Function PQnotifies

src/interfaces/libpq/fe-exec.c:2554–2574

* PQnotifies * returns a PGnotify* structure of the latest async notification * that has not yet been handled * * returns NULL, if there is currently * no unhandled async notification from the backend * * the CALLER is responsible for FREE'ing the structure returned * * Note that this function does not read any new data from the socket; * so usually, caller should call PQconsumeInput()

 * so usually, caller should call PQconsumeInput() first.
 */
PGnotify *
PQnotifies(PGconn *conn)
{
	PGnotify   *event;

	if (!conn)
		return NULL;

	/* Parse any available data to see if we can extract NOTIFY messages. */
	parseInput(conn);

	event = conn->notifyHead;
	if (event)
	{
		conn->notifyHead = event->next;
		if (!conn->notifyHead)
			conn->notifyTail = NULL;
		event->next = NULL;		/* don't let app see the internal state */
	}
	return event;
}

/*
 * PQputCopyData - send some data to the backend during COPY IN or COPY BOTH