Playing with trees

From: Manuel Sanchez Garcia (manuel@fpddux.usc.es)
Date: Mon Jan 17 2000 - 18:43:28 MET 

Hello Rooters,

I have problems reading ROOT trees with the following sequence, in ROOT 2.23/11
and ROOT 2.23/09 both in RedHat 6.1 and Linux Debian 2.1.

1.- In $ROOTSYS/test directory. I execute ./Event, this generates a Event.root
file

2.- Add gSystem->Load("libEvent.so") to rootlogon.C so it is loaded every time
I launch ROOT

3.- In a ROOT session:
root[0] TFile f("Event.root");
root[1] T.MakeClass("test");
	This creates a test.C and test.h

4.- Modify the test::Loop() in test.C to look like:
  if (fTree == 0) return;

   Int_t nentries = Int_t(fTree->GetEntries());

   Int_t nbytes = 0, nb = 0;
   for (Int_t i=0; i<nentries;i++) {
      nb = fTree->GetEntry(i);   nbytes += nb;
      printf("%i\n",fTrack_);  // <--- This is the only addition. 
    }

5.- In another ROOT session:
root[0] .L test.C
root[1] test t;
root[2] t.Loop();

	This prints a lot of zeroes. However, the data seem to be there since I
can do t.Show(200) and I get fTracks_ == 605 (for example).

This sequence was working nicely in ROOT 2.22/10. Am I doing anything wrong
here?	


Thanks in advance,
Manuel


---------------------
Manuel Sanchez Garcia (manuel@fpddux.usc.es)
Univ. Santiago.Spain.

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