[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 1.318 by root, Fri Oct 22 09:40:22 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 interetsing 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 ABI mismatches :).
197		199
198	assert (("libev version mismatch",	200	assert (("libev version mismatch",
199	ev_version_major () == EV_VERSION_MAJOR	201	ev_version_major () == EV_VERSION_MAJOR
200	&& ev_version_minor () >= EV_VERSION_MINOR));	202	&& ev_version_minor () >= EV_VERSION_MINOR));
201		203
…		…
212	assert (("sorry, no epoll, no sex",	214	assert (("sorry, no epoll, no sex",
213	ev_supported_backends () & EVBACKEND_EPOLL));	215	ev_supported_backends () & EVBACKEND_EPOLL));
214		216
215	=item unsigned int ev_recommended_backends ()	217	=item unsigned int ev_recommended_backends ()
216		218
217	Return the set of all backends compiled into this binary of libev and also	219	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	220	also recommended for this platform, meaning it will work for most file
		221	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	222	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	223	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	224	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.	225	probe for if you specify no backends explicitly.
223		226
224	=item unsigned int ev_embeddable_backends ()	227	=item unsigned int ev_embeddable_backends ()
225		228
226	Returns the set of backends that are embeddable in other event loops. This	229	Returns the set of backends that are embeddable in other event loops. This
227	is the theoretical, all-platform, value. To find which backends	230	is the theoretical, all-platform, value. To find which backends
…		…
291		294
292	=back	295	=back
293		296
294	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	297	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP
295		298
296	An event loop is described by a C<struct ev_loop *> (the C<struct>	299	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>	300	I<not> optional in this case unless libev 3 compatibility is disabled, as
298	I<function>).	301	libev 3 had an C<ev_loop> function colliding with the struct name).
299		302
300	The library knows two types of such loops, the I<default> loop, which	303	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	304	supports signals and child events, and dynamically created event loops
302	not.	305	which do not.
303		306
304	=over 4	307	=over 4
305		308
306	=item struct ev_loop *ev_default_loop (unsigned int flags)	309	=item struct ev_loop *ev_default_loop (unsigned int flags)
307		310
…		…
438	of course I<doesn't>, and epoll just loves to report events for totally	441	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	442	I<different> file descriptors (even already closed ones, so one cannot
440	even remove them from the set) than registered in the set (especially	443	even remove them from the set) than registered in the set (especially
441	on SMP systems). Libev tries to counter these spurious notifications by	444	on SMP systems). Libev tries to counter these spurious notifications by
442	employing an additional generation counter and comparing that against the	445	employing an additional generation counter and comparing that against the
443	events to filter out spurious ones, recreating the set when required.	446	events to filter out spurious ones, recreating the set when required. Last
		447	not least, it also refuses to work with some file descriptors which work
		448	perfectly fine with C<select> (files, many character devices...).
444		449
445	While stopping, setting and starting an I/O watcher in the same iteration	450	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	451	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	452	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	453	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	608	Like C<ev_default_destroy>, but destroys an event loop created by an
604	earlier call to C<ev_loop_new>.	609	earlier call to C<ev_loop_new>.
605		610
606	=item ev_default_fork ()	611	=item ev_default_fork ()
607		612
608	This function sets a flag that causes subsequent C<ev_loop> iterations	613	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	614	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	615	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	616	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	617	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.	618	functions, and it will only take effect at the next C<ev_run> iteration.
614		619
615	Again, you I<have> to call it on I<any> loop that you want to re-use after	620	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	621	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	622	because some kernel interfaces cough I<kqueue> cough do funny things
618	during fork.	623	during fork.
619		624
620	On the other hand, you only need to call this function in the child	625	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	626	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	627	you just fork+exec or create a new loop in the child, you don't have to
623	it at all.	628	call it at all (in fact, C<epoll> is so badly broken that it makes a
		629	difference, but libev will usually detect this case on its own and do a
		630	costly reset of the backend).
624		631
625	The function itself is quite fast and it's usually not a problem to call	632	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	633	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>:	634	quite nicely into a call to C<pthread_atfork>:
628		635
…		…
640	Returns true when the given loop is, in fact, the default loop, and false	647	Returns true when the given loop is, in fact, the default loop, and false
641	otherwise.	648	otherwise.
642		649
643	=item unsigned int ev_iteration (loop)	650	=item unsigned int ev_iteration (loop)
644		651
645	Returns the current iteration count for the loop, which is identical to	652	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	653	to the number of times libev did poll for new events. It starts at C<0>
647	happily wraps around with enough iterations.	654	and happily wraps around with enough iterations.
648		655
649	This value can sometimes be useful as a generation counter of sorts (it	656	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	657	"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	658	C<ev_prepare> and C<ev_check> calls - and is incremented between the
652	prepare and check phases.	659	prepare and check phases.
653		660
654	=item unsigned int ev_depth (loop)	661	=item unsigned int ev_depth (loop)
655		662
656	Returns the number of times C<ev_loop> was entered minus the number of	663	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.	664	times C<ev_run> was exited, in other words, the recursion depth.
658		665
659	Outside C<ev_loop>, this number is zero. In a callback, this number is	666	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),	667	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
661	in which case it is higher.	668	in which case it is higher.
662		669
663	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	670	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	671	etc.), doesn't count as "exit" - consider this as a hint to avoid such
665	ungentleman behaviour unless it's really convenient.	672	ungentleman-like behaviour unless it's really convenient.
666		673
667	=item unsigned int ev_backend (loop)	674	=item unsigned int ev_backend (loop)
668		675
669	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	676	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
670	use.	677	use.
…		…
679		686
680	=item ev_now_update (loop)	687	=item ev_now_update (loop)
681		688
682	Establishes the current time by querying the kernel, updating the time	689	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	690	returned by C<ev_now ()> in the progress. This is a costly operation and
684	is usually done automatically within C<ev_loop ()>.	691	is usually done automatically within C<ev_run ()>.
685		692
686	This function is rarely useful, but when some event callback runs for a	693	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	694	very long time without entering the event loop, updating libev's idea of
688	the current time is a good idea.	695	the current time is a good idea.
