Re: TTree with user defined class

Hello Bob,

Yeah, you need a dictionary, a couple of macros in your source file and that's it. Check this out

http://root.cern.ch/drupal/content/interacting-shared-libraries-rootcint

if you have any trouble let me know,

John Idarraga

Bob wrote:
> Hello,
>
> I'm a Root beginner, I'm trying to save a class to a TTree. Until now
> I managed to store and read "simple" type like int and STL objects,
> but not homemade objects.
>
> I'm made a short example :
>
> Code snippet :
>
> #include <TFile.h>
> #include <TTree.h>
> #include <vector>
> #include <iostream>
>
> class Sample {
> public:
> int i;
> std::vector<int> hits;
> };
>
> int main() {
> Sample *s = new Sample();
> TFile *f1 = new TFile("debug.root","RECREATE");
> if (f1->IsZombie()) {
> std::cerr << "! Unable to create debug.root" << std::endl;
> return -1;
> }
> TTree *tree = new TTree("T","Debug");
> //Case C
> // MyClass object;
> // TBranch *branch = tree->Branch(branchname, &object,
> bufsize, splitlevel)
> //
> tree->Branch("debug",s);
> for(int j=0;j<10;j++) {
> s->hits.empty();
> for(int i=0;i<100;i++) {
> s->hits.push_back(42+i);
> }
> tree->Fill();
> }
> f1->Write();
> delete s;
> delete tree;
> delete f1;
> return 0;
> }
>
> I compile with
>
> g++ -Wall -pedantic -pthread -m32
> -I/home/bob/root/root-5.26.00d/include -c ttree_write.cxx -o
> ttree_write.o
>
> and I link with
>
> g++ -L/home/bob/root/root-5.26.00d/lib -lNew -lCore -lCint -lRIO
> -lNet -lHist -lGraf -lGraf3d -lGpad -lTree -lRint -lPostscript
> -lMatrix -lPhysics -lMathCore -lThread -pthread -lm -ldl -rdynamic
> -L/home/bob/root/root-5.26.00d/lib -lNew -lCore -lCint -lRIO -lNet
> -lHist -lGraf -lGraf3d -lGpad -lTree -lRint -lPostscript -lMatrix
> -lPhysics -lMathCore -lThread -lGui -pthread -lm -ldl -rdynamic
> ttree_write.o -o ttree_write
>
> When I run the program I got
> Error in <TTree::Branch>: The pointer specified for debug is not of a
> class known to ROOT
>
> I'm sure that I miss an important step but I'm out of ideas ! Any tips ?
>
>
Received on Mon Sep 27 2010 - 11:33:45 CEST