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

Comparing libev/ev.pod (file contents):
Revision 1.292 by sf-exg, Mon Mar 22 09:57:01 2010 UTC vs.
Revision 1.321 by sf-exg, Fri Oct 22 10:50:24 2010 UTC

…		…
26	puts ("stdin ready");	26	puts ("stdin ready");
27	// for one-shot events, one must manually stop the watcher	27	// for one-shot events, one must manually stop the watcher
28	// with its corresponding stop function.	28	// with its corresponding stop function.
29	ev_io_stop (EV_A_ w);	29	ev_io_stop (EV_A_ w);
30		30
31	// this causes all nested ev_loop's to stop iterating	31	// this causes all nested ev_run's to stop iterating
32	ev_unloop (EV_A_ EVUNLOOP_ALL);	32	ev_break (EV_A_ EVBREAK_ALL);
33	}	33	}
34		34
35	// another callback, this time for a time-out	35	// another callback, this time for a time-out
36	static void	36	static void
37	timeout_cb (EV_P_ ev_timer *w, int revents)	37	timeout_cb (EV_P_ ev_timer *w, int revents)
38	{	38	{
39	puts ("timeout");	39	puts ("timeout");
40	// this causes the innermost ev_loop to stop iterating	40	// this causes the innermost ev_run to stop iterating
41	ev_unloop (EV_A_ EVUNLOOP_ONE);	41	ev_break (EV_A_ EVBREAK_ONE);
42	}	42	}
43		43
44	int	44	int
45	main (void)	45	main (void)
46	{	46	{
…		…
56	// simple non-repeating 5.5 second timeout	56	// simple non-repeating 5.5 second timeout
57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58	ev_timer_start (loop, &timeout_watcher);	58	ev_timer_start (loop, &timeout_watcher);
59		59
60	// now wait for events to arrive	60	// now wait for events to arrive
61	ev_loop (loop, 0);	61	ev_run (loop, 0);
62		62
63	// unloop was called, so exit	63	// unloop was called, so exit
64	return 0;	64	return 0;
65	}	65	}
66		66
…		…
75	While this document tries to be as complete as possible in documenting	75	While this document tries to be as complete as possible in documenting
76	libev, its usage and the rationale behind its design, it is not a tutorial	76	libev, its usage and the rationale behind its design, it is not a tutorial
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
82		82
83	=head1 ABOUT LIBEV	83	=head1 ABOUT LIBEV
84		84
85	Libev is an event loop: you register interest in certain events (such as a	85	Libev is an event loop: you register interest in certain events (such as a
…		…
124	this argument.	124	this argument.
125		125
126	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
127		127
128	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (somewhere	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	near the beginning of 1970, details are complicated, don't ask). This	130	somewhere near the beginning of 1970, details are complicated, don't
131	type is called C<ev_tstamp>, which is what you should use too. It usually	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	aliases to the C<double> type in C. When you need to do any calculations	132	too. It usually aliases to the C<double> type in C. When you need to do
133	on it, you should treat it as some floating point value. Unlike the name	133	any calculations on it, you should treat it as some floating point value.
		134
134	component C<stamp> might indicate, it is also used for time differences	135	Unlike the name component C<stamp> might indicate, it is also used for
135	throughout libev.	136	time differences (e.g. delays) throughout libev.
136		137
137	=head1 ERROR HANDLING	138	=head1 ERROR HANDLING
138		139
139	Libev knows three classes of errors: operating system errors, usage errors	140	Libev knows three classes of errors: operating system errors, usage errors
140	and internal errors (bugs).	141	and internal errors (bugs).
…		…
164		165
165	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
166		167
167	Returns the current time as libev would use it. Please note that the	168	Returns the current time as libev would use it. Please note that the
168	C<ev_now> function is usually faster and also often returns the timestamp	169	C<ev_now> function is usually faster and also often returns the timestamp
169	you actually want to know.	170	you actually want to know. Also interesting is the combination of
		171	C<ev_update_now> and C<ev_now>.
170		172
171	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
172		174
173	Sleep for the given interval: The current thread will be blocked until	175	Sleep for the given interval: The current thread will be blocked until
174	either it is interrupted or the given time interval has passed. Basically	176	either it is interrupted or the given time interval has passed. Basically
…		…
191	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
192	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
193	not a problem.	195	not a problem.
194		196
195	Example: Make sure we haven't accidentally been linked against the wrong	197	Example: Make sure we haven't accidentally been linked against the wrong
196	version.	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
197		200
198	assert (("libev version mismatch",	201	assert (("libev version mismatch",
199	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
200	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
201		204
…		…
212	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
213	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
214		217
215	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
216		219
217	Return the set of all backends compiled into this binary of libev and also	220	Return the set of all backends compiled into this binary of libev and
218	recommended for this platform. This set is often smaller than the one	221	also recommended for this platform, meaning it will work for most file
		222	descriptor types. This set is often smaller than the one returned by
219	returned by C<ev_supported_backends>, as for example kqueue is broken on	223	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
220	most BSDs and will not be auto-detected unless you explicitly request it	224	and will not be auto-detected unless you explicitly request it (assuming
221	(assuming you know what you are doing). This is the set of backends that	225	you know what you are doing). This is the set of backends that libev will
222	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
223		227
224	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
225		229
226	Returns the set of backends that are embeddable in other event loops. This	230	Returns the set of backends that are embeddable in other event loops. This
227	is the theoretical, all-platform, value. To find which backends	231	value is platform-specific but can include backends not available on the
228	might be supported on the current system, you would need to look at	232	current system. To find which embeddable backends might be supported on
229	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
230	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
231		235
232	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
233		237
234	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]	238	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]
235		239
…		…
291		295
292	=back	296	=back
293		297
294	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP
295		299
296	An event loop is described by a C<struct ev_loop *> (the C<struct>	300	An event loop is described by a C<struct ev_loop *> (the C<struct> is
297	is I<not> optional in this case, as there is also an C<ev_loop>	301	I<not> optional in this case unless libev 3 compatibility is disabled, as
298	I<function>).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
299		303
300	The library knows two types of such loops, the I<default> loop, which	304	The library knows two types of such loops, the I<default> loop, which
301	supports signals and child events, and dynamically created loops which do	305	supports signals and child events, and dynamically created event loops
302	not.	306	which do not.
303		307
304	=over 4	308	=over 4
305		309
306	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
307		311
…		…
438	of course I<doesn't>, and epoll just loves to report events for totally	442	of course I<doesn't>, and epoll just loves to report events for totally
439	I<different> file descriptors (even already closed ones, so one cannot	443	I<different> file descriptors (even already closed ones, so one cannot
440	even remove them from the set) than registered in the set (especially	444	even remove them from the set) than registered in the set (especially
441	on SMP systems). Libev tries to counter these spurious notifications by	445	on SMP systems). Libev tries to counter these spurious notifications by
442	employing an additional generation counter and comparing that against the	446	employing an additional generation counter and comparing that against the
443	events to filter out spurious ones, recreating the set when required.	447	events to filter out spurious ones, recreating the set when required. Last
		448	not least, it also refuses to work with some file descriptors which work
		449	perfectly fine with C<select> (files, many character devices...).
444		450
445	While stopping, setting and starting an I/O watcher in the same iteration	451	While stopping, setting and starting an I/O watcher in the same iteration
446	will result in some caching, there is still a system call per such	452	will result in some caching, there is still a system call per such
447	incident (because the same I<file descriptor> could point to a different	453	incident (because the same I<file descriptor> could point to a different
448	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	454	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
603	Like C<ev_default_destroy>, but destroys an event loop created by an	609	Like C<ev_default_destroy>, but destroys an event loop created by an
604	earlier call to C<ev_loop_new>.	610	earlier call to C<ev_loop_new>.
605		611
606	=item ev_default_fork ()	612	=item ev_default_fork ()
607		613
608	This function sets a flag that causes subsequent C<ev_loop> iterations	614	This function sets a flag that causes subsequent C<ev_run> iterations
609	to reinitialise the kernel state for backends that have one. Despite the	615	to reinitialise the kernel state for backends that have one. Despite the
610	name, you can call it anytime, but it makes most sense after forking, in	616	name, you can call it anytime, but it makes most sense after forking, in
611	the child process (or both child and parent, but that again makes little	617	the child process (or both child and parent, but that again makes little
612	sense). You I<must> call it in the child before using any of the libev	618	sense). You I<must> call it in the child before using any of the libev
613	functions, and it will only take effect at the next C<ev_loop> iteration.	619	functions, and it will only take effect at the next C<ev_run> iteration.
614		620
615	Again, you I<have> to call it on I<any> loop that you want to re-use after	621	Again, you I<have> to call it on I<any> loop that you want to re-use after
616	a fork, I<even if you do not plan to use the loop in the parent>. This is	622	a fork, I<even if you do not plan to use the loop in the parent>. This is
617	because some kernel interfaces cough I<kqueue> cough do funny things	623	because some kernel interfaces cough I<kqueue> cough do funny things
618	during fork.	624	during fork.
619		625
620	On the other hand, you only need to call this function in the child	626	On the other hand, you only need to call this function in the child
621	process if and only if you want to use the event loop in the child. If you	627	process if and only if you want to use the event loop in the child. If
622	just fork+exec or create a new loop in the child, you don't have to call	628	you just fork+exec or create a new loop in the child, you don't have to
623	it at all.	629	call it at all (in fact, C<epoll> is so badly broken that it makes a
		630	difference, but libev will usually detect this case on its own and do a
		631	costly reset of the backend).
624		632
625	The function itself is quite fast and it's usually not a problem to call	633	The function itself is quite fast and it's usually not a problem to call
626	it just in case after a fork. To make this easy, the function will fit in	634	it just in case after a fork. To make this easy, the function will fit in
627	quite nicely into a call to C<pthread_atfork>:	635	quite nicely into a call to C<pthread_atfork>:
628		636
…		…
640	Returns true when the given loop is, in fact, the default loop, and false	648	Returns true when the given loop is, in fact, the default loop, and false
641	otherwise.	649	otherwise.