689		696
…		…
691		698
692	=item ev_suspend (loop)	699	=item ev_suspend (loop)
693		700
694	=item ev_resume (loop)	701	=item ev_resume (loop)
695		702
696	These two functions suspend and resume a loop, for use when the loop is	703	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.	704	loop is not used for a while and timeouts should not be processed.
698		705
699	A typical use case would be an interactive program such as a game: When	706	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	707	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	708	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>	709	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
704	C<ev_resume> directly afterwards to resume timer processing.	711	C<ev_resume> directly afterwards to resume timer processing.
705		712
706	Effectively, all C<ev_timer> watchers will be delayed by the time spend	713	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	714	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	715	will be rescheduled (that is, they will lose any events that would have
709	occured while suspended).	716	occurred while suspended).
710		717
711	After calling C<ev_suspend> you B<must not> call I<any> function on the	718	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>	719	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>.	720	without a previous call to C<ev_suspend>.
714		721
715	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	722	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
716	event loop time (see C<ev_now_update>).	723	event loop time (see C<ev_now_update>).
717		724
718	=item ev_loop (loop, int flags)	725	=item ev_run (loop, int flags)
719		726
720	Finally, this is it, the event handler. This function usually is called	727	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	728	after you have initialised all your watchers and you want to start
722	handling events.	729	handling events. It will ask the operating system for any new events, call
		730	the watcher callbacks, an then repeat the whole process indefinitely: This
		731	is why event loops are called I<loops>.
723		732
724	If the flags argument is specified as C<0>, it will not return until	733	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.	734	until either no event watchers are active anymore or C<ev_break> was
		735	called.
726		736
727	Please note that an explicit C<ev_unloop> is usually better than	737	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	738	relying on all watchers to be stopped when deciding when a program has
729	finished (especially in interactive programs), but having a program	739	finished (especially in interactive programs), but having a program
730	that automatically loops as long as it has to and no longer by virtue	740	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	741	of relying on its watchers stopping correctly, that is truly a thing of
732	beauty.	742	beauty.
733		743
734	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	744	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	745	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	746	block your process in case there are no events and will return after one
737	the loop.	747	iteration of the loop. This is sometimes useful to poll and handle new
		748	events while doing lengthy calculations, to keep the program responsive.
738		749
739	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	750	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	751	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	752	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	753	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	754	user-registered callback will be called), and will return after one
744	iteration of the loop.	755	iteration of the loop.
745		756
746	This is useful if you are waiting for some external event in conjunction	757	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	758	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	759	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.	760	usually a better approach for this kind of thing.
750		761
751	Here are the gory details of what C<ev_loop> does:	762	Here are the gory details of what C<ev_run> does:
752		763
		764	- Increment loop depth.
		765	- Reset the ev_break status.
753	- Before the first iteration, call any pending watchers.	766	- Before the first iteration, call any pending watchers.
		767	LOOP:
754	* If EVFLAG_FORKCHECK was used, check for a fork.	768	- If EVFLAG_FORKCHECK was used, check for a fork.
755	- If a fork was detected (by any means), queue and call all fork watchers.	769	- If a fork was detected (by any means), queue and call all fork watchers.
756	- Queue and call all prepare watchers.	770	- Queue and call all prepare watchers.
		771	- If ev_break was called, goto FINISH.
757	- If we have been forked, detach and recreate the kernel state	772	- If we have been forked, detach and recreate the kernel state
758	as to not disturb the other process.	773	as to not disturb the other process.
759	- Update the kernel state with all outstanding changes.	774	- Update the kernel state with all outstanding changes.
760	- Update the "event loop time" (ev_now ()).	775	- Update the "event loop time" (ev_now ()).
761	- Calculate for how long to sleep or block, if at all	776	- Calculate for how long to sleep or block, if at all
762	(active idle watchers, EVLOOP_NONBLOCK or not having	777	(active idle watchers, EVRUN_NOWAIT or not having
763	any active watchers at all will result in not sleeping).	778	any active watchers at all will result in not sleeping).
764	- Sleep if the I/O and timer collect interval say so.	779	- Sleep if the I/O and timer collect interval say so.
		780	- Increment loop iteration counter.
765	- Block the process, waiting for any events.	781	- Block the process, waiting for any events.
766	- Queue all outstanding I/O (fd) events.	782	- Queue all outstanding I/O (fd) events.
767	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	783	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
768	- Queue all expired timers.	784	- Queue all expired timers.
769	- Queue all expired periodics.	785	- Queue all expired periodics.
770	- Unless any events are pending now, queue all idle watchers.	786	- Queue all idle watchers with priority higher than that of pending events.
771	- Queue all check watchers.	787	- Queue all check watchers.
772	- Call all queued watchers in reverse order (i.e. check watchers first).	788	- 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	789	Signals and child watchers are implemented as I/O watchers, and will
774	be handled here by queueing them when their watcher gets executed.	790	be handled here by queueing them when their watcher gets executed.
775	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	791	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
776	were used, or there are no active watchers, return, otherwise	792	were used, or there are no active watchers, goto FINISH, otherwise
777	continue with step *.	793	continue with step LOOP.
		794	FINISH:
		795	- Reset the ev_break status iff it was EVBREAK_ONE.
		796	- Decrement the loop depth.
		797	- Return.
778		798
779	Example: Queue some jobs and then loop until no events are outstanding	799	Example: Queue some jobs and then loop until no events are outstanding
780	anymore.	800	anymore.
781		801
782	... queue jobs here, make sure they register event watchers as long	802	... 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..)	803	... as they still have work to do (even an idle watcher will do..)
784	ev_loop (my_loop, 0);	804	ev_run (my_loop, 0);
785	... jobs done or somebody called unloop. yeah!	805	... jobs done or somebody called unloop. yeah!
786		806
787	=item ev_unloop (loop, how)	807	=item ev_break (loop, how)
788		808
789	Can be used to make a call to C<ev_loop> return early (but only after it	809	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	810	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	811	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.	812	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
793		813
794	This "unloop state" will be cleared when entering C<ev_loop> again.	814	This "unloop state" will be cleared when entering C<ev_run> again.
