Int_t AliTOFanalyzeSDigitsV2(TString headersFile, Int_t ndump=15, Int_t iEvNum=0)
{
  // V2: to be used with transient fSDigits data member
  //
  // Analyzes the TOF sdigits and fills QA-histograms 
  // report problems to pierella@bo.infn.it
  // iEvNum=0 means all events in the file

  // Dynamically link some shared libs
  if (gClassTable->GetID("AliRun") < 0) {
    gROOT->LoadMacro("loadlibs.C");
    loadlibs();
  } else {
    delete gAlice;
    gAlice = 0;
  }
  
  Int_t rc=0;
  
  
  TFile *file = (TFile*)gROOT->GetListOfFiles()->FindObject(headersFile.Data());
  if(file){
    cout<<"headerFile already open \n";
  }
  else {
    if(!file)file=TFile::Open(headersFile.Data());
  }
  
  // Get AliRun object from file
  if (!gAlice) {
    gAlice = (AliRun*)file->Get("gAlice");
    if (gAlice) printf("AliRun object found on file\n");
  }
  
  
  if (iEvNum == 0) iEvNum = (Int_t) gAlice->TreeE()->GetEntries();
  
  AliTOF * tof = (AliTOF *) gAlice->GetDetector("TOF") ;

  if (!tof) {
    cout << "<AliTOFanalyzeSDigitsV2> No TOF detector found" << endl;
    rc = 2;
    return rc;
  }

  // adc and tdc
  TH1F *htdc  = new TH1F("htdc","TDC [bin]",500,0.,15000.);
  TH1F *hadc   = new TH1F("hadc","ADC [bin]",100,0., 3000.);

  // number of slot for each sdigits
  TH1F *hndigits  = new TH1F("hndigits","fNDigits",5,0.,5.);

  // TOF sdigit volumes
  TH1F *hsector  = new TH1F("hsector","Sector",20,0.,20.);
  TH1F *hplate   = new TH1F("hplate","Plate ", 6,0., 6.);
  TH1F *hstrip   = new TH1F("hstrip","Strip ",25,0.,25.);
  TH1F *hpadz    = new TH1F("hpadz","Pad along z ",3,0.,3.);
  TH1F *hpadx    = new TH1F("hpadx","Pad along x",50,0.,50.);
  // ADC-TDC correlation
  TH2F *h2tdcVSadc = new TH2F("h2tdcVSadc","TDC [bin] VS ADC [bin]",100,0.,3000.,500,0.,15000.);

  cout << "First " << ndump << " SDigits found in TOF TreeS branch have:" << endl;


  for (Int_t ievent = 0; ievent < iEvNum; ievent++) {
    
    char tname[100]; sprintf(tname,"TreeS%d",ievent);
    
    TTree *sdigitstree=(TTree*)file->Get(tname);                   
    
    TClonesArray * fSDigits= new TClonesArray("AliTOFSDigit",  1000); 
    sdigitstree->GetBranch("TOF")->SetAddress(&fSDigits);           
    
    Int_t nEntries = sdigitstree->GetEntries();                                
    //cout << nEntries << endl;
    
    // Loop through all entries in the tree
    Int_t nbytes;
    for (Int_t iEntry = 0; iEntry < nEntries; iEntry++) {
      
      // Import the tree
      nbytes += sdigitstree->GetEvent(iEntry);
      
      // Get the number of sdigits
      Int_t ndig = fSDigits->GetEntriesFast();
      cout << "------------------<AliTOFanalyzeSDigitsV2>------------------" << endl;
      cout << "Found " << ndig << " TOF SDigits for event " << ievent << endl;
      cout << "------------------------------------------------------------" << endl;

      // start loop on sdigits
      for (Int_t k = 0; k < ndig; k++) {
	
	// Get the information for this digit
	AliTOFSDigit *tofsdigit = (AliTOFSDigit *) fSDigits->UncheckedAt(k);
	Float_t firstTDC=tofsdigit->GetTdc(0);
	Float_t firstADC=tofsdigit->GetAdc(0);
	Int_t nslot=tofsdigit->GetNDigits();
	hndigits->Fill(nslot);
	htdc->Fill(firstTDC);
	hadc->Fill(firstADC);
	// TOF sdigit volumes
	Int_t sector    = tofsdigit->GetSector(); // range [1-18]
	Int_t plate     = tofsdigit->GetPlate();  // range [1- 5]
	Int_t strip     = tofsdigit->GetStrip();  // range [1-20]
	Int_t padz      = tofsdigit->GetPadz();   // range [1- 2]
	Int_t padx      = tofsdigit->GetPadx();   // range [1-48]
	// it is QA, then I perform QA!
	Bool_t isSDigitBad = (sector<1 || sector>18 || plate<1 || plate >5 || padz<1 || padz>2 || padx<1 || padx>48);
	
	if (isSDigitBad) {
	  cout << "<AliTOFanalyzeSDigitsV2>  strange sdigit found" << endl;
	  rc = 3;
	  return rc;
	}
	
	if(k<ndump){
	  cout << k << "-th | " << "Sector " << sector << " | Plate " << plate << " | Strip " << strip << " | PadZ " << padz << " | PadX " << padx << endl;
	  cout << k << "-th | ADC " << firstADC << " [bin] | TDC " << firstTDC << " [bin]" << endl;
	  cout << "----------------------------------------------------"<< endl;
	}
	
	// filling sdigit volume histos
	hsector->Fill(sector);
	hplate->Fill(plate);
	hstrip->Fill(strip);
	hpadx->Fill(padx);
	hpadz->Fill(padz);
	h2tdcVSadc->Fill(firstADC,firstTDC);
	
	//cout << "firstTDC " << firstTDC << " firstADC " << firstADC << endl;
      } // end loop on sdigits
      
    } // end loop on entries
    
  } // end loop on events 
  
  TFile *fout = new TFile("TOF_sdigitsQA.root","RECREATE");
  htdc->Write();
  hadc->Write();
  hndigits->Write();
  h2tdcVSadc->Write();
  hsector->Write();
  hplate->Write();
  hstrip->Write();
  hpadz->Write();
  hpadx->Write();
  fout->Close(); 


  return rc;
  

}