into "#include E:\CGAL\CGAL-5.4.2\examples\Nef_3\build\ui_ImageInterface.h", it seems nothing else I did. I even tried downloading souece code of 5.4.2 again, but same to failing to compile.
yes, I used cmake to build E:\CGAL\CGAL-5.4.2\examples\Nef_3

[MaelRL]

EPECK doesn't have any square root operators, and some of the output file types need normal (and thus require a normal computation). If you're not using a file type that needs this normal, you can just use CGAL::IO::write_XXX directly.