Hello,
I am getting some Error messages when I write an TNtuple to a root file that
I
don't understand. The good news is that the write operation works.
However, I suspect that I am missing something important here.
Here is what I do:
TFile *f = new TFile("c:\\root\\ap.root");
TNtuple *pIn = (TNtuple *)f->Get("pntup");
.
.
.
TNtuple *pOut = new TNtuple("pOut","x:y:z:a");
pOut->SetDirectroy(0); // keep ntuple "memory resident"
.
use pIn data to populate pOut ntuple
.
At some point, I decide to save pOut. This is what I do:
TDirectory *pSave = gDirectory;
gDirectory->pwd();
TFile *pF = new TFile("fft0600_0600.root","RECREATE");
gDirectory->pwd();
TNtuple *pClone = (TNtuple *)pOut->CloneTree();
pClone->Write();
pF->Close();
delete pF;
gDirectory = pSave;
gDirectory->pwd();
and here is the output I get when I execute save-to-file code:
c:\root\ap.root:/
fft0600_0600.root:/
Error in <TBranch::Write>: File c:\root\ap.root is not writable
Error in <TBranch::Write>: File c:\root\ap.root is not writable
Error in <TBranch::Write>: File c:\root\ap.root is not writable
Error in <TBranch::Write>: File c:\root\ap.root is not writable
c:\root\ap.root:/
It is true that c:\root\ap.root is not writable, but why do I get this
error?
When I later try to open fft0600_0600.root, I can read the ntuple withoug
problem.
Thanks,
Ed Oltman
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