Error accessing an STL vector in a tree from a file

Hello again,

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

class particle_event : public TObject


        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);


        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");

        Int_t nevent = (Int_t) t4->GetEntries();
        for (Int_t i = 0; i < nevent; 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;



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?

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.


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