RE: Error: illegal pointer to class object Spher3D_sig 0x0 396 plot1.C:7: *** Interpreter error recovered ***

From: Meera Lebbai, Mohamed R. <razzak_at_ou.edu>
Date: Tue, 30 Oct 2007 04:46:18 -0500

Hi Rene,

When I do

TH1F *Spher3D_sig = (TH1F*)setA->Get("h_Sphericity3D"); if(Spher3D_sig) Spher3D_sig->Draw();

I don't get any error messages but I can't save this histogram ( I can't see the histogram).

Is there any way to do it.

Note: I also wanted to metion one thing this kind of illegal pointer error only occuring for particular variables such as Spehricity, Aplanarity and Planarity.

Thanks

Razzak

---

From: Rene Brun [Rene.Brun_at_cern.ch]
Sent: Friday, October 26, 2007 9:39 AM
To: Meera Lebbai, Mohamed R.
Cc: ROOT Talk
Subject: Re: [ROOT] Error: illegal pointer to class object Spher3D_sig 0x0 396 plot1.C:7: *** Interpreter error recovered ***

Instead of:

 TH1F *Spher3D_sig = setA->Get("h_Sphericity3D"); Spher3D_sig->Draw();

do:

 TH1F *Spher3D_sig = (TH1F*)setA->Get("h_Sphericity3D"); if(Spher3D_sig) Spher3D_sig->Draw();

Rene Brun

Meera Lebbai, Mohamed R. wrote:
> Hi all,
>
> I am getting illegal pointer error when I try Draw() a histogram ( but I never used to get this before).
>
> I have just included a simple file
>
>
> // test.C
>
>
> { gStyle->SetOptFit(111111);
>
> // signal
> TFile* setA = TFile::Open("hist_stop_sig.root");
>
> TH1F *Spher3D_sig = setA->Get("h_Sphericity3D");
> Spher3D_sig->Draw();
> }
>
> Any help will be appreciated.
>
> Razzak
>
>
Received on Tue Oct 30 2007 - 10:49:38 CET