CGAL users discussion list

[Marc Glisse <>]

On Thu, 3 May 2012, Philipp Moeller wrote:

> I can confirm the same on a recent gcc. Looks like a bug in
> Lazy_exact_nt to me. Point_d::operator[] returns by value as documented
> but assignment does work for some unknown reason.

Why wouldn't it?

struct A {};
A f(){return A();}
void g(){ f()=A(); }

operator= is a member function like any other.

The operation is forbidden for builtin types, or if f returns const A 
(used to be a popular technique), or in C++11 if operator= has a '&' at 
the end of its declaration.

> If operator[] should really return by value is another issue. It is
> certainly necessary for a Homogeneous kernel, but not a Cartesian. Seems
> wasteful in case of a ref counted NT representation.

An important point of ref-counting in CGAL is not to care about this. It 
is for non-ref counted types that it is wasteful.

--
Marc Glisse