[Exim] Log rotation query.

When rotating logs, is there a signal to send exim to force it to close
and reopen it's logfile? Or is it the case that exim does this
frequently enough of it's own accord not to matter?

Can't find in either the documentation, FAQ or mailing list
archives. Seems odd since it must be a question which other people have
asked.

I note that exicyclog doesn't compress the first rotated copy of the
logfile, so using it, it doesn't matter too much if the logfile is closed
promptly. However if I want to rotate and compress immediately, I need
to ensure that the file is no longer being written to.

Thanks.

John