CGAL users discussion list

[Sylvain Pion <>]

Sterpa wrote:
> I've modified the compilation so that I can debug, as suggested on this 
> mailing
> list, so now comes this problem:
>
> void createNode(Line_2 i, Line_2 j) {
>
>                 l_i = i;
>
>                 l_j = j;
>                 Point_2 tmp (v_ij.x() - 1, v_ij.y());
>  /* ERROR */
>                 if(CGAL::compare_y_at_x(tmp, l_i, l_j) == CGAL::SMALLER) {
>
>                         Line_2 l_k = l_i;
>
>                         l_i = l_j;
>
>                         l_j = l_k;
>
>                 }
>
>         }
>
> I got the following error:
> terminate called after throwing an instance of 'CGAL::Assertion_exception'
>   what():  CGAL ERROR: assertion violation!
> Expr: !(i>s)
> File: /usr/local/include/CGAL/Interval_nt.h
> Line: 88
> Explanation:  Variable used before being initialized (or CGAL bug)

This usually means : are you sure that v_ij.x() has been properly initialized 
?
(not simply default constructed)


> Aborted
>
> This is the stack trace:
>
> #0  0xb7fa9410 in __kernel_vsyscall ()
> #1  0xb7c43085 in raise () from /lib/tls/i686/cmov/libc.so.6
> #2  0xb7c44a01 in abort () from /lib/tls/i686/cmov/libc.so.6
> #3  0xb7e53480 in __gnu_cxx::__verbose_terminate_handler ()
>    from /usr/lib/libstdc++.so.6
> #4  0xb7e50d05 in ?? () from /usr/lib/libstdc++.so.6
> #5  0xb7e50d42 in std::terminate () from /usr/lib/libstdc++.so.6
> #6  0xb7e50e6a in __cxa_throw () from /usr/lib/libstdc++.so.6
> #7  0xb7f4af33 in CGAL::assertion_fail () from /usr/local/lib/libCGAL.so.4
> #8  0x082208dc in Interval_nt (this=0xbff52778, i=-0, s=-1)
>     at /usr/local/include/CGAL/Interval_nt.h:87
> #9  0x08220e2d in CGAL::operator-<false> 
> (a=@0x82c73e0,
>  
> b=@0x82c72a0)
>     at /usr/local/include/CGAL/Interval_nt.h:602
> #10 0x082438e1 in Lazy_exact_Sub (this=0x82c73a8, 
> a=@0xbff52818,
>  
> b=@0xbff52810)
>     at /usr/local/include/CGAL/Lazy_exact_nt.h:281
> #11 0x08243ab9 in CGAL::operator-<CGAL::Gmpq, CGAL::Gmpq> (a=@0xbff52818, 
>     b=@0xbff52810) at /usr/local/include/CGAL/Lazy_exact_nt.h:624
> #12 0x08259bfd in Node::createNode (this=0xbff529bc, i=@0xbff5286c, 
>     j=@0xbff52870) at /home/marco/Desktop/cgal.project/arrangement.cpp:80


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