Asynchronous Queries/libpq

Me again.

I am trying to understand the process for asynchronous queries in libpq, and
I want to make sure I understand the process correctly.

Is it that PQgetResult will return a full query result from a single
command, and will only return NULL if there are no more commands that have
not completed, therefore only needing to be called once per command in the
dispatched query; or is it that PQgetResult must be repeatedly called for
even a single command query, and that it will only return NULL after each
command in the dispatched query has completed fully?

Further, can we *always* assume that query results will be returned in the
order they appear in the query dispatch?

Thanks,

Keary Suska
Esoteritech, Inc.
"Demystifying technology for your home or business"