[ROOT] TBranch::GetEntrie(i), EOF detection

From: Jean-Eric Campagne (campagne@lal.in2p3.fr)
Date: Tue Apr 30 2002 - 12:49:38 MEST


Dear developpers,

I would like to ask you the following problem of EOF detection. 

Consider that I have managed to create a Tree with branch created via
the "Post a Tlist in a Folder" mechanism. 

Then, in a session where I am reading this Tree from a file I have made
the following sequences 1 & 2:

1) once for all:
------------
  //Get the Tree of the MC hits
  m_treeMCH = dynamic_cast<TTree*>(m_fileIn->Get("TreeMCH"));
.....
  m_branchMCH = m_treeMCH->FindBranch(".topFold.RunMC.EventMC.Hits.MCHitList");
.....
  m_branchMCH->SetAddress(&m_mcHitList);
	
where  m_mcHitList is a TList


2) each event:
----------
  //Get list of hits from the Root Tree
  m_mcHitList->Delete();
  //Nb: eventId is managed by the main application
  int nbytes = m_branchMCH->GetEntry(eventId);

  cout << " #of bytes read: " << nbytes << endl;

  //loop on Hit 
  TIter nextin(m_mcHitList);
  DMMCHit* aDMHit;
  while ( (aDMHit = (DMMCHit *)nextin()) ) {
	....
  }



It works perfectly, but I do not know how to get a feedback from the 
GetEntry statement if it return 0 bytes, if really there is no hits 
stored in m_mcHitList or if I am at the end of the file.


	Regards,
	J.E Campagne

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