642		650
643	=item unsigned int ev_iteration (loop)	651	=item unsigned int ev_iteration (loop)
644		652
645	Returns the current iteration count for the loop, which is identical to	653	Returns the current iteration count for the event loop, which is identical
646	the number of times libev did poll for new events. It starts at C<0> and	654	to the number of times libev did poll for new events. It starts at C<0>
647	happily wraps around with enough iterations.	655	and happily wraps around with enough iterations.
648		656
649	This value can sometimes be useful as a generation counter of sorts (it	657	This value can sometimes be useful as a generation counter of sorts (it
650	"ticks" the number of loop iterations), as it roughly corresponds with	658	"ticks" the number of loop iterations), as it roughly corresponds with
651	C<ev_prepare> and C<ev_check> calls - and is incremented between the	659	C<ev_prepare> and C<ev_check> calls - and is incremented between the
652	prepare and check phases.	660	prepare and check phases.
653		661
654	=item unsigned int ev_depth (loop)	662	=item unsigned int ev_depth (loop)
655		663
656	Returns the number of times C<ev_loop> was entered minus the number of	664	Returns the number of times C<ev_run> was entered minus the number of
657	times C<ev_loop> was exited, in other words, the recursion depth.	665	times C<ev_run> was exited, in other words, the recursion depth.
658		666
659	Outside C<ev_loop>, this number is zero. In a callback, this number is	667	Outside C<ev_run>, this number is zero. In a callback, this number is
660	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	668	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
661	in which case it is higher.	669	in which case it is higher.
662		670
663	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	671	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
664	etc.), doesn't count as "exit" - consider this as a hint to avoid such	672	etc.), doesn't count as "exit" - consider this as a hint to avoid such
665	ungentleman behaviour unless it's really convenient.	673	ungentleman-like behaviour unless it's really convenient.
666		674
667	=item unsigned int ev_backend (loop)	675	=item unsigned int ev_backend (loop)
668		676
669	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	677	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
670	use.	678	use.
…		…
679		687
680	=item ev_now_update (loop)	688	=item ev_now_update (loop)
681		689
682	Establishes the current time by querying the kernel, updating the time	690	Establishes the current time by querying the kernel, updating the time
683	returned by C<ev_now ()> in the progress. This is a costly operation and	691	returned by C<ev_now ()> in the progress. This is a costly operation and
684	is usually done automatically within C<ev_loop ()>.	692	is usually done automatically within C<ev_run ()>.
685		693
686	This function is rarely useful, but when some event callback runs for a	694	This function is rarely useful, but when some event callback runs for a
687	very long time without entering the event loop, updating libev's idea of	695	very long time without entering the event loop, updating libev's idea of
688	the current time is a good idea.	696	the current time is a good idea.
689		697
…		…
691		699
692	=item ev_suspend (loop)	700	=item ev_suspend (loop)
693		701
694	=item ev_resume (loop)	702	=item ev_resume (loop)
695		703
696	These two functions suspend and resume a loop, for use when the loop is	704	These two functions suspend and resume an event loop, for use when the
697	not used for a while and timeouts should not be processed.	705	loop is not used for a while and timeouts should not be processed.
698		706
699	A typical use case would be an interactive program such as a game: When	707	A typical use case would be an interactive program such as a game: When
700	the user presses C<^Z> to suspend the game and resumes it an hour later it	708	the user presses C<^Z> to suspend the game and resumes it an hour later it
701	would be best to handle timeouts as if no time had actually passed while	709	would be best to handle timeouts as if no time had actually passed while
702	the program was suspended. This can be achieved by calling C<ev_suspend>	710	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
704	C<ev_resume> directly afterwards to resume timer processing.	712	C<ev_resume> directly afterwards to resume timer processing.
705		713
706	Effectively, all C<ev_timer> watchers will be delayed by the time spend	714	Effectively, all C<ev_timer> watchers will be delayed by the time spend
707	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	715	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
708	will be rescheduled (that is, they will lose any events that would have	716	will be rescheduled (that is, they will lose any events that would have
709	occured while suspended).	717	occurred while suspended).
710		718
711	After calling C<ev_suspend> you B<must not> call I<any> function on the	719	After calling C<ev_suspend> you B<must not> call I<any> function on the
712	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	720	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
713	without a previous call to C<ev_suspend>.	721	without a previous call to C<ev_suspend>.
714		722
715	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	723	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
716	event loop time (see C<ev_now_update>).	724	event loop time (see C<ev_now_update>).
717		725
718	=item ev_loop (loop, int flags)	726	=item ev_run (loop, int flags)
719		727
720	Finally, this is it, the event handler. This function usually is called	728	Finally, this is it, the event handler. This function usually is called
721	after you have initialised all your watchers and you want to start	729	after you have initialised all your watchers and you want to start
722	handling events.	730	handling events. It will ask the operating system for any new events, call
		731	the watcher callbacks, an then repeat the whole process indefinitely: This
		732	is why event loops are called I<loops>.
723		733
724	If the flags argument is specified as C<0>, it will not return until	734	If the flags argument is specified as C<0>, it will keep handling events
725	either no event watchers are active anymore or C<ev_unloop> was called.	735	until either no event watchers are active anymore or C<ev_break> was
		736	called.
726		737
727	Please note that an explicit C<ev_unloop> is usually better than	738	Please note that an explicit C<ev_break> is usually better than
728	relying on all watchers to be stopped when deciding when a program has	739	relying on all watchers to be stopped when deciding when a program has
729	finished (especially in interactive programs), but having a program	740	finished (especially in interactive programs), but having a program
730	that automatically loops as long as it has to and no longer by virtue	741	that automatically loops as long as it has to and no longer by virtue
731	of relying on its watchers stopping correctly, that is truly a thing of	742	of relying on its watchers stopping correctly, that is truly a thing of
732	beauty.	743	beauty.
733		744
734	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	745	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
735	those events and any already outstanding ones, but will not block your	746	those events and any already outstanding ones, but will not wait and
736	process in case there are no events and will return after one iteration of	747	block your process in case there are no events and will return after one
737	the loop.	748	iteration of the loop. This is sometimes useful to poll and handle new
		749	events while doing lengthy calculations, to keep the program responsive.
738		750
739	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	751	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
740	necessary) and will handle those and any already outstanding ones. It	752	necessary) and will handle those and any already outstanding ones. It
741	will block your process until at least one new event arrives (which could	753	will block your process until at least one new event arrives (which could
742	be an event internal to libev itself, so there is no guarantee that a	754	be an event internal to libev itself, so there is no guarantee that a
743	user-registered callback will be called), and will return after one	755	user-registered callback will be called), and will return after one
744	iteration of the loop.	756	iteration of the loop.
745		757
746	This is useful if you are waiting for some external event in conjunction	758	This is useful if you are waiting for some external event in conjunction
747	with something not expressible using other libev watchers (i.e. "roll your	759	with something not expressible using other libev watchers (i.e. "roll your
748	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	760	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
749	usually a better approach for this kind of thing.	761	usually a better approach for this kind of thing.
750		762
751	Here are the gory details of what C<ev_loop> does:	763	Here are the gory details of what C<ev_run> does:
752		764
		765	- Increment loop depth.
		766	- Reset the ev_break status.
753	- Before the first iteration, call any pending watchers.	767	- Before the first iteration, call any pending watchers.
		768	LOOP:
754	* If EVFLAG_FORKCHECK was used, check for a fork.	769	- If EVFLAG_FORKCHECK was used, check for a fork.
755	- If a fork was detected (by any means), queue and call all fork watchers.	770	- If a fork was detected (by any means), queue and call all fork watchers.
756	- Queue and call all prepare watchers.	771	- Queue and call all prepare watchers.
		772	- If ev_break was called, goto FINISH.
757	- If we have been forked, detach and recreate the kernel state	773	- If we have been forked, detach and recreate the kernel state
758	as to not disturb the other process.	774	as to not disturb the other process.
759	- Update the kernel state with all outstanding changes.	775	- Update the kernel state with all outstanding changes.
760	- Update the "event loop time" (ev_now ()).	776	- Update the "event loop time" (ev_now ()).
761	- Calculate for how long to sleep or block, if at all	777	- Calculate for how long to sleep or block, if at all
762	(active idle watchers, EVLOOP_NONBLOCK or not having	778	(active idle watchers, EVRUN_NOWAIT or not having
763	any active watchers at all will result in not sleeping).	779	any active watchers at all will result in not sleeping).
764	- Sleep if the I/O and timer collect interval say so.	780	- Sleep if the I/O and timer collect interval say so.
		781	- Increment loop iteration counter.
765	- Block the process, waiting for any events.	782	- Block the process, waiting for any events.
766	- Queue all outstanding I/O (fd) events.	783	- Queue all outstanding I/O (fd) events.
767	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	784	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
768	- Queue all expired timers.	785	- Queue all expired timers.
769	- Queue all expired periodics.	786	- Queue all expired periodics.
770	- Unless any events are pending now, queue all idle watchers.	787	- Queue all idle watchers with priority higher than that of pending events.
771	- Queue all check watchers.	788	- Queue all check watchers.
772	- Call all queued watchers in reverse order (i.e. check watchers first).	789	- Call all queued watchers in reverse order (i.e. check watchers first).
773	Signals and child watchers are implemented as I/O watchers, and will	790	Signals and child watchers are implemented as I/O watchers, and will
774	be handled here by queueing them when their watcher gets executed.	791	be handled here by queueing them when their watcher gets executed.
775	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	792	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
776	were used, or there are no active watchers, return, otherwise	793	were used, or there are no active watchers, goto FINISH, otherwise
777	continue with step *.	794	continue with step LOOP.
		795	FINISH:
		796	- Reset the ev_break status iff it was EVBREAK_ONE.
		797	- Decrement the loop depth.
		798	- Return.
