Hi all,
I want to study a large number of root files and I can't chain them.
So I study files one by one.
FOr somme coding reason, I need to apply a class inherited from a
MakeClass() on each of the files.
What I'm trying to do is :
I open in the "update" mode, the file where I store the results of my
studies. Then I declare (if it's the first time) or I "point at"
the histograms and fill/update them.
I use this in a C++ standalone mode.
At the moment the file with the results is empty, and it seems that
the histograms aren't detected. I coded it this way :
//--- Check if histos exists
TFile * f = TFile::Open("TriggStudies.root");
f->ls();
TH1F * check = NULL;
check = (TH1F * ) f->Get("sJ_nev_mu");
cout << "check = " << check << endl;
if (check == NULL) {
//--- Histograms Creation
cout << "| [#] Create Histograms for Trigger Studies" << endl;
diJets_Nevts_mu = new TH1F("sJ_nev_mu","N evt vs Pt of Jet - L1 mu",75,0,150);
} else {
diJets_Nevts_mu = (TH1F * ) f->Get("sJ_nev_mu");
}
the problem I have is that data files after data files, the "check"
pointer is everytime empty.
Does someone has an idea on what could be the source of this problem ?
In an other way of saying that, Is it possible to fill histograms in a
root file, close it, then reopen this file, update the histograms
and re-close it again, and so on ... ?
many thanks,
take care,
frederic.
*---------------------------------------------------------*
| Frederic Villeneuve-Seguier PHD - D0 experiment |
| |
| Centre de Physique des Particules de Marseille |
| 163, avenue de Luminy 13288 |
| Marseille Cedex 09 |
| France |
*---------------------------------------------------------*
| Tel : 33 (0)4 91 82 76 13 |
| Fax : 33 (0)4 91 82 72 99 |
| e-mail: villeneuve@cppm.in2p3.fr |
| homepage: http://marwww.in2p3.fr/~villeneu |
*---------------------------------------------------------*
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