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

Comparing libev/ev.pod (file contents):
Revision 1.60 by root, Wed Nov 28 18:29:30 2007 UTC vs.
Revision 1.75 by root, Sat Dec 8 14:27:39 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
…		…
266	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	270	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
267	override the flags completely if it is found in the environment. This is	271	override the flags completely if it is found in the environment. This is
268	useful to try out specific backends to test their performance, or to work	272	useful to try out specific backends to test their performance, or to work
269	around bugs.	273	around bugs.
270		274
		275	=item C<EVFLAG_FORKCHECK>
		276
		277	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after
		278	a fork, you can also make libev check for a fork in each iteration by
		279	enabling this flag.
		280
		281	This works by calling C<getpid ()> on every iteration of the loop,
		282	and thus this might slow down your event loop if you do a lot of loop
		283	iterations and little real work, but is usually not noticeable (on my
		284	Linux system for example, C<getpid> is actually a simple 5-insn sequence
		285	without a syscall and thus I<very> fast, but my Linux system also has
		286	C<pthread_atfork> which is even faster).
		287
		288	The big advantage of this flag is that you can forget about fork (and
		289	forget about forgetting to tell libev about forking) when you use this
		290	flag.
		291
		292	This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS>
		293	environment variable.
		294
271	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	295	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
272		296
273	This is your standard select(2) backend. Not I<completely> standard, as	297	This is your standard select(2) backend. Not I<completely> standard, as
274	libev tries to roll its own fd_set with no limits on the number of fds,	298	libev tries to roll its own fd_set with no limits on the number of fds,
275	but if that fails, expect a fairly low limit on the number of fds when	299	but if that fails, expect a fairly low limit on the number of fds when
…		…
409	=item ev_loop_fork (loop)	433	=item ev_loop_fork (loop)
410		434
411	Like C<ev_default_fork>, but acts on an event loop created by	435	Like C<ev_default_fork>, but acts on an event loop created by
412	C<ev_loop_new>. Yes, you have to call this on every allocated event loop	436	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
413	after fork, and how you do this is entirely your own problem.	437	after fork, and how you do this is entirely your own problem.
		438
		439	=item unsigned int ev_loop_count (loop)
		440
		441	Returns the count of loop iterations for the loop, which is identical to
		442	the number of times libev did poll for new events. It starts at C<0> and
		443	happily wraps around with enough iterations.
		444
		445	This value can sometimes be useful as a generation counter of sorts (it
		446	"ticks" the number of loop iterations), as it roughly corresponds with
		447	C<ev_prepare> and C<ev_check> calls.
414		448
415	=item unsigned int ev_backend (loop)	449	=item unsigned int ev_backend (loop)
416		450
417	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	451	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
418	use.	452	use.
…		…
702	=item bool ev_is_pending (ev_TYPE *watcher)	736	=item bool ev_is_pending (ev_TYPE *watcher)
703		737
704	Returns a true value iff the watcher is pending, (i.e. it has outstanding	738	Returns a true value iff the watcher is pending, (i.e. it has outstanding
705	events but its callback has not yet been invoked). As long as a watcher	739	events but its callback has not yet been invoked). As long as a watcher
706	is pending (but not active) you must not call an init function on it (but	740	is pending (but not active) you must not call an init function on it (but
707	C<ev_TYPE_set> is safe) and you must make sure the watcher is available to	741	C<ev_TYPE_set> is safe), you must not change its priority, and you must
708	libev (e.g. you cnanot C<free ()> it).	742	make sure the watcher is available to libev (e.g. you cannot C<free ()>
		743	it).
709		744
710	=item callback ev_cb (ev_TYPE *watcher)	745	=item callback ev_cb (ev_TYPE *watcher)
711		746
712	Returns the callback currently set on the watcher.	747	Returns the callback currently set on the watcher.
713		748
714	=item ev_cb_set (ev_TYPE *watcher, callback)	749	=item ev_cb_set (ev_TYPE *watcher, callback)
715		750
716	Change the callback. You can change the callback at virtually any time	751	Change the callback. You can change the callback at virtually any time
717	(modulo threads).	752	(modulo threads).
		753
		754	=item ev_set_priority (ev_TYPE *watcher, priority)
		755
		756	=item int ev_priority (ev_TYPE *watcher)
		757
		758	Set and query the priority of the watcher. The priority is a small
		759	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
		760	(default: C<-2>). Pending watchers with higher priority will be invoked
		761	before watchers with lower priority, but priority will not keep watchers
		762	from being executed (except for C<ev_idle> watchers).
