Chris Jillings wrote:
>
> Hi,
> I have the following macro which I run off the command line of 2.00/05
> on Linux. If the last four lines are commented out it works as I would
> expect. When the last four lines are added, the interprter complains about
> not being able to handle the copy constructor...
>
> Error: Can't call TH1F::TH1F() in current scope
> FILE:/usr/home/chris/analysis/qdc/clicks/./chargespec.C LINE:68
> *** Interpreter error recovered ***
>
> Thanks,
>
> Chris
>
> sumchargespec(TFile* fin) {
> char hname[100];
> sprintf(hname,"qdcintime");
> TH1F* hintime = (TH1F*)fin->Get(hname);
> sprintf(hname,"qdcearly");
> TH1F* hearly = (TH1F*)fin->Get(hname);
> TCanvas *c1 = new TCanvas("c1","c1",1);
> c1->SetFillColor(kWhite);
> TPad* p1 = new TPad("p1","p1",0.02,0.52,0.98,0.98,kWhite);
> TPad* p2 = new TPad("p2","p2",0.02,0.02,0.98,0.48,kWhite);
> p1->Draw();
> p2->Draw();
>
>
> Float_t xlow = 40;
> Float_t xhigh = 90;
> Int_t low = hintime->GetXaxis()->FindBin(xlow);
> Int_t high = hintime->GetXaxis()->FindBin(xhigh);
> Float_t intimeArea = hintime->Integral(low,high);
> Int_t low = hearly->GetXaxis()->FindBin(xlow);
> Int_t high = hearly->GetXaxis()->FindBin(xhigh);
> Float_t earlyArea = hearly->Integral(low,high);
>
> printf("Early area = %f\n",earlyArea);
> printf("In time area = %f\n",intimeArea);
>
>
> if( intimeArea!=0.0 )
> hintime->Scale(earlyArea/intimeArea);
>
> p1->cd();
> hearly->Draw();
> hintime->Draw("same");
>
> TH1F* hdiff = new TH1F(hearly); // TH1F hdiff(hearly); also fails
> hdiff->Add(hintime,-1.0);
> p2->cd();
> hdiff->Draw();
>
> }
>
Chris,
The copy constructor expects a reference (not a pointer) to an object.
You should replace
TH1F *hdiff = new TH1F(hearly)
by
TH1F *hdiff = new TH1F(*hearly).
You can also do (this is valid for any TObject based object)
TH1F *hdiff = (TH1F*)hearly->Clone()
The later solution is the recommended way to proceed.
Rene Brun
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