Dynamic background workers & docs question

I was looking at
http://www.postgresql.org/docs/devel/static/bgworker.htmlwith a client
today.

It says:
"Unlike RegisterBackgroundWorker, which can only be called from within the
postmaster,RegisterDynamicBackgroundWorker must be called from a regular
backend."

Is that the correct restriction? In particular, don't we allow calling
RegisterDynamicBackgroundWorker from another background worker? (In the
launcher/worker kind of scenario, like AutoVacuum).

Also:
"Background workers are expected to be continuously running; if they exit
cleanly, postgres will restart them immediately. "

This doesn't apply to dynamic ones, which we might want to clarify. Do we
have a "term" for non-dynamic background workers? "static workers"?

--
Magnus Hagander
Me: http://www.hagander.net/
Work: http://www.redpill-linpro.com/