		763
		764	This means that priorities are I<only> used for ordering callback
		765	invocation after new events have been received. This is useful, for
		766	example, to reduce latency after idling, or more often, to bind two
		767	watchers on the same event and make sure one is called first.
		768
		769	If you need to suppress invocation when higher priority events are pending
		770	you need to look at C<ev_idle> watchers, which provide this functionality.
		771
		772	You I<must not> change the priority of a watcher as long as it is active or
		773	pending.
		774
		775	The default priority used by watchers when no priority has been set is
		776	always C<0>, which is supposed to not be too high and not be too low :).
		777
		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
		780	or might not have been adjusted to be within valid range.
		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>.
718		793
719	=back	794	=back
720		795
721		796
722	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	797	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
828	it is best to always use non-blocking I/O: An extra C<read>(2) returning	903	it is best to always use non-blocking I/O: An extra C<read>(2) returning
829	C<EAGAIN> is far preferable to a program hanging until some data arrives.	904	C<EAGAIN> is far preferable to a program hanging until some data arrives.
830		905
831	If you cannot run the fd in non-blocking mode (for example you should not	906	If you cannot run the fd in non-blocking mode (for example you should not
832	play around with an Xlib connection), then you have to seperately re-test	907	play around with an Xlib connection), then you have to seperately re-test
833	wether a file descriptor is really ready with a known-to-be good interface	908	whether a file descriptor is really ready with a known-to-be good interface
834	such as poll (fortunately in our Xlib example, Xlib already does this on	909	such as poll (fortunately in our Xlib example, Xlib already does this on
835	its own, so its quite safe to use).	910	its own, so its quite safe to use).
836		911
837	=over 4	912	=over 4
838		913
…		…
916	=item ev_timer_again (loop)	991	=item ev_timer_again (loop)
917		992
918	This will act as if the timer timed out and restart it again if it is	993	This will act as if the timer timed out and restart it again if it is
919	repeating. The exact semantics are:	994	repeating. The exact semantics are:
920		995
		996	If the timer is pending, its pending status is cleared.
		997
921	If the timer is started but nonrepeating, stop it.	998	If the timer is started but nonrepeating, stop it (as if it timed out).
922		999
923	If the timer is repeating, either start it if necessary (with the repeat	1000	If the timer is repeating, either start it if necessary (with the
924	value), or reset the running timer to the repeat value.	1001	C<repeat> value), or reset the running timer to the C<repeat> value.
925		1002
926	This sounds a bit complicated, but here is a useful and typical	1003	This sounds a bit complicated, but here is a useful and typical
927	example: Imagine you have a tcp connection and you want a so-called	1004	example: Imagine you have a tcp connection and you want a so-called idle
928	idle timeout, that is, you want to be called when there have been,	1005	timeout, that is, you want to be called when there have been, say, 60
929	say, 60 seconds of inactivity on the socket. The easiest way to do	1006	seconds of inactivity on the socket. The easiest way to do this is to
930	this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling	1007	configure an C<ev_timer> with a C<repeat> value of C<60> and then call
931	C<ev_timer_again> each time you successfully read or write some data. If	1008	C<ev_timer_again> each time you successfully read or write some data. If
932	you go into an idle state where you do not expect data to travel on the	1009	you go into an idle state where you do not expect data to travel on the
933	socket, you can stop the timer, and again will automatically restart it if	1010	socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
934	need be.	1011	automatically restart it if need be.
935		1012
936	You can also ignore the C<after> value and C<ev_timer_start> altogether	1013	That means you can ignore the C<after> value and C<ev_timer_start>
937	and only ever use the C<repeat> value:	1014	altogether and only ever use the C<repeat> value and C<ev_timer_again>:
938		1015
939	ev_timer_init (timer, callback, 0., 5.);	1016	ev_timer_init (timer, callback, 0., 5.);
940	ev_timer_again (loop, timer);	1017	ev_timer_again (loop, timer);
941	...	1018	...
942	timer->again = 17.;	1019	timer->again = 17.;
943	ev_timer_again (loop, timer);	1020	ev_timer_again (loop, timer);
944	...	1021	...
945	timer->again = 10.;	1022	timer->again = 10.;
946	ev_timer_again (loop, timer);	1023	ev_timer_again (loop, timer);
947		1024
948	This is more efficient then stopping/starting the timer eahc time you want	1025	This is more slightly efficient then stopping/starting the timer each time
949	to modify its timeout value.	1026	you want to modify its timeout value.
