[ViewVC] Diff of: cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.73 by root, Sat Dec 8 03:53:36 2007 UTC vs.
Revision 1.76 by root, Sat Dec 8 15:30:30 2007 UTC

…		…
777		777
778	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is	778	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
779	fine, as long as you do not mind that the priority value you query might	779	fine, as long as you do not mind that the priority value you query might
780	or might not have been adjusted to be within valid range.	780	or might not have been adjusted to be within valid range.
781		781
		782	=item ev_invoke (loop, ev_TYPE *watcher, int revents)
		783
		784	Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
		785	C<loop> nor C<revents> need to be valid as long as the watcher callback
		786	can deal with that fact.
		787
		788	=item int ev_clear_pending (loop, ev_TYPE *watcher)
		789
		790	If the watcher is pending, this function returns clears its pending status
		791	and returns its C<revents> bitset (as if its callback was invoked). If the
		792	watcher isn't pending it does nothing and returns C<0>.
		793
782	=back	794	=back
783		795
784		796
785	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	797	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
786		798
…		…
1481	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>	1493	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>
1482	macros, but using them is utterly, utterly and completely pointless.	1494	macros, but using them is utterly, utterly and completely pointless.
1483		1495
1484	=back	1496	=back
1485		1497
1486	Example: To include a library such as adns, you would add IO watchers	1498	There are a number of principal ways to embed other event loops or modules
1487	and a timeout watcher in a prepare handler, as required by libadns, and	1499	into libev. Here are some ideas on how to include libadns into libev
		1500	(there is a Perl module named C<EV::ADNS> that does this, which you could
		1501	use for an actually working example. Another Perl module named C<EV::Glib>
		1502	embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV
		1503	into the Glib event loop).
		1504
		1505	Method 1: Add IO watchers and a timeout watcher in a prepare handler,
1488	in a check watcher, destroy them and call into libadns. What follows is	1506	and in a check watcher, destroy them and call into libadns. What follows
1489	pseudo-code only of course:	1507	is pseudo-code only of course. This requires you to either use a low
		1508	priority for the check watcher or use C<ev_clear_pending> explicitly, as
		1509	the callbacks for the IO/timeout watchers might not have been called yet.
1490		1510
1491	static ev_io iow [nfd];	1511	static ev_io iow [nfd];
1492	static ev_timer tw;	1512	static ev_timer tw;
1493		1513
1494	static void	1514	static void
1495	io_cb (ev_loop loop, ev_io w, int revents)	1515	io_cb (ev_loop loop, ev_io w, int revents)
1496	{	1516	{
1497	// set the relevant poll flags
1498	// could also call adns_processreadable etc. here
1499	struct pollfd fd = (struct pollfd )w->data;
1500	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1501	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
1502	}	1517	}
1503		1518
1504	// create io watchers for each fd and a timer before blocking	1519	// create io watchers for each fd and a timer before blocking
1505	static void	1520	static void
1506	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1521	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
…		…
1512		1527
1513	/* the callback is illegal, but won't be called as we stop during check */	1528	/* the callback is illegal, but won't be called as we stop during check */
1514	ev_timer_init (&tw, 0, timeout * 1e-3);	1529	ev_timer_init (&tw, 0, timeout * 1e-3);
1515	ev_timer_start (loop, &tw);	1530	ev_timer_start (loop, &tw);
1516		1531
1517	// create on ev_io per pollfd	1532	// create one ev_io per pollfd
1518	for (int i = 0; i < nfd; ++i)	1533	for (int i = 0; i < nfd; ++i)
1519	{	1534	{
1520	ev_io_init (iow + i, io_cb, fds [i].fd,	1535	ev_io_init (iow + i, io_cb, fds [i].fd,
1521	((fds [i].events & POLLIN ? EV_READ : 0)	1536	((fds [i].events & POLLIN ? EV_READ : 0)
1522	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	1537	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1523		1538
1524	fds [i].revents = 0;	1539	fds [i].revents = 0;
1525	iow [i].data = fds + i;
1526	ev_io_start (loop, iow + i);	1540	ev_io_start (loop, iow + i);
1527	}	1541	}
1528	}	1542	}
1529		1543
1530	// stop all watchers after blocking	1544	// stop all watchers after blocking
…		…
1532	adns_check_cb (ev_loop loop, ev_check w, int revents)	1546	adns_check_cb (ev_loop loop, ev_check w, int revents)
1533	{	1547	{
1534	ev_timer_stop (loop, &tw);	1548	ev_timer_stop (loop, &tw);
1535		1549
1536	for (int i = 0; i < nfd; ++i)	1550	for (int i = 0; i < nfd; ++i)
		1551	{
		1552	// set the relevant poll flags
		1553	// could also call adns_processreadable etc. here
		1554	struct pollfd *fd = fds + i;
		1555	int revents = ev_clear_pending (iow + i);
		1556	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1557	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1558
		1559	// now stop the watcher
1537	ev_io_stop (loop, iow + i);	1560	ev_io_stop (loop, iow + i);
		1561	}
1538		1562
1539	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	1563	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1564	}
		1565
		1566	Method 2: This would be just like method 1, but you run C<adns_afterpoll>
		1567	in the prepare watcher and would dispose of the check watcher.
