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

Comparing libev/ev.pod (file contents):
Revision 1.70 by root, Fri Dec 7 19:23:48 2007 UTC vs.
Revision 1.101 by ayin, Sat Dec 22 14:11:25 2007 UTC

…		…
53	The newest version of this document is also available as a html-formatted	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	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>.	55	time: L<http://cvs.schmorp.de/libev/ev.html>.
56		56
57	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
58	file descriptor being readable or a timeout occuring), and it will manage	58	file descriptor being readable or a timeout occurring), and it will manage
59	these event sources and provide your program with events.	59	these event sources and provide your program with events.
60		60
61	To do this, it must take more or less complete control over your process	61	To do this, it must take more or less complete control over your process
62	(or thread) by executing the I<event loop> handler, and will then	62	(or thread) by executing the I<event loop> handler, and will then
63	communicate events via a callback mechanism.	63	communicate events via a callback mechanism.
…		…
98	Libev represents time as a single floating point number, representing the	98	Libev represents time as a single floating point number, representing the
99	(fractional) number of seconds since the (POSIX) epoch (somewhere near	99	(fractional) number of seconds since the (POSIX) epoch (somewhere near
100	the beginning of 1970, details are complicated, don't ask). This type is	100	the beginning of 1970, details are complicated, don't ask). This type is
101	called C<ev_tstamp>, which is what you should use too. It usually aliases	101	called C<ev_tstamp>, which is what you should use too. It usually aliases
102	to the C<double> type in C, and when you need to do any calculations on	102	to the C<double> type in C, and when you need to do any calculations on
103	it, you should treat it as such.	103	it, you should treat it as some floatingpoint value. Unlike the name
		104	component C<stamp> might indicate, it is also used for time differences
		105	throughout libev.
104		106
105	=head1 GLOBAL FUNCTIONS	107	=head1 GLOBAL FUNCTIONS
106		108
107	These functions can be called anytime, even before initialising the	109	These functions can be called anytime, even before initialising the
108	library in any way.	110	library in any way.
…		…
113		115
114	Returns the current time as libev would use it. Please note that the	116	Returns the current time as libev would use it. Please note that the
115	C<ev_now> function is usually faster and also often returns the timestamp	117	C<ev_now> function is usually faster and also often returns the timestamp
116	you actually want to know.	118	you actually want to know.
117		119
		120	=item ev_sleep (ev_tstamp interval)
		121
		122	Sleep for the given interval: The current thread will be blocked until
		123	either it is interrupted or the given time interval has passed. Basically
		124	this is a subsecond-resolution C<sleep ()>.
		125
118	=item int ev_version_major ()	126	=item int ev_version_major ()
119		127
120	=item int ev_version_minor ()	128	=item int ev_version_minor ()
121		129
122	You can find out the major and minor version numbers of the library	130	You can find out the major and minor ABI version numbers of the library
123	you linked against by calling the functions C<ev_version_major> and	131	you linked against by calling the functions C<ev_version_major> and
124	C<ev_version_minor>. If you want, you can compare against the global	132	C<ev_version_minor>. If you want, you can compare against the global
125	symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the	133	symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the
126	version of the library your program was compiled against.	134	version of the library your program was compiled against.
127		135
		136	These version numbers refer to the ABI version of the library, not the
		137	release version.
		138
128	Usually, it's a good idea to terminate if the major versions mismatch,	139	Usually, it's a good idea to terminate if the major versions mismatch,
129	as this indicates an incompatible change. Minor versions are usually	140	as this indicates an incompatible change. Minor versions are usually
130	compatible to older versions, so a larger minor version alone is usually	141	compatible to older versions, so a larger minor version alone is usually
131	not a problem.	142	not a problem.
132		143
133	Example: Make sure we haven't accidentally been linked against the wrong	144	Example: Make sure we haven't accidentally been linked against the wrong
134	version.	145	version.
…		…
308	lot of inactive fds). It scales similarly to select, i.e. O(total_fds).	319	lot of inactive fds). It scales similarly to select, i.e. O(total_fds).
309		320
310	=item C<EVBACKEND_EPOLL> (value 4, Linux)	321	=item C<EVBACKEND_EPOLL> (value 4, Linux)
311		322
312	For few fds, this backend is a bit little slower than poll and select,	323	For few fds, this backend is a bit little slower than poll and select,
313	but it scales phenomenally better. While poll and select usually scale like	324	but it scales phenomenally better. While poll and select usually scale
314	O(total_fds) where n is the total number of fds (or the highest fd), epoll scales	325	like O(total_fds) where n is the total number of fds (or the highest fd),
315	either O(1) or O(active_fds).	326	epoll scales either O(1) or O(active_fds). The epoll design has a number
		327	of shortcomings, such as silently dropping events in some hard-to-detect
		328	cases and rewiring a syscall per fd change, no fork support and bad
		329	support for dup:
316		330
317	While stopping and starting an I/O watcher in the same iteration will	331	While stopping, setting and starting an I/O watcher in the same iteration
318	result in some caching, there is still a syscall per such incident	332	will result in some caching, there is still a syscall per such incident
319	(because the fd could point to a different file description now), so its	333	(because the fd could point to a different file description now), so its
320	best to avoid that. Also, dup()ed file descriptors might not work very	334	best to avoid that. Also, C<dup ()>'ed file descriptors might not work
321	well if you register events for both fds.	335	very well if you register events for both fds.
322		336
323	Please note that epoll sometimes generates spurious notifications, so you	337	Please note that epoll sometimes generates spurious notifications, so you
324	need to use non-blocking I/O or other means to avoid blocking when no data	338	need to use non-blocking I/O or other means to avoid blocking when no data
325	(or space) is available.	339	(or space) is available.
326		340
327	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)	341	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
328		342
329	Kqueue deserves special mention, as at the time of this writing, it	343	Kqueue deserves special mention, as at the time of this writing, it
330	was broken on all BSDs except NetBSD (usually it doesn't work with	344	was broken on all BSDs except NetBSD (usually it doesn't work reliably
331	anything but sockets and pipes, except on Darwin, where of course its	345	with anything but sockets and pipes, except on Darwin, where of course
332	completely useless). For this reason its not being "autodetected"	346	it's completely useless). For this reason it's not being "autodetected"
333	unless you explicitly specify it explicitly in the flags (i.e. using	347	unless you explicitly specify it explicitly in the flags (i.e. using
334	C<EVBACKEND_KQUEUE>).	348	C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)
		349	system like NetBSD.
		350
		351	You still can embed kqueue into a normal poll or select backend and use it
		352	only for sockets (after having made sure that sockets work with kqueue on
		353	the target platform). See C<ev_embed> watchers for more info.
