[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 1.68 by root, Fri Dec 7 18:09:43 2007 UTC

…		…
266	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	266	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
267	override the flags completely if it is found in the environment. This is	267	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	268	useful to try out specific backends to test their performance, or to work
269	around bugs.	269	around bugs.
270		270
		271	=item C<EVFLAG_FORKCHECK>
		272
		273	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after
		274	a fork, you can also make libev check for a fork in each iteration by
		275	enabling this flag.
		276
		277	This works by calling C<getpid ()> on every iteration of the loop,
		278	and thus this might slow down your event loop if you do a lot of loop
		279	iterations and little real work, but is usually not noticeable (on my
		280	Linux system for example, C<getpid> is actually a simple 5-insn sequence
		281	without a syscall and thus I<very> fast, but my Linux system also has
		282	C<pthread_atfork> which is even faster).
		283
		284	The big advantage of this flag is that you can forget about fork (and
		285	forget about forgetting to tell libev about forking) when you use this
		286	flag.
		287
		288	This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS>
		289	environment variable.
		290
271	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	291	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
272		292
273	This is your standard select(2) backend. Not I<completely> standard, as	293	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,	294	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	295	but if that fails, expect a fairly low limit on the number of fds when
…		…
409	=item ev_loop_fork (loop)	429	=item ev_loop_fork (loop)
410		430
411	Like C<ev_default_fork>, but acts on an event loop created by	431	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	432	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.	433	after fork, and how you do this is entirely your own problem.
		434
		435	=item unsigned int ev_loop_count (loop)
		436
		437	Returns the count of loop iterations for the loop, which is identical to
		438	the number of times libev did poll for new events. It starts at C<0> and
		439	happily wraps around with enough iterations.
		440
		441	This value can sometimes be useful as a generation counter of sorts (it
		442	"ticks" the number of loop iterations), as it roughly corresponds with
		443	C<ev_prepare> and C<ev_check> calls.
414		444
415	=item unsigned int ev_backend (loop)	445	=item unsigned int ev_backend (loop)
416		446
417	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	447	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
418	use.	448	use.
…		…
714	=item ev_cb_set (ev_TYPE *watcher, callback)	744	=item ev_cb_set (ev_TYPE *watcher, callback)
715		745
716	Change the callback. You can change the callback at virtually any time	746	Change the callback. You can change the callback at virtually any time
717	(modulo threads).	747	(modulo threads).
718		748
		749	=item ev_set_priority (ev_TYPE *watcher, priority)
		750
		751	=item int ev_priority (ev_TYPE *watcher)
		752
		753	Set and query the priority of the watcher. The priority is a small
		754	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
		755	(default: C<-2>). Pending watchers with higher priority will be invoked
		756	before watchers with lower priority, but priority will not keep watchers
		757	from being executed (except for C<ev_idle> watchers).
		758
		759	This means that priorities are I<only> used for ordering callback
		760	invocation after new events have been received. This is useful, for
		761	example, to reduce latency after idling, or more often, to bind two
		762	watchers on the same event and make sure one is called first.
		763
		764	If you need to suppress invocation when higher priority events are pending
		765	you need to look at C<ev_idle> watchers, which provide this functionality.
		766
		767	The default priority used by watchers when no priority has been set is
		768	always C<0>, which is supposed to not be too high and not be too low :).
		769
		770	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
		771	fine, as long as you do not mind that the priority value you query might
		772	or might not have been adjusted to be within valid range.
		773
719	=back	774	=back
720		775
721		776
722	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	777	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
723		778
…		…
828	it is best to always use non-blocking I/O: An extra C<read>(2) returning	883	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.	884	C<EAGAIN> is far preferable to a program hanging until some data arrives.
830		885
831	If you cannot run the fd in non-blocking mode (for example you should not	886	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	887	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	888	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	889	such as poll (fortunately in our Xlib example, Xlib already does this on
835	its own, so its quite safe to use).	890	its own, so its quite safe to use).
836		891
837	=over 4	892	=over 4
838		893
…		…
916	=item ev_timer_again (loop)	971	=item ev_timer_again (loop)
917		972
918	This will act as if the timer timed out and restart it again if it is	973	This will act as if the timer timed out and restart it again if it is
919	repeating. The exact semantics are:	974	repeating. The exact semantics are:
920		975
		976	If the timer is pending, its pending status is cleared.
		977
921	If the timer is started but nonrepeating, stop it.	978	If the timer is started but nonrepeating, stop it (as if it timed out).
