CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

On Wednesday 17 February 2010 16:29:12 Jens Seidel wrote:
> On Wed, Feb 17, 2010 at 12:14:11PM +0100, Edoardo Milotti wrote:
> > I am using the Intel compiler on Mac OS X and cgal 3.5.0 compiled with
> > g++ 4.4 and the macports makefile. Since icc does not have the
> > -frounding-math option, the linked program returns an error (the internal
> > rounding-math test fails). I found out that the internal test can be
> > disabled simply changing lines 76-77 in the Interval_nt.h header file to
> >
> > #if !defined(CGAL_DISABLE_ROUNDING_MATH_CHECK) &&
> > defined(__INTEL_COMPILER)
> >
> > In the original file the internal test is disabled only on linux systems,
> > while in this way it is always disabled for the Intel compiler. With this
> > fix my program runs, however I wonder whether this is correct, and if it
> > is, shouldn't it be included in future versions of CGAL?
> 
> I have to define CGAL_DISABLE_ROUNDING_MATH_CHECK also on a Linux box using
> -frounding-math, namely if I want to start the program via valgrind. It is
> not sufficient to define -frounding-math in all cases :-((

valgrind does not emulate the FPU correctly. :-(

For Intel, i recommend that you use the following flags:
  -D_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC=1 -fp-model strict -diag-disable 980

"-fp-model strict" is the equivalent of -frounding-math

I am surprised that the CMake scripts of CGAL have not set that -fp-model 
flag. It is correctly handled by CGAL-3.5.1, and I am pretty sure that it was 
also by CGAL-3.5.0. Do you use CMake?

-- 
Laurent Rineau, PhD
R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
Release Manager of the CGAL Project       http://www.cgal.org/