335		354
336	It scales in the same way as the epoll backend, but the interface to the	355	It scales in the same way as the epoll backend, but the interface to the
337	kernel is more efficient (which says nothing about its actual speed, of	356	kernel is more efficient (which says nothing about its actual speed, of
338	course). While starting and stopping an I/O watcher does not cause an	357	course). While stopping, setting and starting an I/O watcher does never
339	extra syscall as with epoll, it still adds up to four event changes per	358	cause an extra syscall as with C<EVBACKEND_EPOLL>, it still adds up to
340	incident, so its best to avoid that.	359	two event changes per incident, support for C<fork ()> is very bad and it
		360	drops fds silently in similarly hard-to-detect cases.
341		361
342	=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)	362	=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)
343		363
344	This is not implemented yet (and might never be).	364	This is not implemented yet (and might never be).
345		365
346	=item C<EVBACKEND_PORT> (value 32, Solaris 10)	366	=item C<EVBACKEND_PORT> (value 32, Solaris 10)
347		367
348	This uses the Solaris 10 port mechanism. As with everything on Solaris,	368	This uses the Solaris 10 event port mechanism. As with everything on Solaris,
349	it's really slow, but it still scales very well (O(active_fds)).	369	it's really slow, but it still scales very well (O(active_fds)).
350		370
351	Please note that solaris ports can result in a lot of spurious	371	Please note that solaris event ports can deliver a lot of spurious
352	notifications, so you need to use non-blocking I/O or other means to avoid	372	notifications, so you need to use non-blocking I/O or other means to avoid
353	blocking when no data (or space) is available.	373	blocking when no data (or space) is available.
354		374
355	=item C<EVBACKEND_ALL>	375	=item C<EVBACKEND_ALL>
356		376
…		…
399	Destroys the default loop again (frees all memory and kernel state	419	Destroys the default loop again (frees all memory and kernel state
400	etc.). None of the active event watchers will be stopped in the normal	420	etc.). None of the active event watchers will be stopped in the normal
401	sense, so e.g. C<ev_is_active> might still return true. It is your	421	sense, so e.g. C<ev_is_active> might still return true. It is your
402	responsibility to either stop all watchers cleanly yoursef I<before>	422	responsibility to either stop all watchers cleanly yoursef I<before>
403	calling this function, or cope with the fact afterwards (which is usually	423	calling this function, or cope with the fact afterwards (which is usually
404	the easiest thing, youc na just ignore the watchers and/or C<free ()> them	424	the easiest thing, you can just ignore the watchers and/or C<free ()> them
405	for example).	425	for example).
		426
		427	Note that certain global state, such as signal state, will not be freed by
		428	this function, and related watchers (such as signal and child watchers)
		429	would need to be stopped manually.
		430
		431	In general it is not advisable to call this function except in the
		432	rare occasion where you really need to free e.g. the signal handling
		433	pipe fds. If you need dynamically allocated loops it is better to use
		434	C<ev_loop_new> and C<ev_loop_destroy>).
406		435
407	=item ev_loop_destroy (loop)	436	=item ev_loop_destroy (loop)
408		437
409	Like C<ev_default_destroy>, but destroys an event loop created by an	438	Like C<ev_default_destroy>, but destroys an event loop created by an
410	earlier call to C<ev_loop_new>.	439	earlier call to C<ev_loop_new>.
…		…
455		484
456	Returns the current "event loop time", which is the time the event loop	485	Returns the current "event loop time", which is the time the event loop
457	received events and started processing them. This timestamp does not	486	received events and started processing them. This timestamp does not
458	change as long as callbacks are being processed, and this is also the base	487	change as long as callbacks are being processed, and this is also the base
459	time used for relative timers. You can treat it as the timestamp of the	488	time used for relative timers. You can treat it as the timestamp of the
460	event occuring (or more correctly, libev finding out about it).	489	event occurring (or more correctly, libev finding out about it).
461		490
462	=item ev_loop (loop, int flags)	491	=item ev_loop (loop, int flags)
463		492
464	Finally, this is it, the event handler. This function usually is called	493	Finally, this is it, the event handler. This function usually is called
465	after you initialised all your watchers and you want to start handling	494	after you initialised all your watchers and you want to start handling
…		…
486	libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is	515	libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is
487	usually a better approach for this kind of thing.	516	usually a better approach for this kind of thing.
488		517
489	Here are the gory details of what C<ev_loop> does:	518	Here are the gory details of what C<ev_loop> does:
490		519
		520	- Before the first iteration, call any pending watchers.
491	* If there are no active watchers (reference count is zero), return.	521	* If there are no active watchers (reference count is zero), return.
492	- Queue prepare watchers and then call all outstanding watchers.	522	- Queue all prepare watchers and then call all outstanding watchers.
493	- If we have been forked, recreate the kernel state.	523	- If we have been forked, recreate the kernel state.
494	- Update the kernel state with all outstanding changes.	524	- Update the kernel state with all outstanding changes.
495	- Update the "event loop time".	525	- Update the "event loop time".
496	- Calculate for how long to block.	526	- Calculate for how long to block.
497	- Block the process, waiting for any events.	527	- Block the process, waiting for any events.
…		…
548	Example: For some weird reason, unregister the above signal handler again.	578	Example: For some weird reason, unregister the above signal handler again.
549		579
550	ev_ref (loop);	580	ev_ref (loop);
551	ev_signal_stop (loop, &exitsig);	581	ev_signal_stop (loop, &exitsig);
552		582
		583	=item ev_set_io_collect_interval (loop, ev_tstamp interval)
		584
		585	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
		586
		587	These advanced functions influence the time that libev will spend waiting
		588	for events. Both are by default C<0>, meaning that libev will try to
		589	invoke timer/periodic callbacks and I/O callbacks with minimum latency.
		590
		591	Setting these to a higher value (the C<interval> I<must> be >= C<0>)
		592	allows libev to delay invocation of I/O and timer/periodic callbacks to
		593	increase efficiency of loop iterations.
		594
		595	The background is that sometimes your program runs just fast enough to
		596	handle one (or very few) event(s) per loop iteration. While this makes
		597	the program responsive, it also wastes a lot of CPU time to poll for new
		598	events, especially with backends like C<select ()> which have a high
		599	overhead for the actual polling but can deliver many events at once.
		600
		601	By setting a higher I<io collect interval> you allow libev to spend more
		602	time collecting I/O events, so you can handle more events per iteration,
		603	at the cost of increasing latency. Timeouts (both C<ev_periodic> and
		604	C<ev_timer>) will be not affected. Setting this to a non-null value will
		605	introduce an additional C<ev_sleep ()> call into most loop iterations.
