CGAL users discussion list

[Laurent Rineau <>]

On Wednesday 10 September 2008 23:40:28 Qianqian Fang wrote:
> hi
>
> I used the examples at
> Surface_mesh_simplification/edge_collapse_enriched_polyhedron.cpp to
> simplify a surface mesh. The mesh was saved as an OFF file, and feed to the
> program
> by the following lines:
>
>  Surface surface;
>  std::ifstream is(argv[1]) ; is >> surface ;

Just after that line, you can do:
  if(!is) {
    std::cerr << "OFF reading failed.\n";
  }
The test "if(!is)" is equivalent, if i remember well, to "if(is.bad())": that 
checks the state of the input stream. Wherever a operator>> fails to do its 
job, it has to set the bad bit of the stream.

If you want a verbose message about the failure, you can use:

#include <CGAL/IO/Polyhedron_iostream.h>
CGAL::scan_OFF(in, surface, true); // true means "verbose=true"


-- 
Laurent Rineau, PhD
Engineer at GeometryFactory
http://www.geometryfactory.com/