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

Comparing libev/ev.pod (file contents):
Revision 1.68 by root, Fri Dec 7 18:09:43 2007 UTC vs.
Revision 1.79 by root, Sun Dec 9 19:46:56 2007 UTC

…		…
47		47
48	return 0;	48	return 0;
49	}	49	}
50		50
51	=head1 DESCRIPTION	51	=head1 DESCRIPTION
		52
		53	The newest version of this document is also available as a html-formatted
		54	web page you might find easier to navigate when reading it for the first
		55	time: L<http://cvs.schmorp.de/libev/ev.html>.
52		56
53	Libev is an event loop: you register interest in certain events (such as a	57	Libev is an event loop: you register interest in certain events (such as a
54	file descriptor being readable or a timeout occuring), and it will manage	58	file descriptor being readable or a timeout occuring), and it will manage
55	these event sources and provide your program with events.	59	these event sources and provide your program with events.
56		60
…		…
113		117
114	=item int ev_version_major ()	118	=item int ev_version_major ()
115		119
116	=item int ev_version_minor ()	120	=item int ev_version_minor ()
117		121
118	You can find out the major and minor version numbers of the library	122	You can find out the major and minor API/ABI version numbers of the library
119	you linked against by calling the functions C<ev_version_major> and	123	you linked against by calling the functions C<ev_version_major> and
120	C<ev_version_minor>. If you want, you can compare against the global	124	C<ev_version_minor>. If you want, you can compare against the global
121	symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the	125	symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the
122	version of the library your program was compiled against.	126	version of the library your program was compiled against.
123		127
		128	These version numbers refer to the API and ABI version of the library, not
		129	the release version.
		130
124	Usually, it's a good idea to terminate if the major versions mismatch,	131	Usually, it's a good idea to terminate if the major versions mismatch,
125	as this indicates an incompatible change. Minor versions are usually	132	as this indicates an incompatible change. Minor versions are usually
126	compatible to older versions, so a larger minor version alone is usually	133	compatible to older versions, so a larger minor version alone is usually
127	not a problem.	134	not a problem.
128		135
129	Example: Make sure we haven't accidentally been linked against the wrong	136	Example: Make sure we haven't accidentally been linked against the wrong
130	version.	137	version.
…		…
482	libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is	489	libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is
483	usually a better approach for this kind of thing.	490	usually a better approach for this kind of thing.
484		491
485	Here are the gory details of what C<ev_loop> does:	492	Here are the gory details of what C<ev_loop> does:
486		493
		494	- Before the first iteration, call any pending watchers.
487	* If there are no active watchers (reference count is zero), return.	495	* If there are no active watchers (reference count is zero), return.
488	- Queue prepare watchers and then call all outstanding watchers.	496	- Queue all prepare watchers and then call all outstanding watchers.
489	- If we have been forked, recreate the kernel state.	497	- If we have been forked, recreate the kernel state.
490	- Update the kernel state with all outstanding changes.	498	- Update the kernel state with all outstanding changes.
491	- Update the "event loop time".	499	- Update the "event loop time".
492	- Calculate for how long to block.	500	- Calculate for how long to block.
493	- Block the process, waiting for any events.	501	- Block the process, waiting for any events.
…		…
732	=item bool ev_is_pending (ev_TYPE *watcher)	740	=item bool ev_is_pending (ev_TYPE *watcher)
733		741
734	Returns a true value iff the watcher is pending, (i.e. it has outstanding	742	Returns a true value iff the watcher is pending, (i.e. it has outstanding
735	events but its callback has not yet been invoked). As long as a watcher	743	events but its callback has not yet been invoked). As long as a watcher
736	is pending (but not active) you must not call an init function on it (but	744	is pending (but not active) you must not call an init function on it (but
737	C<ev_TYPE_set> is safe) and you must make sure the watcher is available to	745	C<ev_TYPE_set> is safe), you must not change its priority, and you must
738	libev (e.g. you cnanot C<free ()> it).	746	make sure the watcher is available to libev (e.g. you cannot C<free ()>
		747	it).
739		748
740	=item callback ev_cb (ev_TYPE *watcher)	749	=item callback ev_cb (ev_TYPE *watcher)
741		750
742	Returns the callback currently set on the watcher.	751	Returns the callback currently set on the watcher.
743		752
…		…
762	watchers on the same event and make sure one is called first.	771	watchers on the same event and make sure one is called first.