		606
		607	Likewise, by setting a higher I<timeout collect interval> you allow libev
		608	to spend more time collecting timeouts, at the expense of increased
		609	latency (the watcher callback will be called later). C<ev_io> watchers
		610	will not be affected. Setting this to a non-null value will not introduce
		611	any overhead in libev.
		612
		613	Many (busy) programs can usually benefit by setting the io collect
		614	interval to a value near C<0.1> or so, which is often enough for
		615	interactive servers (of course not for games), likewise for timeouts. It
		616	usually doesn't make much sense to set it to a lower value than C<0.01>,
		617	as this approsaches the timing granularity of most systems.
		618
553	=back	619	=back
554		620
555		621
556	=head1 ANATOMY OF A WATCHER	622	=head1 ANATOMY OF A WATCHER
557		623
…		…
736	=item bool ev_is_pending (ev_TYPE *watcher)	802	=item bool ev_is_pending (ev_TYPE *watcher)
737		803
738	Returns a true value iff the watcher is pending, (i.e. it has outstanding	804	Returns a true value iff the watcher is pending, (i.e. it has outstanding
739	events but its callback has not yet been invoked). As long as a watcher	805	events but its callback has not yet been invoked). As long as a watcher
740	is pending (but not active) you must not call an init function on it (but	806	is pending (but not active) you must not call an init function on it (but
741	C<ev_TYPE_set> is safe) and you must make sure the watcher is available to	807	C<ev_TYPE_set> is safe), you must not change its priority, and you must
742	libev (e.g. you cnanot C<free ()> it).	808	make sure the watcher is available to libev (e.g. you cannot C<free ()>
		809	it).
743		810
744	=item callback ev_cb (ev_TYPE *watcher)	811	=item callback ev_cb (ev_TYPE *watcher)
745		812
746	Returns the callback currently set on the watcher.	813	Returns the callback currently set on the watcher.
747		814
…		…
766	watchers on the same event and make sure one is called first.	833	watchers on the same event and make sure one is called first.
767		834
768	If you need to suppress invocation when higher priority events are pending	835	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.	836	you need to look at C<ev_idle> watchers, which provide this functionality.
770		837
		838	You I<must not> change the priority of a watcher as long as it is active or
		839	pending.
		840
771	The default priority used by watchers when no priority has been set is	841	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 :).	842	always C<0>, which is supposed to not be too high and not be too low :).
773		843
774	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is	844	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	845	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.	846	or might not have been adjusted to be within valid range.
		847
		848	=item ev_invoke (loop, ev_TYPE *watcher, int revents)
		849
		850	Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
		851	C<loop> nor C<revents> need to be valid as long as the watcher callback
		852	can deal with that fact.
		853
		854	=item int ev_clear_pending (loop, ev_TYPE *watcher)
		855
		856	If the watcher is pending, this function returns clears its pending status
		857	and returns its C<revents> bitset (as if its callback was invoked). If the
		858	watcher isn't pending it does nothing and returns C<0>.
777		859
778	=back	860	=back
779		861
780		862
781	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	863	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
891	play around with an Xlib connection), then you have to seperately re-test	973	play around with an Xlib connection), then you have to seperately re-test
892	whether a file descriptor is really ready with a known-to-be good interface	974	whether a file descriptor is really ready with a known-to-be good interface
893	such as poll (fortunately in our Xlib example, Xlib already does this on	975	such as poll (fortunately in our Xlib example, Xlib already does this on
894	its own, so its quite safe to use).	976	its own, so its quite safe to use).
895		977
		978	=head3 The special problem of disappearing file descriptors
		979
		980	Some backends (e.g. kqueue, epoll) need to be told about closing a file
		981	descriptor (either by calling C<close> explicitly or by any other means,
		982	such as C<dup>). The reason is that you register interest in some file
		983	descriptor, but when it goes away, the operating system will silently drop
		984	this interest. If another file descriptor with the same number then is
		985	registered with libev, there is no efficient way to see that this is, in
		986	fact, a different file descriptor.
		987
		988	To avoid having to explicitly tell libev about such cases, libev follows
		989	the following policy: Each time C<ev_io_set> is being called, libev
		990	will assume that this is potentially a new file descriptor, otherwise
		991	it is assumed that the file descriptor stays the same. That means that
		992	you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the
		993	descriptor even if the file descriptor number itself did not change.
		994
		995	This is how one would do it normally anyway, the important point is that
		996	the libev application should not optimise around libev but should leave
		997	optimisations to libev.
		998
		999	=head3 The special problem of dup'ed file descriptors
		1000
		1001	Some backends (e.g. epoll), cannot register events for file descriptors,
		1002	but only events for the underlying file descriptions. That menas when you
		1003	have C<dup ()>'ed file descriptors and register events for them, only one
		1004	file descriptor might actually receive events.
		1005
		1006	There is no workaorund possible except not registering events
		1007	for potentially C<dup ()>'ed file descriptors or to resort to
		1008	C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>.
		1009
		1010	=head3 The special problem of fork
		1011
		1012	Some backends (epoll, kqueue) do not support C<fork ()> at all or exhibit
		1013	useless behaviour. Libev fully supports fork, but needs to be told about
		1014	it in the child.
		1015
		1016	To support fork in your programs, you either have to call
		1017	C<ev_default_fork ()> or C<ev_loop_fork ()> after a fork in the child,
		1018	enable C<EVFLAG_FORKCHECK>, or resort to C<EVBACKEND_SELECT> or
		1019	C<EVBACKEND_POLL>.
		1020
		1021
		1022	=head3 Watcher-Specific Functions
		1023
896	=over 4	1024	=over 4
897		1025
898	=item ev_io_init (ev_io *, callback, int fd, int events)	1026	=item ev_io_init (ev_io *, callback, int fd, int events)
899		1027
900	=item ev_io_set (ev_io *, int fd, int events)	1028	=item ev_io_set (ev_io *, int fd, int events)
…		…
952	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);	1080	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
953		1081
954	The callback is guarenteed to be invoked only when its timeout has passed,	1082	The callback is guarenteed to be invoked only when its timeout has passed,
955	but if multiple timers become ready during the same loop iteration then	1083	but if multiple timers become ready during the same loop iteration then
956	order of execution is undefined.	1084	order of execution is undefined.
		1085
		1086	=head3 Watcher-Specific Functions and Data Members
957		1087
958	=over 4	1088	=over 4
959		1089
960	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)	1090	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
961		1091
…		…
1057	but on wallclock time (absolute time). You can tell a periodic watcher	1187	but on wallclock time (absolute time). You can tell a periodic watcher
1058	to trigger "at" some specific point in time. For example, if you tell a	1188	to trigger "at" some specific point in time. For example, if you tell a
1059	periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now ()	1189	periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now ()
1060	+ 10.>) and then reset your system clock to the last year, then it will	1190	+ 10.>) and then reset your system clock to the last year, then it will
1061	take a year to trigger the event (unlike an C<ev_timer>, which would trigger	1191	take a year to trigger the event (unlike an C<ev_timer>, which would trigger
1062	roughly 10 seconds later and of course not if you reset your system time	1192	roughly 10 seconds later).
