I think with the following modification it should work fine:
Cheers,
Krzysztof
//-------------------------------------------------------------
#include <TROOT.h>
#include <TFile.h>
TROOT root( "example","description" ); //initialize root
main ()
{
TFile *rootfile = new TFile("glb.root", "READ", "glb.root");
rootfile->Map();
}