Problem with entering a character string into a ROOT Tree

ROOT
1

Please read tips for efficient and successful posting and posting code

Please fill also the fields below. Note that root -b -q will tell you this info, and starting from 6.28/06 upwards, you can call .forum bug from the ROOT prompt to pre-populate a topic.

ROOT Version: 6.24/08
Platform: Ubuntu 18.04 (bionic)
Compiler: GCC 7.4.0

Hi all,

In ROOT 5.34/38 I had a ROOT macro that correctly stored a character string in a TTree via the following code

TTree\* otree=new TTree(“T”,”GRB data”);
TString aap=”GRB120511B”;
otree–>Branch(“name”,aap.Data(),”name/C”);

…. and then fill the tree

However, now that I have switched to ROOT6 (i.e. version 6.24/08) this code gives me an error in ACliC, since due to the fact thet aap.Data() returns a char*, it gets confused with the other Branch memberfunction.

I tried otree–>Branch(“name”,&aap,”name/C”);

which doesn’t give me an error message, but when I do a scan of the Tree, the stored name shows weird characters, and not the string “GRB120511B”.

Could anyone please tell me how to solve this (silly) problem.

2

Hello @Nick_van_Eijndhoven,

thank you for your question. Maybe @pcanal could help here?

Cheers,

Marta

3

Hi all,

I solved the problem. It seems that in ROOT6 the inline overload of TTree:Branch(…) doesn’t work anymore. The problem is solved by using explicit casting to void*

otree–>Branch(“name”,(void*)(aap.Data()),”name/C”);

I would like to ask you to indicate this explicitly in the docs, in order to avoid further confusion.