the reason for that is that the nullptr literal is available starting from c++11.
This standard is supported only starting from ROOT6: we are working hard to provide this ROOT version natively on windows too.
Additionally, in this case you do not need to initialize the “T” pointer in advance, as the “GetObject” call will always set a new value (regardless whether the “object” was found or not).
Okay so on a similar note, I would like to have my macro display a pedestal histogram that has been created in a root tuple already. I normally do this by just double clicking on the pedestal histogram in the root object browser
you should specify the correct type of object you are reading from the file. In addition, you need to invoke the Draw method of TH1F/D: please refer to root.cern.ch/doc/master/classTH1F.html
Assuming that the histogram is a TH1F (it could be a TH1D, it depends on who wrote it):
TFile f(newrootpath);
TH1F* T = NULL;
f.GetObject("pedestal", T);
T.Draw();
one thing which could be done is to go through the ROOT introductory material we suggest to get started with the Framework: root.cern.ch/getting-started
The histogram goes out of scope and its graphical representation too. Try DrawClone.