Is libpq re-entrant?

Dear Hackers,

Can anyone confirm for me that libpq is re-entrant. Ie, it is safe to
execute libpq calls from within a signal handler when that signal could've
interrupted a libpq function? Of course I don't expect to be able to use
the same PGconn or PGresult structures inside the signal handler as
outside.

I've looked through the 6.4.2 libpq documentation and it doesn't say,
although the existence of non-blocking calls implies it could be made
re-entrant quite easily.

Many thanks
Ian