778		799
779	Example: Queue some jobs and then loop until no events are outstanding	800	Example: Queue some jobs and then loop until no events are outstanding
780	anymore.	801	anymore.
781		802
782	... queue jobs here, make sure they register event watchers as long	803	... queue jobs here, make sure they register event watchers as long
783	... as they still have work to do (even an idle watcher will do..)	804	... as they still have work to do (even an idle watcher will do..)
784	ev_loop (my_loop, 0);	805	ev_run (my_loop, 0);
785	... jobs done or somebody called unloop. yeah!	806	... jobs done or somebody called unloop. yeah!
786		807
787	=item ev_unloop (loop, how)	808	=item ev_break (loop, how)
788		809
789	Can be used to make a call to C<ev_loop> return early (but only after it	810	Can be used to make a call to C<ev_run> return early (but only after it
790	has processed all outstanding events). The C<how> argument must be either	811	has processed all outstanding events). The C<how> argument must be either
791	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	812	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
792	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	813	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
793		814
794	This "unloop state" will be cleared when entering C<ev_loop> again.	815	This "unloop state" will be cleared when entering C<ev_run> again.
795		816
796	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	817	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
797		818
798	=item ev_ref (loop)	819	=item ev_ref (loop)
799		820
800	=item ev_unref (loop)	821	=item ev_unref (loop)
801		822
802	Ref/unref can be used to add or remove a reference count on the event	823	Ref/unref can be used to add or remove a reference count on the event
803	loop: Every watcher keeps one reference, and as long as the reference	824	loop: Every watcher keeps one reference, and as long as the reference
804	count is nonzero, C<ev_loop> will not return on its own.	825	count is nonzero, C<ev_run> will not return on its own.
805		826
806	This is useful when you have a watcher that you never intend to	827	This is useful when you have a watcher that you never intend to
807	unregister, but that nevertheless should not keep C<ev_loop> from	828	unregister, but that nevertheless should not keep C<ev_run> from
808	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	829	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
809	before stopping it.	830	before stopping it.
810		831
811	As an example, libev itself uses this for its internal signal pipe: It	832	As an example, libev itself uses this for its internal signal pipe: It
812	is not visible to the libev user and should not keep C<ev_loop> from	833	is not visible to the libev user and should not keep C<ev_run> from
813	exiting if no event watchers registered by it are active. It is also an	834	exiting if no event watchers registered by it are active. It is also an
814	excellent way to do this for generic recurring timers or from within	835	excellent way to do this for generic recurring timers or from within
815	third-party libraries. Just remember to I<unref after start> and I<ref	836	third-party libraries. Just remember to I<unref after start> and I<ref
816	before stop> (but only if the watcher wasn't active before, or was active	837	before stop> (but only if the watcher wasn't active before, or was active
817	before, respectively. Note also that libev might stop watchers itself	838	before, respectively. Note also that libev might stop watchers itself
818	(e.g. non-repeating timers) in which case you have to C<ev_ref>	839	(e.g. non-repeating timers) in which case you have to C<ev_ref>
819	in the callback).	840	in the callback).
820		841
821	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	842	Example: Create a signal watcher, but keep it from keeping C<ev_run>
822	running when nothing else is active.	843	running when nothing else is active.
823		844
824	ev_signal exitsig;	845	ev_signal exitsig;
825	ev_signal_init (&exitsig, sig_cb, SIGINT);	846	ev_signal_init (&exitsig, sig_cb, SIGINT);
826	ev_signal_start (loop, &exitsig);	847	ev_signal_start (loop, &exitsig);
…		…
871	usually doesn't make much sense to set it to a lower value than C<0.01>,	892	usually doesn't make much sense to set it to a lower value than C<0.01>,
872	as this approaches the timing granularity of most systems. Note that if	893	as this approaches the timing granularity of most systems. Note that if
873	you do transactions with the outside world and you can't increase the	894	you do transactions with the outside world and you can't increase the
874	parallelity, then this setting will limit your transaction rate (if you	895	parallelity, then this setting will limit your transaction rate (if you
875	need to poll once per transaction and the I/O collect interval is 0.01,	896	need to poll once per transaction and the I/O collect interval is 0.01,
876	then you can't do more than 100 transations per second).	897	then you can't do more than 100 transactions per second).
877		898
878	Setting the I<timeout collect interval> can improve the opportunity for	899	Setting the I<timeout collect interval> can improve the opportunity for
879	saving power, as the program will "bundle" timer callback invocations that	900	saving power, as the program will "bundle" timer callback invocations that
880	are "near" in time together, by delaying some, thus reducing the number of	901	are "near" in time together, by delaying some, thus reducing the number of
881	times the process sleeps and wakes up again. Another useful technique to	902	times the process sleeps and wakes up again. Another useful technique to
…		…
889	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	910	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
890		911
891	=item ev_invoke_pending (loop)	912	=item ev_invoke_pending (loop)
892		913
893	This call will simply invoke all pending watchers while resetting their	914	This call will simply invoke all pending watchers while resetting their
894	pending state. Normally, C<ev_loop> does this automatically when required,	915	pending state. Normally, C<ev_run> does this automatically when required,
895	but when overriding the invoke callback this call comes handy.	916	but when overriding the invoke callback this call comes handy. This
		917	function can be invoked from a watcher - this can be useful for example
		918	when you want to do some lengthy calculation and want to pass further
		919	event handling to another thread (you still have to make sure only one
		920	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
896		921
897	=item int ev_pending_count (loop)	922	=item int ev_pending_count (loop)
898		923
899	Returns the number of pending watchers - zero indicates that no watchers	924	Returns the number of pending watchers - zero indicates that no watchers
900	are pending.	925	are pending.
901		926
902	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	927	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
903		928
904	This overrides the invoke pending functionality of the loop: Instead of	929	This overrides the invoke pending functionality of the loop: Instead of
905	invoking all pending watchers when there are any, C<ev_loop> will call	930	invoking all pending watchers when there are any, C<ev_run> will call
906	this callback instead. This is useful, for example, when you want to	931	this callback instead. This is useful, for example, when you want to
907	invoke the actual watchers inside another context (another thread etc.).	932	invoke the actual watchers inside another context (another thread etc.).
908		933
909	If you want to reset the callback, use C<ev_invoke_pending> as new	934	If you want to reset the callback, use C<ev_invoke_pending> as new
910	callback.	935	callback.
…		…
913		938
914	Sometimes you want to share the same loop between multiple threads. This	939	Sometimes you want to share the same loop between multiple threads. This
915	can be done relatively simply by putting mutex_lock/unlock calls around	940	can be done relatively simply by putting mutex_lock/unlock calls around
916	each call to a libev function.	941	each call to a libev function.
917		942
918	However, C<ev_loop> can run an indefinite time, so it is not feasible to	943	However, C<ev_run> can run an indefinite time, so it is not feasible
919	wait for it to return. One way around this is to wake up the loop via	944	to wait for it to return. One way around this is to wake up the event
920	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	945	loop via C<ev_break> and C<av_async_send>, another way is to set these
921	and I<acquire> callbacks on the loop.	946	I<release> and I<acquire> callbacks on the loop.
922		947
923	When set, then C<release> will be called just before the thread is	948	When set, then C<release> will be called just before the thread is
924	suspended waiting for new events, and C<acquire> is called just	949	suspended waiting for new events, and C<acquire> is called just
925	afterwards.	950	afterwards.
926		951
…		…
929		954
930	While event loop modifications are allowed between invocations of	955	While event loop modifications are allowed between invocations of
931	C<release> and C<acquire> (that's their only purpose after all), no	956	C<release> and C<acquire> (that's their only purpose after all), no
932	modifications done will affect the event loop, i.e. adding watchers will	957	modifications done will affect the event loop, i.e. adding watchers will
933	have no effect on the set of file descriptors being watched, or the time	958	have no effect on the set of file descriptors being watched, or the time
934	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	959	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
935	to take note of any changes you made.	960	to take note of any changes you made.
936		961
937	In theory, threads executing C<ev_loop> will be async-cancel safe between	962	In theory, threads executing C<ev_run> will be async-cancel safe between
938	invocations of C<release> and C<acquire>.	963	invocations of C<release> and C<acquire>.
939		964
940	See also the locking example in the C<THREADS> section later in this	965	See also the locking example in the C<THREADS> section later in this
941	document.	966	document.
942		967
…		…
951	These two functions can be used to associate arbitrary data with a loop,	976	These two functions can be used to associate arbitrary data with a loop,
952	and are intended solely for the C<invoke_pending_cb>, C<release> and	977	and are intended solely for the C<invoke_pending_cb>, C<release> and
953	C<acquire> callbacks described above, but of course can be (ab-)used for	978	C<acquire> callbacks described above, but of course can be (ab-)used for
954	any other purpose as well.	979	any other purpose as well.
955		980
956	=item ev_loop_verify (loop)	981	=item ev_verify (loop)
957		982
958	This function only does something when C<EV_VERIFY> support has been	983	This function only does something when C<EV_VERIFY> support has been
959	compiled in, which is the default for non-minimal builds. It tries to go	984	compiled in, which is the default for non-minimal builds. It tries to go
960	through all internal structures and checks them for validity. If anything	985	through all internal structures and checks them for validity. If anything
961	is found to be inconsistent, it will print an error message to standard	986	is found to be inconsistent, it will print an error message to standard
…		…
972		997
973	In the following description, uppercase C<TYPE> in names stands for the	998	In the following description, uppercase C<TYPE> in names stands for the
974	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	999	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
975	watchers and C<ev_io_start> for I/O watchers.	1000	watchers and C<ev_io_start> for I/O watchers.
