Hi Rene,
Thanks again for your help !
Actually, I have one more thing to point out about the script below.
In this script, it's just like you load 44 times the last object into
the TObjArray because each time you perform branch->GetEntry(), you
modify the pointer emap and then all objects already stored in the
TObjArray.
That's why I had written it this way :
for(Int_t i = 0 ; i < tree->GetEntries() ; i++) {
TExpositionMap *emap = new TExpositionMap();
branch->SetAddress(emap);
branch->GetEntry();
A->AddLast(emap);
}
to really have 44 different objects TExpositionMap and not 44 times the
same.
Is there a better way to do that ?
Bye,
Julien
Le 6 sept. 04, à 22:25, Rene Brun a écrit :
> Hi Julien,
>
> See your main.C file modified below. (see comments)
> Read chapter about Object Ownership in the Users guide
>
> Rene Brun
>
> {
> gSystem->Load("libTExpositionMap.so");
>
> TObjArray *A = new TObjArray(1);
>
> TFile f("expo-time.tree.root");
>
> if(f.IsZombie()) {
> return;
> } else {
>
> TTree *tree = (TTree *)f.Get("tree");
> TBranch *branch = tree->GetBranch("Exposition_Maps");
> TExpositionMap *emap =0;
> branch->SetAddress(&emap);
> TH1::AddDirectory(kFALSE); //by default histograms are addeed to
> the
> current dir
> for(Int_t i = 0 ; i < tree->GetEntries() ; i++) {
> branch->GetEntry(i);
>
> A->AddLast(emap);
>
> }
>
> TExpositionMap *emap2 = (TExpositionMap *)A->At(15);
> TH2D *map2 = emap2->GetHExpoMap();
> cout << map2->GetBinContent(10,10) << endl;
>
> f.Close(); //histogram in the current dirs are deleted
>
> TExpositionMap *emap3 = (TExpositionMap *)A->At(15);
> TH2D *map3 = emap3->GetHExpoMap();
> cout << map3->GetBinContent(10,10) << endl;
> }
> }
>
> On Mon, 6 Sep 2004,
> Julien Bolmont
> wrote:
>
>>
>> Hi Rene,
>>
>> Here is a short program reproducing my problem.
>> 1. Build the library typing :
>> make (I hope it will work this time !)
>> 2. Run the macro "main.C". It should write "18240" twice with ROOT
>> 3.10/02 and only once with ROOT 4.00/08 because in this version,
>> TFile::Close() seems to destroy all objects read in the file which
>> leads to a Seg. Fault.
>>
>> Could you explain me why the two versions have such different
>> behaviours ?
>> What is the proper way to manage ressources from a TFile ? Shall I
>> keep
>> it open from the beginning to the end of the execution ?
>>
>> Thanks again,
>> Julien
>>
>>
>
>
------------------------------------------------------
Julien Bolmont
Ingénieur diplômé - doctorant
Groupe d'Astroparticules de Montpellier
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