763		772
764	If you need to suppress invocation when higher priority events are pending	773	If you need to suppress invocation when higher priority events are pending
765	you need to look at C<ev_idle> watchers, which provide this functionality.	774	you need to look at C<ev_idle> watchers, which provide this functionality.
766		775
		776	You I<must not> change the priority of a watcher as long as it is active or
		777	pending.
		778
767	The default priority used by watchers when no priority has been set is	779	The default priority used by watchers when no priority has been set is
768	always C<0>, which is supposed to not be too high and not be too low :).	780	always C<0>, which is supposed to not be too high and not be too low :).
769		781
770	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is	782	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
771	fine, as long as you do not mind that the priority value you query might	783	fine, as long as you do not mind that the priority value you query might
772	or might not have been adjusted to be within valid range.	784	or might not have been adjusted to be within valid range.
		785
		786	=item ev_invoke (loop, ev_TYPE *watcher, int revents)
		787
		788	Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
		789	C<loop> nor C<revents> need to be valid as long as the watcher callback
		790	can deal with that fact.
		791
		792	=item int ev_clear_pending (loop, ev_TYPE *watcher)
		793
		794	If the watcher is pending, this function returns clears its pending status
		795	and returns its C<revents> bitset (as if its callback was invoked). If the
		796	watcher isn't pending it does nothing and returns C<0>.
773		797
774	=back	798	=back
775		799
776		800
777	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	801	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
1053	but on wallclock time (absolute time). You can tell a periodic watcher	1077	but on wallclock time (absolute time). You can tell a periodic watcher
1054	to trigger "at" some specific point in time. For example, if you tell a	1078	to trigger "at" some specific point in time. For example, if you tell a
1055	periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now ()	1079	periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now ()
1056	+ 10.>) and then reset your system clock to the last year, then it will	1080	+ 10.>) and then reset your system clock to the last year, then it will
1057	take a year to trigger the event (unlike an C<ev_timer>, which would trigger	1081	take a year to trigger the event (unlike an C<ev_timer>, which would trigger
1058	roughly 10 seconds later and of course not if you reset your system time	1082	roughly 10 seconds later).
1059	again).
1060		1083
1061	They can also be used to implement vastly more complex timers, such as	1084	They can also be used to implement vastly more complex timers, such as
1062	triggering an event on eahc midnight, local time.	1085	triggering an event on each midnight, local time or other, complicated,
		1086	rules.
1063		1087
1064	As with timers, the callback is guarenteed to be invoked only when the	1088	As with timers, the callback is guarenteed to be invoked only when the
1065	time (C<at>) has been passed, but if multiple periodic timers become ready	1089	time (C<at>) has been passed, but if multiple periodic timers become ready
1066	during the same loop iteration then order of execution is undefined.	1090	during the same loop iteration then order of execution is undefined.
1067		1091
…		…
1074	Lots of arguments, lets sort it out... There are basically three modes of	1098	Lots of arguments, lets sort it out... There are basically three modes of
1075	operation, and we will explain them from simplest to complex:	1099	operation, and we will explain them from simplest to complex:
1076		1100
1077	=over 4	1101	=over 4
1078		1102
1079	=item * absolute timer (interval = reschedule_cb = 0)	1103	=item * absolute timer (at = time, interval = reschedule_cb = 0)
1080		1104
1081	In this configuration the watcher triggers an event at the wallclock time	1105	In this configuration the watcher triggers an event at the wallclock time
1082	C<at> and doesn't repeat. It will not adjust when a time jump occurs,	1106	C<at> and doesn't repeat. It will not adjust when a time jump occurs,
1083	that is, if it is to be run at January 1st 2011 then it will run when the	1107	that is, if it is to be run at January 1st 2011 then it will run when the
1084	system time reaches or surpasses this time.	1108	system time reaches or surpasses this time.
1085		1109
1086	=item * non-repeating interval timer (interval > 0, reschedule_cb = 0)	1110	=item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)
1087		1111
1088	In this mode the watcher will always be scheduled to time out at the next	1112	In this mode the watcher will always be scheduled to time out at the next
1089	C<at + N * interval> time (for some integer N) and then repeat, regardless	1113	C<at + N * interval> time (for some integer N, which can also be negative)
1090	of any time jumps.	1114	and then repeat, regardless of any time jumps.