922		979
923	If the timer is repeating, either start it if necessary (with the repeat	980	If the timer is repeating, either start it if necessary (with the
924	value), or reset the running timer to the repeat value.	981	C<repeat> value), or reset the running timer to the C<repeat> value.
925		982
926	This sounds a bit complicated, but here is a useful and typical	983	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	984	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,	985	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	986	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	987	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	988	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	989	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	990	socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
934	need be.	991	automatically restart it if need be.
935		992
936	You can also ignore the C<after> value and C<ev_timer_start> altogether	993	That means you can ignore the C<after> value and C<ev_timer_start>
937	and only ever use the C<repeat> value:	994	altogether and only ever use the C<repeat> value and C<ev_timer_again>:
938		995
939	ev_timer_init (timer, callback, 0., 5.);	996	ev_timer_init (timer, callback, 0., 5.);
940	ev_timer_again (loop, timer);	997	ev_timer_again (loop, timer);
941	...	998	...
942	timer->again = 17.;	999	timer->again = 17.;
943	ev_timer_again (loop, timer);	1000	ev_timer_again (loop, timer);
944	...	1001	...
945	timer->again = 10.;	1002	timer->again = 10.;
946	ev_timer_again (loop, timer);	1003	ev_timer_again (loop, timer);
947		1004
948	This is more efficient then stopping/starting the timer eahc time you want	1005	This is more slightly efficient then stopping/starting the timer each time
949	to modify its timeout value.	1006	you want to modify its timeout value.
950		1007
951	=item ev_tstamp repeat [read-write]	1008	=item ev_tstamp repeat [read-write]
952		1009
953	The current C<repeat> value. Will be used each time the watcher times out	1010	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),	1011	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	1279	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	1280	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	1281	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	1282	otherwise always forced to be at least one) and all the other fields of
1226	the stat buffer having unspecified contents.	1283	the stat buffer having unspecified contents.
		1284
		1285	The path I<should> be absolute and I<must not> end in a slash. If it is
		1286	relative and your working directory changes, the behaviour is undefined.
1227		1287
1228	Since there is no standard to do this, the portable implementation simply	1288	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	1289	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	1290	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,	1291	a polling interval of C<0> (highly recommended!) then a I<suitable,
…		…
1316	ev_stat_start (loop, &passwd);	1376	ev_stat_start (loop, &passwd);
1317		1377
1318		1378
1319	=head2 C<ev_idle> - when you've got nothing better to do...	1379	=head2 C<ev_idle> - when you've got nothing better to do...
1320		1380
1321	Idle watchers trigger events when there are no other events are pending	1381	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	1382	priority are pending (prepare, check and other idle watchers do not
1323	as your process is busy handling sockets or timeouts (or even signals,	1383	count).
1324	imagine) it will not be triggered. But when your process is idle all idle	1384
1325	watchers are being called again and again, once per event loop iteration -	1385	That is, as long as your process is busy handling sockets or timeouts
		1386	(or even signals, imagine) of the same or higher priority it will not be
		1387	triggered. But when your process is idle (or only lower-priority watchers
		1388	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	1389	iteration - until stopped, that is, or your process receives more events
1327	busy.	1390	and becomes busy again with higher priority stuff.
1328		1391
1329	The most noteworthy effect is that as long as any idle watchers are	1392	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.	1393	active, the process will not block when waiting for new events.
1331		1394
1332	Apart from keeping your process non-blocking (which is a useful	1395	Apart from keeping your process non-blocking (which is a useful
…		…
1432		1495
1433	// create io watchers for each fd and a timer before blocking	1496	// create io watchers for each fd and a timer before blocking
1434	static void	1497	static void
1435	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1498	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1436	{	1499	{
1437	int timeout = 3600000;truct pollfd fds [nfd];	1500	int timeout = 3600000;
		1501	struct pollfd fds [nfd];
1438	// actual code will need to loop here and realloc etc.	1502	// actual code will need to loop here and realloc etc.
1439	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1503	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1440		1504
1441	/* the callback is illegal, but won't be called as we stop during check */	1505	/* the callback is illegal, but won't be called as we stop during check */
1442	ev_timer_init (&tw, 0, timeout * 1e-3);	1506	ev_timer_init (&tw, 0, timeout * 1e-3);
…		…
1780		1844
1781		1845
1782	=head1 MACRO MAGIC	1846	=head1 MACRO MAGIC
1783		1847
1784	Libev can be compiled with a variety of options, the most fundemantal is	1848	Libev can be compiled with a variety of options, the most fundemantal is
1785	C<EV_MULTIPLICITY>. This option determines wether (most) functions and	1849	C<EV_MULTIPLICITY>. This option determines whether (most) functions and
1786	callbacks have an initial C<struct ev_loop *> argument.	1850	callbacks have an initial C<struct ev_loop *> argument.
