[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 1.72 by root, Fri Dec 7 20:19:16 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.
…		…
714	=item ev_cb_set (ev_TYPE *watcher, callback)	748	=item ev_cb_set (ev_TYPE *watcher, callback)
715		749
716	Change the callback. You can change the callback at virtually any time	750	Change the callback. You can change the callback at virtually any time
717	(modulo threads).	751	(modulo threads).
718		752
		753	=item ev_set_priority (ev_TYPE *watcher, priority)
		754
		755	=item int ev_priority (ev_TYPE *watcher)
		756
		757	Set and query the priority of the watcher. The priority is a small
		758	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
		759	(default: C<-2>). Pending watchers with higher priority will be invoked
		760	before watchers with lower priority, but priority will not keep watchers
		761	from being executed (except for C<ev_idle> watchers).
		762
		763	This means that priorities are I<only> used for ordering callback
		764	invocation after new events have been received. This is useful, for
		765	example, to reduce latency after idling, or more often, to bind two
		766	watchers on the same event and make sure one is called first.
		767
		768	If you need to suppress invocation when higher priority events are pending
		769	you need to look at C<ev_idle> watchers, which provide this functionality.
		770
		771	The default priority used by watchers when no priority has been set is
		772	always C<0>, which is supposed to not be too high and not be too low :).
		773
		774	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
		775	fine, as long as you do not mind that the priority value you query might
		776	or might not have been adjusted to be within valid range.
		777
719	=back	778	=back
720		779
721		780
722	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	781	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
723		782
…		…
828	it is best to always use non-blocking I/O: An extra C<read>(2) returning	887	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.	888	C<EAGAIN> is far preferable to a program hanging until some data arrives.
830		889
831	If you cannot run the fd in non-blocking mode (for example you should not	890	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	891	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	892	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	893	such as poll (fortunately in our Xlib example, Xlib already does this on
835	its own, so its quite safe to use).	894	its own, so its quite safe to use).
836		895
837	=over 4	896	=over 4
838		897
…		…
916	=item ev_timer_again (loop)	975	=item ev_timer_again (loop)
917		976
918	This will act as if the timer timed out and restart it again if it is	977	This will act as if the timer timed out and restart it again if it is
919	repeating. The exact semantics are:	978	repeating. The exact semantics are:
920		979
		980	If the timer is pending, its pending status is cleared.
		981
921	If the timer is started but nonrepeating, stop it.	982	If the timer is started but nonrepeating, stop it (as if it timed out).
922		983
923	If the timer is repeating, either start it if necessary (with the repeat	984	If the timer is repeating, either start it if necessary (with the
924	value), or reset the running timer to the repeat value.	985	C<repeat> value), or reset the running timer to the C<repeat> value.
925		986
926	This sounds a bit complicated, but here is a useful and typical	987	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	988	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,	989	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	990	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	991	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	992	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	993	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	994	socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
934	need be.	995	automatically restart it if need be.
935		996
936	You can also ignore the C<after> value and C<ev_timer_start> altogether	997	That means you can ignore the C<after> value and C<ev_timer_start>
937	and only ever use the C<repeat> value:	998	altogether and only ever use the C<repeat> value and C<ev_timer_again>:
938		999
939	ev_timer_init (timer, callback, 0., 5.);	1000	ev_timer_init (timer, callback, 0., 5.);
940	ev_timer_again (loop, timer);	1001	ev_timer_again (loop, timer);
941	...	1002	...
942	timer->again = 17.;	1003	timer->again = 17.;
943	ev_timer_again (loop, timer);	1004	ev_timer_again (loop, timer);
944	...	1005	...
945	timer->again = 10.;	1006	timer->again = 10.;
946	ev_timer_again (loop, timer);	1007	ev_timer_again (loop, timer);
947		1008
948	This is more efficient then stopping/starting the timer eahc time you want	1009	This is more slightly efficient then stopping/starting the timer each time
949	to modify its timeout value.	1010	you want to modify its timeout value.