795		815
796	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	816	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
797		817
798	=item ev_ref (loop)	818	=item ev_ref (loop)
799		819
800	=item ev_unref (loop)	820	=item ev_unref (loop)
801		821
802	Ref/unref can be used to add or remove a reference count on the event	822	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	823	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.	824	count is nonzero, C<ev_run> will not return on its own.
805		825
806	This is useful when you have a watcher that you never intend to	826	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	827	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>	828	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
809	before stopping it.	829	before stopping it.
810		830
811	As an example, libev itself uses this for its internal signal pipe: It	831	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	832	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	833	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	834	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	835	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	836	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	837	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>	838	(e.g. non-repeating timers) in which case you have to C<ev_ref>
819	in the callback).	839	in the callback).
820		840
821	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	841	Example: Create a signal watcher, but keep it from keeping C<ev_run>
822	running when nothing else is active.	842	running when nothing else is active.
823		843
824	ev_signal exitsig;	844	ev_signal exitsig;
825	ev_signal_init (&exitsig, sig_cb, SIGINT);	845	ev_signal_init (&exitsig, sig_cb, SIGINT);
826	ev_signal_start (loop, &exitsig);	846	ev_signal_start (loop, &exitsig);
…		…
871	usually doesn't make much sense to set it to a lower value than C<0.01>,	891	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	892	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	893	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	894	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,	895	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).	896	then you can't do more than 100 transactions per second).
877		897
878	Setting the I<timeout collect interval> can improve the opportunity for	898	Setting the I<timeout collect interval> can improve the opportunity for
879	saving power, as the program will "bundle" timer callback invocations that	899	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	900	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	901	times the process sleeps and wakes up again. Another useful technique to
…		…
889	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	909	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
890		910
891	=item ev_invoke_pending (loop)	911	=item ev_invoke_pending (loop)
892		912
893	This call will simply invoke all pending watchers while resetting their	913	This call will simply invoke all pending watchers while resetting their
894	pending state. Normally, C<ev_loop> does this automatically when required,	914	pending state. Normally, C<ev_run> does this automatically when required,
895	but when overriding the invoke callback this call comes handy.	915	but when overriding the invoke callback this call comes handy. This
		916	function can be invoked from a watcher - this can be useful for example
		917	when you want to do some lengthy calculation and want to pass further
		918	event handling to another thread (you still have to make sure only one
		919	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
896		920
897	=item int ev_pending_count (loop)	921	=item int ev_pending_count (loop)
898		922
899	Returns the number of pending watchers - zero indicates that no watchers	923	Returns the number of pending watchers - zero indicates that no watchers
900	are pending.	924	are pending.
901		925
902	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	926	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
903		927
904	This overrides the invoke pending functionality of the loop: Instead of	928	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	929	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	930	this callback instead. This is useful, for example, when you want to
907	invoke the actual watchers inside another context (another thread etc.).	931	invoke the actual watchers inside another context (another thread etc.).
908		932
909	If you want to reset the callback, use C<ev_invoke_pending> as new	933	If you want to reset the callback, use C<ev_invoke_pending> as new
910	callback.	934	callback.
…		…
913		937
914	Sometimes you want to share the same loop between multiple threads. This	938	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	939	can be done relatively simply by putting mutex_lock/unlock calls around
916	each call to a libev function.	940	each call to a libev function.
917		941
918	However, C<ev_loop> can run an indefinite time, so it is not feasible to	942	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	943	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>	944	loop via C<ev_break> and C<av_async_send>, another way is to set these
921	and I<acquire> callbacks on the loop.	945	I<release> and I<acquire> callbacks on the loop.
922		946
923	When set, then C<release> will be called just before the thread is	947	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	948	suspended waiting for new events, and C<acquire> is called just
925	afterwards.	949	afterwards.
926		950
…		…
929		953
930	While event loop modifications are allowed between invocations of	954	While event loop modifications are allowed between invocations of
931	C<release> and C<acquire> (that's their only purpose after all), no	955	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	956	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	957	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	958	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.	959	to take note of any changes you made.
936		960
937	In theory, threads executing C<ev_loop> will be async-cancel safe between	961	In theory, threads executing C<ev_run> will be async-cancel safe between
938	invocations of C<release> and C<acquire>.	962	invocations of C<release> and C<acquire>.
939		963
940	See also the locking example in the C<THREADS> section later in this	964	See also the locking example in the C<THREADS> section later in this
941	document.	965	document.
942		966
…		…
951	These two functions can be used to associate arbitrary data with a loop,	975	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	976	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	977	C<acquire> callbacks described above, but of course can be (ab-)used for
954	any other purpose as well.	978	any other purpose as well.
955		979
956	=item ev_loop_verify (loop)	980	=item ev_verify (loop)
957		981
958	This function only does something when C<EV_VERIFY> support has been	982	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	983	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	984	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	985	is found to be inconsistent, it will print an error message to standard
…		…
972		996
973	In the following description, uppercase C<TYPE> in names stands for the	997	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	998	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.	999	watchers and C<ev_io_start> for I/O watchers.
976		1000
977	A watcher is a structure that you create and register to record your	1001	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	1002	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:	1003	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1004	for that:
980		1005
981	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1006	static void my_cb (struct ev_loop loop, ev_io w, int revents)
982	{	1007	{
983	ev_io_stop (w);	1008	ev_io_stop (w);
984	ev_unloop (loop, EVUNLOOP_ALL);	1009	ev_break (loop, EVBREAK_ALL);
985	}	1010	}
986		1011
987	struct ev_loop *loop = ev_default_loop (0);	1012	struct ev_loop *loop = ev_default_loop (0);
988		1013
989	ev_io stdin_watcher;	1014	ev_io stdin_watcher;
990		1015
991	ev_init (&stdin_watcher, my_cb);	1016	ev_init (&stdin_watcher, my_cb);
992	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1017	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
993	ev_io_start (loop, &stdin_watcher);	1018	ev_io_start (loop, &stdin_watcher);
994		1019
995	ev_loop (loop, 0);	1020	ev_run (loop, 0);
996		1021
997	As you can see, you are responsible for allocating the memory for your	1022	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	1023	watcher structures (and it is I<usually> a bad idea to do this on the
999	stack).	1024	stack).
