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

Comparing libev/ev.pod (file contents):
Revision 1.59 by root, Wed Nov 28 17:32:24 2007 UTC vs.
Revision 1.74 by root, Sat Dec 8 14:12:08 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),
…		…
1222	The path does not need to exist: changing from "path exists" to "path does	1299	The path does not need to exist: changing from "path exists" to "path does
1223	not exist" is a status change like any other. The condition "path does	1300	not exist" is a status change like any other. The condition "path does
1224	not exist" is signified by the C<st_nlink> field being zero (which is	1301	not exist" is signified by the C<st_nlink> field being zero (which is
1225	otherwise always forced to be at least one) and all the other fields of	1302	otherwise always forced to be at least one) and all the other fields of
1226	the stat buffer having unspecified contents.	1303	the stat buffer having unspecified contents.
		1304
		1305	The path I<should> be absolute and I<must not> end in a slash. If it is
		1306	relative and your working directory changes, the behaviour is undefined.
1227		1307
1228	Since there is no standard to do this, the portable implementation simply	1308	Since there is no standard to do this, the portable implementation simply
1229	calls C<stat (2)> regularly on the path to see if it changed somehow. You	1309	calls C<stat (2)> regularly on the path to see if it changed somehow. You
1230	can specify a recommended polling interval for this case. If you specify	1310	can specify a recommended polling interval for this case. If you specify
1231	a polling interval of C<0> (highly recommended!) then a I<suitable,	1311	a polling interval of C<0> (highly recommended!) then a I<suitable,
…		…
1316	ev_stat_start (loop, &passwd);	1396	ev_stat_start (loop, &passwd);
1317		1397
1318		1398
1319	=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...
1320		1400
1321	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
1322	(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
1323	as your process is busy handling sockets or timeouts (or even signals,	1403	count).
1324	imagine) it will not be triggered. But when your process is idle all idle	1404
1325	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
1326	until stopped, that is, or your process receives more events and becomes	1409	iteration - until stopped, that is, or your process receives more events
1327	busy.	1410	and becomes busy again with higher priority stuff.
1328		1411
1329	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
1330	active, the process will not block when waiting for new events.	1413	active, the process will not block when waiting for new events.
1331		1414
1332	Apart from keeping your process non-blocking (which is a useful	1415	Apart from keeping your process non-blocking (which is a useful
…		…
1432		1515
1433	// create io watchers for each fd and a timer before blocking	1516	// create io watchers for each fd and a timer before blocking
1434	static void	1517	static void
1435	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1518	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1436	{	1519	{
1437	int timeout = 3600000;truct pollfd fds [nfd];	1520	int timeout = 3600000;
		1521	struct pollfd fds [nfd];
1438	// actual code will need to loop here and realloc etc.	1522	// actual code will need to loop here and realloc etc.
1439	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1523	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1440		1524
1441	/* 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 */
1442	ev_timer_init (&tw, 0, timeout * 1e-3);	1526	ev_timer_init (&tw, 0, timeout * 1e-3);
…		…
1676		1760
1677	To use it,	1761	To use it,
1678		1762
1679	#include <ev++.h>	1763	#include <ev++.h>
1680		1764
1681	(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
1682	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
1683	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>.
1684		1769
1685	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++
1686	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).
1687		1780
1688	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:
1689		1782
1690	=over 4	1783	=over 4
1691		1784
…		…
1707		1800
1708	All of those classes have these methods:	1801	All of those classes have these methods:
1709		1802
1710	=over 4	1803	=over 4
1711		1804
1712	=item ev::TYPE::TYPE (object , object::method )	1805	=item ev::TYPE::TYPE ()
1713		1806
1714	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)	1807	=item ev::TYPE::TYPE (struct ev_loop *)
1715		1808
1716	=item ev::TYPE::~TYPE	1809	=item ev::TYPE::~TYPE
1717		1810
1718	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
1719	the event handler callback to call in this class. The constructor calls	1812	with. If it is omitted, it will use C<EV_DEFAULT>.
1720	C<ev_init> for you, which means you have to call the C<set> method	1813
1721	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
1722	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).
1723		1822
1724	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 (void (function)(watcher &w, int), 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	See the method-C<set> above for more details.
1725		1856
1726	=item w->set (struct ev_loop *)	1857	=item w->set (struct ev_loop *)
1727		1858
1728	Associates a different C<struct ev_loop> with this watcher. You can only	1859	Associates a different C<struct ev_loop> with this watcher. You can only
1729	do this when the watcher is inactive (and not pending either).	1860	do this when the watcher is inactive (and not pending either).
1730		1861
1731	=item w->set ([args])	1862	=item w->set ([args])
1732		1863
1733	Basically the same as C<ev_TYPE_set>, with the same args. Must be	1864	Basically the same as C<ev_TYPE_set>, with the same args. Must be
1734	called at least once. Unlike the C counterpart, an active watcher gets	1865	called at least once. Unlike the C counterpart, an active watcher gets
1735	automatically stopped and restarted.	1866	automatically stopped and restarted when reconfiguring it with this
		1867	method.
