sven schagen wrote:
>
> Dear All,
>
> First of all, I hope that this bug has not been reported before (I
> thought it might have been, but I can't find it so....)
>
> After an upgrade from 1.03 to 2.00 I found that some of my programs
> didnt work anymore.
> After working out different possible causes, I found that the core of
> the error seems to be that TChain::CloneTree() by default (and always) a
> NULL Pointer returns.
>
> For instance:
>
> // Usual stuff and declarations
> .....
>
> TChain mychain("h1");
> mychain.Add("somefile");
> mychain.Draw("some_variable_from_somefile");
> cout << mychain.GetTree();
>
> .....
>
> The output will then be that some_variable_from_somefile will be plotted
> , but the output of cout will be 0x0, the NULL pointer.
>
> So my question now is: is this a bug ?
>
Do you mean CloneTree or GetTree?
Tree::CloneTree clones an existing TTree (see doc). You should use this
function on a TTree, not a TChain.
Use TChain::Merge if you want to Merge teh files of a TChain
into one single file.
Please be more specific and give a more complete example.
Reply to me directly, not to the list.
Rene Brun
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