Hi Lee,
Thanks for reporting this missing protection.
Now fixed in CVS (thanks Philippe)
Rene Brun
On Wed, 2 Oct 2002, LEE, KERRY T. (JSC-SR) (UHCL) wrote:
> Hi,
>
> I am using ROOT from CVS on September 30, 2002, running on Red Hat 7.1.
>
> I have run into what appears to be a bug in TChain when using a graphical
> cut (TCutG). To see if it was a problem just in my code, I went back to the
> Event example provided in ROOT. I ran the Event example and produced the
> Event.root file, I then made a copy of Event.root and called it Event2.root
> so that I could make a TChain with more than one file.
>
> I then ran an interactive session of ROOT.
>
> root [0] .L libEvent.so
> root [1] TChain f("T")
> root [2] f.Add("Event.root")
> (Int_t)1
> root [3] f.Add("Event2.root")
> (Int_t)1
> root [4] f.StartViewer()
> tv__tree = (TTree *) gROOT->FindObject("T");
> tv__tree_list->Add(tv__tree);
> File name : Event2.root
>
> After I started the tree viewer I plotted fNtrack:fNseg. I then made a
> graphical cut using the editor from the Edit menu, and renamed it cut1.
>
> root [5] tv__tree->Draw("fNtrack:fNseg","","", 800, 0);
> <TCanvas::MakeDefCanvas>: created default TCanvas with name c1
>
> root [5] f.Draw("fNtrack:fNseg","cut1")
> (Int_t)424
> root [6] f.Draw("fNtrack:fNseg","cut1 && fNseg<6000")
>
> *** Break *** segmentation violation
>
> Notice that when doing f.Draw() with only the graphical cut things work
> fine, but when an additional selection requirement is added it breaks. I
> noticed that it seems to break after it has iterated through the first file
> and breaks when reading the second file.
>
> Is this a bug or am I missing something?
>
> Thanks
> Kerry
>
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