Re: BrTrack problem

From: Christian Holm Christensen (cholm@hehi03.nbi.dk)
Date: Wed Dec 18 2002 - 13:17:52 EST

  • Next message: Djamel Ouerdane: "Re: BrTrack problem"
    Hi Djam,
    
    Djamel Ouerdane <ouerdane@nbi.dk> wrote concerning
      BrTrack problem [Tue, 17 Dec 2002 20:27:41 +0100 (CET)] 
    ----------------------------------------------------------------------
    > Hi,
    > 
    > It's not the first time I notice a problem with the BrTrack class 
    > streamer. Each time I open a dst in bratroot, I get a warning about the 
    > class version.
    > Today, I checked out the newest brat and merged my changes in the tof 
    > software and in other places but NOT in BrTrack.
    > 
    > when I tried a reco test from local track files (data01 and 02) to DSTs, I 
    > got this message :
    > 
    > Error in <TBuffer::CheckByteCount>: object of class BrTrack read too few 
    > bytes: 102 instead of 166
    > 
    > Warning in <TBuffer::CheckByteCount>: BrTrack::Streamer() not in sync with 
    > data on file, fix Streamer() 
    > 
    > It makes the reco job crash. What is going on with this class ?
    > I can see in the header file that nothing changed since august 2001!
    > In the cxx file, the only change is about iostream (cout). Any clue ?
    
    CINT makes a checksum based on the member, etc. of a class, and ROOT
    matches that against the read checksum.  If those are not the same,
    well, you can get errors.  Hence, when going from 
    
      ostream operator<<(std:ostream& o, const BrTrack& t);
    
    to 
    
      std::ostream operator<<(std::ostream& o, const BrTrack& t);
    
    or similar, you _may_ get a different checksum.   The solution to
    _that_ problem is to bump the class version. 
    
    Yours,
    
     ___  |  Christian Holm Christensen 
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