1063	again).
1064		1193
1065	They can also be used to implement vastly more complex timers, such as	1194	They can also be used to implement vastly more complex timers, such as
1066	triggering an event on eahc midnight, local time.	1195	triggering an event on each midnight, local time or other, complicated,
		1196	rules.
1067		1197
1068	As with timers, the callback is guarenteed to be invoked only when the	1198	As with timers, the callback is guarenteed to be invoked only when the
1069	time (C<at>) has been passed, but if multiple periodic timers become ready	1199	time (C<at>) has been passed, but if multiple periodic timers become ready
1070	during the same loop iteration then order of execution is undefined.	1200	during the same loop iteration then order of execution is undefined.
1071		1201
		1202	=head3 Watcher-Specific Functions and Data Members
		1203
1072	=over 4	1204	=over 4
1073		1205
1074	=item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)	1206	=item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)
1075		1207
1076	=item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)	1208	=item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)
…		…
1078	Lots of arguments, lets sort it out... There are basically three modes of	1210	Lots of arguments, lets sort it out... There are basically three modes of
1079	operation, and we will explain them from simplest to complex:	1211	operation, and we will explain them from simplest to complex:
1080		1212
1081	=over 4	1213	=over 4
1082		1214
1083	=item * absolute timer (interval = reschedule_cb = 0)	1215	=item * absolute timer (at = time, interval = reschedule_cb = 0)
1084		1216
1085	In this configuration the watcher triggers an event at the wallclock time	1217	In this configuration the watcher triggers an event at the wallclock time
1086	C<at> and doesn't repeat. It will not adjust when a time jump occurs,	1218	C<at> and doesn't repeat. It will not adjust when a time jump occurs,
1087	that is, if it is to be run at January 1st 2011 then it will run when the	1219	that is, if it is to be run at January 1st 2011 then it will run when the
1088	system time reaches or surpasses this time.	1220	system time reaches or surpasses this time.
1089		1221
1090	=item * non-repeating interval timer (interval > 0, reschedule_cb = 0)	1222	=item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)
1091		1223
1092	In this mode the watcher will always be scheduled to time out at the next	1224	In this mode the watcher will always be scheduled to time out at the next
1093	C<at + N * interval> time (for some integer N) and then repeat, regardless	1225	C<at + N * interval> time (for some integer N, which can also be negative)
1094	of any time jumps.	1226	and then repeat, regardless of any time jumps.
1095		1227
1096	This can be used to create timers that do not drift with respect to system	1228	This can be used to create timers that do not drift with respect to system
1097	time:	1229	time:
1098		1230
1099	ev_periodic_set (&periodic, 0., 3600., 0);	1231	ev_periodic_set (&periodic, 0., 3600., 0);
…		…
1105		1237
1106	Another way to think about it (for the mathematically inclined) is that	1238	Another way to think about it (for the mathematically inclined) is that
1107	C<ev_periodic> will try to run the callback in this mode at the next possible	1239	C<ev_periodic> will try to run the callback in this mode at the next possible
1108	time where C<time = at (mod interval)>, regardless of any time jumps.	1240	time where C<time = at (mod interval)>, regardless of any time jumps.
1109		1241
		1242	For numerical stability it is preferable that the C<at> value is near
		1243	C<ev_now ()> (the current time), but there is no range requirement for
		1244	this value.
		1245
1110	=item * manual reschedule mode (reschedule_cb = callback)	1246	=item * manual reschedule mode (at and interval ignored, reschedule_cb = callback)
1111		1247
1112	In this mode the values for C<interval> and C<at> are both being	1248	In this mode the values for C<interval> and C<at> are both being
1113	ignored. Instead, each time the periodic watcher gets scheduled, the	1249	ignored. Instead, each time the periodic watcher gets scheduled, the
1114	reschedule callback will be called with the watcher as first, and the	1250	reschedule callback will be called with the watcher as first, and the
1115	current time as second argument.	1251	current time as second argument.
1116		1252
1117	NOTE: I<This callback MUST NOT stop or destroy any periodic watcher,	1253	NOTE: I<This callback MUST NOT stop or destroy any periodic watcher,
1118	ever, or make any event loop modifications>. If you need to stop it,	1254	ever, or make any event loop modifications>. If you need to stop it,
1119	return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by	1255	return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by
1120	starting a prepare watcher).	1256	starting an C<ev_prepare> watcher, which is legal).
1121		1257
1122	Its prototype is C<ev_tstamp (reschedule_cb)(struct ev_periodic w,	1258	Its prototype is C<ev_tstamp (reschedule_cb)(struct ev_periodic w,
1123	ev_tstamp now)>, e.g.:	1259	ev_tstamp now)>, e.g.:
1124		1260
1125	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)	1261	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)
…		…
1148	Simply stops and restarts the periodic watcher again. This is only useful	1284	Simply stops and restarts the periodic watcher again. This is only useful
1149	when you changed some parameters or the reschedule callback would return	1285	when you changed some parameters or the reschedule callback would return
1150	a different time than the last time it was called (e.g. in a crond like	1286	a different time than the last time it was called (e.g. in a crond like
1151	program when the crontabs have changed).	1287	program when the crontabs have changed).
1152		1288
		1289	=item ev_tstamp offset [read-write]
		1290
		1291	When repeating, this contains the offset value, otherwise this is the
		1292	absolute point in time (the C<at> value passed to C<ev_periodic_set>).
		1293
		1294	Can be modified any time, but changes only take effect when the periodic
		1295	timer fires or C<ev_periodic_again> is being called.
		1296
1153	=item ev_tstamp interval [read-write]	1297	=item ev_tstamp interval [read-write]
1154		1298
1155	The current interval value. Can be modified any time, but changes only	1299	The current interval value. Can be modified any time, but changes only
1156	take effect when the periodic timer fires or C<ev_periodic_again> is being	1300	take effect when the periodic timer fires or C<ev_periodic_again> is being
1157	called.	1301	called.
…		…
1159	=item ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]	1303	=item ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]
1160		1304
1161	The current reschedule callback, or C<0>, if this functionality is	1305	The current reschedule callback, or C<0>, if this functionality is
1162	switched off. Can be changed any time, but changes only take effect when	1306	switched off. Can be changed any time, but changes only take effect when
1163	the periodic timer fires or C<ev_periodic_again> is being called.	1307	the periodic timer fires or C<ev_periodic_again> is being called.