1091		1115
1092	This can be used to create timers that do not drift with respect to system	1116	This can be used to create timers that do not drift with respect to system
1093	time:	1117	time:
1094		1118
1095	ev_periodic_set (&periodic, 0., 3600., 0);	1119	ev_periodic_set (&periodic, 0., 3600., 0);
…		…
1101		1125
1102	Another way to think about it (for the mathematically inclined) is that	1126	Another way to think about it (for the mathematically inclined) is that
1103	C<ev_periodic> will try to run the callback in this mode at the next possible	1127	C<ev_periodic> will try to run the callback in this mode at the next possible
1104	time where C<time = at (mod interval)>, regardless of any time jumps.	1128	time where C<time = at (mod interval)>, regardless of any time jumps.
1105		1129
		1130	For numerical stability it is preferable that the C<at> value is near
		1131	C<ev_now ()> (the current time), but there is no range requirement for
		1132	this value.
		1133
1106	=item * manual reschedule mode (reschedule_cb = callback)	1134	=item * manual reschedule mode (at and interval ignored, reschedule_cb = callback)
1107		1135
1108	In this mode the values for C<interval> and C<at> are both being	1136	In this mode the values for C<interval> and C<at> are both being
1109	ignored. Instead, each time the periodic watcher gets scheduled, the	1137	ignored. Instead, each time the periodic watcher gets scheduled, the
1110	reschedule callback will be called with the watcher as first, and the	1138	reschedule callback will be called with the watcher as first, and the
1111	current time as second argument.	1139	current time as second argument.
1112		1140
1113	NOTE: I<This callback MUST NOT stop or destroy any periodic watcher,	1141	NOTE: I<This callback MUST NOT stop or destroy any periodic watcher,
1114	ever, or make any event loop modifications>. If you need to stop it,	1142	ever, or make any event loop modifications>. If you need to stop it,
1115	return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by	1143	return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by
1116	starting a prepare watcher).	1144	starting an C<ev_prepare> watcher, which is legal).
1117		1145
1118	Its prototype is C<ev_tstamp (reschedule_cb)(struct ev_periodic w,	1146	Its prototype is C<ev_tstamp (reschedule_cb)(struct ev_periodic w,
1119	ev_tstamp now)>, e.g.:	1147	ev_tstamp now)>, e.g.:
1120		1148
1121	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)	1149	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)
…		…
1143		1171
1144	Simply stops and restarts the periodic watcher again. This is only useful	1172	Simply stops and restarts the periodic watcher again. This is only useful
1145	when you changed some parameters or the reschedule callback would return	1173	when you changed some parameters or the reschedule callback would return
1146	a different time than the last time it was called (e.g. in a crond like	1174	a different time than the last time it was called (e.g. in a crond like
1147	program when the crontabs have changed).	1175	program when the crontabs have changed).
		1176
		1177	=item ev_tstamp offset [read-write]
		1178
		1179	When repeating, this contains the offset value, otherwise this is the
		1180	absolute point in time (the C<at> value passed to C<ev_periodic_set>).
		1181
		1182	Can be modified any time, but changes only take effect when the periodic
		1183	timer fires or C<ev_periodic_again> is being called.
1148		1184
1149	=item ev_tstamp interval [read-write]	1185	=item ev_tstamp interval [read-write]
1150		1186
1151	The current interval value. Can be modified any time, but changes only	1187	The current interval value. Can be modified any time, but changes only
1152	take effect when the periodic timer fires or C<ev_periodic_again> is being	1188	take effect when the periodic timer fires or C<ev_periodic_again> is being
…		…
1461	with priority higher than or equal to the event loop and one coroutine	1497	with priority higher than or equal to the event loop and one coroutine
1462	of lower priority, but only once, using idle watchers to keep the event	1498	of lower priority, but only once, using idle watchers to keep the event
1463	loop from blocking if lower-priority coroutines are active, thus mapping	1499	loop from blocking if lower-priority coroutines are active, thus mapping
1464	low-priority coroutines to idle/background tasks).	1500	low-priority coroutines to idle/background tasks).
1465		1501
		1502	It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>)
		1503	priority, to ensure that they are being run before any other watchers
		1504	after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers,
		1505	too) should not activate ("feed") events into libev. While libev fully
		1506	supports this, they will be called before other C<ev_check> watchers did
		1507	their job. As C<ev_check> watchers are often used to embed other event
		1508	loops those other event loops might be in an unusable state until their
		1509	C<ev_check> watcher ran (always remind yourself to coexist peacefully with
		1510	others).
