.rootlogon.C

ROOT
#1

When I run this in CINT:

TFile *_file0 = TFile::Open("wood_2.7_0.55_48mln.root");
  if(gDirectory->Get("scan")!=NULL) {
   scan->SetAlias("costh","-(z-z1v)/sqrt((x-x1v)**2+(y-y1v)**2+(z-z1v)**2)");
  }

it runs fine and sets the alias.

However, if I place the IF condition in my .rootlogon.C, and then do (from the command line)

root wood_2.7_0.55_48mln.root
it doesn’t get executed.

My guess is – it’s probably because the .root file gets loaded AFTER .rootlogon.C is executed.

Well, is there a way to reverse this? To force TFile::Open() to go first?

p.s. I realize that this is somewhat confusing…my final goal is to get an alias set up for the TTree scan, IF that tree is present.

#2

It looks like you are wanting to open root in a certain “ready” state depending on the command-line arugment (the root file). My suggestion would be to write a short macro that you would call, e.g.:

// SetScan.C
void SetScan(TString fname)
{
TFile *_file0 = TFile::Open(s);
  if(gDirectory->Get("scan")!=NULL) 
  {
   scan->SetAlias("costh","-(z-z1v)/sqrt((x-x1v)**2+(y-y1v)**2+(z-z1v)**2)");
  }
}

I don’t know if it’s possible to do this with an “unnamed” macro, so that stuff would go into the global scope.

Jean-François