Hi Rene,
I didn't have a problem in interactive usage either. My problem came
when I tried to use the code in a stand-alone application.
I was able to get around the problem by just using SetBranchStatus in the
Notify() method. In this way, I only loaded in the Branches I needed.
This saved time, as there are a lot of branches in my scaled-up
application. Further time savings would result if I didn't read some
branches unless the cut was passed, but I am content.
Chris
*** Today, you (Rene Brun) wrote ***
>Hi Chris,
>
>I do not see a problem with this basic example. Using your generator
>example, I created the two files testSel.h and testSel.C (in attachment).
>I modified testSel.C in ProcessCut, adding the two statements:
> b_p->GetEntry(entry);
> printf("p=%f\n",p);
>
>then, from an interactive ROOT session, I did
>
>root [0] TFile *f= new TFile("test.root");
>root [1] TTree *t= (TTree*)f->Get("test");
>root [2] .L testSel.C++
>root [3] testSel selector;
>root [4] t->Process(&selector);
>
>This gives:
>
>p=3.200000
>p=2.100000
>p=2.400000
>
>
>Rene Brun
>
>Chris Roat wrote:
>>
>> Hi ROOTers,
>>
>> I am having a problem using the code generated by TTree::MakeSelector in a
>> standalone application. Below I show how I create a very basic tree with
>> one branch, "p", that is filled with three entries. I then run
>> MakeSelector to generate an analysis skeleton. I add ClassDef(test,1) and
>> ClassImp(testSel) macros to the resulting skeleton files.
>>
>> Making an appropriate LinkDef file, I compile and run the simple main
>> program, also shown below. It runs fine, but at this point the skeleton
>> is still empty - a sterile application. I add the following simple line
>> to testSel::ProcessCut(),
>>
>> b_p->GetEntry(entry);
>>
>> which is, I think, supposed to fill the branch with the entry - based on
>> my experience on the command line. The code compiles without hassle, but
>> then I get a seg fault when the new line runs. The traceback is shown
>> below.
>>
>> I am running on a linux box with g++-2.95.2, ROOT version 3.01/06.
>>
>> Can someone point me to what I am doing wrong? Thanks much,
>> Chris
>>
>> // create a basic tree
>>
>> hfile = new TFile("test.root","RECREATE");
>> tree = new TTree("test","A Tree");
>> Float_t p;
>> b = tree->Branch("p", &p, "p/F" );
>> p= 3.2; tree->Fill();
>> p= 2.1; tree->Fill();
>> p= 2.4; tree->Fill();
>> hfile->Write();
>> tree->MakeSelector("testSel")
>>
>> // main program
>>
>> #include <TTree.h>
>> #include <TFile.h>
>> #include "testSel.h"
>>
>> int main() {
>>
>> TROOT myroot("myroot","Required TROOT object");
>> TFile *f= new TFile("test.root");
>> TTree *t= (TTree*)f->Get("test");
>> testSel selector;
>> t->Process(&selector);
>> return 0;
>>
>> }
>>
>> // traceback
>>
>> (gdb) where
>> #0 0x400d8204 in TBuffer::ReadFastArray () from
>> /afs/slac.stanford.edu/g/babar/package/root/3.01-06/Linux2/lib/libCore.so
>> #1 0x40a6d3b6 in TLeafF::ReadBasketExport () from
>> /afs/slac.stanford.edu/g/babar/package/root/3.01-06/Linux2/lib/libTree.so
>> #2 0x40a5c397 in TBranch::GetEntryExport () from
>> /afs/slac.stanford.edu/g/babar/package/root/3.01-06/Linux2/lib/libTree.so
>> #3 0x804b5e3 in testSel::ProcessCut (this=0xbfffeec0, entry=0) at
>> testSel.C:49
>> #4 0x40dafd4d in TTreePlayer::Process () from
>> /afs/slac.stanford.edu/g/babar/package/root/3.01-06/Linux2/lib/libTreePlayer.so
>> #5 0x40a766ab in TTree::Process () from
>> /afs/slac.stanford.edu/g/babar/package/root/3.01-06/Linux2/lib/libTree.so
>> #6 0x804b33f in main () at pid.C:11
>
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