		1308
		1309	=item ev_tstamp at [read-only]
		1310
		1311	When active, contains the absolute time that the watcher is supposed to
		1312	trigger next.
1164		1313
1165	=back	1314	=back
1166		1315
1167	Example: Call a callback every hour, or, more precisely, whenever the	1316	Example: Call a callback every hour, or, more precisely, whenever the
1168	system clock is divisible by 3600. The callback invocation times have	1317	system clock is divisible by 3600. The callback invocation times have
…		…
1210	with the kernel (thus it coexists with your own signal handlers as long	1359	with the kernel (thus it coexists with your own signal handlers as long
1211	as you don't register any with libev). Similarly, when the last signal	1360	as you don't register any with libev). Similarly, when the last signal
1212	watcher for a signal is stopped libev will reset the signal handler to	1361	watcher for a signal is stopped libev will reset the signal handler to
1213	SIG_DFL (regardless of what it was set to before).	1362	SIG_DFL (regardless of what it was set to before).
1214		1363
		1364	=head3 Watcher-Specific Functions and Data Members
		1365
1215	=over 4	1366	=over 4
1216		1367
1217	=item ev_signal_init (ev_signal *, callback, int signum)	1368	=item ev_signal_init (ev_signal *, callback, int signum)
1218		1369
1219	=item ev_signal_set (ev_signal *, int signum)	1370	=item ev_signal_set (ev_signal *, int signum)
…		…
1230		1381
1231	=head2 C<ev_child> - watch out for process status changes	1382	=head2 C<ev_child> - watch out for process status changes
1232		1383
1233	Child watchers trigger when your process receives a SIGCHLD in response to	1384	Child watchers trigger when your process receives a SIGCHLD in response to
1234	some child status changes (most typically when a child of yours dies).	1385	some child status changes (most typically when a child of yours dies).
		1386
		1387	=head3 Watcher-Specific Functions and Data Members
1235		1388
1236	=over 4	1389	=over 4
1237		1390
1238	=item ev_child_init (ev_child *, callback, int pid)	1391	=item ev_child_init (ev_child *, callback, int pid)
1239		1392
…		…
1307	reader). Inotify will be used to give hints only and should not change the	1460	reader). Inotify will be used to give hints only and should not change the
1308	semantics of C<ev_stat> watchers, which means that libev sometimes needs	1461	semantics of C<ev_stat> watchers, which means that libev sometimes needs
1309	to fall back to regular polling again even with inotify, but changes are	1462	to fall back to regular polling again even with inotify, but changes are
1310	usually detected immediately, and if the file exists there will be no	1463	usually detected immediately, and if the file exists there will be no
1311	polling.	1464	polling.
		1465
		1466	=head3 Watcher-Specific Functions and Data Members
1312		1467
1313	=over 4	1468	=over 4
1314		1469
1315	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)	1470	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)
1316		1471
…		…
1399	Apart from keeping your process non-blocking (which is a useful	1554	Apart from keeping your process non-blocking (which is a useful
1400	effect on its own sometimes), idle watchers are a good place to do	1555	effect on its own sometimes), idle watchers are a good place to do
1401	"pseudo-background processing", or delay processing stuff to after the	1556	"pseudo-background processing", or delay processing stuff to after the
1402	event loop has handled all outstanding events.	1557	event loop has handled all outstanding events.
1403		1558
		1559	=head3 Watcher-Specific Functions and Data Members
		1560
1404	=over 4	1561	=over 4
1405		1562
1406	=item ev_idle_init (ev_signal *, callback)	1563	=item ev_idle_init (ev_signal *, callback)
1407		1564
1408	Initialises and configures the idle watcher - it has no parameters of any	1565	Initialises and configures the idle watcher - it has no parameters of any
…		…
1465	with priority higher than or equal to the event loop and one coroutine	1622	with priority higher than or equal to the event loop and one coroutine
1466	of lower priority, but only once, using idle watchers to keep the event	1623	of lower priority, but only once, using idle watchers to keep the event
1467	loop from blocking if lower-priority coroutines are active, thus mapping	1624	loop from blocking if lower-priority coroutines are active, thus mapping
1468	low-priority coroutines to idle/background tasks).	1625	low-priority coroutines to idle/background tasks).
1469		1626
		1627	It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>)
		1628	priority, to ensure that they are being run before any other watchers
		1629	after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers,
		1630	too) should not activate ("feed") events into libev. While libev fully
		1631	supports this, they will be called before other C<ev_check> watchers
		1632	did their job. As C<ev_check> watchers are often used to embed other
		1633	(non-libev) event loops those other event loops might be in an unusable
		1634	state until their C<ev_check> watcher ran (always remind yourself to
		1635	coexist peacefully with others).
		1636
		1637	=head3 Watcher-Specific Functions and Data Members
		1638
1470	=over 4	1639	=over 4
1471		1640
1472	=item ev_prepare_init (ev_prepare *, callback)	1641	=item ev_prepare_init (ev_prepare *, callback)
1473		1642
1474	=item ev_check_init (ev_check *, callback)	1643	=item ev_check_init (ev_check *, callback)
…		…
1477	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>	1646	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>
1478	macros, but using them is utterly, utterly and completely pointless.	1647	macros, but using them is utterly, utterly and completely pointless.
1479		1648
1480	=back	1649	=back
1481		1650
1482	Example: To include a library such as adns, you would add IO watchers	1651	There are a number of principal ways to embed other event loops or modules
1483	and a timeout watcher in a prepare handler, as required by libadns, and	1652	into libev. Here are some ideas on how to include libadns into libev
		1653	(there is a Perl module named C<EV::ADNS> that does this, which you could
		1654	use for an actually working example. Another Perl module named C<EV::Glib>
		1655	embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV
		1656	into the Glib event loop).
		1657
		1658	Method 1: Add IO watchers and a timeout watcher in a prepare handler,
1484	in a check watcher, destroy them and call into libadns. What follows is	1659	and in a check watcher, destroy them and call into libadns. What follows
1485	pseudo-code only of course:	1660	is pseudo-code only of course. This requires you to either use a low
		1661	priority for the check watcher or use C<ev_clear_pending> explicitly, as
		1662	the callbacks for the IO/timeout watchers might not have been called yet.