950		1011
951	=item ev_tstamp repeat [read-write]	1012	=item ev_tstamp repeat [read-write]
952		1013
953	The current C<repeat> value. Will be used each time the watcher times out	1014	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),	1015	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	1283	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	1284	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	1285	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	1286	otherwise always forced to be at least one) and all the other fields of
1226	the stat buffer having unspecified contents.	1287	the stat buffer having unspecified contents.
		1288
		1289	The path I<should> be absolute and I<must not> end in a slash. If it is
		1290	relative and your working directory changes, the behaviour is undefined.
1227		1291
1228	Since there is no standard to do this, the portable implementation simply	1292	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	1293	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	1294	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,	1295	a polling interval of C<0> (highly recommended!) then a I<suitable,
…		…
1316	ev_stat_start (loop, &passwd);	1380	ev_stat_start (loop, &passwd);
1317		1381
1318		1382
1319	=head2 C<ev_idle> - when you've got nothing better to do...	1383	=head2 C<ev_idle> - when you've got nothing better to do...
1320		1384
1321	Idle watchers trigger events when there are no other events are pending	1385	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	1386	priority are pending (prepare, check and other idle watchers do not
1323	as your process is busy handling sockets or timeouts (or even signals,	1387	count).
1324	imagine) it will not be triggered. But when your process is idle all idle	1388
1325	watchers are being called again and again, once per event loop iteration -	1389	That is, as long as your process is busy handling sockets or timeouts
		1390	(or even signals, imagine) of the same or higher priority it will not be
		1391	triggered. But when your process is idle (or only lower-priority watchers
		1392	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	1393	iteration - until stopped, that is, or your process receives more events
1327	busy.	1394	and becomes busy again with higher priority stuff.
1328		1395
1329	The most noteworthy effect is that as long as any idle watchers are	1396	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.	1397	active, the process will not block when waiting for new events.
1331		1398
1332	Apart from keeping your process non-blocking (which is a useful	1399	Apart from keeping your process non-blocking (which is a useful
…		…
1432		1499
1433	// create io watchers for each fd and a timer before blocking	1500	// create io watchers for each fd and a timer before blocking
1434	static void	1501	static void
1435	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1502	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1436	{	1503	{
1437	int timeout = 3600000;truct pollfd fds [nfd];	1504	int timeout = 3600000;
		1505	struct pollfd fds [nfd];
1438	// actual code will need to loop here and realloc etc.	1506	// actual code will need to loop here and realloc etc.
1439	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1507	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1440		1508
1441	/* the callback is illegal, but won't be called as we stop during check */	1509	/* the callback is illegal, but won't be called as we stop during check */
1442	ev_timer_init (&tw, 0, timeout * 1e-3);	1510	ev_timer_init (&tw, 0, timeout * 1e-3);
…		…
1676		1744
1677	To use it,	1745	To use it,
1678		1746
1679	#include <ev++.h>	1747	#include <ev++.h>
1680		1748
1681	(it is not installed by default). This automatically includes F<ev.h>	1749	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	1750	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.	1751	put into the C<ev> namespace. It should support all the same embedding
		1752	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
1684		1753
1685	It should support all the same embedding options as F<ev.h>, most notably	1754	Care has been taken to keep the overhead low. The only data member the C++
1686	C<EV_MULTIPLICITY>.	1755	classes add (compared to plain C-style watchers) is the event loop pointer
		1756	that the watcher is associated with (or no additional members at all if
		1757	you disable C<EV_MULTIPLICITY> when embedding libev).
		1758
		1759	Currently, functions, and static and non-static member functions can be
		1760	used as callbacks. Other types should be easy to add as long as they only
		1761	need one additional pointer for context. If you need support for other
		1762	types of functors please contact the author (preferably after implementing
		1763	it).
