SetBranchStatus for elements of array of objects

ROOT
1

Hello,
my event object has a class member - array of devices, I can write it to the tree and read back via usual receipt:

[code]class Event : TObject {
Device *m_dev[100];
}

// writing…
m_tree->Branch(“EventBranch”,“Event”, &m_event, 32000, 99);
m_tree->Fill();

// reading…
m_tree->SetBranchAddress(“EventBranch”, &m_event);
m_tree->GetEntry(i)
[/code]
Is it possible now, while reading tree, to save time and have filled only selected devices? I tried
m_tree->SetBranchStatus("*",0);
m_tree->SetBranchStatus(“m_dev[1]”,1)
but it can’t find such branch.

I also tried

[code]class ColdEvent : public TObject {
public:
TClonesArray *m_dev;
};

// where
m_dev = new TClonesArray(“Device”,100);

// and tried to read it with
TBranch *b_branch = m_tree->GetBranch(“m_dev[1]”);
b_branch->GetEntry(i);
[/code]
but pointer to branch is zero in that case. Could you please help me with that, i.e. “disabling/enabling” unnecessary devices in array?
Many thanks in advance and cheers.
Gennady.

2

When you use:Device *m_dev[100];all the device will be stored in the same branch. You will not be able to read them individual (i.e. when asking any of them, you will end up reading them all from the file).

Cheers,
Philippe.