1486		1663
1487	static ev_io iow [nfd];	1664	static ev_io iow [nfd];
1488	static ev_timer tw;	1665	static ev_timer tw;
1489		1666
1490	static void	1667	static void
1491	io_cb (ev_loop loop, ev_io w, int revents)	1668	io_cb (ev_loop loop, ev_io w, int revents)
1492	{	1669	{
1493	// set the relevant poll flags
1494	// could also call adns_processreadable etc. here
1495	struct pollfd fd = (struct pollfd )w->data;
1496	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1497	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
1498	}	1670	}
1499		1671
1500	// create io watchers for each fd and a timer before blocking	1672	// create io watchers for each fd and a timer before blocking
1501	static void	1673	static void
1502	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1674	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
…		…
1508		1680
1509	/* the callback is illegal, but won't be called as we stop during check */	1681	/* the callback is illegal, but won't be called as we stop during check */
1510	ev_timer_init (&tw, 0, timeout * 1e-3);	1682	ev_timer_init (&tw, 0, timeout * 1e-3);
1511	ev_timer_start (loop, &tw);	1683	ev_timer_start (loop, &tw);
1512		1684
1513	// create on ev_io per pollfd	1685	// create one ev_io per pollfd
1514	for (int i = 0; i < nfd; ++i)	1686	for (int i = 0; i < nfd; ++i)
1515	{	1687	{
1516	ev_io_init (iow + i, io_cb, fds [i].fd,	1688	ev_io_init (iow + i, io_cb, fds [i].fd,
1517	((fds [i].events & POLLIN ? EV_READ : 0)	1689	((fds [i].events & POLLIN ? EV_READ : 0)
1518	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	1690	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1519		1691
1520	fds [i].revents = 0;	1692	fds [i].revents = 0;
1521	iow [i].data = fds + i;
1522	ev_io_start (loop, iow + i);	1693	ev_io_start (loop, iow + i);
1523	}	1694	}
1524	}	1695	}
1525		1696
1526	// stop all watchers after blocking	1697	// stop all watchers after blocking
…		…
1528	adns_check_cb (ev_loop loop, ev_check w, int revents)	1699	adns_check_cb (ev_loop loop, ev_check w, int revents)
1529	{	1700	{
1530	ev_timer_stop (loop, &tw);	1701	ev_timer_stop (loop, &tw);
1531		1702
1532	for (int i = 0; i < nfd; ++i)	1703	for (int i = 0; i < nfd; ++i)
		1704	{
		1705	// set the relevant poll flags
		1706	// could also call adns_processreadable etc. here
		1707	struct pollfd *fd = fds + i;
		1708	int revents = ev_clear_pending (iow + i);
		1709	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1710	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1711
		1712	// now stop the watcher
1533	ev_io_stop (loop, iow + i);	1713	ev_io_stop (loop, iow + i);
		1714	}
1534		1715
1535	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	1716	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1717	}
		1718
		1719	Method 2: This would be just like method 1, but you run C<adns_afterpoll>
		1720	in the prepare watcher and would dispose of the check watcher.
		1721
		1722	Method 3: If the module to be embedded supports explicit event
		1723	notification (adns does), you can also make use of the actual watcher
		1724	callbacks, and only destroy/create the watchers in the prepare watcher.
		1725
		1726	static void
		1727	timer_cb (EV_P_ ev_timer *w, int revents)
		1728	{
		1729	adns_state ads = (adns_state)w->data;
		1730	update_now (EV_A);
		1731
		1732	adns_processtimeouts (ads, &tv_now);
		1733	}
		1734
		1735	static void
		1736	io_cb (EV_P_ ev_io *w, int revents)
		1737	{
		1738	adns_state ads = (adns_state)w->data;
		1739	update_now (EV_A);
		1740
		1741	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
		1742	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
		1743	}
		1744
		1745	// do not ever call adns_afterpoll
		1746
		1747	Method 4: Do not use a prepare or check watcher because the module you
		1748	want to embed is too inflexible to support it. Instead, youc na override
		1749	their poll function. The drawback with this solution is that the main
		1750	loop is now no longer controllable by EV. The C<Glib::EV> module does
		1751	this.
		1752
		1753	static gint
		1754	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
		1755	{
		1756	int got_events = 0;
		1757
		1758	for (n = 0; n < nfds; ++n)
		1759	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
		1760
		1761	if (timeout >= 0)
		1762	// create/start timer
		1763
		1764	// poll
		1765	ev_loop (EV_A_ 0);
		1766
		1767	// stop timer again
		1768	if (timeout >= 0)
		1769	ev_timer_stop (EV_A_ &to);
		1770
		1771	// stop io watchers again - their callbacks should have set
		1772	for (n = 0; n < nfds; ++n)
		1773	ev_io_stop (EV_A_ iow [n]);
		1774
		1775	return got_events;
1536	}	1776	}
1537		1777
1538		1778
1539	=head2 C<ev_embed> - when one backend isn't enough...	1779	=head2 C<ev_embed> - when one backend isn't enough...
1540		1780
…		…
1604	ev_embed_start (loop_hi, &embed);	1844	ev_embed_start (loop_hi, &embed);
1605	}	1845	}
1606	else	1846	else
1607	loop_lo = loop_hi;	1847	loop_lo = loop_hi;
1608		1848
		1849	=head3 Watcher-Specific Functions and Data Members
		1850
1609	=over 4	1851	=over 4
1610		1852
1611	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)	1853	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)
1612		1854
1613	=item ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)	1855	=item ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)
…		…
1622		1864
1623	Make a single, non-blocking sweep over the embedded loop. This works	1865	Make a single, non-blocking sweep over the embedded loop. This works
1624	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	1866	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
1625	apropriate way for embedded loops.	1867	apropriate way for embedded loops.
1626		1868
1627	=item struct ev_loop *loop [read-only]	1869	=item struct ev_loop *other [read-only]
1628		1870
1629	The embedded event loop.	1871	The embedded event loop.
1630		1872
1631	=back	1873	=back
1632		1874
…		…
1639	event loop blocks next and before C<ev_check> watchers are being called,	1881	event loop blocks next and before C<ev_check> watchers are being called,
1640	and only in the child after the fork. If whoever good citizen calling	1882	and only in the child after the fork. If whoever good citizen calling
1641	C<ev_default_fork> cheats and calls it in the wrong process, the fork	1883	C<ev_default_fork> cheats and calls it in the wrong process, the fork
1642	handlers will be invoked, too, of course.	1884	handlers will be invoked, too, of course.
