message: Fix in variable type, add protections for non existing input files
diff: #if !defined(__CINT__) || defined(__MAKECINT__)
  #include "TFile.h"
  +#include "TSystem.h"
  #include "TNtuple.h"
  #include "TString.h"
  #include "TGraphAsymmErrors.h"
  @@ -114,8 +115,8 @@ void ComputeDmesonYield(){
  Int_t linewiaaC=2;
  Int_t markerppC=21;
  Int_t markeraaC=23;
  - Int_t msizppC=1.2;
  - Int_t msizaaC=1.2;
  + Double_t msizppC=1.2;
  + Double_t msizaaC=1.2;
  Float_t sizesystdata=0.4;
  Float_t sizesystfd=0.3;
  Float_t sizesystrb=0.2;
  @@ -124,6 +125,10 @@ void ComputeDmesonYield(){
  // pp reference
  + if(gSystem->Exec(Form("ls -l %s > /dev/null 2>&1",filnamPPref.Data())) !=0){
  + printf("File %s with pp reference not found -> exiting\n",filnamPPref.Data());
  + return;
  + }
  TFile *filPP=new TFile(filnamPPref.Data());
  TH1D *hppRef = (TH1D*)filPP->Get("hReference");
  if(!hppRef) hppRef = (TH1D*)filPP->Get("fhScaledData");
  @@ -198,6 +203,10 @@ void ComputeDmesonYield(){
  printf("--- %s events ---\n",collSyst.Data());
  + if(gSystem->Exec(Form("ls -l %s > /dev/null 2>&1",filnamChi.Data())) !=0){
  + printf("File %s with A-A (p-A) yield not found -> exiting\n",filnamChi.Data());
  + return;
  + }
  TFile *filChi= new TFile(filnamChi.Data());
  TH1D *hSpC = (TH1D*)filChi->Get("hRECpt");
  Float_t relstaterrPbPb[nPtBins];
  @@ -243,6 +252,10 @@ void ComputeDmesonYield(){
  }
  }
  + if(gSystem->Exec(Form("ls -l %s > /dev/null 2>&1",filnamCnt.Data())) !=0){
  + printf("File %s with R_AA not found -> exiting\n",filnamCnt.Data());
  + return;
  + }
  TFile *filCnt=new TFile(filnamCnt.Data());
  Float_t relstaterrPbPb2[nPtBins];
  TH1D* hraaCcheck2=(TH1D*)filCnt->Get("hRABvsPt");
  @@ -367,6 +380,10 @@ void ComputeDmesonYield(){
  }
  }
  + if(gSystem->Exec(Form("ls -l %s > /dev/null 2>&1",filnamCntS.Data())) !=0){
  + printf("File %s with R_AA (for syst) not found -> exiting\n",filnamCntS.Data());
  + return;
  + }
  TFile *filCntS=new TFile(filnamCntS.Data());
  TNtuple* ntCS=(TNtuple*)filCntS->Get("ntupleRAB");
  ntCS->SetBranchAddress("pt",&pt);
  