		1511
1466	=over 4	1512	=over 4
1467		1513
1468	=item ev_prepare_init (ev_prepare *, callback)	1514	=item ev_prepare_init (ev_prepare *, callback)
1469		1515
1470	=item ev_check_init (ev_check *, callback)	1516	=item ev_check_init (ev_check *, callback)
…		…
1473	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>	1519	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>
1474	macros, but using them is utterly, utterly and completely pointless.	1520	macros, but using them is utterly, utterly and completely pointless.
1475		1521
1476	=back	1522	=back
1477		1523
1478	Example: To include a library such as adns, you would add IO watchers	1524	There are a number of principal ways to embed other event loops or modules
1479	and a timeout watcher in a prepare handler, as required by libadns, and	1525	into libev. Here are some ideas on how to include libadns into libev
		1526	(there is a Perl module named C<EV::ADNS> that does this, which you could
		1527	use for an actually working example. Another Perl module named C<EV::Glib>
		1528	embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV
		1529	into the Glib event loop).
		1530
		1531	Method 1: Add IO watchers and a timeout watcher in a prepare handler,
1480	in a check watcher, destroy them and call into libadns. What follows is	1532	and in a check watcher, destroy them and call into libadns. What follows
1481	pseudo-code only of course:	1533	is pseudo-code only of course. This requires you to either use a low
		1534	priority for the check watcher or use C<ev_clear_pending> explicitly, as
		1535	the callbacks for the IO/timeout watchers might not have been called yet.
1482		1536
1483	static ev_io iow [nfd];	1537	static ev_io iow [nfd];
1484	static ev_timer tw;	1538	static ev_timer tw;
1485		1539
1486	static void	1540	static void
1487	io_cb (ev_loop loop, ev_io w, int revents)	1541	io_cb (ev_loop loop, ev_io w, int revents)
1488	{	1542	{
1489	// set the relevant poll flags
1490	// could also call adns_processreadable etc. here
1491	struct pollfd fd = (struct pollfd )w->data;
1492	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1493	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
1494	}	1543	}
1495		1544
1496	// create io watchers for each fd and a timer before blocking	1545	// create io watchers for each fd and a timer before blocking
1497	static void	1546	static void
1498	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1547	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
…		…
1504		1553
1505	/* the callback is illegal, but won't be called as we stop during check */	1554	/* the callback is illegal, but won't be called as we stop during check */
1506	ev_timer_init (&tw, 0, timeout * 1e-3);	1555	ev_timer_init (&tw, 0, timeout * 1e-3);
1507	ev_timer_start (loop, &tw);	1556	ev_timer_start (loop, &tw);
1508		1557
1509	// create on ev_io per pollfd	1558	// create one ev_io per pollfd
1510	for (int i = 0; i < nfd; ++i)	1559	for (int i = 0; i < nfd; ++i)
1511	{	1560	{
1512	ev_io_init (iow + i, io_cb, fds [i].fd,	1561	ev_io_init (iow + i, io_cb, fds [i].fd,
1513	((fds [i].events & POLLIN ? EV_READ : 0)	1562	((fds [i].events & POLLIN ? EV_READ : 0)
1514	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	1563	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1515		1564
1516	fds [i].revents = 0;	1565	fds [i].revents = 0;
1517	iow [i].data = fds + i;
1518	ev_io_start (loop, iow + i);	1566	ev_io_start (loop, iow + i);
1519	}	1567	}
1520	}	1568	}
1521		1569
1522	// stop all watchers after blocking	1570	// stop all watchers after blocking
…		…
1524	adns_check_cb (ev_loop loop, ev_check w, int revents)	1572	adns_check_cb (ev_loop loop, ev_check w, int revents)
1525	{	1573	{
1526	ev_timer_stop (loop, &tw);	1574	ev_timer_stop (loop, &tw);
1527		1575
1528	for (int i = 0; i < nfd; ++i)	1576	for (int i = 0; i < nfd; ++i)
		1577	{
		1578	// set the relevant poll flags
		1579	// could also call adns_processreadable etc. here
		1580	struct pollfd *fd = fds + i;
		1581	int revents = ev_clear_pending (iow + i);
		1582	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1583	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1584
		1585	// now stop the watcher
1529	ev_io_stop (loop, iow + i);	1586	ev_io_stop (loop, iow + i);
		1587	}
1530		1588
1531	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	1589	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1590	}
		1591
		1592	Method 2: This would be just like method 1, but you run C<adns_afterpoll>
		1593	in the prepare watcher and would dispose of the check watcher.
