The HepMC event record provides both the functionality of an event record for event generators and an interface to the /HEPEVT/ standard common block for Fortran event generators.  It has code for I/O into an ascii format.  For use in STAR it would ideally be streamable into a ROOT file... addition of ROOT I/O features are investigated in this blog entry.

1) Simple integration into STAR environment

$ lynx http://lcgapp.cern.ch/project/simu/HepMC/download/
# Get the latest tar ball
$ mkdir StRoot
$ mkdir StRoot/HepMC
$ tar xvzf *.tar.gz
$ cp HepMC*/{src,HepMC,fio}/* StRoot/HepMC
$ cons

This minimal build produces a standalone HepMC library which can be loaded into ROOT, but w/out ROOT I/O or integration w/ CINT.

2) Few attempts to add ROOT I/O to the code failed.  Get errors in compiling the root dictionary.  Probably need a custom linkdef.  After a google search came up with following post in ROOT talk.