1000		1025
1001	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1026	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).	1027	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1003		1028
1004	Each watcher structure must be initialised by a call to C<ev_init	1029	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	1030	*, 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	1031	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	1032	time the event loop detects that the file descriptor given is readable
1008	is readable and/or writable).	1033	and/or writable).
1009		1034
1010	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1035	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	1036	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<<	1037	is also a macro to combine initialisation and setting in one call: C<<
1013	ev_TYPE_init (watcher *, callback, ...) >>.	1038	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1064		1089
1065	=item C<EV_PREPARE>	1090	=item C<EV_PREPARE>
1066		1091
1067	=item C<EV_CHECK>	1092	=item C<EV_CHECK>
1068		1093
1069	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1094	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	1095	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	1096	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	1097	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	1098	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	1099	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1075	C<ev_loop> from blocking).	1100	C<ev_run> from blocking).
1076		1101
1077	=item C<EV_EMBED>	1102	=item C<EV_EMBED>
1078		1103
1079	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1104	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1080		1105
…		…
1108	example it might indicate that a fd is readable or writable, and if your	1133	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	1134	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	1135	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	1136	programs, though, as the fd could already be closed and reused for another
1112	thing, so beware.	1137	thing, so beware.
		1138
		1139	=back
		1140
		1141	=head2 WATCHER STATES
		1142
		1143	There are various watcher states mentioned throughout this manual -
		1144	active, pending and so on. In this section these states and the rules to
		1145	transition between them will be described in more detail - and while these
		1146	rules might look complicated, they usually do "the right thing".
		1147
		1148	=over 4
		1149
		1150	=item initialiased
		1151
		1152	Before a watcher can be registered with the event looop it has to be
		1153	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1154	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1155
		1156	In this state it is simply some block of memory that is suitable for use
		1157	in an event loop. It can be moved around, freed, reused etc. at will.
		1158
		1159	=item started/running/active
		1160
		1161	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1162	property of the event loop, and is actively waiting for events. While in
		1163	this state it cannot be accessed (except in a few documented ways), moved,
		1164	freed or anything else - the only legal thing is to keep a pointer to it,
		1165	and call libev functions on it that are documented to work on active watchers.
		1166
		1167	=item pending
		1168
		1169	If a watcher is active and libev determines that an event it is interested
		1170	in has occurred (such as a timer expiring), it will become pending. It will
		1171	stay in this pending state until either it is stopped or its callback is
		1172	about to be invoked, so it is not normally pending inside the watcher
		1173	callback.
		1174
		1175	The watcher might or might not be active while it is pending (for example,
		1176	an expired non-repeating timer can be pending but no longer active). If it
		1177	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1178	but it is still property of the event loop at this time, so cannot be
		1179	moved, freed or reused. And if it is active the rules described in the
		1180	previous item still apply.
		1181
		1182	It is also possible to feed an event on a watcher that is not active (e.g.
		1183	via C<ev_feed_event>), in which case it becomes pending without being
		1184	active.
		1185
		1186	=item stopped
		1187
		1188	A watcher can be stopped implicitly by libev (in which case it might still
		1189	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1190	latter will clear any pending state the watcher might be in, regardless
		1191	of whether it was active or not, so stopping a watcher explicitly before
		1192	freeing it is often a good idea.
		1193
		1194	While stopped (and not pending) the watcher is essentially in the
		1195	initialised state, that is it can be reused, moved, modified in any way
		1196	you wish.
1113		1197
1114	=back	1198	=back
1115		1199
1116	=head2 GENERIC WATCHER FUNCTIONS	1200	=head2 GENERIC WATCHER FUNCTIONS
1117		1201
…		…
1379		1463
1380	For example, to emulate how many other event libraries handle priorities,	1464	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	1465	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	1466	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	1467	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	1468	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	1469	the lock-out case is known to be rare (which in turn is rare :), this is
1386	workable.	1470	workable.
1387		1471
1388	Usually, however, the lock-out model implemented that way will perform	1472	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,	1473	miserably under the type of load it was designed to handle. In that case,
…		…
1403	{	1487	{
1404	// stop the I/O watcher, we received the event, but	1488	// stop the I/O watcher, we received the event, but
1405	// are not yet ready to handle it.	1489	// are not yet ready to handle it.
1406	ev_io_stop (EV_A_ w);	1490	ev_io_stop (EV_A_ w);
1407		1491
1408	// start the idle watcher to ahndle the actual event.	1492	// start the idle watcher to handle the actual event.
1409	// it will not be executed as long as other watchers	1493	// it will not be executed as long as other watchers
1410	// with the default priority are receiving events.	1494	// with the default priority are receiving events.
1411	ev_idle_start (EV_A_ &idle);	1495	ev_idle_start (EV_A_ &idle);
1412	}	1496	}
1413		1497
…		…
1467		1551
1468	If you cannot use non-blocking mode, then force the use of a	1552	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	1553	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	1554	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1471	descriptors for which non-blocking operation makes no sense (such as	1555	descriptors for which non-blocking operation makes no sense (such as
1472	files) - libev doesn't guarentee any specific behaviour in that case.	1556	files) - libev doesn't guarantee any specific behaviour in that case.
1473		1557
1474	Another thing you have to watch out for is that it is quite easy to	1558	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	1559	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	1560	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	1561	because there is no data. Not only are some backends known to create a
…		…
1621	...	1705	...
1622	struct ev_loop *loop = ev_default_init (0);	1706	struct ev_loop *loop = ev_default_init (0);
1623	ev_io stdin_readable;	1707	ev_io stdin_readable;
1624	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1708	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1625	ev_io_start (loop, &stdin_readable);	1709	ev_io_start (loop, &stdin_readable);
1626	ev_loop (loop, 0);	1710	ev_run (loop, 0);
1627		1711
1628		1712
1629	=head2 C<ev_timer> - relative and optionally repeating timeouts	1713	=head2 C<ev_timer> - relative and optionally repeating timeouts
1630		1714
1631	Timer watchers are simple relative timers that generate an event after a	1715	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	1724	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	1725	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	1726	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	1727	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	1728	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).	1729	no longer true when a callback calls C<ev_run> recursively).
