cet-is » art

Dear root experts:

I have a problem using code which defines root schema using an inherited struct. My class structure is:

struct TrkHitInfo {
.. data members
};

struct DeltaHitInfo : TrkHitInfo {
... additional data members
};

I use these in root schema using reflex:

(classes.h):

#include <vector>
#include "TrkPatRec/inc/StrawHitInfo.hh" 
#include "TrkPatRec/inc/DeltaHitInfo.hh" 
template class std::vector<mu2e::StrawHitInfo>;
template class std::vector<mu2e::DeltaHitInfo>;

(classes_def.xml):

<lcgdict>
    <class name="mu2e::StrawHitInfo" />
    <class name="std::vector<mu2e::StrawHitInfo>" />
    <class name="mu2e::DeltaHitInfo" />
    <class name="std::vector<mu2e::DeltaHitInfo>" />
</lcgdict>

The schema and generated code compile fine, however there is a runtime error:

-bash-3.2$ mu2e -c debug.fcl
%MSG-i MF_INIT_OK:  mu2e 22-Sep-2012 07:38:06 PDT JobSetup
Messagelogger initialization complete.
%MSG
terminate called after throwing an instance of
'cet::coded_exception<art::errors::ErrorCodes,
&(art::ExceptionDetail::translate(art::errors::ErrorCodes))>'
  what():  ---- Configuration BEGIN
  Unable to load requested library
/home/online1/brownd/mu2e/Mu2eSim/art2/Offline/lib/libTrkPatRec_dict.so
  /home/online1/brownd/mu2e/Mu2eSim/art2/Offline/lib/libTrkPatRec_dict.so:
undefined symbol: vtable for mu2e::DeltaHitInfo
---- Configuration END

By contrast, persistent forms of StrawHitInfo work fine.

I have tried to force the creation of a virtual table in DeltaHitInfo
by declaring and implementing a virtual destructor, with no change in
the above. I'd be interested to know if root experts think this is an
art issue or a root issue.
thanks, David Brown