		1594
		1595	Method 3: If the module to be embedded supports explicit event
		1596	notification (adns does), you can also make use of the actual watcher
		1597	callbacks, and only destroy/create the watchers in the prepare watcher.
		1598
		1599	static void
		1600	timer_cb (EV_P_ ev_timer *w, int revents)
		1601	{
		1602	adns_state ads = (adns_state)w->data;
		1603	update_now (EV_A);
		1604
		1605	adns_processtimeouts (ads, &tv_now);
		1606	}
		1607
		1608	static void
		1609	io_cb (EV_P_ ev_io *w, int revents)
		1610	{
		1611	adns_state ads = (adns_state)w->data;
		1612	update_now (EV_A);
		1613
		1614	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
		1615	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
		1616	}
		1617
		1618	// do not ever call adns_afterpoll
		1619
		1620	Method 4: Do not use a prepare or check watcher because the module you
		1621	want to embed is too inflexible to support it. Instead, youc na override
		1622	their poll function. The drawback with this solution is that the main
		1623	loop is now no longer controllable by EV. The C<Glib::EV> module does
		1624	this.
		1625
		1626	static gint
		1627	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
		1628	{
		1629	int got_events = 0;
		1630
		1631	for (n = 0; n < nfds; ++n)
		1632	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
		1633
		1634	if (timeout >= 0)
		1635	// create/start timer
		1636
		1637	// poll
		1638	ev_loop (EV_A_ 0);
		1639
		1640	// stop timer again
		1641	if (timeout >= 0)
		1642	ev_timer_stop (EV_A_ &to);
		1643
		1644	// stop io watchers again - their callbacks should have set
		1645	for (n = 0; n < nfds; ++n)
		1646	ev_io_stop (EV_A_ iow [n]);
		1647
		1648	return got_events;
1532	}	1649	}
1533		1650
1534		1651
1535	=head2 C<ev_embed> - when one backend isn't enough...	1652	=head2 C<ev_embed> - when one backend isn't enough...
1536		1653
…		…
1740		1857
1741	To use it,	1858	To use it,
1742		1859
1743	#include <ev++.h>	1860	#include <ev++.h>
1744		1861
1745	(it is not installed by default). This automatically includes F<ev.h>	1862	This automatically includes F<ev.h> and puts all of its definitions (many
1746	and puts all of its definitions (many of them macros) into the global	1863	of them macros) into the global namespace. All C++ specific things are
1747	namespace. All C++ specific things are put into the C<ev> namespace.	1864	put into the C<ev> namespace. It should support all the same embedding
		1865	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
1748		1866
1749	It should support all the same embedding options as F<ev.h>, most notably	1867	Care has been taken to keep the overhead low. The only data member the C++
1750	C<EV_MULTIPLICITY>.	1868	classes add (compared to plain C-style watchers) is the event loop pointer
		1869	that the watcher is associated with (or no additional members at all if
		1870	you disable C<EV_MULTIPLICITY> when embedding libev).
		1871
		1872	Currently, functions, and static and non-static member functions can be
		1873	used as callbacks. Other types should be easy to add as long as they only
		1874	need one additional pointer for context. If you need support for other
		1875	types of functors please contact the author (preferably after implementing
		1876	it).
1751		1877
1752	Here is a list of things available in the C<ev> namespace:	1878	Here is a list of things available in the C<ev> namespace:
1753		1879
1754	=over 4	1880	=over 4
1755		1881
…		…
1771		1897
1772	All of those classes have these methods:	1898	All of those classes have these methods:
1773		1899
1774	=over 4	1900	=over 4
1775		1901
1776	=item ev::TYPE::TYPE (object , object::method )	1902	=item ev::TYPE::TYPE ()
1777		1903
1778	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)	1904	=item ev::TYPE::TYPE (struct ev_loop *)
1779		1905
1780	=item ev::TYPE::~TYPE	1906	=item ev::TYPE::~TYPE
1781		1907
1782	The constructor takes a pointer to an object and a method pointer to	1908	The constructor (optionally) takes an event loop to associate the watcher
1783	the event handler callback to call in this class. The constructor calls	1909	with. If it is omitted, it will use C<EV_DEFAULT>.