1646		1730
1647	=head3 Be smart about timeouts	1731	=head3 Be smart about timeouts
1648		1732
1649	Many real-world problems involve some kind of timeout, usually for error	1733	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,	1734	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1736	ev_tstamp timeout = last_activity + 60.;	1820	ev_tstamp timeout = last_activity + 60.;
1737		1821
1738	// if last_activity + 60. is older than now, we did time out	1822	// if last_activity + 60. is older than now, we did time out
1739	if (timeout < now)	1823	if (timeout < now)
1740	{	1824	{
1741	// timeout occured, take action	1825	// timeout occurred, take action
1742	}	1826	}
1743	else	1827	else
1744	{	1828	{
1745	// callback was invoked, but there was some activity, re-arm	1829	// callback was invoked, but there was some activity, re-arm
1746	// the watcher to fire in last_activity + 60, which is	1830	// the watcher to fire in last_activity + 60, which is
…		…
1773	callback (loop, timer, EV_TIMER);	1857	callback (loop, timer, EV_TIMER);
1774		1858
1775	And when there is some activity, simply store the current time in	1859	And when there is some activity, simply store the current time in
1776	C<last_activity>, no libev calls at all:	1860	C<last_activity>, no libev calls at all:
1777		1861
1778	last_actiivty = ev_now (loop);	1862	last_activity = ev_now (loop);
1779		1863
1780	This technique is slightly more complex, but in most cases where the	1864	This technique is slightly more complex, but in most cases where the
1781	time-out is unlikely to be triggered, much more efficient.	1865	time-out is unlikely to be triggered, much more efficient.
1782		1866
1783	Changing the timeout is trivial as well (if it isn't hard-coded in the	1867	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1821		1905
1822	=head3 The special problem of time updates	1906	=head3 The special problem of time updates
1823		1907
1824	Establishing the current time is a costly operation (it usually takes at	1908	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	1909	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	1910	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	1911	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1828	lots of events in one iteration.	1912	lots of events in one iteration.
1829		1913
1830	The relative timeouts are calculated relative to the C<ev_now ()>	1914	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	1915	time. This is usually the right thing as this timestamp refers to the time
…		…
1948	}	2032	}
1949		2033
1950	ev_timer mytimer;	2034	ev_timer mytimer;
1951	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2035	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1952	ev_timer_again (&mytimer); /* start timer */	2036	ev_timer_again (&mytimer); /* start timer */
1953	ev_loop (loop, 0);	2037	ev_run (loop, 0);
1954		2038
1955	// and in some piece of code that gets executed on any "activity":	2039	// and in some piece of code that gets executed on any "activity":
1956	// reset the timeout to start ticking again at 10 seconds	2040	// reset the timeout to start ticking again at 10 seconds
1957	ev_timer_again (&mytimer);	2041	ev_timer_again (&mytimer);
1958		2042
…		…
1984		2068
1985	As with timers, the callback is guaranteed to be invoked only when the	2069	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	2070	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	2071	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	2072	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).	2073	(but this is no longer true when a callback calls C<ev_run> recursively).
1990		2074
1991	=head3 Watcher-Specific Functions and Data Members	2075	=head3 Watcher-Specific Functions and Data Members
1992		2076
1993	=over 4	2077	=over 4
1994		2078
…		…
2122	Example: Call a callback every hour, or, more precisely, whenever the	2206	Example: Call a callback every hour, or, more precisely, whenever the
2123	system time is divisible by 3600. The callback invocation times have	2207	system time is divisible by 3600. The callback invocation times have
2124	potentially a lot of jitter, but good long-term stability.	2208	potentially a lot of jitter, but good long-term stability.
2125		2209
2126	static void	2210	static void
2127	clock_cb (struct ev_loop loop, ev_io w, int revents)	2211	clock_cb (struct ev_loop loop, ev_periodic w, int revents)
2128	{	2212	{
2129	... its now a full hour (UTC, or TAI or whatever your clock follows)	2213	... its now a full hour (UTC, or TAI or whatever your clock follows)
2130	}	2214	}
2131		2215
2132	ev_periodic hourly_tick;	2216	ev_periodic hourly_tick;
…		…
2232	Example: Try to exit cleanly on SIGINT.	2316	Example: Try to exit cleanly on SIGINT.
2233		2317
2234	static void	2318	static void
2235	sigint_cb (struct ev_loop loop, ev_signal w, int revents)	2319	sigint_cb (struct ev_loop loop, ev_signal w, int revents)
2236	{	2320	{
2237	ev_unloop (loop, EVUNLOOP_ALL);	2321	ev_break (loop, EVBREAK_ALL);
2238	}	2322	}
2239		2323
2240	ev_signal signal_watcher;	2324	ev_signal signal_watcher;
2241	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2325	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2242	ev_signal_start (loop, &signal_watcher);	2326	ev_signal_start (loop, &signal_watcher);
…		…
2628		2712
2629	Prepare and check watchers are usually (but not always) used in pairs:	2713	Prepare and check watchers are usually (but not always) used in pairs:
2630	prepare watchers get invoked before the process blocks and check watchers	2714	prepare watchers get invoked before the process blocks and check watchers
2631	afterwards.	2715	afterwards.
2632		2716
2633	You I<must not> call C<ev_loop> or similar functions that enter	2717	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>	2718	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	2719	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	2720	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,	2721	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	2722	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2806		2890
2807	if (timeout >= 0)	2891	if (timeout >= 0)
2808	// create/start timer	2892	// create/start timer
2809		2893
2810	// poll	2894	// poll
2811	ev_loop (EV_A_ 0);	2895	ev_run (EV_A_ 0);
2812		2896
2813	// stop timer again	2897	// stop timer again
2814	if (timeout >= 0)	2898	if (timeout >= 0)
2815	ev_timer_stop (EV_A_ &to);	2899	ev_timer_stop (EV_A_ &to);
2816		2900
…		…
2894	if you do not want that, you need to temporarily stop the embed watcher).	2978	if you do not want that, you need to temporarily stop the embed watcher).
