CGAL users discussion list

[Laurent Rineau <>]

On Wednesday 19 November 2008 04:17:34 Rui Guo wrote:
> It seems that the operator>> is the std::operator>>.

> #include <CGAL/IO/Polyhedron_iostream.h>
> use CGAL::operator>>

No. std::operator>> cannot has a polyhedron as second operand. Due to Koenig 
lookup¹ (also named "argument dependent name lookup"), the compiler search a 
matching operator>> in the namespace of the second operand, which is CGAL. 
And it find the following operator:

template < class Traits,
           class Items,
           template < class T, class I, class A>
           class HDS, class Alloc>
std::istream& operator>>(std::istream& in,
                         Polyhedron_3<Traits,Items,HDS,Alloc>& P)

which is defined in <CGAL/IO/Polyhedron_iostream.h> (unless that file is not 
included).

¹) For Koenig lookup, see:
  http://en.wikipedia.org/wiki/Koenig_Lookup
-- 
Laurent Rineau, PhD
Engineer at GeometryFactory
http://www.geometryfactory.com/