Hi Christoph,
What do you want to do exactly?
You can do all sorts of operations with an histogram:
TH1::Reset()
TH1::Add to replace its contents by another histogram contents
Also note that you can detach an histogram from a directory by calling
TH1::SetDirectory(0)
Rene Brun
> Fons Rademakers wrote on 25 Jun 1998:
> > use either the histogram TH1::operator=() or the TH1::Copy()
> > or the TObject::Clone() methods.
> >
> > Cheers, Fons.
> >
> > Wei Xie wrote:
> > >
> > > Dear ROOTers'
> > >
> > > Is there a way to copy one histogram directly to another
> > > histogram ?
> [...]
>
> As far as I understand it,
>
> * TH1::operator does not copy the entire object (no polymorphism
> possible),
>
> * TH1::Copy() is protected,
>
> * TObject::Clone() creates a new object in a different memory location.
>
> Do I miss the point here? Do I have to use memcpy (*shudder*)?
>
> Thank you for your answer
> Christoph
>
> --
> Christoph Borgmeier Mail: DESY F15/HERA-B, Geb. 61/117
> Notkestr. 85, 22607 Hamburg
> Humboldt Univ Berlin Phone: +49 40 8998 4850
> Email: Christoph.Borgmeier@desy.de