1784	C<ev_init> for you, which means you have to call the C<set> method	1910
1785	before starting it. If you do not specify a loop then the constructor	1911	The constructor calls C<ev_init> for you, which means you have to call the
1786	automatically associates the default loop with this watcher.	1912	C<set> method before starting it.
		1913
		1914	It will not set a callback, however: You have to call the templated C<set>
		1915	method to set a callback before you can start the watcher.
		1916
		1917	(The reason why you have to use a method is a limitation in C++ which does
		1918	not allow explicit template arguments for constructors).
1787		1919
1788	The destructor automatically stops the watcher if it is active.	1920	The destructor automatically stops the watcher if it is active.
		1921
		1922	=item w->set<class, &class::method> (object *)
		1923
		1924	This method sets the callback method to call. The method has to have a
		1925	signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
		1926	first argument and the C<revents> as second. The object must be given as
		1927	parameter and is stored in the C<data> member of the watcher.
		1928
		1929	This method synthesizes efficient thunking code to call your method from
		1930	the C callback that libev requires. If your compiler can inline your
		1931	callback (i.e. it is visible to it at the place of the C<set> call and
		1932	your compiler is good :), then the method will be fully inlined into the
		1933	thunking function, making it as fast as a direct C callback.
		1934
		1935	Example: simple class declaration and watcher initialisation
		1936
		1937	struct myclass
		1938	{
		1939	void io_cb (ev::io &w, int revents) { }
		1940	}
		1941
		1942	myclass obj;
		1943	ev::io iow;
		1944	iow.set <myclass, &myclass::io_cb> (&obj);
		1945
		1946	=item w->set<function> (void *data = 0)
		1947
		1948	Also sets a callback, but uses a static method or plain function as
		1949	callback. The optional C<data> argument will be stored in the watcher's
		1950	C<data> member and is free for you to use.
		1951
		1952	The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>.
		1953
		1954	See the method-C<set> above for more details.
		1955
		1956	Example:
		1957
		1958	static void io_cb (ev::io &w, int revents) { }
		1959	iow.set <io_cb> ();
1789		1960
1790	=item w->set (struct ev_loop *)	1961	=item w->set (struct ev_loop *)
1791		1962
1792	Associates a different C<struct ev_loop> with this watcher. You can only	1963	Associates a different C<struct ev_loop> with this watcher. You can only
1793	do this when the watcher is inactive (and not pending either).	1964	do this when the watcher is inactive (and not pending either).
1794		1965
1795	=item w->set ([args])	1966	=item w->set ([args])
1796		1967
1797	Basically the same as C<ev_TYPE_set>, with the same args. Must be	1968	Basically the same as C<ev_TYPE_set>, with the same args. Must be
1798	called at least once. Unlike the C counterpart, an active watcher gets	1969	called at least once. Unlike the C counterpart, an active watcher gets
1799	automatically stopped and restarted.	1970	automatically stopped and restarted when reconfiguring it with this
		1971	method.
1800		1972
1801	=item w->start ()	1973	=item w->start ()
1802		1974
1803	Starts the watcher. Note that there is no C<loop> argument as the	1975	Starts the watcher. Note that there is no C<loop> argument, as the
1804	constructor already takes the loop.	1976	constructor already stores the event loop.
1805		1977
1806	=item w->stop ()	1978	=item w->stop ()
1807		1979
1808	Stops the watcher if it is active. Again, no C<loop> argument.	1980	Stops the watcher if it is active. Again, no C<loop> argument.
1809		1981
…		…
1834		2006
1835	myclass ();	2007	myclass ();
1836	}	2008	}
1837		2009
1838	myclass::myclass (int fd)	2010	myclass::myclass (int fd)
1839	: io (this, &myclass::io_cb),
1840	idle (this, &myclass::idle_cb)
1841	{	2011	{
		2012	io .set <myclass, &myclass::io_cb > (this);
		2013	idle.set <myclass, &myclass::idle_cb> (this);
		2014
1842	io.start (fd, ev::READ);	2015	io.start (fd, ev::READ);
1843	}	2016	}
1844		2017
1845		2018
1846	=head1 MACRO MAGIC	2019	=head1 MACRO MAGIC
…		…
2123	will have the C<struct ev_loop *> as first argument, and you can create	2296	will have the C<struct ev_loop *> as first argument, and you can create
2124	additional independent event loops. Otherwise there will be no support	2297	additional independent event loops. Otherwise there will be no support
2125	for multiple event loops and there is no first event loop pointer	2298	for multiple event loops and there is no first event loop pointer
2126	argument. Instead, all functions act on the single default loop.	2299	argument. Instead, all functions act on the single default loop.
