hierclass::base::iterator b=h->begin(), e=h->end(); const std::list<keyClass> &name=*b; hierclass::base::readlock lock=b.clone();
begin() acquires a reader lock on the
container, then return a beginning value for an input iterator over a
sequence
of keys that have values in the container.
end() returns the ending iterator value.
end() does not acquire a reader lock.
A non ending-valued iterator releases its read lock when it reaches
the ending iterator value.
When the container is empty,
begin() acquires a reader lock, releases it,
then returns the ending iterator value.
A non-ending iterator also implements clone(),
which clones a reader lock, positioned at the node referenced by
the iterator's current key value.