976		1001
977	A watcher is a structure that you create and register to record your	1002	A watcher is an opaque structure that you allocate and register to record
978	interest in some event. For instance, if you want to wait for STDIN to	1003	your interest in some event. To make a concrete example, imagine you want
979	become readable, you would create an C<ev_io> watcher for that:	1004	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1005	for that:
980		1006
981	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1007	static void my_cb (struct ev_loop loop, ev_io w, int revents)
982	{	1008	{
983	ev_io_stop (w);	1009	ev_io_stop (w);
984	ev_unloop (loop, EVUNLOOP_ALL);	1010	ev_break (loop, EVBREAK_ALL);
985	}	1011	}
986		1012
987	struct ev_loop *loop = ev_default_loop (0);	1013	struct ev_loop *loop = ev_default_loop (0);
988		1014
989	ev_io stdin_watcher;	1015	ev_io stdin_watcher;
990		1016
991	ev_init (&stdin_watcher, my_cb);	1017	ev_init (&stdin_watcher, my_cb);
992	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1018	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
993	ev_io_start (loop, &stdin_watcher);	1019	ev_io_start (loop, &stdin_watcher);
994		1020
995	ev_loop (loop, 0);	1021	ev_run (loop, 0);
996		1022
997	As you can see, you are responsible for allocating the memory for your	1023	As you can see, you are responsible for allocating the memory for your
998	watcher structures (and it is I<usually> a bad idea to do this on the	1024	watcher structures (and it is I<usually> a bad idea to do this on the
999	stack).	1025	stack).
1000		1026
1001	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1027	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1002	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1028	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1003		1029
1004	Each watcher structure must be initialised by a call to C<ev_init	1030	Each watcher structure must be initialised by a call to C<ev_init (watcher
1005	(watcher *, callback)>, which expects a callback to be provided. This	1031	*, callback)>, which expects a callback to be provided. This callback is
1006	callback gets invoked each time the event occurs (or, in the case of I/O	1032	invoked each time the event occurs (or, in the case of I/O watchers, each
1007	watchers, each time the event loop detects that the file descriptor given	1033	time the event loop detects that the file descriptor given is readable
1008	is readable and/or writable).	1034	and/or writable).
1009		1035
1010	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1036	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1011	macro to configure it, with arguments specific to the watcher type. There	1037	macro to configure it, with arguments specific to the watcher type. There
1012	is also a macro to combine initialisation and setting in one call: C<<	1038	is also a macro to combine initialisation and setting in one call: C<<
1013	ev_TYPE_init (watcher *, callback, ...) >>.	1039	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1064		1090
1065	=item C<EV_PREPARE>	1091	=item C<EV_PREPARE>
1066		1092
1067	=item C<EV_CHECK>	1093	=item C<EV_CHECK>
1068		1094
1069	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1095	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1070	to gather new events, and all C<ev_check> watchers are invoked just after	1096	to gather new events, and all C<ev_check> watchers are invoked just after
1071	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1097	C<ev_run> has gathered them, but before it invokes any callbacks for any
1072	received events. Callbacks of both watcher types can start and stop as	1098	received events. Callbacks of both watcher types can start and stop as
1073	many watchers as they want, and all of them will be taken into account	1099	many watchers as they want, and all of them will be taken into account
1074	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1100	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1075	C<ev_loop> from blocking).	1101	C<ev_run> from blocking).
1076		1102
1077	=item C<EV_EMBED>	1103	=item C<EV_EMBED>
1078		1104
1079	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1105	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1080		1106
…		…
1108	example it might indicate that a fd is readable or writable, and if your	1134	example it might indicate that a fd is readable or writable, and if your
1109	callbacks is well-written it can just attempt the operation and cope with	1135	callbacks is well-written it can just attempt the operation and cope with
1110	the error from read() or write(). This will not work in multi-threaded	1136	the error from read() or write(). This will not work in multi-threaded
1111	programs, though, as the fd could already be closed and reused for another	1137	programs, though, as the fd could already be closed and reused for another
1112	thing, so beware.	1138	thing, so beware.
		1139
		1140	=back
		1141
		1142	=head2 WATCHER STATES
		1143
		1144	There are various watcher states mentioned throughout this manual -
		1145	active, pending and so on. In this section these states and the rules to
		1146	transition between them will be described in more detail - and while these
		1147	rules might look complicated, they usually do "the right thing".
		1148
		1149	=over 4
		1150
		1151	=item initialiased
		1152
		1153	Before a watcher can be registered with the event looop it has to be
		1154	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1155	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1156
		1157	In this state it is simply some block of memory that is suitable for use
		1158	in an event loop. It can be moved around, freed, reused etc. at will.
		1159
		1160	=item started/running/active
		1161
		1162	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1163	property of the event loop, and is actively waiting for events. While in
		1164	this state it cannot be accessed (except in a few documented ways), moved,
		1165	freed or anything else - the only legal thing is to keep a pointer to it,
		1166	and call libev functions on it that are documented to work on active watchers.
		1167
		1168	=item pending
		1169
		1170	If a watcher is active and libev determines that an event it is interested
		1171	in has occurred (such as a timer expiring), it will become pending. It will
		1172	stay in this pending state until either it is stopped or its callback is
		1173	about to be invoked, so it is not normally pending inside the watcher
		1174	callback.
		1175
		1176	The watcher might or might not be active while it is pending (for example,
		1177	an expired non-repeating timer can be pending but no longer active). If it
		1178	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1179	but it is still property of the event loop at this time, so cannot be
		1180	moved, freed or reused. And if it is active the rules described in the
		1181	previous item still apply.
		1182
		1183	It is also possible to feed an event on a watcher that is not active (e.g.
		1184	via C<ev_feed_event>), in which case it becomes pending without being
		1185	active.
		1186
		1187	=item stopped
		1188
		1189	A watcher can be stopped implicitly by libev (in which case it might still
		1190	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1191	latter will clear any pending state the watcher might be in, regardless
		1192	of whether it was active or not, so stopping a watcher explicitly before
		1193	freeing it is often a good idea.
		1194
		1195	While stopped (and not pending) the watcher is essentially in the
		1196	initialised state, that is it can be reused, moved, modified in any way
		1197	you wish.
1113		1198
1114	=back	1199	=back
1115		1200
1116	=head2 GENERIC WATCHER FUNCTIONS	1201	=head2 GENERIC WATCHER FUNCTIONS
1117		1202
…		…
1379		1464
1380	For example, to emulate how many other event libraries handle priorities,	1465	For example, to emulate how many other event libraries handle priorities,
1381	you can associate an C<ev_idle> watcher to each such watcher, and in	1466	you can associate an C<ev_idle> watcher to each such watcher, and in
1382	the normal watcher callback, you just start the idle watcher. The real	1467	the normal watcher callback, you just start the idle watcher. The real
1383	processing is done in the idle watcher callback. This causes libev to	1468	processing is done in the idle watcher callback. This causes libev to
1384	continously poll and process kernel event data for the watcher, but when	1469	continuously poll and process kernel event data for the watcher, but when
1385	the lock-out case is known to be rare (which in turn is rare :), this is	1470	the lock-out case is known to be rare (which in turn is rare :), this is
1386	workable.	1471	workable.
1387		1472
1388	Usually, however, the lock-out model implemented that way will perform	1473	Usually, however, the lock-out model implemented that way will perform
1389	miserably under the type of load it was designed to handle. In that case,	1474	miserably under the type of load it was designed to handle. In that case,
…		…
1403	{	1488	{
1404	// stop the I/O watcher, we received the event, but	1489	// stop the I/O watcher, we received the event, but
1405	// are not yet ready to handle it.	1490	// are not yet ready to handle it.
1406	ev_io_stop (EV_A_ w);	1491	ev_io_stop (EV_A_ w);
1407		1492
1408	// start the idle watcher to ahndle the actual event.	1493	// start the idle watcher to handle the actual event.
1409	// it will not be executed as long as other watchers	1494	// it will not be executed as long as other watchers
1410	// with the default priority are receiving events.	1495	// with the default priority are receiving events.
1411	ev_idle_start (EV_A_ &idle);	1496	ev_idle_start (EV_A_ &idle);
1412	}	1497	}
1413		1498
…		…
1467		1552
1468	If you cannot use non-blocking mode, then force the use of a	1553	If you cannot use non-blocking mode, then force the use of a
1469	known-to-be-good backend (at the time of this writing, this includes only	1554	known-to-be-good backend (at the time of this writing, this includes only
1470	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1555	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1471	descriptors for which non-blocking operation makes no sense (such as	1556	descriptors for which non-blocking operation makes no sense (such as
1472	files) - libev doesn't guarentee any specific behaviour in that case.	1557	files) - libev doesn't guarantee any specific behaviour in that case.
1473		1558
1474	Another thing you have to watch out for is that it is quite easy to	1559	Another thing you have to watch out for is that it is quite easy to
1475	receive "spurious" readiness notifications, that is your callback might	1560	receive "spurious" readiness notifications, that is your callback might
1476	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1561	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1477	because there is no data. Not only are some backends known to create a	1562	because there is no data. Not only are some backends known to create a
…		…
1621	...	1706	...
1622	struct ev_loop *loop = ev_default_init (0);	1707	struct ev_loop *loop = ev_default_init (0);
1623	ev_io stdin_readable;	1708	ev_io stdin_readable;
1624	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1709	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1625	ev_io_start (loop, &stdin_readable);	1710	ev_io_start (loop, &stdin_readable);
1626	ev_loop (loop, 0);	1711	ev_run (loop, 0);
1627		1712
1628		1713
1629	=head2 C<ev_timer> - relative and optionally repeating timeouts	1714	=head2 C<ev_timer> - relative and optionally repeating timeouts
1630		1715
1631	Timer watchers are simple relative timers that generate an event after a	1716	Timer watchers are simple relative timers that generate an event after a
…		…
1640	The callback is guaranteed to be invoked only I<after> its timeout has	1725	The callback is guaranteed to be invoked only I<after> its timeout has
1641	passed (not I<at>, so on systems with very low-resolution clocks this	1726	passed (not I<at>, so on systems with very low-resolution clocks this
1642	might introduce a small delay). If multiple timers become ready during the	1727	might introduce a small delay). If multiple timers become ready during the
1643	same loop iteration then the ones with earlier time-out values are invoked	1728	same loop iteration then the ones with earlier time-out values are invoked
1644	before ones of the same priority with later time-out values (but this is	1729	before ones of the same priority with later time-out values (but this is
1645	no longer true when a callback calls C<ev_loop> recursively).	1730	no longer true when a callback calls C<ev_run> recursively).
