[ROOT] Tree not readable

From: Hermann-Josef.Mathes@ik.fzk.de
Date: Fri Mar 22 2002 - 14:53:45 MET 

Dear rooters,

I have a problem in reading objects written to a tree from my program. If
I load the shared library into a ROOT session, everything works fine, I
can see the leaves of the branch and plot their content.
 
Writing is done in the following way:

LogMessage   *fLogMessage = new LogMessage();

TFile*  fLogFile = new TFile( filename, "recreate" );

TTree* fTree = new TTree( "LogTree", "Tree containing LogMessage objects" );

// class LogMessage in namespace Logging
fTree->Branch( "LogBranch", "Logging::LogMessage", &fLogMessage, 10000, 1 );

fTree->Fill();

after writing many LogMessage objects to the file I do:

fLogFile->Write( 0, TObject::kOverwrite );
fLogFile->Close();

Reading is (should be) then done be the following code fragment:
(I tried also the variants as offered by the MakeClass() method).

  TFile *file = new TFile( argv[1] );
  TTree *tree = (TTree *)file->Get( "LogTree" );
  
  if ( tree ) {
    
    TBranch *logb = tree->GetBranch( "LogBranch" );
    logb->SetAddress( &logm );    
    for ( Int_t n_entry=0; n_entry<tree->GetEntries(); n_entry++ ) {
    
      tree->GetEvent( n_entry );
    }
    delete tree;
  }

The code crashes in the GetEvent() method:
Program received signal SIGSEGV, Segmentation fault.
0x4022d930 in G__TString_ShowMembers_3_12__FP8G__valuePCcP8G__parami ()
    at include/TStreamerInfo.h:127
127     include/TStreamerInfo.h: No such file or directory.
(gdb) back
#0  0x4022d930 in G__TString_ShowMembers_3_12__FP8G__valuePCcP8G__parami ()
    at include/TStreamerInfo.h:127
#1  0x40560b0e in G__CallFunc::Exec () from /cern/root/lib/libCint.so
#2  0x4014f063 in TClass::BuildRealData (this=0x84235c8, pointer=0x8467520)
    at meta/src/TClass.cxx:478
#3  0x40152d92 in TClass::ReadBuffer (this=0x84235c8, b=@0x85401c8, 
    pointer=0x8467520) at meta/src/TClass.cxx:1583
#4  0x40167e31 in TStreamerInfo::ReadBuffer (this=0x841b828, b=@0x85401c8, 
    pointer=0x8467510 "", first=2) at meta/src/TStreamerInfo.cxx:1864
#5  0x40ade7bd in TBranchElement::ReadLeaves () from /cern/root/lib/libTree.so
#6  0x40ad7e3a in TBranch::GetEntry () from /cern/root/lib/libTree.so
#7  0x40add6ec in TBranchElement::GetEntry () from /cern/root/lib/libTree.so
#8  0x40add69c in TBranchElement::GetEntry () from /cern/root/lib/libTree.so
#9  0x40af3ea0 in TTree::GetEntry () from /cern/root/lib/libTree.so
#10 0x40af6ae5 in TTree::GetEvent () from /cern/root/lib/libTree.so
#11 0x804d683 in main (argc=2, argv=0xbfffee24) at FileBrowser.cc:70

I think it is a very trivial error which I do but I cannot find it. Do
have any suggestions ? I am using 2.03/07

Thank you
  Hermann-Josef

**************************************************************************
*                                                                        *
*   Dr. Hermann-Josef Mathes                                             *
*   KASCADE & AUGER Collaboration                                        *
*   Forschungszentrum Karlsruhe                Phone: +49 7247 822429    *
*   Institut fuer Kernphysik                   FAX:   +49 7247 824075    *
*   POB 3640                                                             *
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*                                                                        *
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