On Nov 10, 2010, at 4:30 PM, Daniel Verite wrote: > Filonenko Michael wrote: > >> I create simple mechanism to inform user about something in database >> triggers. In my front-end I use PQsetNoticeReceiver, and display messages >> in QTextEdit. >> I think about multi-user environment. I read about NOTIFY/LISTEN, but find >> no callback mechanism. Is it planning? > > Not sure what the multi-user environment implies, but since you're using Qt, > you're probably interested in getting a Qt signal when a db notification > arrives. It turns out it's not hard to do: before calling LISTEN, instantiate > a QSocketNotifier object bound to the socket of the libpq connection, and > connect its activated() signal to a slot. In this slot, your code can deal > with the notification at the libpq level with PQconsumeInput() and > PQnotifies(), do your own processing, and just return. > With this method, you don't have any need for a callback or managing your own > loop: it is Qt's event loop that calls the slot, just as it does for > GUI-related events. It's even easier than that - Qt supports listen/notify directly. QSqlDriver::subscribeToNotification(), and connect the the notification() signal. Cheers, Steve -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