2895		2979
2896	=item ev_embed_sweep (loop, ev_embed *)	2980	=item ev_embed_sweep (loop, ev_embed *)
2897		2981
2898	Make a single, non-blocking sweep over the embedded loop. This works	2982	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	2983	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2900	appropriate way for embedded loops.	2984	appropriate way for embedded loops.
2901		2985
2902	=item struct ev_loop *other [read-only]	2986	=item struct ev_loop *other [read-only]
2903		2987
2904	The embedded event loop.	2988	The embedded event loop.
…		…
2964	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3048	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2965	handlers will be invoked, too, of course.	3049	handlers will be invoked, too, of course.
2966		3050
2967	=head3 The special problem of life after fork - how is it possible?	3051	=head3 The special problem of life after fork - how is it possible?
2968		3052
2969	Most uses of C<fork()> consist of forking, then some simple calls to ste	3053	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	3054	up/change the process environment, followed by a call to C<exec()>. This
2971	sequence should be handled by libev without any problems.	3055	sequence should be handled by libev without any problems.
2972		3056
2973	This changes when the application actually wants to do event handling	3057	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	3058	in the child, or both parent in child, in effect "continuing" after the
…		…
3008	believe me.	3092	believe me.
3009		3093
3010	=back	3094	=back
3011		3095
3012		3096
3013	=head2 C<ev_async> - how to wake up another event loop	3097	=head2 C<ev_async> - how to wake up an event loop
3014		3098
3015	In general, you cannot use an C<ev_loop> from multiple threads or other	3099	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	3100	asynchronous sources such as signal handlers (as opposed to multiple event
3017	loops - those are of course safe to use in different threads).	3101	loops - those are of course safe to use in different threads).
3018		3102
3019	Sometimes, however, you need to wake up another event loop you do not	3103	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	3104	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	3105	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	3106	it by calling C<ev_async_send>, which is thread- and signal safe.
3023	safe.
3024		3107
3025	This functionality is very similar to C<ev_signal> watchers, as signals,	3108	This functionality is very similar to C<ev_signal> watchers, as signals,
3026	too, are asynchronous in nature, and signals, too, will be compressed	3109	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	3110	(i.e. the number of callback invocations may be less than the number of
3028	C<ev_async_sent> calls).	3111	C<ev_async_sent> calls).
…		…
3340	myclass obj;	3423	myclass obj;
3341	ev::io iow;	3424	ev::io iow;
3342	iow.set <myclass, &myclass::io_cb> (&obj);	3425	iow.set <myclass, &myclass::io_cb> (&obj);
3343		3426
3344	=item w->set (object *)	3427	=item w->set (object *)
3345
3346	This is an B<experimental> feature that might go away in a future version.
3347		3428
3348	This is a variation of a method callback - leaving out the method to call	3429	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	3430	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	3431	functor objects without having to manually specify the C<operator ()> all
3351	the time. Incidentally, you can then also leave out the template argument	3432	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	3472	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).	3473	do this when the watcher is inactive (and not pending either).
3393		3474
3394	=item w->set ([arguments])	3475	=item w->set ([arguments])
3395		3476
3396	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3477	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	3478	method or a suitable start method must be called at least once. Unlike the
3398	automatically stopped and restarted when reconfiguring it with this	3479	C counterpart, an active watcher gets automatically stopped and restarted
3399	method.	3480	when reconfiguring it with this method.
3400		3481
3401	=item w->start ()	3482	=item w->start ()
3402		3483
3403	Starts the watcher. Note that there is no C<loop> argument, as the	3484	Starts the watcher. Note that there is no C<loop> argument, as the
3404	constructor already stores the event loop.	3485	constructor already stores the event loop.
3405		3486
		3487	=item w->start ([arguments])
		3488
		3489	Instead of calling C<set> and C<start> methods separately, it is often
		3490	convenient to wrap them in one call. Uses the same type of arguments as
		3491	the configure C<set> method of the watcher.
		3492
3406	=item w->stop ()	3493	=item w->stop ()
3407		3494
3408	Stops the watcher if it is active. Again, no C<loop> argument.	3495	Stops the watcher if it is active. Again, no C<loop> argument.
3409		3496
3410	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3497	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3422		3509
3423	=back	3510	=back
3424		3511
3425	=back	3512	=back
3426		3513
3427	Example: Define a class with an IO and idle watcher, start one of them in	3514	Example: Define a class with two I/O and idle watchers, start the I/O
3428	the constructor.	3515	watchers in the constructor.
3429		3516
3430	class myclass	3517	class myclass
3431	{	3518	{
3432	ev::io io ; void io_cb (ev::io &w, int revents);	3519	ev::io io ; void io_cb (ev::io &w, int revents);
		3520	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3433	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3521	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3434		3522
3435	myclass (int fd)	3523	myclass (int fd)
3436	{	3524	{
3437	io .set <myclass, &myclass::io_cb > (this);	3525	io .set <myclass, &myclass::io_cb > (this);
		3526	io2 .set <myclass, &myclass::io2_cb > (this);
3438	idle.set <myclass, &myclass::idle_cb> (this);	3527	idle.set <myclass, &myclass::idle_cb> (this);
3439		3528
3440	io.start (fd, ev::READ);	3529	io.set (fd, ev::WRITE); // configure the watcher
		3530	io.start (); // start it whenever convenient
		3531
		3532	io2.start (fd, ev::READ); // set + start in one call
3441	}	3533	}
3442	};	3534	};
3443		3535
3444		3536
3445	=head1 OTHER LANGUAGE BINDINGS	3537	=head1 OTHER LANGUAGE BINDINGS
…		…
3519	loop argument"). The C<EV_A> form is used when this is the sole argument,	3611	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:	3612	C<EV_A_> is used when other arguments are following. Example:
3521		3613
3522	ev_unref (EV_A);	3614	ev_unref (EV_A);
3523	ev_timer_add (EV_A_ watcher);	3615	ev_timer_add (EV_A_ watcher);
3524	ev_loop (EV_A_ 0);	3616	ev_run (EV_A_ 0);
3525		3617
3526	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3618	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3527	which is often provided by the following macro.	3619	which is often provided by the following macro.
