TTree::Branch question

ROOT
1

Hello.
I am trying to make my own class and store objects of it on a tree.
My class looks like this:

Point.cpp:

#include <TObject.h>

class Point : public TObject
{
private:
  float x;
  float y;
  float z;

public:
  Point(float x, float y, float z);
  
  void SetPoint(float x, float y, float z);
  
  float GetPointX(void);
  float GetPointY(void);
  float GetPointZ(void);


  ClassDef(Point, 1);
};

Point::Point(float x, float y, float z)
{ this->x = x; this->y = y; this->z = z; }

void Point::SetPoint(float x, float y, float z)
{ this->x = x; this->y = y; this->z = z; }

float Point::GetPointX(void)
{ return this->x; }

float Point::GetPointY(void)
{ return this->y; }

float Point::GetPointZ(void)
{ return this->z; }

#if !defined(_CINT_)
ClassImp(Point);
#endif

.

My program is the following.
treestuff.cpp:

#include <stdio.h>
#include <TFile.h>
#include <TTree.h>
#include <TObject.h>
#include "Point.cpp"


int go(void)
{
  if (!TClass::GetDict("Point"))
    gROOT->ProcessLine(".L Point.cpp+");

  TFile *file = new TFile("foo.root","RECREATE","practice file");
  TTree *tree = new TTree("tree1","A glorious tree");

  Point *pnt = new Point(0,0,0);
  
  tree->Branch("PointBranch","Point",&pnt);
  
  return 0;
}

When I literally type what is in my program directly into the interpreter, everything seems to work fine, but when I try to do it by loading treestuff.cpp, I get the following output.

root [0] .L treestuff.cpp
root [1] go()
Error in <TTree::Branch>: The actual class (TObject) of the object provided for the definition of the branch "PointBranch" does not inherit from Point
(int)0

I don’t know what to make of this error. My object *pnt seems to be of class Point, not just TObject…

2

in your version of treestuff.cpp, you include Point.cpp before loading the compiled code, so CINT will create its own interpreted class and you will get a mismatch between the two. The solution is to do

root > .L Point.cpp+ root > .L treestuff.C or .L treestuff.C+ root > go()
with treetuff.C without the gROOT->ProcessLine statement

Rene

3

Thank you very much for the help. Everything seems to work now, but there is some output that I don’t understand when I compile:

root [1] .L treestuff.C+
Info in <TUnixSystem::ACLiC>: creating shared library /root/playground/./treestuff_C.so
Error in <TUnixSystem::DynamicPathName>: libvectorDict[.so | .sl | .dl | .a | .dll] does not exist in .:/root/software/root/lib::/root/software/root/lib:/root/software/root/lib:/root/software/root/lib:/root/software/root/cint/cint/stl

Is this something I should be concerned about?
Thanks!

4

Nothing to worry to run this simple example, but you may have a problem if you use std::vector.
I would need more info about your installation.

Ree