950		1027
951	=item ev_tstamp repeat [read-write]	1028	=item ev_tstamp repeat [read-write]
952		1029
953	The current C<repeat> value. Will be used each time the watcher times out	1030	The current C<repeat> value. Will be used each time the watcher times out
954	or C<ev_timer_again> is called and determines the next timeout (if any),	1031	or C<ev_timer_again> is called and determines the next timeout (if any),
…		…
1319	ev_stat_start (loop, &passwd);	1396	ev_stat_start (loop, &passwd);
1320		1397
1321		1398
1322	=head2 C<ev_idle> - when you've got nothing better to do...	1399	=head2 C<ev_idle> - when you've got nothing better to do...
1323		1400
1324	Idle watchers trigger events when there are no other events are pending	1401	Idle watchers trigger events when no other events of the same or higher
1325	(prepare, check and other idle watchers do not count). That is, as long	1402	priority are pending (prepare, check and other idle watchers do not
1326	as your process is busy handling sockets or timeouts (or even signals,	1403	count).
1327	imagine) it will not be triggered. But when your process is idle all idle	1404
1328	watchers are being called again and again, once per event loop iteration -	1405	That is, as long as your process is busy handling sockets or timeouts
		1406	(or even signals, imagine) of the same or higher priority it will not be
		1407	triggered. But when your process is idle (or only lower-priority watchers
		1408	are pending), the idle watchers are being called once per event loop
1329	until stopped, that is, or your process receives more events and becomes	1409	iteration - until stopped, that is, or your process receives more events
1330	busy.	1410	and becomes busy again with higher priority stuff.
1331		1411
1332	The most noteworthy effect is that as long as any idle watchers are	1412	The most noteworthy effect is that as long as any idle watchers are
1333	active, the process will not block when waiting for new events.	1413	active, the process will not block when waiting for new events.
1334		1414
1335	Apart from keeping your process non-blocking (which is a useful	1415	Apart from keeping your process non-blocking (which is a useful
…		…
1435		1515
1436	// create io watchers for each fd and a timer before blocking	1516	// create io watchers for each fd and a timer before blocking
1437	static void	1517	static void
1438	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1518	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1439	{	1519	{
1440	int timeout = 3600000;truct pollfd fds [nfd];	1520	int timeout = 3600000;
		1521	struct pollfd fds [nfd];
1441	// actual code will need to loop here and realloc etc.	1522	// actual code will need to loop here and realloc etc.
1442	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1523	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1443		1524
1444	/* the callback is illegal, but won't be called as we stop during check */	1525	/* the callback is illegal, but won't be called as we stop during check */
1445	ev_timer_init (&tw, 0, timeout * 1e-3);	1526	ev_timer_init (&tw, 0, timeout * 1e-3);
…		…
1679		1760
1680	To use it,	1761	To use it,
1681		1762
1682	#include <ev++.h>	1763	#include <ev++.h>
1683		1764
1684	(it is not installed by default). This automatically includes F<ev.h>	1765	This automatically includes F<ev.h> and puts all of its definitions (many
1685	and puts all of its definitions (many of them macros) into the global	1766	of them macros) into the global namespace. All C++ specific things are
1686	namespace. All C++ specific things are put into the C<ev> namespace.	1767	put into the C<ev> namespace. It should support all the same embedding
		1768	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
1687		1769
1688	It should support all the same embedding options as F<ev.h>, most notably	1770	Care has been taken to keep the overhead low. The only data member the C++
1689	C<EV_MULTIPLICITY>.	1771	classes add (compared to plain C-style watchers) is the event loop pointer
		1772	that the watcher is associated with (or no additional members at all if
		1773	you disable C<EV_MULTIPLICITY> when embedding libev).
		1774
		1775	Currently, functions, and static and non-static member functions can be
		1776	used as callbacks. Other types should be easy to add as long as they only
		1777	need one additional pointer for context. If you need support for other
		1778	types of functors please contact the author (preferably after implementing
		1779	it).
1690		1780
1691	Here is a list of things available in the C<ev> namespace:	1781	Here is a list of things available in the C<ev> namespace:
1692		1782
1693	=over 4	1783	=over 4
1694		1784
…		…
1710		1800
1711	All of those classes have these methods:	1801	All of those classes have these methods:
1712		1802
1713	=over 4	1803	=over 4
1714		1804
1715	=item ev::TYPE::TYPE (object , object::method )	1805	=item ev::TYPE::TYPE ()
1716		1806
1717	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)	1807	=item ev::TYPE::TYPE (struct ev_loop *)
1718		1808
1719	=item ev::TYPE::~TYPE	1809	=item ev::TYPE::~TYPE
1720		1810
1721	The constructor takes a pointer to an object and a method pointer to	1811	The constructor (optionally) takes an event loop to associate the watcher
1722	the event handler callback to call in this class. The constructor calls	1812	with. If it is omitted, it will use C<EV_DEFAULT>.
