CGAL users discussion list

[Peter Hachenberger <>]

> I encountered a rediculous problem that I once did before.
> 
> with code
> 
> Polyhedron_3 P;
> std::cin >> P;
> 
> and command line
> [nef.exe] < [sample.off]
> 
> it works well. but with code
> 
>       ReadPolyhedron(path, P);
> 
> which is difined as follows:
> 
> template <class Polyhedron_3>
> bool ReadPolyhedron(std::string path, Polyhedron_3& P)
> {
>       std::ifstream is;
>       try { is.open(path.c_str()); } catch(...) { return false; }
>       try { is >> P; } catch(...) { is.close(); return false; }
> 
>       is.close();
>       return true;
> }
> 
> P is not properly read. it's really strange.

I have no clue, either. But I also have no clue about exception handling
under C++.


> I know nothing about indexed item before. But it works quite well.

That's good to know. Than there is an alternative to
Exact_construction_excat_predicate_kernel. I'm curious about the
performance.

> One more question, the program output 'Constructor not available for this 
> Kernel'
> What does it mean? Could this message be ignored?

This means that you called the constructor for creating a halfspace
while you use a standard kernel. This constructor has can not work
without an extended kernel.

Peter