new classes

From: Mario Kadastik <mario.kadastik_at_cern.ch>
Date: Sat, 1 Jul 2006 00:06:44 +0300

Hello,

could someone please help me as I'm utterly confused.

I'd like to create a new object to be used in TTree -s. I did create the following:

MyEvent.h

---

#include "TObject.h"
#include <cstdlib>

using namespace std;

class MyEvent : public TObject {
public:

   MyEvent();
   ~MyEvent() {};
   void setNr(Int_t nr);
   Int_t getNr();
private:

   Int_t nr;
   ClassDef(MyEvent,1)
};

MyEvent.cpp

---

#include "TObject.h"
#include "MyEvent.h"
#include <cstdlib>

using namespace std;

void MyEvent::setNr(Int_t nr_new) {

   nr = nr_new;
}

Int_t MyEvent::getNr() {

   return nr;
}

MyEvent::MyEvent() {

   nr=0;
}

ClassImp(MyEvent);

test.cpp

---

#include "TObject.h"
#include "MyEvent.h"
#include <cstdlib>
#include <iostream>

using namespace std;

int main(int argc, char **argv) {

         MyEvent * ev = new MyEvent();
         ev->setNr(1);
         cout << "Event nr: " << ev->getNr() << endl;
         return 0;

}

compiling it results in this:

[oberon] /home/mario/pythia/test > g++ -o libparticles.so -shared - rdynamic -O -Wall -fPIC MyEvent.cpp `root-config --cflags --libs -- glibs`
[oberon] /home/mario/pythia/test > g++ -o test test.cpp `root-config --cflags --libs --glibs` -L$PWD -lparticles/home/mario/pythia/test/ libparticles.so: undefined reference to `vtable for MyEvent' /home/mario/pythia/test/libparticles.so: undefined reference to `ROOT::GenerateInitInstance(MyEvent const*)' collect2: ld returned 1 exit status

what am I doing wrong? I really need just a basic class with some objects to use in trees. The trouble is there is no simple example I could reference ...

---

Mario Kadastik
CMS experiment
mario.kadastik_at_cern.ch

"Physics is like sex, sure it may give some practical results, but that's not why we do it"

• Richard P. Feynman

Received on Fri Jun 30 2006 - 23:06:54 MEST