1643		1885
		1886	=head3 Watcher-Specific Functions and Data Members
		1887
1644	=over 4	1888	=over 4
1645		1889
1646	=item ev_fork_init (ev_signal *, callback)	1890	=item ev_fork_init (ev_signal *, callback)
1647		1891
1648	Initialises and configures the fork watcher - it has no parameters of any	1892	Initialises and configures the fork watcher - it has no parameters of any
…		…
1744		1988
1745	To use it,	1989	To use it,
1746		1990
1747	#include <ev++.h>	1991	#include <ev++.h>
1748		1992
1749	(it is not installed by default). This automatically includes F<ev.h>	1993	This automatically includes F<ev.h> and puts all of its definitions (many
1750	and puts all of its definitions (many of them macros) into the global	1994	of them macros) into the global namespace. All C++ specific things are
1751	namespace. All C++ specific things are put into the C<ev> namespace.	1995	put into the C<ev> namespace. It should support all the same embedding
		1996	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
1752		1997
1753	It should support all the same embedding options as F<ev.h>, most notably	1998	Care has been taken to keep the overhead low. The only data member the C++
1754	C<EV_MULTIPLICITY>.	1999	classes add (compared to plain C-style watchers) is the event loop pointer
		2000	that the watcher is associated with (or no additional members at all if
		2001	you disable C<EV_MULTIPLICITY> when embedding libev).
		2002
		2003	Currently, functions, and static and non-static member functions can be
		2004	used as callbacks. Other types should be easy to add as long as they only
		2005	need one additional pointer for context. If you need support for other
		2006	types of functors please contact the author (preferably after implementing
		2007	it).
1755		2008
1756	Here is a list of things available in the C<ev> namespace:	2009	Here is a list of things available in the C<ev> namespace:
1757		2010
1758	=over 4	2011	=over 4
1759		2012
…		…
1775		2028
1776	All of those classes have these methods:	2029	All of those classes have these methods:
1777		2030
1778	=over 4	2031	=over 4
1779		2032
1780	=item ev::TYPE::TYPE (object , object::method )	2033	=item ev::TYPE::TYPE ()
1781		2034
1782	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)	2035	=item ev::TYPE::TYPE (struct ev_loop *)
1783		2036
1784	=item ev::TYPE::~TYPE	2037	=item ev::TYPE::~TYPE
1785		2038
1786	The constructor takes a pointer to an object and a method pointer to	2039	The constructor (optionally) takes an event loop to associate the watcher
1787	the event handler callback to call in this class. The constructor calls	2040	with. If it is omitted, it will use C<EV_DEFAULT>.
1788	C<ev_init> for you, which means you have to call the C<set> method	2041
1789	before starting it. If you do not specify a loop then the constructor	2042	The constructor calls C<ev_init> for you, which means you have to call the
1790	automatically associates the default loop with this watcher.	2043	C<set> method before starting it.
		2044
		2045	It will not set a callback, however: You have to call the templated C<set>
		2046	method to set a callback before you can start the watcher.
		2047
		2048	(The reason why you have to use a method is a limitation in C++ which does
		2049	not allow explicit template arguments for constructors).
1791		2050
1792	The destructor automatically stops the watcher if it is active.	2051	The destructor automatically stops the watcher if it is active.
		2052
		2053	=item w->set<class, &class::method> (object *)
		2054
		2055	This method sets the callback method to call. The method has to have a
		2056	signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
		2057	first argument and the C<revents> as second. The object must be given as
		2058	parameter and is stored in the C<data> member of the watcher.
		2059
		2060	This method synthesizes efficient thunking code to call your method from
		2061	the C callback that libev requires. If your compiler can inline your
		2062	callback (i.e. it is visible to it at the place of the C<set> call and
		2063	your compiler is good :), then the method will be fully inlined into the
		2064	thunking function, making it as fast as a direct C callback.
		2065
		2066	Example: simple class declaration and watcher initialisation
		2067
		2068	struct myclass
		2069	{
		2070	void io_cb (ev::io &w, int revents) { }
		2071	}
		2072
		2073	myclass obj;
		2074	ev::io iow;
		2075	iow.set <myclass, &myclass::io_cb> (&obj);
		2076
		2077	=item w->set<function> (void *data = 0)
		2078
		2079	Also sets a callback, but uses a static method or plain function as
		2080	callback. The optional C<data> argument will be stored in the watcher's
		2081	C<data> member and is free for you to use.
		2082
		2083	The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>.
		2084
		2085	See the method-C<set> above for more details.
		2086
		2087	Example:
		2088
		2089	static void io_cb (ev::io &w, int revents) { }
		2090	iow.set <io_cb> ();
1793		2091
1794	=item w->set (struct ev_loop *)	2092	=item w->set (struct ev_loop *)
1795		2093
1796	Associates a different C<struct ev_loop> with this watcher. You can only	2094	Associates a different C<struct ev_loop> with this watcher. You can only
1797	do this when the watcher is inactive (and not pending either).	2095	do this when the watcher is inactive (and not pending either).
1798		2096
1799	=item w->set ([args])	2097	=item w->set ([args])
1800		2098
1801	Basically the same as C<ev_TYPE_set>, with the same args. Must be	2099	Basically the same as C<ev_TYPE_set>, with the same args. Must be
1802	called at least once. Unlike the C counterpart, an active watcher gets	2100	called at least once. Unlike the C counterpart, an active watcher gets
1803	automatically stopped and restarted.	2101	automatically stopped and restarted when reconfiguring it with this
		2102	method.
1804		2103
1805	=item w->start ()	2104	=item w->start ()
1806		2105
1807	Starts the watcher. Note that there is no C<loop> argument as the	2106	Starts the watcher. Note that there is no C<loop> argument, as the
1808	constructor already takes the loop.	2107	constructor already stores the event loop.
1809		2108
1810	=item w->stop ()	2109	=item w->stop ()
1811		2110
1812	Stops the watcher if it is active. Again, no C<loop> argument.	2111	Stops the watcher if it is active. Again, no C<loop> argument.
1813		2112
1814	=item w->again () C<ev::timer>, C<ev::periodic> only	2113	=item w->again () (C<ev::timer>, C<ev::periodic> only)
1815		2114
1816	For C<ev::timer> and C<ev::periodic>, this invokes the corresponding	2115	For C<ev::timer> and C<ev::periodic>, this invokes the corresponding
1817	C<ev_TYPE_again> function.	2116	C<ev_TYPE_again> function.
1818		2117
1819	=item w->sweep () C<ev::embed> only	2118	=item w->sweep () (C<ev::embed> only)
1820		2119
1821	Invokes C<ev_embed_sweep>.	2120	Invokes C<ev_embed_sweep>.
1822		2121
1823	=item w->update () C<ev::stat> only	2122	=item w->update () (C<ev::stat> only)
1824		2123
1825	Invokes C<ev_stat_stat>.	2124	Invokes C<ev_stat_stat>.
1826		2125
1827	=back	2126	=back
1828		2127
…		…
1838		2137
1839	myclass ();	2138	myclass ();
1840	}	2139	}
1841		2140
1842	myclass::myclass (int fd)	2141	myclass::myclass (int fd)
1843	: io (this, &myclass::io_cb),
1844	idle (this, &myclass::idle_cb)
1845	{	2142	{
		2143	io .set <myclass, &myclass::io_cb > (this);
		2144	idle.set <myclass, &myclass::idle_cb> (this);
		2145
1846	io.start (fd, ev::READ);	2146	io.start (fd, ev::READ);
1847	}	2147	}
1848		2148
1849		2149
1850	=head1 MACRO MAGIC	2150	=head1 MACRO MAGIC
1851		2151
1852	Libev can be compiled with a variety of options, the most fundemantal is	2152	Libev can be compiled with a variety of options, the most fundamantal
1853	C<EV_MULTIPLICITY>. This option determines whether (most) functions and	2153	of which is C<EV_MULTIPLICITY>. This option determines whether (most)
1854	callbacks have an initial C<struct ev_loop *> argument.	2154	functions and callbacks have an initial C<struct ev_loop *> argument.
