CGAL::parallel

bool parallel ( Line_2<Kernel> l1, Line_2<Kernel> l2)
returns true, if l1 and l2 are parallel or if one of those (or both) is degenerate.

bool parallel ( Ray_2<Kernel> r1, Ray_2<Kernel> r2)
returns true, if r1 and r2 are parallel or if one of those (or both) is degenerate.

bool parallel ( Segment_2<Kernel> s1, Segment_2<Kernel> s2)
returns true, if s1 and s2 are parallel or if one of those (or both) is degenerate.

bool parallel ( Line_3<Kernel> l1, Line_3<Kernel> l2)
returns true, if l1 and l2 are parallel or if one of those (or both) is degenerate.

bool parallel ( Plane_3<Kernel> h1, Plane_3<Kernel> h2)
returns true, if h1 and h2 are parallel or if one of those (or both) is degenerate.

bool parallel ( Ray_3<Kernel> r1, Ray_3<Kernel> r2)
returns true, if r1 and r2 are parallel or if one of those (or both) is degenerate.

bool parallel ( Segment_3<Kernel> s1, Segment_3<Kernel> s2)
returns true, if s1 and s2 are parallel or if one of those (or both) is degenerate.