Unable to clone histogram

[amytee]

I can open the file and access the first histogram. The script then crashes when I try to clone it with the error message :

warning: null passed to a callee that requires a non-null argument [-Wnonnull]
          TH1D *F0 = (TH1D*)h->Clone("F0");

Here is a short snippet:

     for (int i=0; i<1; i++){

        File[i] = TFile::Open(Ratio_File_Names[i].c_str() ); 

        File[i]->Print();
    
      
	    for (Int_t r=0; r<8; r++){
	   
	     TH1D *h;
	       File[i]->GetObject(Ratio_Histogram_Names[r].c_str(), h);

	        if (h==0){

	         std::cout << Ratio_Histogram_Names[r].c_str() << std::endl;
	    }

	    // TH1D *F0 = new TH1D(*h);  //Create a clone of h for the correct binning
	     TH1D *F0 = (TH1D*)h->Clone("F0");
	     F0->Print();

      }
      }

---

ROOT Version: Not Provided
Platform: Not Provided
Compiler: Not Provided

---

[Wile_E_Coyote]

Try with:

if (h != 0) {
  // TH1D *F0 = new TH1D(*h); F0->SetName("F0");
  TH1D *F0 = ((TH1D*)(h->Clone("F0")));
  F0->Print();
 } else {
  std::cout << Ratio_Histogram_Names[r].c_str() << " NOT found!" << std::endl;
}

[amytee]

Hey,

So I implemented the change:

 for (int i=0; i<1; i++){

    File[i] = TFile::Open(Ratio_File_Names[i].c_str() ); 

     File[i]->Print();
    
      
	 for (Int_t r=0; r<8; r++){
	   
	  TH1D *h;
	  File[i]->GetObject(Ratio_Histogram_Names[r].c_str(), h);

	  if (h==0){

	    std::cout << Ratio_Histogram_Names[r].c_str() << std::endl;
	  } 
 } else {
  std::cout << Ratio_Histogram_Names[r].c_str() << "NOT found!" << std::endl;
}

And it says:

      TFile: name=Ratio_Plots.root, title=, option=READ
       R_29099_N0A2byN2A0
      R_29099_N0A2byN2A0NOT found!
      R_20099_N0A2byN2A0
      R_20099_N0A2byN2A0NOT found!
      R_28099_N0A2byN2A0
      R_28099_N0A2byN2A0NOT found!
      R_26099_N0A2byN2A0
      R_26099_N0A2byN2A0NOT found!
      R_29099_N2A4byN4A0
      R_29099_N2A4byN4A0NOT found!
      R_20099_N2A4byN4A0
      R_20099_N2A4byN4A0NOT found!
      R_28099_N2A4byN4A0
      R_28099_N2A4byN4A0NOT found!
      R_26099_N0A2byN2A0
      R_26099_N0A2byN2A0NOT found!

It’s suggesting that it can’t find the histograms in the root file which is odd. I’ve double checked the root file and I can see the histograms in there, and its located in the same directory as the script.

[Wile_E_Coyote]

You edited it wrong. See my previous post again.

Also, post here the output of: File[i]->ls();

BTW. When you post “source code” or “output” here, do remember to enclose them into two lines which contain just three characters ``` (see how your posts have been edited above).