2127		2300
		2301	=item EV_MINPRI
		2302
		2303	=item EV_MAXPRI
		2304
		2305	The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
		2306	C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
		2307	provide for more priorities by overriding those symbols (usually defined
		2308	to be C<-2> and C<2>, respectively).
		2309
		2310	When doing priority-based operations, libev usually has to linearly search
		2311	all the priorities, so having many of them (hundreds) uses a lot of space
		2312	and time, so using the defaults of five priorities (-2 .. +2) is usually
		2313	fine.
		2314
		2315	If your embedding app does not need any priorities, defining these both to
		2316	C<0> will save some memory and cpu.
		2317
2128	=item EV_PERIODIC_ENABLE	2318	=item EV_PERIODIC_ENABLE
2129		2319
2130	If undefined or defined to be C<1>, then periodic timers are supported. If	2320	If undefined or defined to be C<1>, then periodic timers are supported. If
2131	defined to be C<0>, then they are not. Disabling them saves a few kB of	2321	defined to be C<0>, then they are not. Disabling them saves a few kB of
2132	code.	2322	code.
…		…
2234		2424
2235	In this section the complexities of (many of) the algorithms used inside	2425	In this section the complexities of (many of) the algorithms used inside
2236	libev will be explained. For complexity discussions about backends see the	2426	libev will be explained. For complexity discussions about backends see the
2237	documentation for C<ev_default_init>.	2427	documentation for C<ev_default_init>.
2238		2428
		2429	All of the following are about amortised time: If an array needs to be
		2430	extended, libev needs to realloc and move the whole array, but this
		2431	happens asymptotically never with higher number of elements, so O(1) might
		2432	mean it might do a lengthy realloc operation in rare cases, but on average
		2433	it is much faster and asymptotically approaches constant time.
		2434
2239	=over 4	2435	=over 4
2240		2436
2241	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2437	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2242		2438
		2439	This means that, when you have a watcher that triggers in one hour and
		2440	there are 100 watchers that would trigger before that then inserting will
		2441	have to skip those 100 watchers.
		2442
2243	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2443	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)
2244		2444
		2445	That means that for changing a timer costs less than removing/adding them
		2446	as only the relative motion in the event queue has to be paid for.
		2447
2245	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2448	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2246		2449
		2450	These just add the watcher into an array or at the head of a list.
2247	=item Stopping check/prepare/idle watchers: O(1)	2451	=item Stopping check/prepare/idle watchers: O(1)
2248		2452
2249	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	2453	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2250		2454
		2455	These watchers are stored in lists then need to be walked to find the
		2456	correct watcher to remove. The lists are usually short (you don't usually
		2457	have many watchers waiting for the same fd or signal).
		2458
2251	=item Finding the next timer per loop iteration: O(1)	2459	=item Finding the next timer per loop iteration: O(1)
2252		2460
2253	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2461	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2254		2462
		2463	A change means an I/O watcher gets started or stopped, which requires
		2464	libev to recalculate its status (and possibly tell the kernel).
		2465
2255	=item Activating one watcher: O(1)	2466	=item Activating one watcher: O(1)
2256		2467
		2468	=item Priority handling: O(number_of_priorities)
		2469
		2470	Priorities are implemented by allocating some space for each
		2471	priority. When doing priority-based operations, libev usually has to
		2472	linearly search all the priorities.
		2473
2257	=back	2474	=back
2258		2475
2259		2476
2260	=head1 AUTHOR	2477	=head1 AUTHOR
2261		2478

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Comparing libev/ev.pod (file contents): Revision 1.68 by root, Fri Dec 7 18:09:43 2007 UTC vs. Revision 1.79 by root, Sun Dec 9 19:46:56 2007 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.68 by root, Fri Dec 7 18:09:43 2007 UTC vs.
Revision 1.79 by root, Sun Dec 9 19:46:56 2007 UTC