1723	C<ev_init> for you, which means you have to call the C<set> method	1813
1724	before starting it. If you do not specify a loop then the constructor	1814	The constructor calls C<ev_init> for you, which means you have to call the
1725	automatically associates the default loop with this watcher.	1815	C<set> method before starting it.
		1816
		1817	It will not set a callback, however: You have to call the templated C<set>
		1818	method to set a callback before you can start the watcher.
		1819
		1820	(The reason why you have to use a method is a limitation in C++ which does
		1821	not allow explicit template arguments for constructors).
1726		1822
1727	The destructor automatically stops the watcher if it is active.	1823	The destructor automatically stops the watcher if it is active.
		1824
		1825	=item w->set<class, &class::method> (object *)
		1826
		1827	This method sets the callback method to call. The method has to have a
		1828	signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
		1829	first argument and the C<revents> as second. The object must be given as
		1830	parameter and is stored in the C<data> member of the watcher.
		1831
		1832	This method synthesizes efficient thunking code to call your method from
		1833	the C callback that libev requires. If your compiler can inline your
		1834	callback (i.e. it is visible to it at the place of the C<set> call and
		1835	your compiler is good :), then the method will be fully inlined into the
		1836	thunking function, making it as fast as a direct C callback.
		1837
		1838	Example: simple class declaration and watcher initialisation
		1839
		1840	struct myclass
		1841	{
		1842	void io_cb (ev::io &w, int revents) { }
		1843	}
		1844
		1845	myclass obj;
		1846	ev::io iow;
		1847	iow.set <myclass, &myclass::io_cb> (&obj);
		1848
		1849	=item w->set<function> (void *data = 0)
		1850
		1851	Also sets a callback, but uses a static method or plain function as
		1852	callback. The optional C<data> argument will be stored in the watcher's
		1853	C<data> member and is free for you to use.
		1854
		1855	The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>.
		1856
		1857	See the method-C<set> above for more details.
		1858
		1859	Example:
		1860
		1861	static void io_cb (ev::io &w, int revents) { }
		1862	iow.set <io_cb> ();
1728		1863
1729	=item w->set (struct ev_loop *)	1864	=item w->set (struct ev_loop *)
1730		1865
1731	Associates a different C<struct ev_loop> with this watcher. You can only	1866	Associates a different C<struct ev_loop> with this watcher. You can only
1732	do this when the watcher is inactive (and not pending either).	1867	do this when the watcher is inactive (and not pending either).
1733		1868
1734	=item w->set ([args])	1869	=item w->set ([args])
1735		1870
1736	Basically the same as C<ev_TYPE_set>, with the same args. Must be	1871	Basically the same as C<ev_TYPE_set>, with the same args. Must be
1737	called at least once. Unlike the C counterpart, an active watcher gets	1872	called at least once. Unlike the C counterpart, an active watcher gets
1738	automatically stopped and restarted.	1873	automatically stopped and restarted when reconfiguring it with this
		1874	method.
1739		1875
1740	=item w->start ()	1876	=item w->start ()
1741		1877
1742	Starts the watcher. Note that there is no C<loop> argument as the	1878	Starts the watcher. Note that there is no C<loop> argument, as the
1743	constructor already takes the loop.	1879	constructor already stores the event loop.
1744		1880
1745	=item w->stop ()	1881	=item w->stop ()
1746		1882
1747	Stops the watcher if it is active. Again, no C<loop> argument.	1883	Stops the watcher if it is active. Again, no C<loop> argument.
1748		1884
…		…
1773		1909
1774	myclass ();	1910	myclass ();
1775	}	1911	}
1776		1912
1777	myclass::myclass (int fd)	1913	myclass::myclass (int fd)
1778	: io (this, &myclass::io_cb),
1779	idle (this, &myclass::idle_cb)
1780	{	1914	{
		1915	io .set <myclass, &myclass::io_cb > (this);
		1916	idle.set <myclass, &myclass::idle_cb> (this);
		1917
1781	io.start (fd, ev::READ);	1918	io.start (fd, ev::READ);
1782	}	1919	}
1783		1920
1784		1921
1785	=head1 MACRO MAGIC	1922	=head1 MACRO MAGIC
1786		1923
1787	Libev can be compiled with a variety of options, the most fundemantal is	1924	Libev can be compiled with a variety of options, the most fundemantal is
1788	C<EV_MULTIPLICITY>. This option determines wether (most) functions and	1925	C<EV_MULTIPLICITY>. This option determines whether (most) functions and
1789	callbacks have an initial C<struct ev_loop *> argument.	1926	callbacks have an initial C<struct ev_loop *> argument.
