Strange crash making draw in a macro

ROOT 5.26/00a (tags/v5-26-00a_at_32053, Jan 19 2010, 12:43:52 on linux)

CINT/ROOT C/C++ Interpreter version 5.17.00, Dec 21, 2008

In executing the following simple minded macro:

TH1D* hDo=0;
TString hDoName="";
TH1D* doDraw(TTree* tup) {

   sAndB(0);
   hDoName="hVar";
   hDoName+=getTagI();

   cout << "hDoName:" << hDoName << endl;    hDo=new TH1D(hDoName,yyvar,nyy,yylo,yyup);    cout << "hDo:" << hDo << endl;

   if(tup->GetTitle()=="front") hDo->SetLineColor(2);    if(tup->GetTitle()=="back") hDo->SetLineColor(4);

   cout << "drawing ..." << endl;

   tup->Draw(yyvar+">>"+hDoName,cut);
   return hDo;

}

I get the following strange error:

hDoName:hVar671
hDo:0x947be20
drawing ...

Error in <TSelectorDraw::Begin>: An object of type 'TH1D' has the same name as the requested event list (hVar671)
(class TH1D*)0x947be20

What does that mean?

-Arthur S.

If I try to execute the Draw command by hand using the same TH1D name I get the same error. If w/o ">>" to specifiy histogram to use, it works.

If I clone a copy of the histogram |hDo|, change it's name, and use that, so

root [18] hDo2->GetName()
(const char* 0x956dbd0)"hVar673_2"

root [19] tFront->Draw(xxvar+">>hVar673_2",cut)
(Long64_t)20934

that works too!

?????

A.E. Snyder, The Former Group C (TFC)        \!c*p?/
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