		1568
		1569	Method 3: If the module to be embedded supports explicit event
		1570	notification (adns does), you can also make use of the actual watcher
		1571	callbacks, and only destroy/create the watchers in the prepare watcher.
		1572
		1573	static void
		1574	timer_cb (EV_P_ ev_timer *w, int revents)
		1575	{
		1576	adns_state ads = (adns_state)w->data;
		1577	update_now (EV_A);
		1578
		1579	adns_processtimeouts (ads, &tv_now);
		1580	}
		1581
		1582	static void
		1583	io_cb (EV_P_ ev_io *w, int revents)
		1584	{
		1585	adns_state ads = (adns_state)w->data;
		1586	update_now (EV_A);
		1587
		1588	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
		1589	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
		1590	}
		1591
		1592	// do not ever call adns_afterpoll
		1593
		1594	Method 4: Do not use a prepare or check watcher because the module you
		1595	want to embed is too inflexible to support it. Instead, youc na override
		1596	their poll function. The drawback with this solution is that the main
		1597	loop is now no longer controllable by EV. The C<Glib::EV> module does
		1598	this.
		1599
		1600	static gint
		1601	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
		1602	{
		1603	int got_events = 0;
		1604
		1605	for (n = 0; n < nfds; ++n)
		1606	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
		1607
		1608	if (timeout >= 0)
		1609	// create/start timer
		1610
		1611	// poll
		1612	ev_loop (EV_A_ 0);
		1613
		1614	// stop timer again
		1615	if (timeout >= 0)
		1616	ev_timer_stop (EV_A_ &to);
		1617
		1618	// stop io watchers again - their callbacks should have set
		1619	for (n = 0; n < nfds; ++n)
		1620	ev_io_stop (EV_A_ iow [n]);
		1621
		1622	return got_events;
1540	}	1623	}
1541		1624
1542		1625
1543	=head2 C<ev_embed> - when one backend isn't enough...	1626	=head2 C<ev_embed> - when one backend isn't enough...
1544		1627
…		…
1832		1915
1833	myclass obj;	1916	myclass obj;
1834	ev::io iow;	1917	ev::io iow;
1835	iow.set <myclass, &myclass::io_cb> (&obj);	1918	iow.set <myclass, &myclass::io_cb> (&obj);
1836		1919
1837	=item w->set (void (function)(watcher &w, int), void data = 0)	1920	=item w->set<function> (void *data = 0)
1838		1921
1839	Also sets a callback, but uses a static method or plain function as	1922	Also sets a callback, but uses a static method or plain function as
1840	callback. The optional C<data> argument will be stored in the watcher's	1923	callback. The optional C<data> argument will be stored in the watcher's
1841	C<data> member and is free for you to use.	1924	C<data> member and is free for you to use.
1842		1925
		1926	The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>.
		1927
1843	See the method-C<set> above for more details.	1928	See the method-C<set> above for more details.
		1929
		1930	Example:
		1931
		1932	static void io_cb (ev::io &w, int revents) { }
		1933	iow.set <io_cb> ();
1844		1934
1845	=item w->set (struct ev_loop *)	1935	=item w->set (struct ev_loop *)
1846		1936
1847	Associates a different C<struct ev_loop> with this watcher. You can only	1937	Associates a different C<struct ev_loop> with this watcher. You can only
1848	do this when the watcher is inactive (and not pending either).	1938	do this when the watcher is inactive (and not pending either).

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Comparing libev/ev.pod (file contents): Revision 1.73 by root, Sat Dec 8 03:53:36 2007 UTC vs. Revision 1.76 by root, Sat Dec 8 15:30:30 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.73 by root, Sat Dec 8 03:53:36 2007 UTC vs.
Revision 1.76 by root, Sat Dec 8 15:30:30 2007 UTC