1790		1927
1791	To make it easier to write programs that cope with either variant, the	1928	To make it easier to write programs that cope with either variant, the
1792	following macros are defined:	1929	following macros are defined:
1793		1930
…		…
1826	Similar to the other two macros, this gives you the value of the default	1963	Similar to the other two macros, this gives you the value of the default
1827	loop, if multiple loops are supported ("ev loop default").	1964	loop, if multiple loops are supported ("ev loop default").
1828		1965
1829	=back	1966	=back
1830		1967
1831	Example: Declare and initialise a check watcher, working regardless of	1968	Example: Declare and initialise a check watcher, utilising the above
1832	wether multiple loops are supported or not.	1969	macros so it will work regardless of whether multiple loops are supported
		1970	or not.
1833		1971
1834	static void	1972	static void
1835	check_cb (EV_P_ ev_timer *w, int revents)	1973	check_cb (EV_P_ ev_timer *w, int revents)
1836	{	1974	{
1837	ev_check_stop (EV_A_ w);	1975	ev_check_stop (EV_A_ w);
…		…
1839		1977
1840	ev_check check;	1978	ev_check check;
1841	ev_check_init (&check, check_cb);	1979	ev_check_init (&check, check_cb);
1842	ev_check_start (EV_DEFAULT_ &check);	1980	ev_check_start (EV_DEFAULT_ &check);
1843	ev_loop (EV_DEFAULT_ 0);	1981	ev_loop (EV_DEFAULT_ 0);
1844
1845		1982
1846	=head1 EMBEDDING	1983	=head1 EMBEDDING
1847		1984
1848	Libev can (and often is) directly embedded into host	1985	Libev can (and often is) directly embedded into host
1849	applications. Examples of applications that embed it include the Deliantra	1986	applications. Examples of applications that embed it include the Deliantra
…		…
1889	ev_vars.h	2026	ev_vars.h
1890	ev_wrap.h	2027	ev_wrap.h
1891		2028
1892	ev_win32.c required on win32 platforms only	2029	ev_win32.c required on win32 platforms only
1893		2030
1894	ev_select.c only when select backend is enabled (which is by default)	2031	ev_select.c only when select backend is enabled (which is enabled by default)
1895	ev_poll.c only when poll backend is enabled (disabled by default)	2032	ev_poll.c only when poll backend is enabled (disabled by default)
1896	ev_epoll.c only when the epoll backend is enabled (disabled by default)	2033	ev_epoll.c only when the epoll backend is enabled (disabled by default)
1897	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2034	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1898	ev_port.c only when the solaris port backend is enabled (disabled by default)	2035	ev_port.c only when the solaris port backend is enabled (disabled by default)
1899		2036
…		…
2062	will have the C<struct ev_loop *> as first argument, and you can create	2199	will have the C<struct ev_loop *> as first argument, and you can create
2063	additional independent event loops. Otherwise there will be no support	2200	additional independent event loops. Otherwise there will be no support
2064	for multiple event loops and there is no first event loop pointer	2201	for multiple event loops and there is no first event loop pointer
2065	argument. Instead, all functions act on the single default loop.	2202	argument. Instead, all functions act on the single default loop.
2066		2203
		2204	=item EV_MINPRI
		2205
		2206	=item EV_MAXPRI
		2207
		2208	The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
		2209	C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
		2210	provide for more priorities by overriding those symbols (usually defined
		2211	to be C<-2> and C<2>, respectively).
		2212
		2213	When doing priority-based operations, libev usually has to linearly search
		2214	all the priorities, so having many of them (hundreds) uses a lot of space
		2215	and time, so using the defaults of five priorities (-2 .. +2) is usually
		2216	fine.
		2217
		2218	If your embedding app does not need any priorities, defining these both to
		2219	C<0> will save some memory and cpu.
		2220
2067	=item EV_PERIODIC_ENABLE	2221	=item EV_PERIODIC_ENABLE
2068		2222
2069	If undefined or defined to be C<1>, then periodic timers are supported. If	2223	If undefined or defined to be C<1>, then periodic timers are supported. If
		2224	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2225	code.