1646		1731
1647	=head3 Be smart about timeouts	1732	=head3 Be smart about timeouts
1648		1733
1649	Many real-world problems involve some kind of timeout, usually for error	1734	Many real-world problems involve some kind of timeout, usually for error
1650	recovery. A typical example is an HTTP request - if the other side hangs,	1735	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1736	ev_tstamp timeout = last_activity + 60.;	1821	ev_tstamp timeout = last_activity + 60.;
1737		1822
1738	// if last_activity + 60. is older than now, we did time out	1823	// if last_activity + 60. is older than now, we did time out
1739	if (timeout < now)	1824	if (timeout < now)
1740	{	1825	{
1741	// timeout occured, take action	1826	// timeout occurred, take action
1742	}	1827	}
1743	else	1828	else
1744	{	1829	{
1745	// callback was invoked, but there was some activity, re-arm	1830	// callback was invoked, but there was some activity, re-arm
1746	// the watcher to fire in last_activity + 60, which is	1831	// the watcher to fire in last_activity + 60, which is
…		…
1773	callback (loop, timer, EV_TIMER);	1858	callback (loop, timer, EV_TIMER);
1774		1859
1775	And when there is some activity, simply store the current time in	1860	And when there is some activity, simply store the current time in
1776	C<last_activity>, no libev calls at all:	1861	C<last_activity>, no libev calls at all:
1777		1862
1778	last_actiivty = ev_now (loop);	1863	last_activity = ev_now (loop);
1779		1864
1780	This technique is slightly more complex, but in most cases where the	1865	This technique is slightly more complex, but in most cases where the
1781	time-out is unlikely to be triggered, much more efficient.	1866	time-out is unlikely to be triggered, much more efficient.
1782		1867
1783	Changing the timeout is trivial as well (if it isn't hard-coded in the	1868	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1821		1906
1822	=head3 The special problem of time updates	1907	=head3 The special problem of time updates
1823		1908
1824	Establishing the current time is a costly operation (it usually takes at	1909	Establishing the current time is a costly operation (it usually takes at
1825	least two system calls): EV therefore updates its idea of the current	1910	least two system calls): EV therefore updates its idea of the current
1826	time only before and after C<ev_loop> collects new events, which causes a	1911	time only before and after C<ev_run> collects new events, which causes a
1827	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1912	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1828	lots of events in one iteration.	1913	lots of events in one iteration.
1829		1914
1830	The relative timeouts are calculated relative to the C<ev_now ()>	1915	The relative timeouts are calculated relative to the C<ev_now ()>
1831	time. This is usually the right thing as this timestamp refers to the time	1916	time. This is usually the right thing as this timestamp refers to the time
…		…
1948	}	2033	}
1949		2034
1950	ev_timer mytimer;	2035	ev_timer mytimer;
1951	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2036	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1952	ev_timer_again (&mytimer); /* start timer */	2037	ev_timer_again (&mytimer); /* start timer */
1953	ev_loop (loop, 0);	2038	ev_run (loop, 0);
1954		2039
1955	// and in some piece of code that gets executed on any "activity":	2040	// and in some piece of code that gets executed on any "activity":
1956	// reset the timeout to start ticking again at 10 seconds	2041	// reset the timeout to start ticking again at 10 seconds
1957	ev_timer_again (&mytimer);	2042	ev_timer_again (&mytimer);
1958		2043
…		…
1984		2069
1985	As with timers, the callback is guaranteed to be invoked only when the	2070	As with timers, the callback is guaranteed to be invoked only when the
1986	point in time where it is supposed to trigger has passed. If multiple	2071	point in time where it is supposed to trigger has passed. If multiple
1987	timers become ready during the same loop iteration then the ones with	2072	timers become ready during the same loop iteration then the ones with
1988	earlier time-out values are invoked before ones with later time-out values	2073	earlier time-out values are invoked before ones with later time-out values
1989	(but this is no longer true when a callback calls C<ev_loop> recursively).	2074	(but this is no longer true when a callback calls C<ev_run> recursively).
1990		2075
1991	=head3 Watcher-Specific Functions and Data Members	2076	=head3 Watcher-Specific Functions and Data Members
1992		2077
1993	=over 4	2078	=over 4
1994		2079
…		…
2122	Example: Call a callback every hour, or, more precisely, whenever the	2207	Example: Call a callback every hour, or, more precisely, whenever the
2123	system time is divisible by 3600. The callback invocation times have	2208	system time is divisible by 3600. The callback invocation times have
2124	potentially a lot of jitter, but good long-term stability.	2209	potentially a lot of jitter, but good long-term stability.
2125		2210
2126	static void	2211	static void
2127	clock_cb (struct ev_loop loop, ev_io w, int revents)	2212	clock_cb (struct ev_loop loop, ev_periodic w, int revents)
2128	{	2213	{
2129	... its now a full hour (UTC, or TAI or whatever your clock follows)	2214	... its now a full hour (UTC, or TAI or whatever your clock follows)
2130	}	2215	}
2131		2216
2132	ev_periodic hourly_tick;	2217	ev_periodic hourly_tick;
…		…
2232	Example: Try to exit cleanly on SIGINT.	2317	Example: Try to exit cleanly on SIGINT.
2233		2318
2234	static void	2319	static void
2235	sigint_cb (struct ev_loop loop, ev_signal w, int revents)	2320	sigint_cb (struct ev_loop loop, ev_signal w, int revents)
2236	{	2321	{
2237	ev_unloop (loop, EVUNLOOP_ALL);	2322	ev_break (loop, EVBREAK_ALL);
2238	}	2323	}
2239		2324
2240	ev_signal signal_watcher;	2325	ev_signal signal_watcher;
2241	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2326	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2242	ev_signal_start (loop, &signal_watcher);	2327	ev_signal_start (loop, &signal_watcher);
…		…
2628		2713
2629	Prepare and check watchers are usually (but not always) used in pairs:	2714	Prepare and check watchers are usually (but not always) used in pairs:
2630	prepare watchers get invoked before the process blocks and check watchers	2715	prepare watchers get invoked before the process blocks and check watchers
2631	afterwards.	2716	afterwards.
2632		2717
2633	You I<must not> call C<ev_loop> or similar functions that enter	2718	You I<must not> call C<ev_run> or similar functions that enter
2634	the current event loop from either C<ev_prepare> or C<ev_check>	2719	the current event loop from either C<ev_prepare> or C<ev_check>
2635	watchers. Other loops than the current one are fine, however. The	2720	watchers. Other loops than the current one are fine, however. The
2636	rationale behind this is that you do not need to check for recursion in	2721	rationale behind this is that you do not need to check for recursion in
2637	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2722	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2638	C<ev_check> so if you have one watcher of each kind they will always be	2723	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2806		2891
2807	if (timeout >= 0)	2892	if (timeout >= 0)
2808	// create/start timer	2893	// create/start timer
2809		2894
2810	// poll	2895	// poll
2811	ev_loop (EV_A_ 0);	2896	ev_run (EV_A_ 0);
2812		2897
2813	// stop timer again	2898	// stop timer again
2814	if (timeout >= 0)	2899	if (timeout >= 0)
2815	ev_timer_stop (EV_A_ &to);	2900	ev_timer_stop (EV_A_ &to);
2816		2901
…		…
2894	if you do not want that, you need to temporarily stop the embed watcher).	2979	if you do not want that, you need to temporarily stop the embed watcher).
2895		2980
2896	=item ev_embed_sweep (loop, ev_embed *)	2981	=item ev_embed_sweep (loop, ev_embed *)
2897		2982
2898	Make a single, non-blocking sweep over the embedded loop. This works	2983	Make a single, non-blocking sweep over the embedded loop. This works
2899	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2984	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2900	appropriate way for embedded loops.	2985	appropriate way for embedded loops.
2901		2986
2902	=item struct ev_loop *other [read-only]	2987	=item struct ev_loop *other [read-only]
2903		2988
2904	The embedded event loop.	2989	The embedded event loop.
…		…
2964	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3049	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2965	handlers will be invoked, too, of course.	3050	handlers will be invoked, too, of course.
2966		3051
2967	=head3 The special problem of life after fork - how is it possible?	3052	=head3 The special problem of life after fork - how is it possible?
2968		3053
2969	Most uses of C<fork()> consist of forking, then some simple calls to ste	3054	Most uses of C<fork()> consist of forking, then some simple calls to set
2970	up/change the process environment, followed by a call to C<exec()>. This	3055	up/change the process environment, followed by a call to C<exec()>. This
2971	sequence should be handled by libev without any problems.	3056	sequence should be handled by libev without any problems.
2972		3057
2973	This changes when the application actually wants to do event handling	3058	This changes when the application actually wants to do event handling
2974	in the child, or both parent in child, in effect "continuing" after the	3059	in the child, or both parent in child, in effect "continuing" after the
…		…
3008	believe me.	3093	believe me.
3009		3094
3010	=back	3095	=back
3011		3096
3012		3097
3013	=head2 C<ev_async> - how to wake up another event loop	3098	=head2 C<ev_async> - how to wake up an event loop
3014		3099
3015	In general, you cannot use an C<ev_loop> from multiple threads or other	3100	In general, you cannot use an C<ev_run> from multiple threads or other
3016	asynchronous sources such as signal handlers (as opposed to multiple event	3101	asynchronous sources such as signal handlers (as opposed to multiple event
3017	loops - those are of course safe to use in different threads).	3102	loops - those are of course safe to use in different threads).
