RE: [ROOT] Trees, ClonesArrays and an obsolete call error

From: Philippe Canal (pcanal@fnal.gov)
Date: Wed Jul 23 2003 - 04:56:10 MEST 

Hi,

This is bug in ROOT 3.05/06.  I am working on a fix.
You can not ignore this message.

Cheers,
Philippe

-----Original Message-----
From: owner-roottalk@pcroot.cern.ch
[mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of Hamlet
Sent: Tuesday, July 22, 2003 6:02 PM
To: roottalk
Subject: [ROOT] Trees, ClonesArrays and an obsolete call error


Hello!

While messing with TTrees, I've run into the following error:

Error in <TBranchElement::GetDataMemberOffset>: obsolete call with 
(PhotonsList,Clusters)


The object I'm going to write in TTree is something which recall this 
scheme:

// start of code
class PhotonsList: public TObject {
    public:
  TClonesArray* pPhotons; //photons data

  PhotonsList() { pPhotons = NULL; }
  ~PhotonsList() {
    if (!pPhotons) return;
    pPhotons->Delete();
    delete pPhotons;
    }

  void Init() { pPhotons = new TClonesArray(TObject::Class(), 8); }

  ClassDef(PhotonsList,1) //list of photons for an event
}; // PhotonsList


class STreeEvent: public TObject {
    public:
  PhotonsList Clusters;           //original photons data

  void Init() { Clusters.Init(); }

  ClassDef(STreeEvent,1) //event encapsulated in a tree
}; // STreeEvent
// end of code

Linking header file is:

// start of code
#ifdef __CINT__

#pragma link off all globals;
#pragma link off all classes;
#pragma link off all functions;

#pragma link C++ class PhotonsList;
#pragma link C++ class STreeEvent;

#endif
// end of code

while the object file (namely, STreeEvent.cpp) is the couple of calls to 
macro to implement classes (ClassImp).

That is to say, I've a class fated to be main tree branch (STreeEvent) 
which directly holds a TObject derived class, which has a pointer to a 
clones-array of photons (a TObject or whatever); this pointer is not 
initted in constructor since some tutorials teach so.

Now with CINT and ROOT 3.05/06 the sequence:
  // loads object code to CINT:
[0] .x STreeEvent.so
  // create and init an object:
[1] STreeEvent* pEvent = new STreeEvent; pEvent->Init();
  // create a tree and a branch with that object as address:
[2] TTree tree; tree.Branch("Event", "STreeEvent", &pEvent);

that message prints out. It's very reasonable that a call to
TBranchElement::GetDataMemberOffset(PhotonsList,Clusters) fails, since 
there is no "Clusters" field in PhotonsList and Clusters is a field /of 
type/ PhotonsList (in another object).
I could bet that with 3.05/05 this did not happen, but I'm not sure.
I've no idea whether this is a message that can be safely ignored or 
not.

Written enough. Any suggestion?

-- 
Hamlet

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