		2226
		2227	=item EV_IDLE_ENABLE
		2228
		2229	If undefined or defined to be C<1>, then idle watchers are supported. If
2070	defined to be C<0>, then they are not. Disabling them saves a few kB of	2230	defined to be C<0>, then they are not. Disabling them saves a few kB of
2071	code.	2231	code.
2072		2232
2073	=item EV_EMBED_ENABLE	2233	=item EV_EMBED_ENABLE
2074		2234
…		…
2141	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file	2301	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file
2142	will be compiled. It is pretty complex because it provides its own header	2302	will be compiled. It is pretty complex because it provides its own header
2143	file.	2303	file.
2144		2304
2145	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	2305	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
2146	that everybody includes and which overrides some autoconf choices:	2306	that everybody includes and which overrides some configure choices:
2147		2307
		2308	#define EV_MINIMAL 1
2148	#define EV_USE_POLL 0	2309	#define EV_USE_POLL 0
2149	#define EV_MULTIPLICITY 0	2310	#define EV_MULTIPLICITY 0
2150	#define EV_PERIODICS 0	2311	#define EV_PERIODIC_ENABLE 0
		2312	#define EV_STAT_ENABLE 0
		2313	#define EV_FORK_ENABLE 0
2151	#define EV_CONFIG_H <config.h>	2314	#define EV_CONFIG_H <config.h>
		2315	#define EV_MINPRI 0
		2316	#define EV_MAXPRI 0
2152		2317
2153	#include "ev++.h"	2318	#include "ev++.h"
2154		2319
2155	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	2320	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
2156		2321
…		…
2162		2327
2163	In this section the complexities of (many of) the algorithms used inside	2328	In this section the complexities of (many of) the algorithms used inside
2164	libev will be explained. For complexity discussions about backends see the	2329	libev will be explained. For complexity discussions about backends see the
2165	documentation for C<ev_default_init>.	2330	documentation for C<ev_default_init>.
2166		2331
		2332	All of the following are about amortised time: If an array needs to be
		2333	extended, libev needs to realloc and move the whole array, but this
		2334	happens asymptotically never with higher number of elements, so O(1) might
		2335	mean it might do a lengthy realloc operation in rare cases, but on average
		2336	it is much faster and asymptotically approaches constant time.
		2337
2167	=over 4	2338	=over 4
2168		2339
2169	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2340	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2170		2341
		2342	This means that, when you have a watcher that triggers in one hour and
		2343	there are 100 watchers that would trigger before that then inserting will
		2344	have to skip those 100 watchers.
		2345
2171	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2346	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)
2172		2347
		2348	That means that for changing a timer costs less than removing/adding them
		2349	as only the relative motion in the event queue has to be paid for.
		2350
2173	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2351	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2174		2352
		2353	These just add the watcher into an array or at the head of a list.
2175	=item Stopping check/prepare/idle watchers: O(1)	2354	=item Stopping check/prepare/idle watchers: O(1)
2176		2355
2177	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	2356	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2178		2357
		2358	These watchers are stored in lists then need to be walked to find the
		2359	correct watcher to remove. The lists are usually short (you don't usually
		2360	have many watchers waiting for the same fd or signal).
		2361
2179	=item Finding the next timer per loop iteration: O(1)	2362	=item Finding the next timer per loop iteration: O(1)
2180		2363
2181	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2364	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2182		2365
		2366	A change means an I/O watcher gets started or stopped, which requires
		2367	libev to recalculate its status (and possibly tell the kernel).
		2368
2183	=item Activating one watcher: O(1)	2369	=item Activating one watcher: O(1)
2184		2370
		2371	=item Priority handling: O(number_of_priorities)
		2372
		2373	Priorities are implemented by allocating some space for each
		2374	priority. When doing priority-based operations, libev usually has to
		2375	linearly search all the priorities.
		2376
2185	=back	2377	=back
2186		2378
2187		2379
2188	=head1 AUTHOR	2380	=head1 AUTHOR
2189		2381

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Comparing libev/ev.pod (file contents): Revision 1.60 by root, Wed Nov 28 18:29:30 2007 UTC vs. Revision 1.75 by root, Sat Dec 8 14:27:39 2007 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.60 by root, Wed Nov 28 18:29:30 2007 UTC vs.
Revision 1.75 by root, Sat Dec 8 14:27:39 2007 UTC