In my SteppingAction:public G4UserSteppingAction class,  I have the following
code:

void
SteppingAction::
UserSteppingAction(
    G4Step const* pStepData)
{
....

    G4String processName = ' ';
    G4VProcess const* processStep =
        pStepData->GetPostStepPoint()->GetProcessDefinedStep();
    if(processStep)
    {
        processName = processStep->GetProcessName();
        if (processName == "LowEnCompton")
        {
            G4VParticleChange *pch = fpSteppingManager->GetfParticleChange();

            G4int nOfSecondaries = pch->numberOfSecondaries();
            G4Track const* secondary = temp->GetSecondary(0);

            .....

        }
etc.

The values of nOfSecondaries should never be zero, because Compton scattering
always produces an electron.  Indeed, when I check the pointer to the first
secondary in the list of secondaries (G4Track const* secondary) - it is a valid
non-zero pointer, and the secondary particle described there is an electron, as
it should be.  However, the value returned by
G4VParticleChange::numberOfSecondaries() method is a dead zero.

Here is what I was trying to accomplish in my SteppingAction class: for each
particle species and each process, I wanted to get the number of secondaries
through G4VParticleChange::numberOfSecondaries() as shown in the code snippet
above, and then I wanted to access every secondary via
G4VParticleChange::GetSecondary(index). I sure can go around the fact that
G4VParticleChange::numberOfSecondaries() does not work as I expected, but it
would be nice to know whether

 *** I am doing something wrong or this is a bug? ***

Thanks,
-- Elena.