On Wed, Nov 10, 2010 at 5:20 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Not in libpq. libpq is just a passive library, it can't cause actions
> to happen when you aren't calling it. So there's no point in a
> callback: you might as well just test for occurrences of a NOTIFY at
> times when you're prepared to handle it.
>
On my systems where I use them more or less as "wakeup and do work"
signals, I just do a select() call on the connection socket. When the
signal arrives, the socket becomes readable, and then I just query for
the notification.