CGAL users discussion list

[Sebastien Loriot <>]

Dear Marc,

the doc of the master branch is available here:
https://cgal.geometryfactory.com/CGAL/doc/master/Manual/index.html

std::variant can be accessed using std::get_if and it return nullptr if 
empty. Note that the return type of intersection is 
std::optional<std::variant<...>>. To check if there is an intersection,
you should check if the optional is equal to std::nullopt.

Best,

Sebastien.

On 1/25/24 13:55, Marc Alexa ( via cgal-discuss 
Mailing List) wrote:
> Thanks Andreas,
>
> yes, I was looking at the ‘latest’ part of the website, which still shows the 
> code using boost::get. I did figure out that std::get_if was an alternative 
> that compiled. Interestingly, get_if returns something other than nullptr if 
> there is no intersection. Not sure if this is expected behavior.
>
> Best,
> Marc
>
>
>
> > On Jan 24, 2024, at 18:01, Andreas Fabri <> 
> > wrote:
> >
> > Hi Marc,
> >
> > It compiles in the testsuites of master, tested last Sunday:
> >
> > https://cgal.geometryfactory.com/CGAL/testsuite/results-6.0-I-155.shtml#Kernel_23
> >
> > This is probably because the example has changed (my guess is that we had the 
> > problem you encountered).
> >
> > https://github.com/CGAL/cgal/blob/master/Kernel_23/examples/Kernel_23/intersection_get.cpp
> >
> > Best,
> >
> > Andreas
> >
> > On 1/20/2024 10:03 PM, Marc Alexa ( via cgal-discuss 
> > Mailing List) wrote:
> > > Dear all,
> > >
> > > I have trouble compiling the the above example. g++ is unhappy with the type 
> > > passed to boost::get, specifying either C++17 or C++20 as standard. My Boost 
> > > Version 1.83, and g++  links to Apple Clang 15. Can anybody suggest what the 
> > > problem is?
> > >
> > > Thanks!
> > > -Marc
> > --
> > Andreas Fabri, PhD
> > Chief Officer, GeometryFactory
> > Editor, The CGAL Project
> >
> >
> > --
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