1855		2155
1856	To make it easier to write programs that cope with either variant, the	2156	To make it easier to write programs that cope with either variant, the
1857	following macros are defined:	2157	following macros are defined:
1858		2158
1859	=over 4	2159	=over 4
…		…
1913	Libev can (and often is) directly embedded into host	2213	Libev can (and often is) directly embedded into host
1914	applications. Examples of applications that embed it include the Deliantra	2214	applications. Examples of applications that embed it include the Deliantra
1915	Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)	2215	Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
1916	and rxvt-unicode.	2216	and rxvt-unicode.
1917		2217
1918	The goal is to enable you to just copy the neecssary files into your	2218	The goal is to enable you to just copy the necessary files into your
1919	source directory without having to change even a single line in them, so	2219	source directory without having to change even a single line in them, so
1920	you can easily upgrade by simply copying (or having a checked-out copy of	2220	you can easily upgrade by simply copying (or having a checked-out copy of
1921	libev somewhere in your source tree).	2221	libev somewhere in your source tree).
1922		2222
1923	=head2 FILESETS	2223	=head2 FILESETS
…		…
2013		2313
2014	If defined to be C<1>, libev will try to detect the availability of the	2314	If defined to be C<1>, libev will try to detect the availability of the
2015	monotonic clock option at both compiletime and runtime. Otherwise no use	2315	monotonic clock option at both compiletime and runtime. Otherwise no use
2016	of the monotonic clock option will be attempted. If you enable this, you	2316	of the monotonic clock option will be attempted. If you enable this, you
2017	usually have to link against librt or something similar. Enabling it when	2317	usually have to link against librt or something similar. Enabling it when
2018	the functionality isn't available is safe, though, althoguh you have	2318	the functionality isn't available is safe, though, although you have
2019	to make sure you link against any libraries where the C<clock_gettime>	2319	to make sure you link against any libraries where the C<clock_gettime>
2020	function is hiding in (often F<-lrt>).	2320	function is hiding in (often F<-lrt>).
2021		2321
2022	=item EV_USE_REALTIME	2322	=item EV_USE_REALTIME
2023		2323
2024	If defined to be C<1>, libev will try to detect the availability of the	2324	If defined to be C<1>, libev will try to detect the availability of the
2025	realtime clock option at compiletime (and assume its availability at	2325	realtime clock option at compiletime (and assume its availability at
2026	runtime if successful). Otherwise no use of the realtime clock option will	2326	runtime if successful). Otherwise no use of the realtime clock option will
2027	be attempted. This effectively replaces C<gettimeofday> by C<clock_get	2327	be attempted. This effectively replaces C<gettimeofday> by C<clock_get
2028	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries	2328	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
2029	in the description of C<EV_USE_MONOTONIC>, though.	2329	note about libraries in the description of C<EV_USE_MONOTONIC>, though.
		2330
		2331	=item EV_USE_NANOSLEEP
		2332
		2333	If defined to be C<1>, libev will assume that C<nanosleep ()> is available
		2334	and will use it for delays. Otherwise it will use C<select ()>.
2030		2335
2031	=item EV_USE_SELECT	2336	=item EV_USE_SELECT
2032		2337
2033	If undefined or defined to be C<1>, libev will compile in support for the	2338	If undefined or defined to be C<1>, libev will compile in support for the
2034	C<select>(2) backend. No attempt at autodetection will be done: if no	2339	C<select>(2) backend. No attempt at autodetection will be done: if no
…		…
2213		2518
2214	=item ev_set_cb (ev, cb)	2519	=item ev_set_cb (ev, cb)
2215		2520
2216	Can be used to change the callback member declaration in each watcher,	2521	Can be used to change the callback member declaration in each watcher,
2217	and the way callbacks are invoked and set. Must expand to a struct member	2522	and the way callbacks are invoked and set. Must expand to a struct member
2218	definition and a statement, respectively. See the F<ev.v> header file for	2523	definition and a statement, respectively. See the F<ev.h> header file for
2219	their default definitions. One possible use for overriding these is to	2524	their default definitions. One possible use for overriding these is to
2220	avoid the C<struct ev_loop *> as first argument in all cases, or to use	2525	avoid the C<struct ev_loop *> as first argument in all cases, or to use
2221	method calls instead of plain function calls in C++.	2526	method calls instead of plain function calls in C++.
		2527
		2528	=head2 EXPORTED API SYMBOLS
		2529
		2530	If you need to re-export the API (e.g. via a dll) and you need a list of
		2531	exported symbols, you can use the provided F<Symbol.*> files which list
		2532	all public symbols, one per line:
		2533
		2534	Symbols.ev for libev proper
		2535	Symbols.event for the libevent emulation
		2536
		2537	This can also be used to rename all public symbols to avoid clashes with
		2538	multiple versions of libev linked together (which is obviously bad in
		2539	itself, but sometimes it is inconvinient to avoid this).
		2540
		2541	A sed command like this will create wrapper C<#define>'s that you need to
		2542	include before including F<ev.h>:
		2543
		2544	<Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h
		2545
		2546	This would create a file F<wrap.h> which essentially looks like this:
		2547
		2548	#define ev_backend myprefix_ev_backend
		2549	#define ev_check_start myprefix_ev_check_start
		2550	#define ev_check_stop myprefix_ev_check_stop
		2551	...
2222		2552
2223	=head2 EXAMPLES	2553	=head2 EXAMPLES
2224		2554
2225	For a real-world example of a program the includes libev	2555	For a real-world example of a program the includes libev
2226	verbatim, you can have a look at the EV perl module	2556	verbatim, you can have a look at the EV perl module

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing libev/ev.pod (file contents): Revision 1.70 by root, Fri Dec 7 19:23:48 2007 UTC vs. Revision 1.101 by ayin, Sat Dec 22 14:11:25 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.70 by root, Fri Dec 7 19:23:48 2007 UTC vs.
Revision 1.101 by ayin, Sat Dec 22 14:11:25 2007 UTC