3018		3103
3019	Sometimes, however, you need to wake up another event loop you do not	3104	Sometimes, however, you need to wake up an event loop you do not control,
3020	control, for example because it belongs to another thread. This is what	3105	for example because it belongs to another thread. This is what C<ev_async>
3021	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3106	watchers do: as long as the C<ev_async> watcher is active, you can signal
3022	can signal it by calling C<ev_async_send>, which is thread- and signal	3107	it by calling C<ev_async_send>, which is thread- and signal safe.
3023	safe.
3024		3108
3025	This functionality is very similar to C<ev_signal> watchers, as signals,	3109	This functionality is very similar to C<ev_signal> watchers, as signals,
3026	too, are asynchronous in nature, and signals, too, will be compressed	3110	too, are asynchronous in nature, and signals, too, will be compressed
3027	(i.e. the number of callback invocations may be less than the number of	3111	(i.e. the number of callback invocations may be less than the number of
3028	C<ev_async_sent> calls).	3112	C<ev_async_sent> calls).
…		…
3340	myclass obj;	3424	myclass obj;
3341	ev::io iow;	3425	ev::io iow;
3342	iow.set <myclass, &myclass::io_cb> (&obj);	3426	iow.set <myclass, &myclass::io_cb> (&obj);
3343		3427
3344	=item w->set (object *)	3428	=item w->set (object *)
3345
3346	This is an B<experimental> feature that might go away in a future version.
3347		3429
3348	This is a variation of a method callback - leaving out the method to call	3430	This is a variation of a method callback - leaving out the method to call
3349	will default the method to C<operator ()>, which makes it possible to use	3431	will default the method to C<operator ()>, which makes it possible to use
3350	functor objects without having to manually specify the C<operator ()> all	3432	functor objects without having to manually specify the C<operator ()> all
3351	the time. Incidentally, you can then also leave out the template argument	3433	the time. Incidentally, you can then also leave out the template argument
…		…
3391	Associates a different C<struct ev_loop> with this watcher. You can only	3473	Associates a different C<struct ev_loop> with this watcher. You can only
3392	do this when the watcher is inactive (and not pending either).	3474	do this when the watcher is inactive (and not pending either).
3393		3475
3394	=item w->set ([arguments])	3476	=item w->set ([arguments])
3395		3477
3396	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3478	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3397	called at least once. Unlike the C counterpart, an active watcher gets	3479	method or a suitable start method must be called at least once. Unlike the
3398	automatically stopped and restarted when reconfiguring it with this	3480	C counterpart, an active watcher gets automatically stopped and restarted
3399	method.	3481	when reconfiguring it with this method.
3400		3482
3401	=item w->start ()	3483	=item w->start ()
3402		3484
3403	Starts the watcher. Note that there is no C<loop> argument, as the	3485	Starts the watcher. Note that there is no C<loop> argument, as the
3404	constructor already stores the event loop.	3486	constructor already stores the event loop.
3405		3487
		3488	=item w->start ([arguments])
		3489
		3490	Instead of calling C<set> and C<start> methods separately, it is often
		3491	convenient to wrap them in one call. Uses the same type of arguments as
		3492	the configure C<set> method of the watcher.
		3493
3406	=item w->stop ()	3494	=item w->stop ()
3407		3495
3408	Stops the watcher if it is active. Again, no C<loop> argument.	3496	Stops the watcher if it is active. Again, no C<loop> argument.
3409		3497
3410	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3498	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3422		3510
3423	=back	3511	=back
3424		3512
3425	=back	3513	=back
3426		3514
3427	Example: Define a class with an IO and idle watcher, start one of them in	3515	Example: Define a class with two I/O and idle watchers, start the I/O
3428	the constructor.	3516	watchers in the constructor.
3429		3517
3430	class myclass	3518	class myclass
3431	{	3519	{
3432	ev::io io ; void io_cb (ev::io &w, int revents);	3520	ev::io io ; void io_cb (ev::io &w, int revents);
		3521	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3433	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3522	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3434		3523
3435	myclass (int fd)	3524	myclass (int fd)
3436	{	3525	{
3437	io .set <myclass, &myclass::io_cb > (this);	3526	io .set <myclass, &myclass::io_cb > (this);
		3527	io2 .set <myclass, &myclass::io2_cb > (this);
3438	idle.set <myclass, &myclass::idle_cb> (this);	3528	idle.set <myclass, &myclass::idle_cb> (this);
3439		3529
3440	io.start (fd, ev::READ);	3530	io.set (fd, ev::WRITE); // configure the watcher
		3531	io.start (); // start it whenever convenient
		3532
		3533	io2.start (fd, ev::READ); // set + start in one call
3441	}	3534	}
3442	};	3535	};
3443		3536
3444		3537
3445	=head1 OTHER LANGUAGE BINDINGS	3538	=head1 OTHER LANGUAGE BINDINGS
…		…
3519	loop argument"). The C<EV_A> form is used when this is the sole argument,	3612	loop argument"). The C<EV_A> form is used when this is the sole argument,
3520	C<EV_A_> is used when other arguments are following. Example:	3613	C<EV_A_> is used when other arguments are following. Example:
3521		3614
3522	ev_unref (EV_A);	3615	ev_unref (EV_A);
3523	ev_timer_add (EV_A_ watcher);	3616	ev_timer_add (EV_A_ watcher);
3524	ev_loop (EV_A_ 0);	3617	ev_run (EV_A_ 0);
3525		3618
3526	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3619	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3527	which is often provided by the following macro.	3620	which is often provided by the following macro.
3528		3621
3529	=item C<EV_P>, C<EV_P_>	3622	=item C<EV_P>, C<EV_P_>
…		…
3569	}	3662	}
3570		3663
3571	ev_check check;	3664	ev_check check;
3572	ev_check_init (&check, check_cb);	3665	ev_check_init (&check, check_cb);
3573	ev_check_start (EV_DEFAULT_ &check);	3666	ev_check_start (EV_DEFAULT_ &check);
3574	ev_loop (EV_DEFAULT_ 0);	3667	ev_run (EV_DEFAULT_ 0);
3575		3668
3576	=head1 EMBEDDING	3669	=head1 EMBEDDING
3577		3670
3578	Libev can (and often is) directly embedded into host	3671	Libev can (and often is) directly embedded into host
3579	applications. Examples of applications that embed it include the Deliantra	3672	applications. Examples of applications that embed it include the Deliantra
…		…
3670	to a compiled library. All other symbols change the ABI, which means all	3763	to a compiled library. All other symbols change the ABI, which means all
3671	users of libev and the libev code itself must be compiled with compatible	3764	users of libev and the libev code itself must be compiled with compatible
3672	settings.	3765	settings.
3673		3766
3674	=over 4	3767	=over 4
		3768
		3769	=item EV_COMPAT3 (h)
		3770
		3771	Backwards compatibility is a major concern for libev. This is why this
		3772	release of libev comes with wrappers for the functions and symbols that
		3773	have been renamed between libev version 3 and 4.
		3774
		3775	You can disable these wrappers (to test compatibility with future
		3776	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3777	sources. This has the additional advantage that you can drop the C<struct>
		3778	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3779	typedef in that case.
		3780
		3781	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3782	and in some even more future version the compatibility code will be
		3783	removed completely.
3675		3784
3676	=item EV_STANDALONE (h)	3785	=item EV_STANDALONE (h)
3677		3786
3678	Must always be C<1> if you do not use autoconf configuration, which	3787	Must always be C<1> if you do not use autoconf configuration, which
3679	keeps libev from including F<config.h>, and it also defines dummy	3788	keeps libev from including F<config.h>, and it also defines dummy
…		…
3886	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,	3995	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
3887	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.	3996	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3888		3997
3889	If undefined or defined to be C<1> (and the platform supports it), then	3998	If undefined or defined to be C<1> (and the platform supports it), then
3890	the respective watcher type is supported. If defined to be C<0>, then it	3999	the respective watcher type is supported. If defined to be C<0>, then it
3891	is not. Disabling watcher types mainly saves codesize.	4000	is not. Disabling watcher types mainly saves code size.
3892		4001
3893	=item EV_FEATURES	4002	=item EV_FEATURES
3894		4003
3895	If you need to shave off some kilobytes of code at the expense of some	4004	If you need to shave off some kilobytes of code at the expense of some
3896	speed (but with the full API), you can define this symbol to request	4005	speed (but with the full API), you can define this symbol to request
…		…
3916		4025
3917	=item C<1> - faster/larger code	4026	=item C<1> - faster/larger code
3918		4027
3919	Use larger code to speed up some operations.	4028	Use larger code to speed up some operations.
3920		4029
3921	Currently this is used to override some inlining decisions (enlarging the roughly	4030	Currently this is used to override some inlining decisions (enlarging the
3922	30% code size on amd64.	4031	code size by roughly 30% on amd64).
3923		4032
3924	When optimising for size, use of compiler flags such as C<-Os> with	4033	When optimising for size, use of compiler flags such as C<-Os> with
3925	gcc recommended, as well as C<-DNDEBUG>, as libev contains a number of	4034	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
3926	assertions.	4035	assertions.
3927		4036
3928	=item C<2> - faster/larger data structures	4037	=item C<2> - faster/larger data structures
3929		4038
3930	Replaces the small 2-heap for timer management by a faster 4-heap, larger	4039	Replaces the small 2-heap for timer management by a faster 4-heap, larger
3931	hash table sizes and so on. This will usually further increase codesize	4040	hash table sizes and so on. This will usually further increase code size
3932	and can additionally have an effect on the size of data structures at	4041	and can additionally have an effect on the size of data structures at
3933	runtime.	4042	runtime.
3934		4043
3935	=item C<4> - full API configuration	4044	=item C<4> - full API configuration
3936		4045
…		…
3973	I/O watcher then might come out at only 5Kb.	4082	I/O watcher then might come out at only 5Kb.
3974		4083
3975	=item EV_AVOID_STDIO	4084	=item EV_AVOID_STDIO
3976		4085
3977	If this is set to C<1> at compiletime, then libev will avoid using stdio	4086	If this is set to C<1> at compiletime, then libev will avoid using stdio
3978	functions (printf, scanf, perror etc.). This will increase the codesize	4087	functions (printf, scanf, perror etc.). This will increase the code size
3979	somewhat, but if your program doesn't otherwise depend on stdio and your	4088	somewhat, but if your program doesn't otherwise depend on stdio and your
3980	libc allows it, this avoids linking in the stdio library which is quite	4089	libc allows it, this avoids linking in the stdio library which is quite
3981	big.	4090	big.
