CGAL users discussion list

[Marc Mörig <>]

Dear CGAL maintainers,

for comparison purposes I use the following combination of 
kernels/traits to compute arrangements of circles:

typedef CGAL::Exact_predicates_exact_constructions_kernel Linear_k;
typedef Linear_k::FT                                      NT;
typedef CGAL::Algebraic_kernel_for_circles_2_2<NT>        Algebraic_k;
typedef CGAL::Circular_kernel_2<Linear_k,Algebraic_k>     Circular_k;
typedef CGAL::Arr_circular_line_arc_traits_2<Circular_k>  Traits;

The compiler warns about returning temporaries by reference in several 
places, eg

/scratch/LIBS/CGAL/CGAL-4.0.2/include/CGAL/Circle_2.h:107:55: warning: 
returning reference to temporary [enabled by default]

In this and other places, there is a Qualified_result_of mechanism which 
seems to be not working, while in other places there is not. If I modify 
CGAL code to return by value in all places the compiler warns about I 
get working code. This may however result in inefficiencies for
other use cases.

Regards,
Marc Mörig

--
Marc Mörig                                 Email:  

Institut für Simulation und Graphik        Phone: +49 391 67-52858
Otto-von-Guericke Universität Magdeburg    Office:         G29-227