Error in <TChain::SetBranchAddress>

In my code, I read some variables who are 2-d vector from the ntuple,
and show the error :

Error in TChain::SetBranchAddress: The class requested (vector<vector >) for the branch “truth_parents_e” refer to an stl collection and do not have a compiled CollectionProxy. Please generate the dictionary for this class (vector<vector >)

How can I add vector<vector > class in my code.

Since the code is a bit complicate, I am not running on the Macro, I compile my code
and produce the executable file.
I tried to add
#pragma link C++ class vector<vector >+
in *.C code or
gROOT->ProcessLine("#pragma link C++ class vector<vector >+;");
in main code.
but both do not work,
any idea, thanks in advance.


The pragma must be seen by rootcint in order to be useful.
Use a simple file loader.C// Loader.C #include <vector> #ifdef __MAKECINT__ #pragma link C++ class vector<vector<double> >+; #endif
and use:gROOT->ProcessLine(".L loader.C+");