bool PVTimeStamp::set(TimeStamp const & timeStamp)
{
    if(pvSecs.get()==NULL) {
        throw std::logic_error(notAttached);
    }
    if(pvSecs->isImmutable() || pvNano->isImmutable()) return false;
    pvSecs->put(timeStamp.getSecondsPastEpoch());
    pvUserTag->put(timeStamp.getUserTag());
    pvNano->put(timeStamp.getNanoseconds());
    return true;
}