Error accessing an STL vector in a tree from a file

ROOT
1

Hello again,

I have run into a snag trying to read objects of the following class from ROOT trees:

class particle_event : public TObject
{
public:

        particle_event();
        ~particle_event();

        void Clear(Option_t *opt = "");

        inline vector<st_track> &getPrimaryElectronPlus(void);
        inline UInt_t getNumPrimaryElectronPlus(void) const;
        inline vector<st_track> &getPrimaryElectronMinus(void);
        inline UInt_t getNumPrimaryElectronMinus(void) const;
        inline vector<st_track> &getGlobalElectronPlus(void);
        inline UInt_t getNumGlobalElectronPlus(void) const;
        inline vector<st_track> &getGlobalElectronMinus(void);
        inline UInt_t getNumGlobalElectronMinus(void) const;

        inline UShort_t getCentralityClass(void) const;
        inline Int_t getEventNum(void) const;
        inline Int_t getNTrack(void) const;
        inline Double_t getVZ(void) const;

        inline void setCentralityClass(const UShort_t a);
        inline void setEventNum(const Int_t a);
        inline void setNTrack(const Int_t a);
        inline void setVZ(const Double_t a);


private:

        vector<st_track> mPrimaryElectronPlus;  //||
        vector<st_track> mPrimaryElectronMinus; //||
        vector<st_track> mGlobalElectronPlus;   //||
        vector<st_track> mGlobalElectronMinus;  //||

        UShort_t mCentralityClass;
        Int_t mEventNum;
        Int_t mNTrack;
        Double_t mVZ;

        ClassDef(particle_event, 1)

};

The writing code seems to work fine (calling Show() on the tree displays all the numbers that were supposed to end up stored) and I have no problems reading fundamental data members, but trying to do anything on any of the vectors causes the interpreter to throw an error.

The reader macro looks as follows:

void treeReadTest(void)
{
        gSystem->Load("libMKS"); // this is where particle_event is

        TFile *f = new TFile("test.root");
        TTree *t4 = (TTree *) f->Get("PicoTree");
        particle_event *event = new particle_event();

        TBranch *branch = t4->GetBranch("particle_events");
        branch->SetAddress(&event);

        Int_t nevent = (Int_t) t4->GetEntries();
        for (Int_t i = 0; i < nevent; i++) {
                branch->GetEntry(i);

                cout << "Read event " << event->getEventNum()
                        << "\n\tnTrack: " <<event->getNTrack()
                        << "\n\tprimary tracks (+/-): " << event->getNumPrimaryElectronPlus() << " / " << event->getNumPrimaryElectronMinus()
                        << "\n\tglobal tracks (+/-): " << event->getNumGlobalElectronPlus() << " / " << event->getNumGlobalElectronMinus()
                        << '\n' << endl;

                if (event->getNumPrimaryElectronMinus() > 0)
                        cout << "VECT " << event->getPrimaryElectronMinus().size() << endl;

                event->Clear();
        }

        return;
}

and the error in question is shown below:

Processing treeReadTest.C...
Read event 187986
	nTrack: 174
	primary tracks (+/-): 0 / 1
	global tracks (+/-): 0 / 1

Error: Can't call vector<st_track,allocator<st_track> >::size() in current scope treeReadTest.C:28:
Possible candidates are...
(in vector<st_track,allocator<st_track> >)
Error: non class,struct,union object getPrimaryElectronMinus() used with . or -> treeReadTest.C:28:
VECT (class G__CINT_ENDL)192951200
*** Interpreter error recovered ***

This is the end of ROOT -- Goodbye

What is wrong here?

2

I’ve worked it out - it seems the problem lies with CINT, as running the reader macro in compiled mode makes the problem go away.

3

Hi,

To run in CINT you are most likely missing the dictionary for vector<st_track>

Cheers,
Philippe