Re: GetUserInfo() for TChain

From: Hovhannes Khandanyan <khandan_at_cern.ch>
Date: Wed, 2 Mar 2011 14:56:33 +0100

Hello Rene,

> TH1F* h = (TH1F*)chain->GetTree()->GetUserInfo()->At(0);

This approach did not work causing segmentation violation, and that's probably due to the fact that I use the chain only to;

chain->Draw("Leaf >> Histo","","goff")

dump a leaf into a histo. Since the content of UserInfo is exactly the same for all of the trees in chain, I could do smth like

> TH1F* h = (TH1F*)chain->GetTree(0)->GetUserInfo()->At(0);

but GetTree() does not seem to take a tree index as an argument. What would be the best work around?

Thanks,
Hovhannes

> 
> 
> Rene
> 
> 
> On 02/03/2011 13:08, Hovhannes Khandanyan wrote:

>> Dear ROOTers,
>>
>> I have a TChain of TTrees each of which has UserInfo object with a TH1F in it. Things are OK when I operate with individual tree. Anyhow, as soon as I ask for :
>>
>> TH1F* h = (TH1F*)chain->GetUserInfo()->At(0);
>>
>> I get a NULL pointer. Please let me know what I am doing wrong.
>>
>> Thanks,
>> Hovhannes
>>

> Received on Wed Mar 02 2011 - 14:56:37 CET