Hi Rene,
I am trying to find a bug which may be in the way TChain works. My problem
is that GetEntry(1) seems not to fill the objects which are read correctly
if 2 files are on the chain while it works for both files individually. It
already crashes reading the first event on the first file. During my
investigation I started to wonder why constructors of Objects are called
by GetEntry, even if we did not attach to any branch on the tree. In my
opinion this should not happen since calling default constructors may not
work in a certain context and may be time-consuming. So if I dont read a
branch the constructors of the object on the branch should never be
called. If you want to reproduce this, try the following: (libRawEvent is
J. Bourottes H4 ECAL code and the ecs file was produced by him).
On lxplus do:
> cd /afs/cern.ch/user/k/koblitz/scratch0/h4
> root
*******************************************
* *
* W E L C O M E to R O O T *
* *
* Version 3.05/05 8 May 2003 *
* *
* You are welcome to visit our Web site *
* http://root.cern.ch *
* *
*******************************************
FreeType Engine v2.1.3 used to render TrueType fonts.
Compiled for linux with thread support.
CINT/ROOT C/C++ Interpreter version 5.15.86, Apr 29 2003
Type ? for help. Commands must be C++ statements.
Enclose multiple statements between { }.
root [0]
gSystem.Load("/afs/cern.ch/user/k/koblitz/public/h4/rawroot/Linux/libRawEvent.so");
root [1] TChain *inputChain = new TChain("T13","H4 Analyis Input Chain");
root [2] inputChain->Add("ecs63138");
root [3] inputChain->GetEntry(1);
end TRawTdcInfo::Init()
end TRawTdcInfo::Init()
end TRawTdcInfo::Init()
TRawTower constructor
TRawTower constructor
root [4]
A trace gives:
Breakpoint 2, TRawTdcInfo::Init (this=0x89fb140) at TRawTdcInfo.cxx:48
48 fNValue = 0;
(gdb) bt
#0 TRawTdcInfo::Init (this=0x89fb140) at TRawTdcInfo.cxx:48
#1 0x401297e2 in TRawTdcInfo::TRawTdcInfo (this=0x89fb140) at
TRawTdcInfo.cxx:20
#2 0x401387b7 in ROOT::new_TRawTdcInfo (p=0x0)
at /coda/software/root/v3.05.05/include/TObject.h:154
#3 0x4031af79 in TClass::New () from
/coda/software/root/v3.05.05//lib/libCore.so
#4 0x40ec3de0 in TBranchElement::SetAddress ()
from /coda/software/root/v3.05.05//lib/libTree.so
#5 0x40ec2843 in TBranchElement::GetEntry ()
from /coda/software/root/v3.05.05//lib/libTree.so
#6 0x40edbc90 in TTree::GetEntry () from
/coda/software/root/v3.05.05//lib/libTree.so
#7 0x40ec7add in TChain::GetEntry ()
from /coda/software/root/v3.05.05//lib/libTree.so
#8 0x4006c9a5 in H4Analysis::nextEvent (this=0x86b8f28) at
H4Analysis.cxx:384 (---------> chain->GetEntry(1) )
#9 0x08049415 in main (argc=1, argv=0xbffff654) at pulse.cc:29
#10 0x42017499 in __libc_start_main () from /lib/i686/libc.so.6
Maybe if I understand this puzzel, I finally understand why a chain works
with 1 file but not with 2.
Cheers,
Birger
--
Birger Koblitz Tel: +33/1 69 33 31 73
Ecole Polytechnique - LLR
Route de Saclay
F-91128 Palaiseau
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