1736		1868
1737	=item w->start ()	1869	=item w->start ()
1738		1870
1739	Starts the watcher. Note that there is no C<loop> argument as the	1871	Starts the watcher. Note that there is no C<loop> argument, as the
1740	constructor already takes the loop.	1872	constructor already stores the event loop.
1741		1873
1742	=item w->stop ()	1874	=item w->stop ()
1743		1875
1744	Stops the watcher if it is active. Again, no C<loop> argument.	1876	Stops the watcher if it is active. Again, no C<loop> argument.
1745		1877
…		…
1770		1902
1771	myclass ();	1903	myclass ();
1772	}	1904	}
1773		1905
1774	myclass::myclass (int fd)	1906	myclass::myclass (int fd)
1775	: io (this, &myclass::io_cb),
1776	idle (this, &myclass::idle_cb)
1777	{	1907	{
		1908	io .set <myclass, &myclass::io_cb > (this);
		1909	idle.set <myclass, &myclass::idle_cb> (this);
		1910
1778	io.start (fd, ev::READ);	1911	io.start (fd, ev::READ);
1779	}	1912	}
1780		1913
1781		1914
1782	=head1 MACRO MAGIC	1915	=head1 MACRO MAGIC
1783		1916
1784	Libev can be compiled with a variety of options, the most fundemantal is	1917	Libev can be compiled with a variety of options, the most fundemantal is
1785	C<EV_MULTIPLICITY>. This option determines wether (most) functions and	1918	C<EV_MULTIPLICITY>. This option determines whether (most) functions and
1786	callbacks have an initial C<struct ev_loop *> argument.	1919	callbacks have an initial C<struct ev_loop *> argument.
1787		1920
1788	To make it easier to write programs that cope with either variant, the	1921	To make it easier to write programs that cope with either variant, the
1789	following macros are defined:	1922	following macros are defined:
1790		1923
…		…
1823	Similar to the other two macros, this gives you the value of the default	1956	Similar to the other two macros, this gives you the value of the default
1824	loop, if multiple loops are supported ("ev loop default").	1957	loop, if multiple loops are supported ("ev loop default").
1825		1958
1826	=back	1959	=back
1827		1960
1828	Example: Declare and initialise a check watcher, working regardless of	1961	Example: Declare and initialise a check watcher, utilising the above
1829	wether multiple loops are supported or not.	1962	macros so it will work regardless of whether multiple loops are supported
		1963	or not.
1830		1964
1831	static void	1965	static void
1832	check_cb (EV_P_ ev_timer *w, int revents)	1966	check_cb (EV_P_ ev_timer *w, int revents)
1833	{	1967	{
1834	ev_check_stop (EV_A_ w);	1968	ev_check_stop (EV_A_ w);
…		…
1836		1970
1837	ev_check check;	1971	ev_check check;
1838	ev_check_init (&check, check_cb);	1972	ev_check_init (&check, check_cb);
1839	ev_check_start (EV_DEFAULT_ &check);	1973	ev_check_start (EV_DEFAULT_ &check);
1840	ev_loop (EV_DEFAULT_ 0);	1974	ev_loop (EV_DEFAULT_ 0);
1841
1842		1975
1843	=head1 EMBEDDING	1976	=head1 EMBEDDING
1844		1977
1845	Libev can (and often is) directly embedded into host	1978	Libev can (and often is) directly embedded into host
1846	applications. Examples of applications that embed it include the Deliantra	1979	applications. Examples of applications that embed it include the Deliantra
…		…
1886	ev_vars.h	2019	ev_vars.h
1887	ev_wrap.h	2020	ev_wrap.h
1888		2021
1889	ev_win32.c required on win32 platforms only	2022	ev_win32.c required on win32 platforms only
1890		2023
1891	ev_select.c only when select backend is enabled (which is by default)	2024	ev_select.c only when select backend is enabled (which is enabled by default)
1892	ev_poll.c only when poll backend is enabled (disabled by default)	2025	ev_poll.c only when poll backend is enabled (disabled by default)
1893	ev_epoll.c only when the epoll backend is enabled (disabled by default)	2026	ev_epoll.c only when the epoll backend is enabled (disabled by default)
1894	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2027	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1895	ev_port.c only when the solaris port backend is enabled (disabled by default)	2028	ev_port.c only when the solaris port backend is enabled (disabled by default)
1896		2029
…		…
2059	will have the C<struct ev_loop *> as first argument, and you can create	2192	will have the C<struct ev_loop *> as first argument, and you can create
2060	additional independent event loops. Otherwise there will be no support	2193	additional independent event loops. Otherwise there will be no support
2061	for multiple event loops and there is no first event loop pointer	2194	for multiple event loops and there is no first event loop pointer
2062	argument. Instead, all functions act on the single default loop.	2195	argument. Instead, all functions act on the single default loop.
2063		2196
		2197	=item EV_MINPRI
		2198
		2199	=item EV_MAXPRI
		2200
		2201	The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
		2202	C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
		2203	provide for more priorities by overriding those symbols (usually defined
		2204	to be C<-2> and C<2>, respectively).