1687		1764
1688	Here is a list of things available in the C<ev> namespace:	1765	Here is a list of things available in the C<ev> namespace:
1689		1766
1690	=over 4	1767	=over 4
1691		1768
…		…
1707		1784
1708	All of those classes have these methods:	1785	All of those classes have these methods:
1709		1786
1710	=over 4	1787	=over 4
1711		1788
1712	=item ev::TYPE::TYPE (object , object::method )	1789	=item ev::TYPE::TYPE ()
1713		1790
1714	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)	1791	=item ev::TYPE::TYPE (struct ev_loop *)
1715		1792
1716	=item ev::TYPE::~TYPE	1793	=item ev::TYPE::~TYPE
1717		1794
1718	The constructor takes a pointer to an object and a method pointer to	1795	The constructor (optionally) takes an event loop to associate the watcher
1719	the event handler callback to call in this class. The constructor calls	1796	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	1797
1721	before starting it. If you do not specify a loop then the constructor	1798	The constructor calls C<ev_init> for you, which means you have to call the
1722	automatically associates the default loop with this watcher.	1799	C<set> method before starting it.
		1800
		1801	It will not set a callback, however: You have to call the templated C<set>
		1802	method to set a callback before you can start the watcher.
		1803
		1804	(The reason why you have to use a method is a limitation in C++ which does
		1805	not allow explicit template arguments for constructors).
1723		1806
1724	The destructor automatically stops the watcher if it is active.	1807	The destructor automatically stops the watcher if it is active.
		1808
		1809	=item w->set<class, &class::method> (object *)
		1810
		1811	This method sets the callback method to call. The method has to have a
		1812	signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
		1813	first argument and the C<revents> as second. The object must be given as
		1814	parameter and is stored in the C<data> member of the watcher.
		1815
		1816	This method synthesizes efficient thunking code to call your method from
		1817	the C callback that libev requires. If your compiler can inline your
		1818	callback (i.e. it is visible to it at the place of the C<set> call and
		1819	your compiler is good :), then the method will be fully inlined into the
		1820	thunking function, making it as fast as a direct C callback.
		1821
		1822	Example: simple class declaration and watcher initialisation
		1823
		1824	struct myclass
		1825	{
		1826	void io_cb (ev::io &w, int revents) { }
		1827	}
		1828
		1829	myclass obj;
		1830	ev::io iow;
		1831	iow.set <myclass, &myclass::io_cb> (&obj);
		1832
		1833	=item w->set (void (function)(watcher &w, int), void data = 0)
		1834
		1835	Also sets a callback, but uses a static method or plain function as
		1836	callback. The optional C<data> argument will be stored in the watcher's
		1837	C<data> member and is free for you to use.
		1838
		1839	See the method-C<set> above for more details.
1725		1840
1726	=item w->set (struct ev_loop *)	1841	=item w->set (struct ev_loop *)
1727		1842
1728	Associates a different C<struct ev_loop> with this watcher. You can only	1843	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).	1844	do this when the watcher is inactive (and not pending either).
1730		1845
1731	=item w->set ([args])	1846	=item w->set ([args])
1732		1847
1733	Basically the same as C<ev_TYPE_set>, with the same args. Must be	1848	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	1849	called at least once. Unlike the C counterpart, an active watcher gets
1735	automatically stopped and restarted.	1850	automatically stopped and restarted when reconfiguring it with this
		1851	method.
1736		1852
1737	=item w->start ()	1853	=item w->start ()
1738		1854
1739	Starts the watcher. Note that there is no C<loop> argument as the	1855	Starts the watcher. Note that there is no C<loop> argument, as the
1740	constructor already takes the loop.	1856	constructor already stores the event loop.
1741		1857
1742	=item w->stop ()	1858	=item w->stop ()
1743		1859
1744	Stops the watcher if it is active. Again, no C<loop> argument.	1860	Stops the watcher if it is active. Again, no C<loop> argument.
