Copying histogram from TFile

ROOT
1

I want to open TFile, read histogram from it and than close TFile, having histogram still in the memory (than I’ll open another TFile etc.). I thought that Clone() should do the job, but my code is crashing:

{
	TFile *f = new TFile("par_histo/par20_rad.root");
	TH2D *tmp_histo = (TH2D*)(f->Get("par_histo"));
	TH2D *par_histo = (TH2D*)tmp_histo->Clone("aaa");
	delete f;
	par_histo->Draw("colz");
}

What am I doing wrong?

2

simply do

{ TFile *f = new TFile("par_histo/par20_rad.root"); TH2D *tmp_histo = (TH2D*)(f->Get("par_histo")); tmp_histo->SetDirectory(0); delete f; tmp_histo->Draw("colz"); }

Rene

3

Thanks, I seem to forget about this directory connection…