3528		3620
3529	=item C<EV_P>, C<EV_P_>	3621	=item C<EV_P>, C<EV_P_>
…		…
3569	}	3661	}
3570		3662
3571	ev_check check;	3663	ev_check check;
3572	ev_check_init (&check, check_cb);	3664	ev_check_init (&check, check_cb);
3573	ev_check_start (EV_DEFAULT_ &check);	3665	ev_check_start (EV_DEFAULT_ &check);
3574	ev_loop (EV_DEFAULT_ 0);	3666	ev_run (EV_DEFAULT_ 0);
3575		3667
3576	=head1 EMBEDDING	3668	=head1 EMBEDDING
3577		3669
3578	Libev can (and often is) directly embedded into host	3670	Libev can (and often is) directly embedded into host
3579	applications. Examples of applications that embed it include the Deliantra	3671	applications. Examples of applications that embed it include the Deliantra
…		…
3670	to a compiled library. All other symbols change the ABI, which means all	3762	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	3763	users of libev and the libev code itself must be compiled with compatible
3672	settings.	3764	settings.
3673		3765
3674	=over 4	3766	=over 4
		3767
		3768	=item EV_COMPAT3 (h)
		3769
		3770	Backwards compatibility is a major concern for libev. This is why this
		3771	release of libev comes with wrappers for the functions and symbols that
		3772	have been renamed between libev version 3 and 4.
		3773
		3774	You can disable these wrappers (to test compatibility with future
		3775	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3776	sources. This has the additional advantage that you can drop the C<struct>
		3777	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3778	typedef in that case.
		3779
		3780	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3781	and in some even more future version the compatibility code will be
		3782	removed completely.
3675		3783
3676	=item EV_STANDALONE (h)	3784	=item EV_STANDALONE (h)
3677		3785
3678	Must always be C<1> if you do not use autoconf configuration, which	3786	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	3787	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,	3994	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
3887	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.	3995	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3888		3996
3889	If undefined or defined to be C<1> (and the platform supports it), then	3997	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	3998	the respective watcher type is supported. If defined to be C<0>, then it
3891	is not. Disabling watcher types mainly saves codesize.	3999	is not. Disabling watcher types mainly saves code size.
3892		4000
3893	=item EV_FEATURES	4001	=item EV_FEATURES
3894		4002
3895	If you need to shave off some kilobytes of code at the expense of some	4003	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	4004	speed (but with the full API), you can define this symbol to request
…		…
3916		4024
3917	=item C<1> - faster/larger code	4025	=item C<1> - faster/larger code
3918		4026
3919	Use larger code to speed up some operations.	4027	Use larger code to speed up some operations.
3920		4028
3921	Currently this is used to override some inlining decisions (enlarging the roughly	4029	Currently this is used to override some inlining decisions (enlarging the
3922	30% code size on amd64.	4030	code size by roughly 30% on amd64).
3923		4031
3924	When optimising for size, use of compiler flags such as C<-Os> with	4032	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	4033	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
3926	assertions.	4034	assertions.
3927		4035
3928	=item C<2> - faster/larger data structures	4036	=item C<2> - faster/larger data structures
3929		4037
3930	Replaces the small 2-heap for timer management by a faster 4-heap, larger	4038	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	4039	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	4040	and can additionally have an effect on the size of data structures at
3933	runtime.	4041	runtime.
3934		4042
3935	=item C<4> - full API configuration	4043	=item C<4> - full API configuration
3936		4044
…		…
3973	I/O watcher then might come out at only 5Kb.	4081	I/O watcher then might come out at only 5Kb.
3974		4082
3975	=item EV_AVOID_STDIO	4083	=item EV_AVOID_STDIO
3976		4084
3977	If this is set to C<1> at compiletime, then libev will avoid using stdio	4085	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	4086	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	4087	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	4088	libc allows it, this avoids linking in the stdio library which is quite
3981	big.	4089	big.
3982		4090
3983	Note that error messages might become less precise when this option is	4091	Note that error messages might become less precise when this option is
…		…
3987		4095
3988	The highest supported signal number, +1 (or, the number of	4096	The highest supported signal number, +1 (or, the number of
3989	signals): Normally, libev tries to deduce the maximum number of signals	4097	signals): Normally, libev tries to deduce the maximum number of signals
3990	automatically, but sometimes this fails, in which case it can be	4098	automatically, but sometimes this fails, in which case it can be
3991	specified. Also, using a lower number than detected (C<32> should be	4099	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	4100	good for about any system in existence) can save some memory, as libev
3993	statically allocates some 12-24 bytes per signal number.	4101	statically allocates some 12-24 bytes per signal number.
3994		4102
3995	=item EV_PID_HASHSIZE	4103	=item EV_PID_HASHSIZE
3996		4104
3997	C<ev_child> watchers use a small hash table to distribute workload by	4105	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	4137	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4030	will be C<0>.	4138	will be C<0>.
4031		4139
4032	=item EV_VERIFY	4140	=item EV_VERIFY
4033		4141
4034	Controls how much internal verification (see C<ev_loop_verify ()>) will	4142	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	4143	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	4144	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	4145	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	4146	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	4147	verification code will be called very frequently, which will slow down
…		…
4043	will be C<0>.	4151	will be C<0>.
4044		4152
4045	=item EV_COMMON	4153	=item EV_COMMON
4046		4154
4047	By default, all watchers have a C<void *data> member. By redefining	4155	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	4156	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,	4157	members. You have to define it each time you include one of the files,
4050	though, and it must be identical each time.	4158	though, and it must be identical each time.
