Dear ROOT Users,
In using the methods tree_ptr->Write() and file_ptr->Write(), how does the
TTree object communicates with the TFile object?
For instance in writing a root file, I noticed the ff. steps from the
tutorial(filename: tree*.C) or manual (Users Man. 3.05, pp.212-214):
1. a declaration of the form
TFile * firstFILEinput = new TFile("INPUT.root",MODE);
TTree * myTree= new TTree("T","Oak Tree");
2. Creating branches;
myTree->Branch(.......arguments.......);
.......
3. Filling the branches with data;
branchName = data_one;
.............
myTree->Fill();
4. actual writing;
myTree->Write();
(sometimes: fileOUT->Write(); )
Now what about if one has to create another TFile object
TFile * anotherFileOUTPUT = new TFile("OUTPUT.root",MODE),
how will the TTree select which TFile's to direct?
(Or, how intelligent this tree is to choose w/c from the two files to
write?)
I did not see an explicit
declaration on the part of TTree that it has to write to a specific file.
So far in the manual, we are told that it is for writing or reading
through its MODE.
In otherwords, is it INPUT.root or UTPUT.root ?
Are we assured that it will not overwrite, for instance, the file
"INPUT.root" with mode=>READ?
My apology for the many questions.
Thanks.
--
--------------------------------------------------------
Zaldy A. Nawang
PS Users Room 2
Yon Gokan,
E362, Neutrino Group,
IPNS, KEK,
Japan
e-mail: zaldy@neutrino.kek.jp
Tel. No. : (81) 029864 - 5387
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