1787		1851
1788	To make it easier to write programs that cope with either variant, the	1852	To make it easier to write programs that cope with either variant, the
1789	following macros are defined:	1853	following macros are defined:
1790		1854
…		…
1823	Similar to the other two macros, this gives you the value of the default	1887	Similar to the other two macros, this gives you the value of the default
1824	loop, if multiple loops are supported ("ev loop default").	1888	loop, if multiple loops are supported ("ev loop default").
1825		1889
1826	=back	1890	=back
1827		1891
1828	Example: Declare and initialise a check watcher, working regardless of	1892	Example: Declare and initialise a check watcher, utilising the above
1829	wether multiple loops are supported or not.	1893	macros so it will work regardless of whether multiple loops are supported
		1894	or not.
1830		1895
1831	static void	1896	static void
1832	check_cb (EV_P_ ev_timer *w, int revents)	1897	check_cb (EV_P_ ev_timer *w, int revents)
1833	{	1898	{
1834	ev_check_stop (EV_A_ w);	1899	ev_check_stop (EV_A_ w);
…		…
1836		1901
1837	ev_check check;	1902	ev_check check;
1838	ev_check_init (&check, check_cb);	1903	ev_check_init (&check, check_cb);
1839	ev_check_start (EV_DEFAULT_ &check);	1904	ev_check_start (EV_DEFAULT_ &check);
1840	ev_loop (EV_DEFAULT_ 0);	1905	ev_loop (EV_DEFAULT_ 0);
1841
1842		1906
1843	=head1 EMBEDDING	1907	=head1 EMBEDDING
1844		1908
1845	Libev can (and often is) directly embedded into host	1909	Libev can (and often is) directly embedded into host
1846	applications. Examples of applications that embed it include the Deliantra	1910	applications. Examples of applications that embed it include the Deliantra
…		…
1886	ev_vars.h	1950	ev_vars.h
1887	ev_wrap.h	1951	ev_wrap.h
1888		1952
1889	ev_win32.c required on win32 platforms only	1953	ev_win32.c required on win32 platforms only
1890		1954
1891	ev_select.c only when select backend is enabled (which is by default)	1955	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)	1956	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)	1957	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)	1958	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)	1959	ev_port.c only when the solaris port backend is enabled (disabled by default)
1896		1960
…		…
2065		2129
2066	If undefined or defined to be C<1>, then periodic timers are supported. If	2130	If undefined or defined to be C<1>, then periodic timers are supported. If
2067	defined to be C<0>, then they are not. Disabling them saves a few kB of	2131	defined to be C<0>, then they are not. Disabling them saves a few kB of
2068	code.	2132	code.
2069		2133
		2134	=item EV_IDLE_ENABLE
		2135
		2136	If undefined or defined to be C<1>, then idle watchers are supported. If
		2137	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2138	code.
		2139
2070	=item EV_EMBED_ENABLE	2140	=item EV_EMBED_ENABLE
2071		2141
2072	If undefined or defined to be C<1>, then embed watchers are supported. If	2142	If undefined or defined to be C<1>, then embed watchers are supported. If
2073	defined to be C<0>, then they are not.	2143	defined to be C<0>, then they are not.
2074		2144
…		…
2138	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file	2208	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	2209	will be compiled. It is pretty complex because it provides its own header
2140	file.	2210	file.
2141		2211
2142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	2212	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:	2213	that everybody includes and which overrides some configure choices:
2144		2214
		2215	#define EV_MINIMAL 1
2145	#define EV_USE_POLL 0	2216	#define EV_USE_POLL 0
2146	#define EV_MULTIPLICITY 0	2217	#define EV_MULTIPLICITY 0
2147	#define EV_PERIODICS 0	2218	#define EV_PERIODIC_ENABLE 0
		2219	#define EV_STAT_ENABLE 0
		2220	#define EV_FORK_ENABLE 0
2148	#define EV_CONFIG_H <config.h>	2221	#define EV_CONFIG_H <config.h>
		2222	#define EV_MINPRI 0
		2223	#define EV_MAXPRI 0
2149		2224
2150	#include "ev++.h"	2225	#include "ev++.h"
2151		2226
2152	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	2227	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
2153		2228

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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 1.68 by root, Fri Dec 7 18:09:43 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.59 by root, Wed Nov 28 17:32:24 2007 UTC vs.
Revision 1.68 by root, Fri Dec 7 18:09:43 2007 UTC