1745		1861
…		…
1770		1886
1771	myclass ();	1887	myclass ();
1772	}	1888	}
1773		1889
1774	myclass::myclass (int fd)	1890	myclass::myclass (int fd)
1775	: io (this, &myclass::io_cb),
1776	idle (this, &myclass::idle_cb)
1777	{	1891	{
		1892	io .set <myclass, &myclass::io_cb > (this);
		1893	idle.set <myclass, &myclass::idle_cb> (this);
		1894
1778	io.start (fd, ev::READ);	1895	io.start (fd, ev::READ);
1779	}	1896	}
1780		1897
1781		1898
1782	=head1 MACRO MAGIC	1899	=head1 MACRO MAGIC
1783		1900
1784	Libev can be compiled with a variety of options, the most fundemantal is	1901	Libev can be compiled with a variety of options, the most fundemantal is
1785	C<EV_MULTIPLICITY>. This option determines wether (most) functions and	1902	C<EV_MULTIPLICITY>. This option determines whether (most) functions and
1786	callbacks have an initial C<struct ev_loop *> argument.	1903	callbacks have an initial C<struct ev_loop *> argument.
1787		1904
1788	To make it easier to write programs that cope with either variant, the	1905	To make it easier to write programs that cope with either variant, the
1789	following macros are defined:	1906	following macros are defined:
1790		1907
…		…
1823	Similar to the other two macros, this gives you the value of the default	1940	Similar to the other two macros, this gives you the value of the default
1824	loop, if multiple loops are supported ("ev loop default").	1941	loop, if multiple loops are supported ("ev loop default").
1825		1942
1826	=back	1943	=back
1827		1944
1828	Example: Declare and initialise a check watcher, working regardless of	1945	Example: Declare and initialise a check watcher, utilising the above
1829	wether multiple loops are supported or not.	1946	macros so it will work regardless of whether multiple loops are supported
		1947	or not.
1830		1948
1831	static void	1949	static void
1832	check_cb (EV_P_ ev_timer *w, int revents)	1950	check_cb (EV_P_ ev_timer *w, int revents)
1833	{	1951	{
1834	ev_check_stop (EV_A_ w);	1952	ev_check_stop (EV_A_ w);
…		…
1836		1954
1837	ev_check check;	1955	ev_check check;
1838	ev_check_init (&check, check_cb);	1956	ev_check_init (&check, check_cb);
1839	ev_check_start (EV_DEFAULT_ &check);	1957	ev_check_start (EV_DEFAULT_ &check);
1840	ev_loop (EV_DEFAULT_ 0);	1958	ev_loop (EV_DEFAULT_ 0);
1841
1842		1959
1843	=head1 EMBEDDING	1960	=head1 EMBEDDING
1844		1961
1845	Libev can (and often is) directly embedded into host	1962	Libev can (and often is) directly embedded into host
1846	applications. Examples of applications that embed it include the Deliantra	1963	applications. Examples of applications that embed it include the Deliantra
…		…
1886	ev_vars.h	2003	ev_vars.h
1887	ev_wrap.h	2004	ev_wrap.h
1888		2005
1889	ev_win32.c required on win32 platforms only	2006	ev_win32.c required on win32 platforms only
1890		2007
1891	ev_select.c only when select backend is enabled (which is by default)	2008	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)	2009	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)	2010	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)	2011	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)	2012	ev_port.c only when the solaris port backend is enabled (disabled by default)
1896		2013
…		…
2059	will have the C<struct ev_loop *> as first argument, and you can create	2176	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	2177	additional independent event loops. Otherwise there will be no support
2061	for multiple event loops and there is no first event loop pointer	2178	for multiple event loops and there is no first event loop pointer
2062	argument. Instead, all functions act on the single default loop.	2179	argument. Instead, all functions act on the single default loop.
2063		2180
		2181	=item EV_MINPRI
		2182
		2183	=item EV_MAXPRI
		2184
		2185	The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
		2186	C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
		2187	provide for more priorities by overriding those symbols (usually defined
		2188	to be C<-2> and C<2>, respectively).
		2189
		2190	When doing priority-based operations, libev usually has to linearly search
		2191	all the priorities, so having many of them (hundreds) uses a lot of space
		2192	and time, so using the defaults of five priorities (-2 .. +2) is usually
		2193	fine.
		2194
		2195	If your embedding app does not need any priorities, defining these both to
		2196	C<0> will save some memory and cpu.
		2197
2064	=item EV_PERIODIC_ENABLE	2198	=item EV_PERIODIC_ENABLE
2065		2199
2066	If undefined or defined to be C<1>, then periodic timers are supported. If	2200	If undefined or defined to be C<1>, then periodic timers are supported. If
		2201	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2202	code.
