using namespace RooFit;

void jimMacro()
{
  // Set up p.d.f.
  TString xName("x");
  RooRealVar *x = new RooRealVar(xName,xName,-3.0,3.0);
  RooRealVar m("m","m",0.0), s("s","s",1.0);
  RooAbsPdf *pdf = new RooGaussian("pdf","pdf",*x,m,s);

  // Create histo from p.d.f.
  TString hName("h");
  TH1* h = pdf->createHistogram(hName,*x,Binning(20));

  // As I understand it, h is owned by the current directory (gDirectory)
  TString pName(hName); pName += "__"; pName += xName;
  TH1 *p = (TH1*)gDirectory->GetList()->FindObject(pName);

  // Check that the object was found
  cout << "\nBefore h->SetDirectory(0) call:\n" << endl;
  cout << "Address pointed to by h = " << h << endl;
  cout << "Address pointed to by p = " << p << endl;

  // Remove from directory
  h->SetDirectory(0);

  // Should no longer be able to find in gDirectory
  TString qName(pName);
  TH1 *q = (TH1*)gDirectory->GetList()->FindObject(qName);
  cout << "\nAfter h->SetDirectory(0) call:\n" << endl;
  cout << "Address pointed to by h = " << h << endl;
  cout << "Address pointed to by q = " << q << endl << endl;

  // It is now my responsibility to delete h when I've finished with it
  delete h; h = NULL; p = NULL;

  // Tidy up other stuff
  delete x; x = NULL;
  delete pdf; pdf = NULL;
}