Garbage collection

ROOT
1

Dear ROOT users and developers,

I am curious about the following code of TH1::Build():

   if (fgAddDirectory && gDirectory) {
      if (!gDirectory->GetList()) {
         Warning("Build","Current directory is not a valid directory");
         return;
      }
      TH1 *hold = (TH1*)gDirectory->GetList()->FindObject(GetName());
      if (hold) {
         Warning("Build","Replacing existing histogram: %s (Potential memory leak).",GetName());
         gDirectory->GetList()->Remove(hold);
         hold->SetDirectory(0);
         //  delete hold;
      }
      gDirectory->Append(this);
      fDirectory = gDirectory;
   }

I am wondering why the delete statement is disabled.
When we create histograms in a named script, to save the memory, we have to delete them by hand every time before executing the script again.
We can put a code like gDirectory->Get(“histoname”)->Delete(); in the script ahead of the histogram definition, but it is troublesome to write this for all of a large number of histogram.

Be generous with your life.
Satoru KAMEOKA

2

You can delete all histograms in teh current directiry in memory with

gDirectory->GetList()->Delete();
Rene