		2203
		2204	=item EV_IDLE_ENABLE
		2205
		2206	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	2207	defined to be C<0>, then they are not. Disabling them saves a few kB of
2068	code.	2208	code.
2069		2209
2070	=item EV_EMBED_ENABLE	2210	=item EV_EMBED_ENABLE
2071		2211
…		…
2138	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file	2278	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	2279	will be compiled. It is pretty complex because it provides its own header
2140	file.	2280	file.
2141		2281
2142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	2282	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:	2283	that everybody includes and which overrides some configure choices:
2144		2284
		2285	#define EV_MINIMAL 1
2145	#define EV_USE_POLL 0	2286	#define EV_USE_POLL 0
2146	#define EV_MULTIPLICITY 0	2287	#define EV_MULTIPLICITY 0
2147	#define EV_PERIODICS 0	2288	#define EV_PERIODIC_ENABLE 0
		2289	#define EV_STAT_ENABLE 0
		2290	#define EV_FORK_ENABLE 0
2148	#define EV_CONFIG_H <config.h>	2291	#define EV_CONFIG_H <config.h>
		2292	#define EV_MINPRI 0
		2293	#define EV_MAXPRI 0
2149		2294
2150	#include "ev++.h"	2295	#include "ev++.h"
2151		2296
2152	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	2297	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
2153		2298
…		…
2159		2304
2160	In this section the complexities of (many of) the algorithms used inside	2305	In this section the complexities of (many of) the algorithms used inside
2161	libev will be explained. For complexity discussions about backends see the	2306	libev will be explained. For complexity discussions about backends see the
2162	documentation for C<ev_default_init>.	2307	documentation for C<ev_default_init>.
2163		2308
		2309	All of the following are about amortised time: If an array needs to be
		2310	extended, libev needs to realloc and move the whole array, but this
		2311	happens asymptotically never with higher number of elements, so O(1) might
		2312	mean it might do a lengthy realloc operation in rare cases, but on average
		2313	it is much faster and asymptotically approaches constant time.
		2314
2164	=over 4	2315	=over 4
2165		2316
2166	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2317	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2167		2318
		2319	This means that, when you have a watcher that triggers in one hour and
		2320	there are 100 watchers that would trigger before that then inserting will
		2321	have to skip those 100 watchers.
		2322
2168	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2323	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)
2169		2324
		2325	That means that for changing a timer costs less than removing/adding them
		2326	as only the relative motion in the event queue has to be paid for.
		2327
2170	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2328	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2171		2329
		2330	These just add the watcher into an array or at the head of a list.
2172	=item Stopping check/prepare/idle watchers: O(1)	2331	=item Stopping check/prepare/idle watchers: O(1)
2173		2332
2174	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	2333	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2175		2334
		2335	These watchers are stored in lists then need to be walked to find the
		2336	correct watcher to remove. The lists are usually short (you don't usually
		2337	have many watchers waiting for the same fd or signal).
		2338
2176	=item Finding the next timer per loop iteration: O(1)	2339	=item Finding the next timer per loop iteration: O(1)
2177		2340
2178	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2341	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2179		2342
		2343	A change means an I/O watcher gets started or stopped, which requires
		2344	libev to recalculate its status (and possibly tell the kernel).
		2345
2180	=item Activating one watcher: O(1)	2346	=item Activating one watcher: O(1)
2181		2347
		2348	=item Priority handling: O(number_of_priorities)
		2349
		2350	Priorities are implemented by allocating some space for each
		2351	priority. When doing priority-based operations, libev usually has to
		2352	linearly search all the priorities.
		2353
2182	=back	2354	=back
2183		2355
2184		2356
2185	=head1 AUTHOR	2357	=head1 AUTHOR
2186		2358

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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 1.72 by root, Fri Dec 7 20:19:16 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 1.72 by root, Fri Dec 7 20:19:16 2007 UTC