3982		4091
3983	Note that error messages might become less precise when this option is	4092	Note that error messages might become less precise when this option is
…		…
3987		4096
3988	The highest supported signal number, +1 (or, the number of	4097	The highest supported signal number, +1 (or, the number of
3989	signals): Normally, libev tries to deduce the maximum number of signals	4098	signals): Normally, libev tries to deduce the maximum number of signals
3990	automatically, but sometimes this fails, in which case it can be	4099	automatically, but sometimes this fails, in which case it can be
3991	specified. Also, using a lower number than detected (C<32> should be	4100	specified. Also, using a lower number than detected (C<32> should be
3992	good for about any system in existance) can save some memory, as libev	4101	good for about any system in existence) can save some memory, as libev
3993	statically allocates some 12-24 bytes per signal number.	4102	statically allocates some 12-24 bytes per signal number.
3994		4103
3995	=item EV_PID_HASHSIZE	4104	=item EV_PID_HASHSIZE
3996		4105
3997	C<ev_child> watchers use a small hash table to distribute workload by	4106	C<ev_child> watchers use a small hash table to distribute workload by
…		…
4029	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4138	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4030	will be C<0>.	4139	will be C<0>.
4031		4140
4032	=item EV_VERIFY	4141	=item EV_VERIFY
4033		4142
4034	Controls how much internal verification (see C<ev_loop_verify ()>) will	4143	Controls how much internal verification (see C<ev_verify ()>) will
4035	be done: If set to C<0>, no internal verification code will be compiled	4144	be done: If set to C<0>, no internal verification code will be compiled
4036	in. If set to C<1>, then verification code will be compiled in, but not	4145	in. If set to C<1>, then verification code will be compiled in, but not
4037	called. If set to C<2>, then the internal verification code will be	4146	called. If set to C<2>, then the internal verification code will be
4038	called once per loop, which can slow down libev. If set to C<3>, then the	4147	called once per loop, which can slow down libev. If set to C<3>, then the
4039	verification code will be called very frequently, which will slow down	4148	verification code will be called very frequently, which will slow down
…		…
4043	will be C<0>.	4152	will be C<0>.
4044		4153
4045	=item EV_COMMON	4154	=item EV_COMMON
4046		4155
4047	By default, all watchers have a C<void *data> member. By redefining	4156	By default, all watchers have a C<void *data> member. By redefining
4048	this macro to a something else you can include more and other types of	4157	this macro to something else you can include more and other types of
4049	members. You have to define it each time you include one of the files,	4158	members. You have to define it each time you include one of the files,
4050	though, and it must be identical each time.	4159	though, and it must be identical each time.
4051		4160
4052	For example, the perl EV module uses something like this:	4161	For example, the perl EV module uses something like this:
4053		4162
…		…
4254	userdata *u = ev_userdata (EV_A);	4363	userdata *u = ev_userdata (EV_A);
4255	pthread_mutex_lock (&u->lock);	4364	pthread_mutex_lock (&u->lock);
4256	}	4365	}
4257		4366
4258	The event loop thread first acquires the mutex, and then jumps straight	4367	The event loop thread first acquires the mutex, and then jumps straight
4259	into C<ev_loop>:	4368	into C<ev_run>:
4260		4369
4261	void *	4370	void *
4262	l_run (void *thr_arg)	4371	l_run (void *thr_arg)
4263	{	4372	{
4264	struct ev_loop loop = (struct ev_loop )thr_arg;	4373	struct ev_loop loop = (struct ev_loop )thr_arg;
4265		4374
4266	l_acquire (EV_A);	4375	l_acquire (EV_A);
4267	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4376	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4268	ev_loop (EV_A_ 0);	4377	ev_run (EV_A_ 0);
4269	l_release (EV_A);	4378	l_release (EV_A);
4270		4379
4271	return 0;	4380	return 0;
4272	}	4381	}
4273		4382
…		…
4325		4434
4326	=head3 COROUTINES	4435	=head3 COROUTINES
4327		4436
4328	Libev is very accommodating to coroutines ("cooperative threads"):	4437	Libev is very accommodating to coroutines ("cooperative threads"):
4329	libev fully supports nesting calls to its functions from different	4438	libev fully supports nesting calls to its functions from different
4330	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4439	coroutines (e.g. you can call C<ev_run> on the same loop from two
4331	different coroutines, and switch freely between both coroutines running	4440	different coroutines, and switch freely between both coroutines running
4332	the loop, as long as you don't confuse yourself). The only exception is	4441	the loop, as long as you don't confuse yourself). The only exception is
4333	that you must not do this from C<ev_periodic> reschedule callbacks.	4442	that you must not do this from C<ev_periodic> reschedule callbacks.
4334		4443
4335	Care has been taken to ensure that libev does not keep local state inside	4444	Care has been taken to ensure that libev does not keep local state inside
4336	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4445	C<ev_run>, and other calls do not usually allow for coroutine switches as
4337	they do not call any callbacks.	4446	they do not call any callbacks.
4338		4447
4339	=head2 COMPILER WARNINGS	4448	=head2 COMPILER WARNINGS
4340		4449
4341	Depending on your compiler and compiler settings, you might get no or a	4450	Depending on your compiler and compiler settings, you might get no or a
…		…
4352	maintainable.	4461	maintainable.
4353		4462
4354	And of course, some compiler warnings are just plain stupid, or simply	4463	And of course, some compiler warnings are just plain stupid, or simply
4355	wrong (because they don't actually warn about the condition their message	4464	wrong (because they don't actually warn about the condition their message
4356	seems to warn about). For example, certain older gcc versions had some	4465	seems to warn about). For example, certain older gcc versions had some
4357	warnings that resulted an extreme number of false positives. These have	4466	warnings that resulted in an extreme number of false positives. These have
4358	been fixed, but some people still insist on making code warn-free with	4467	been fixed, but some people still insist on making code warn-free with
4359	such buggy versions.	4468	such buggy versions.
4360		4469
4361	While libev is written to generate as few warnings as possible,	4470	While libev is written to generate as few warnings as possible,
4362	"warn-free" code is not a goal, and it is recommended not to build libev	4471	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4398	I suggest using suppression lists.	4507	I suggest using suppression lists.
4399		4508
4400		4509
4401	=head1 PORTABILITY NOTES	4510	=head1 PORTABILITY NOTES
4402		4511
		4512	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4513
		4514	GNU/Linux is the only common platform that supports 64 bit file/large file
		4515	interfaces but I<disables> them by default.
		4516
		4517	That means that libev compiled in the default environment doesn't support
		4518	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4519
		4520	Unfortunately, many programs try to work around this GNU/Linux issue
		4521	by enabling the large file API, which makes them incompatible with the
		4522	standard libev compiled for their system.
		4523
		4524	Likewise, libev cannot enable the large file API itself as this would
		4525	suddenly make it incompatible to the default compile time environment,
		4526	i.e. all programs not using special compile switches.
		4527
		4528	=head2 OS/X AND DARWIN BUGS
		4529
		4530	The whole thing is a bug if you ask me - basically any system interface
		4531	you touch is broken, whether it is locales, poll, kqueue or even the
		4532	OpenGL drivers.
		4533
		4534	=head3 C<kqueue> is buggy
		4535
		4536	The kqueue syscall is broken in all known versions - most versions support
		4537	only sockets, many support pipes.
		4538
		4539	Libev tries to work around this by not using C<kqueue> by default on this
		4540	rotten platform, but of course you can still ask for it when creating a
		4541	loop - embedding a socket-only kqueue loop into a select-based one is
		4542	probably going to work well.
		4543
		4544	=head3 C<poll> is buggy
		4545
		4546	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4547	implementation by something calling C<kqueue> internally around the 10.5.6
		4548	release, so now C<kqueue> I<and> C<poll> are broken.
		4549
		4550	Libev tries to work around this by not using C<poll> by default on
		4551	this rotten platform, but of course you can still ask for it when creating
		4552	a loop.
		4553
		4554	=head3 C<select> is buggy
		4555
		4556	All that's left is C<select>, and of course Apple found a way to fuck this
		4557	one up as well: On OS/X, C<select> actively limits the number of file
		4558	descriptors you can pass in to 1024 - your program suddenly crashes when
		4559	you use more.
		4560
		4561	There is an undocumented "workaround" for this - defining
		4562	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4563	work on OS/X.
		4564
		4565	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4566
		4567	=head3 C<errno> reentrancy
		4568
		4569	The default compile environment on Solaris is unfortunately so
		4570	thread-unsafe that you can't even use components/libraries compiled
		4571	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4572	defined by default. A valid, if stupid, implementation choice.
		4573
		4574	If you want to use libev in threaded environments you have to make sure
		4575	it's compiled with C<_REENTRANT> defined.
		4576
		4577	=head3 Event port backend
		4578
		4579	The scalable event interface for Solaris is called "event
		4580	ports". Unfortunately, this mechanism is very buggy in all major
		4581	releases. If you run into high CPU usage, your program freezes or you get
		4582	a large number of spurious wakeups, make sure you have all the relevant
		4583	and latest kernel patches applied. No, I don't know which ones, but there
		4584	are multiple ones to apply, and afterwards, event ports actually work
		4585	great.
		4586
		4587	If you can't get it to work, you can try running the program by setting
		4588	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4589	C<select> backends.
		4590
		4591	=head2 AIX POLL BUG
		4592
		4593	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4594	this by trying to avoid the poll backend altogether (i.e. it's not even
		4595	compiled in), which normally isn't a big problem as C<select> works fine
		4596	with large bitsets on AIX, and AIX is dead anyway.
