Re: filling histograms

From: Rene Brun (Rene.Brun@cern.ch)
Date: Fri Aug 15 1997 - 14:00:37 MEST


Robert Loke wrote:
> 
> Hi,
> 
> probably it's just a silly mistake ...
> 
> I try to fill an existent histogram using
> 
> TH1F* InvMassSpectrum = new TH1F("invariant mass","invariant mass",500,0,5);
>  ....
> InvMassSpectrum->Fill(InvMass);
> 
> and receive such a strange strange error message like
> 
> Error in <TList::AddBefore>: before not fond, object not added
> 
> does anybody has an idea what went wrong? Or even better: how to
> repair this?

You may get this king of errors if you compiled your program
using old header files with a new library or vice-versa.
In this case the virtual table of pointers to member functions
is wrong and the system  calls the wrong function.

Rene Brun



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