Re: Virtual inheritance support? EXC_BAD_ACCESS when trying...

Hi Nicholas,

this is now fixed in the trunk. Thanks for your report!

Cheers, Axel.

On 2009-10-20 02:07, Nicholas Devenish wrote:
> Dear Roottalk,
>
> I have been implementing a class structure, that uses multiple
> inheritance for interfaces - needing virtual inheritance. This all
> works perfectly in compiled code, but it turns out that if I try to
> downcast a pointer from a ROOT macro, and then try to access one of
> the virtual functions, I get a EXC_BAD_ACCESS failure. I read that
> dynamic_cast is not well supported in CINT (albeit from a 10 year old
> roottalk thread), but would like to know if it is something I am doing
> wrong or an actual CINT limitation that I can try to work around.
>
> I have attached the .h and .cxx that I compiled into a
> shared object with:
> rootcint -f matrixdict.cxx -c matrix.h LinkDef.h
> g++ -g *.cxx -shared -o matrix.so `root-config --cflags --glibs`
>
> The code I am running (on ROOT v5-24-00) is the following:
> {
> gSystem->Load("matrix.so");
>
> NuMatrix1D m1;
> NuMatrix *p1 = &m1;
> NuMatrix1D *rp = dynamic_cast<NuMatrix1D*>(p1);
>
> cout << "POT m1: " << m1.GetPOT() << endl;
> cout << "POT p1: " << p1->GetPOT() << endl;
> cout << "POT rp: " << rp->GetPOT() << endl; // ERROR HAPPENS HERE
>
> }
>
> And this gives me the following error, at line 667 of the dictionary file:
>
> Program received signal EXC_BAD_ACCESS, Could not access memory.
> Reason: KERN_INVALID_ADDRESS at address: 0xffb16639
>
> (gdb) list
> 665 static long G__2vbo_NuMatrix1D_NuMatrix_0(long pobject) {
> 666 NuMatrix1D *G__Lderived=(NuMatrix1D*)pobject;
> 667 NuMatrix *G__Lbase=G__Lderived; // <---------
> This line here
> causes the error, according to GDB
> 668 return((long)G__Lbase-(long)G__Lderived);
> 669 }
>
>
> Is this a limitation, or is there something I am doing wrong?
>
> Many thanks,
>
> Nick Devenish
>
> (I sent this yesterday, but it doesn't seem to have shown up onthe
> mailing list - apologies if it comes through twice)
Received on Fri Oct 23 2009 - 14:46:08 CEST