		4597
4403	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4598	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4599
		4600	=head3 General issues
4404		4601
4405	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4602	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4406	requires, and its I/O model is fundamentally incompatible with the POSIX	4603	requires, and its I/O model is fundamentally incompatible with the POSIX
4407	model. Libev still offers limited functionality on this platform in	4604	model. Libev still offers limited functionality on this platform in
4408	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4605	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4409	descriptors. This only applies when using Win32 natively, not when using	4606	descriptors. This only applies when using Win32 natively, not when using
4410	e.g. cygwin.	4607	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4608	as every compielr comes with a slightly differently broken/incompatible
		4609	environment.
4411		4610
4412	Lifting these limitations would basically require the full	4611	Lifting these limitations would basically require the full
4413	re-implementation of the I/O system. If you are into these kinds of	4612	re-implementation of the I/O system. If you are into this kind of thing,
4414	things, then note that glib does exactly that for you in a very portable	4613	then note that glib does exactly that for you in a very portable way (note
4415	way (note also that glib is the slowest event library known to man).	4614	also that glib is the slowest event library known to man).
4416		4615
4417	There is no supported compilation method available on windows except	4616	There is no supported compilation method available on windows except
4418	embedding it into other applications.	4617	embedding it into other applications.
4419		4618
4420	Sensible signal handling is officially unsupported by Microsoft - libev	4619	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4448	you do I<not> compile the F<ev.c> or any other embedded source files!):	4647	you do I<not> compile the F<ev.c> or any other embedded source files!):
4449		4648
4450	#include "evwrap.h"	4649	#include "evwrap.h"
4451	#include "ev.c"	4650	#include "ev.c"
4452		4651
4453	=over 4
4454
4455	=item The winsocket select function	4652	=head3 The winsocket C<select> function
4456		4653
4457	The winsocket C<select> function doesn't follow POSIX in that it	4654	The winsocket C<select> function doesn't follow POSIX in that it
4458	requires socket I<handles> and not socket I<file descriptors> (it is	4655	requires socket I<handles> and not socket I<file descriptors> (it is
4459	also extremely buggy). This makes select very inefficient, and also	4656	also extremely buggy). This makes select very inefficient, and also
4460	requires a mapping from file descriptors to socket handles (the Microsoft	4657	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4469	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4666	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4470		4667
4471	Note that winsockets handling of fd sets is O(n), so you can easily get a	4668	Note that winsockets handling of fd sets is O(n), so you can easily get a
4472	complexity in the O(n²) range when using win32.	4669	complexity in the O(n²) range when using win32.
4473		4670
4474	=item Limited number of file descriptors	4671	=head3 Limited number of file descriptors
4475		4672
4476	Windows has numerous arbitrary (and low) limits on things.	4673	Windows has numerous arbitrary (and low) limits on things.
4477		4674
4478	Early versions of winsocket's select only supported waiting for a maximum	4675	Early versions of winsocket's select only supported waiting for a maximum
4479	of C<64> handles (probably owning to the fact that all windows kernels	4676	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4494	runtime libraries. This might get you to about C<512> or C<2048> sockets	4691	runtime libraries. This might get you to about C<512> or C<2048> sockets
4495	(depending on windows version and/or the phase of the moon). To get more,	4692	(depending on windows version and/or the phase of the moon). To get more,
4496	you need to wrap all I/O functions and provide your own fd management, but	4693	you need to wrap all I/O functions and provide your own fd management, but
4497	the cost of calling select (O(n²)) will likely make this unworkable.	4694	the cost of calling select (O(n²)) will likely make this unworkable.
4498		4695
4499	=back
4500
4501	=head2 PORTABILITY REQUIREMENTS	4696	=head2 PORTABILITY REQUIREMENTS
4502		4697
4503	In addition to a working ISO-C implementation and of course the	4698	In addition to a working ISO-C implementation and of course the
4504	backend-specific APIs, libev relies on a few additional extensions:	4699	backend-specific APIs, libev relies on a few additional extensions:
4505		4700
…		…
4543	watchers.	4738	watchers.
4544		4739
4545	=item C<double> must hold a time value in seconds with enough accuracy	4740	=item C<double> must hold a time value in seconds with enough accuracy
4546		4741
4547	The type C<double> is used to represent timestamps. It is required to	4742	The type C<double> is used to represent timestamps. It is required to
4548	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4743	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4549	enough for at least into the year 4000. This requirement is fulfilled by	4744	good enough for at least into the year 4000 with millisecond accuracy
		4745	(the design goal for libev). This requirement is overfulfilled by
4550	implementations implementing IEEE 754, which is basically all existing	4746	implementations using IEEE 754, which is basically all existing ones. With
4551	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4747	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4552	2200.
4553		4748
4554	=back	4749	=back
4555		4750
4556	If you know of other additional requirements drop me a note.	4751	If you know of other additional requirements drop me a note.
4557		4752
…		…
4635	compatibility, so most programs should still compile. Those might be	4830	compatibility, so most programs should still compile. Those might be
4636	removed in later versions of libev, so better update early than late.	4831	removed in later versions of libev, so better update early than late.
4637		4832
4638	=over 4	4833	=over 4
4639		4834
4640	=item C<ev_loop_count> renamed to C<ev_iteration>	4835	=item function/symbol renames
4641		4836
4642	=item C<ev_loop_depth> renamed to C<ev_depth>	4837	A number of functions and symbols have been renamed:
4643		4838
4644	=item C<ev_loop_verify> renamed to C<ev_verify>	4839	ev_loop => ev_run
		4840	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4841	EVLOOP_ONESHOT => EVRUN_ONCE
		4842
		4843	ev_unloop => ev_break
		4844	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4845	EVUNLOOP_ONE => EVBREAK_ONE
		4846	EVUNLOOP_ALL => EVBREAK_ALL
		4847
		4848	EV_TIMEOUT => EV_TIMER
		4849
		4850	ev_loop_count => ev_iteration
		4851	ev_loop_depth => ev_depth
		4852	ev_loop_verify => ev_verify
4645		4853
4646	Most functions working on C<struct ev_loop> objects don't have an	4854	Most functions working on C<struct ev_loop> objects don't have an
4647	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is	4855	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4856	associated constants have been renamed to not collide with the C<struct
		4857	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4858	as all other watcher types. Note that C<ev_loop_fork> is still called
4648	still called C<ev_loop_fork> because it would otherwise clash with the	4859	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4649	C<ev_fork> typedef.	4860	typedef.
4650		4861
4651	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>	4862	=item C<EV_COMPAT3> backwards compatibility mechanism
4652		4863
4653	This is a simple rename - all other watcher types use their name	4864	The backward compatibility mechanism can be controlled by
4654	as revents flag, and now C<ev_timer> does, too.	4865	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4655		4866	section.
4656	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4657	and continue to be present for the forseeable future, so this is mostly a
4658	documentation change.
4659		4867
4660	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4868	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4661		4869
4662	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4870	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4663	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4871	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4670		4878
4671	=over 4	4879	=over 4
4672		4880
4673	=item active	4881	=item active
4674		4882
4675	A watcher is active as long as it has been started (has been attached to	4883	A watcher is active as long as it has been started and not yet stopped.
4676	an event loop) but not yet stopped (disassociated from the event loop).	4884	See L<WATCHER STATES> for details.
4677		4885
4678	=item application	4886	=item application
4679		4887
4680	In this document, an application is whatever is using libev.	4888	In this document, an application is whatever is using libev.
		4889
		4890	=item backend
		4891
		4892	The part of the code dealing with the operating system interfaces.
4681		4893
4682	=item callback	4894	=item callback
4683		4895
4684	The address of a function that is called when some event has been	4896	The address of a function that is called when some event has been
4685	detected. Callbacks are being passed the event loop, the watcher that	4897	detected. Callbacks are being passed the event loop, the watcher that
4686	received the event, and the actual event bitset.	4898	received the event, and the actual event bitset.
4687		4899
4688	=item callback invocation	4900	=item callback/watcher invocation
4689		4901
4690	The act of calling the callback associated with a watcher.	4902	The act of calling the callback associated with a watcher.
4691		4903
4692	=item event	4904	=item event
4693		4905
…		…
4712	The model used to describe how an event loop handles and processes	4924	The model used to describe how an event loop handles and processes
4713	watchers and events.	4925	watchers and events.
4714		4926
4715	=item pending	4927	=item pending
4716		4928
4717	A watcher is pending as soon as the corresponding event has been detected,	4929	A watcher is pending as soon as the corresponding event has been
4718	and stops being pending as soon as the watcher will be invoked or its	4930	detected. See L<WATCHER STATES> for details.
4719	pending status is explicitly cleared by the application.
4720
4721	A watcher can be pending, but not active. Stopping a watcher also clears
4722	its pending status.
4723		4931
4724	=item real time	4932	=item real time
4725		4933
4726	The physical time that is observed. It is apparently strictly monotonic :)	4934	The physical time that is observed. It is apparently strictly monotonic :)
4727		4935
…		…
4734	=item watcher	4942	=item watcher
4735		4943
4736	A data structure that describes interest in certain events. Watchers need	4944	A data structure that describes interest in certain events. Watchers need
4737	to be started (attached to an event loop) before they can receive events.	4945	to be started (attached to an event loop) before they can receive events.
4738		4946
4739	=item watcher invocation
4740
4741	The act of calling the callback associated with a watcher.
4742
4743	=back	4947	=back
4744		4948
4745	=head1 AUTHOR	4949	=head1 AUTHOR
4746		4950
4747	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4951	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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Comparing libev/ev.pod (file contents): Revision 1.292 by sf-exg, Mon Mar 22 09:57:01 2010 UTC vs. Revision 1.321 by sf-exg, Fri Oct 22 10:50:24 2010 UTC

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Revision 1.292 by sf-exg, Mon Mar 22 09:57:01 2010 UTC vs.
Revision 1.321 by sf-exg, Fri Oct 22 10:50:24 2010 UTC