		2205
		2206	When doing priority-based operations, libev usually has to linearly search
		2207	all the priorities, so having many of them (hundreds) uses a lot of space
		2208	and time, so using the defaults of five priorities (-2 .. +2) is usually
		2209	fine.
		2210
		2211	If your embedding app does not need any priorities, defining these both to
		2212	C<0> will save some memory and cpu.
		2213
2064	=item EV_PERIODIC_ENABLE	2214	=item EV_PERIODIC_ENABLE
2065		2215
2066	If undefined or defined to be C<1>, then periodic timers are supported. If	2216	If undefined or defined to be C<1>, then periodic timers are supported. If
		2217	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2218	code.
		2219
		2220	=item EV_IDLE_ENABLE
		2221
		2222	If undefined or defined to be C<1>, then idle watchers are supported. If
2067	defined to be C<0>, then they are not. Disabling them saves a few kB of	2223	defined to be C<0>, then they are not. Disabling them saves a few kB of
2068	code.	2224	code.
2069		2225
2070	=item EV_EMBED_ENABLE	2226	=item EV_EMBED_ENABLE
2071		2227
…		…
2138	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file	2294	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file
2139	will be compiled. It is pretty complex because it provides its own header	2295	will be compiled. It is pretty complex because it provides its own header
2140	file.	2296	file.
2141		2297
2142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	2298	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
2143	that everybody includes and which overrides some autoconf choices:	2299	that everybody includes and which overrides some configure choices:
2144		2300
		2301	#define EV_MINIMAL 1
2145	#define EV_USE_POLL 0	2302	#define EV_USE_POLL 0
2146	#define EV_MULTIPLICITY 0	2303	#define EV_MULTIPLICITY 0
2147	#define EV_PERIODICS 0	2304	#define EV_PERIODIC_ENABLE 0
		2305	#define EV_STAT_ENABLE 0
		2306	#define EV_FORK_ENABLE 0
2148	#define EV_CONFIG_H <config.h>	2307	#define EV_CONFIG_H <config.h>
		2308	#define EV_MINPRI 0
		2309	#define EV_MAXPRI 0
2149		2310
2150	#include "ev++.h"	2311	#include "ev++.h"
2151		2312
2152	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	2313	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
2153		2314
…		…
2159		2320
2160	In this section the complexities of (many of) the algorithms used inside	2321	In this section the complexities of (many of) the algorithms used inside
2161	libev will be explained. For complexity discussions about backends see the	2322	libev will be explained. For complexity discussions about backends see the
2162	documentation for C<ev_default_init>.	2323	documentation for C<ev_default_init>.
2163		2324
		2325	All of the following are about amortised time: If an array needs to be
		2326	extended, libev needs to realloc and move the whole array, but this
		2327	happens asymptotically never with higher number of elements, so O(1) might
		2328	mean it might do a lengthy realloc operation in rare cases, but on average
		2329	it is much faster and asymptotically approaches constant time.
		2330
2164	=over 4	2331	=over 4
2165		2332
2166	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2333	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2167		2334
		2335	This means that, when you have a watcher that triggers in one hour and
		2336	there are 100 watchers that would trigger before that then inserting will
		2337	have to skip those 100 watchers.
		2338
2168	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2339	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)
2169		2340
		2341	That means that for changing a timer costs less than removing/adding them
		2342	as only the relative motion in the event queue has to be paid for.
		2343
2170	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2344	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2171		2345
		2346	These just add the watcher into an array or at the head of a list.
2172	=item Stopping check/prepare/idle watchers: O(1)	2347	=item Stopping check/prepare/idle watchers: O(1)
2173		2348
2174	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	2349	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2175		2350
		2351	These watchers are stored in lists then need to be walked to find the
		2352	correct watcher to remove. The lists are usually short (you don't usually
		2353	have many watchers waiting for the same fd or signal).
		2354
2176	=item Finding the next timer per loop iteration: O(1)	2355	=item Finding the next timer per loop iteration: O(1)
2177		2356
2178	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2357	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2179		2358
		2359	A change means an I/O watcher gets started or stopped, which requires
		2360	libev to recalculate its status (and possibly tell the kernel).
		2361
2180	=item Activating one watcher: O(1)	2362	=item Activating one watcher: O(1)
2181		2363
		2364	=item Priority handling: O(number_of_priorities)
		2365
		2366	Priorities are implemented by allocating some space for each
		2367	priority. When doing priority-based operations, libev usually has to
		2368	linearly search all the priorities.
		2369
2182	=back	2370	=back
2183		2371
2184		2372
2185	=head1 AUTHOR	2373	=head1 AUTHOR
2186		2374

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Comparing libev/ev.pod (file contents): Revision 1.59 by root, Wed Nov 28 17:32:24 2007 UTC vs. Revision 1.74 by root, Sat Dec 8 14:12:08 2007 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.59 by root, Wed Nov 28 17:32:24 2007 UTC vs.
Revision 1.74 by root, Sat Dec 8 14:12:08 2007 UTC