CGAL users discussion list

[Sylvain Pion <>]

Shamyl Zakariya wrote:
> I just installed CGAL 3.4 ( was using 3.1 ) and on running my app,
> CGAL terminates with the following error during static initialization:
>
> terminate called after throwing an instance of 'CGAL::Assertion_exception'
>   what():  CGAL ERROR: assertion violation!
> Expr: -CGAL_IA_MUL(-1.1, 10.1) != CGAL_IA_MUL(1.1, 10.1)
> File: /usr/local/include/CGAL/Interval_nt.h
> Line: 154
> Explanation: Wrong rounding: did you forget the -frounding-math option
> if you use GCC?
>
> This is on Mac OS X, 10.5.7
>
> So, assuming I made some sort of mistake during the configuration of
> CGAL, I redownloaded the tarball and reconfigured it as such:
>
> # cmake . -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=FALSE
>
> And I'm seeing the following during configuration, which implies to me
> that the build system is automatically adding -frounding-math...
>
> -- Targetting Unix Makefiles
> -- Using /opt/local/bin/c++ compiler.
> -- DARWIN_VERSION=9
> -- Mac Leopard detected
> -- USING CMake version: 2.6.4
> -- System: Darwin
> -- USING GCC_VERSION = '4.0.1 (Apple Inc. build 5490)'
> -- Using gcc version 4 or later. Adding -frounding-math
> -- Build type: Release
> -- USING CXXFLAGS = ' -frounding-math -O3 -DNDEBUG'
>
> However, ever after this rebuild/reinstall my apps still die on the assertion.
>
> (Please note, I'm not using any of the optional numeric packages, and
> I'm using boost 1.36, and cmake 2.6)

I'm not sure what you mean exactly by "optional numeric packages",
but this check is useful as soon as you use CGAL::Interval_nt, which
is used in the filtered kernels (e.g. when you use Delaunay).

This check can be disabled with -DCGAL_DISABLE_ROUNDING_MATH_CHECK
(though of course you should never have to do that).

However, note that -DNDEBUG (which you have), also should disable this check.
Which means that the flags you see are not passed to the compilation
process correctly.  Note that -frounding-math is also needed when
compiling/installing CGAL itself.

I'm not proficient enough in CMake to tell what can go wrong there,
maybe someone else can help.


Side note : Apple's g++ 4.0.1 is strongly discouraged for CGAL as soon
as you want to compile with optimization (you can e.g. upgrade Xcode
to get g++ 4.2).

--
Sylvain Pion
INRIA Sophia-Antipolis
Geometrica Project-Team
CGAL, http://cgal.org/