> > > However I notice something strange with the second approach: your
> > > macro only works if I do *not* load the shared library with the class
> > > info (amsmc.sl in the files I sent). If I load the lib, GetEntry
> > > reads nothing for the sub-branch.
> > >
> >
> > You must have an incompatibility between your shared lib and Root.
> > Could you recompile your shared lib in particular the CINT dictionary?
> >
>
> I think some shared lib incompatibility is basically my problem. The
> library is compiled with up-to-date dictionary, but I am now looking
> carefully at the classes (which I did not write) and noticing some
> things which may not be kosher with respect to the examples in the
> docs (for instance, they don't seem to have default constructors).
> Next I'll try simplifying/modifying some of these classes to see if I
> can get this to work.
Hi,
I've returned to working on this after a break...
Now I am not so sure that the problem is with my shared lib.
I've tried to replicate the behavior using the Event class in
the $ROOTSYS/test directory (for Root 2.25 and 3.01, on Linux
and OSF). Accessing the sub-branch directly still doesn't work
(in this case, it doesn't seem to matter if I load the lib or not).
I made only one change to Event.h, which was to make the Event class
data members public. Then I compiled the shared lib, and ran the
Event executable with default arguments to make Event.root.
The following macro works fine:
------------------------------------------------------------
void testread()
{
// Set top-level branch address and navigate object -- works
gROOT->Reset();
gSystem.Load("libEvent");
TFile file("Event.root");
TTree *evtree = (TTree*)file->Get("T");
int nevent = evtree->GetEntries();
Event* event = new Event;
evtree->SetBranchAddress("event", &event);
nevent = 3;
for(int i=0;i<nevent;i++)
{
evtree->GetEvent(i);
printf("%d fNtrack, top level branch address set %d\n",i,event->fNtrack);
}
}
------------------------------------------------------------
However, this isn't what I want to do. I want to avoid setting the
top-level branch address, and instead go to the fNtrack sub-branch
directly.
Your suggested macro of July 6 is adapted below for this class:
------------------------------------------------------------
void testread2()
{
// Attempt to access sub-branch directly
gROOT->Reset();
gSystem.Load("libEvent");
TFile file("Event.root");
TTree *evtree = (TTree*)file->Get("T");
int nevent = evtree->GetEntries();
printf("nevent %d\n",nevent);
int ntr = 0;
evtree->SetBranchStatus("*",0);
evtree->SetBranchStatus("fNtrack",1);
evtree->SetBranchAddress("fNtrack", &ntr);
nevent = 3;
for(int i=0;i<nevent;i++) {
evtree->GetEntry(i);
printf("i %d, ntr=%d\n",i,ntr);
}
}
------------------------------------------------------------
.. but this just returns zeroes (no error messages).
Your first suggestion of July 6 is implemented in:
------------------------------------------------------------
void testread3()
{
// Attempt to access sub-branch directly
gROOT->Reset();
gSystem.Load("libEvent");
TFile file("Event.root");
TTree *evtree = (TTree*)file->Get("T");
int nevent = evtree->GetEntries();
printf("nevent %d\n",nevent);
int ntr=0;
TBranch *branch = T->GetBranch("fNtrack");
branch->SetAddress(&ntr);
nevent = 3;
for(int i=0;i<nevent;i++) {
branch->GetEntry(i);
printf("i %d, ntr=%d\n",i,ntr);
}
}
------------------------------------------------------------
But this doesn't work either. (Strangely, for my original
classes/libs, these solutions work under some conditions but not
others.)
Any ideas?
Thanks for any help,
Kate Scholberg
schol@mit.edu
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