4051		4159
4052	For example, the perl EV module uses something like this:	4160	For example, the perl EV module uses something like this:
4053		4161
…		…
4254	userdata *u = ev_userdata (EV_A);	4362	userdata *u = ev_userdata (EV_A);
4255	pthread_mutex_lock (&u->lock);	4363	pthread_mutex_lock (&u->lock);
4256	}	4364	}
4257		4365
4258	The event loop thread first acquires the mutex, and then jumps straight	4366	The event loop thread first acquires the mutex, and then jumps straight
4259	into C<ev_loop>:	4367	into C<ev_run>:
4260		4368
4261	void *	4369	void *
4262	l_run (void *thr_arg)	4370	l_run (void *thr_arg)
4263	{	4371	{
4264	struct ev_loop loop = (struct ev_loop )thr_arg;	4372	struct ev_loop loop = (struct ev_loop )thr_arg;
4265		4373
4266	l_acquire (EV_A);	4374	l_acquire (EV_A);
4267	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4375	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4268	ev_loop (EV_A_ 0);	4376	ev_run (EV_A_ 0);
4269	l_release (EV_A);	4377	l_release (EV_A);
4270		4378
4271	return 0;	4379	return 0;
4272	}	4380	}
4273		4381
…		…
4325		4433
4326	=head3 COROUTINES	4434	=head3 COROUTINES
4327		4435
4328	Libev is very accommodating to coroutines ("cooperative threads"):	4436	Libev is very accommodating to coroutines ("cooperative threads"):
4329	libev fully supports nesting calls to its functions from different	4437	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	4438	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	4439	different coroutines, and switch freely between both coroutines running
4332	the loop, as long as you don't confuse yourself). The only exception is	4440	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.	4441	that you must not do this from C<ev_periodic> reschedule callbacks.
4334		4442
4335	Care has been taken to ensure that libev does not keep local state inside	4443	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	4444	C<ev_run>, and other calls do not usually allow for coroutine switches as
4337	they do not call any callbacks.	4445	they do not call any callbacks.
4338		4446
4339	=head2 COMPILER WARNINGS	4447	=head2 COMPILER WARNINGS
4340		4448
4341	Depending on your compiler and compiler settings, you might get no or a	4449	Depending on your compiler and compiler settings, you might get no or a
…		…
4352	maintainable.	4460	maintainable.
4353		4461
4354	And of course, some compiler warnings are just plain stupid, or simply	4462	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	4463	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	4464	seems to warn about). For example, certain older gcc versions had some
4357	warnings that resulted an extreme number of false positives. These have	4465	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	4466	been fixed, but some people still insist on making code warn-free with
4359	such buggy versions.	4467	such buggy versions.
4360		4468
4361	While libev is written to generate as few warnings as possible,	4469	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	4470	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4398	I suggest using suppression lists.	4506	I suggest using suppression lists.
4399		4507
4400		4508
4401	=head1 PORTABILITY NOTES	4509	=head1 PORTABILITY NOTES
4402		4510
		4511	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4512
		4513	GNU/Linux is the only common platform that supports 64 bit file/large file
		4514	interfaces but I<disables> them by default.
		4515
		4516	That means that libev compiled in the default environment doesn't support
		4517	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4518
		4519	Unfortunately, many programs try to work around this GNU/Linux issue
		4520	by enabling the large file API, which makes them incompatible with the
		4521	standard libev compiled for their system.
		4522
		4523	Likewise, libev cannot enable the large file API itself as this would
		4524	suddenly make it incompatible to the default compile time environment,
		4525	i.e. all programs not using special compile switches.
		4526
		4527	=head2 OS/X AND DARWIN BUGS
		4528
		4529	The whole thing is a bug if you ask me - basically any system interface
		4530	you touch is broken, whether it is locales, poll, kqueue or even the
		4531	OpenGL drivers.
		4532
		4533	=head3 C<kqueue> is buggy
		4534
		4535	The kqueue syscall is broken in all known versions - most versions support
		4536	only sockets, many support pipes.
		4537
		4538	Libev tries to work around this by not using C<kqueue> by default on this
		4539	rotten platform, but of course you can still ask for it when creating a
		4540	loop - embedding a socket-only kqueue loop into a select-based one is
		4541	probably going to work well.
		4542
		4543	=head3 C<poll> is buggy
		4544
		4545	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4546	implementation by something calling C<kqueue> internally around the 10.5.6
		4547	release, so now C<kqueue> I<and> C<poll> are broken.
		4548
		4549	Libev tries to work around this by not using C<poll> by default on
		4550	this rotten platform, but of course you can still ask for it when creating
		4551	a loop.
		4552
		4553	=head3 C<select> is buggy
		4554
		4555	All that's left is C<select>, and of course Apple found a way to fuck this
		4556	one up as well: On OS/X, C<select> actively limits the number of file
		4557	descriptors you can pass in to 1024 - your program suddenly crashes when
		4558	you use more.
		4559
		4560	There is an undocumented "workaround" for this - defining
		4561	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4562	work on OS/X.
		4563
		4564	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4565
		4566	=head3 C<errno> reentrancy
		4567
		4568	The default compile environment on Solaris is unfortunately so
		4569	thread-unsafe that you can't even use components/libraries compiled
		4570	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4571	defined by default. A valid, if stupid, implementation choice.
		4572
		4573	If you want to use libev in threaded environments you have to make sure
		4574	it's compiled with C<_REENTRANT> defined.
		4575
		4576	=head3 Event port backend
		4577
		4578	The scalable event interface for Solaris is called "event
		4579	ports". Unfortunately, this mechanism is very buggy in all major
		4580	releases. If you run into high CPU usage, your program freezes or you get
		4581	a large number of spurious wakeups, make sure you have all the relevant
		4582	and latest kernel patches applied. No, I don't know which ones, but there
		4583	are multiple ones to apply, and afterwards, event ports actually work
		4584	great.
		4585
		4586	If you can't get it to work, you can try running the program by setting
		4587	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4588	C<select> backends.
		4589
		4590	=head2 AIX POLL BUG
		4591
		4592	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4593	this by trying to avoid the poll backend altogether (i.e. it's not even
		4594	compiled in), which normally isn't a big problem as C<select> works fine
		4595	with large bitsets on AIX, and AIX is dead anyway.
		4596
4403	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4597	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4598
		4599	=head3 General issues
4404		4600
4405	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4601	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	4602	requires, and its I/O model is fundamentally incompatible with the POSIX
4407	model. Libev still offers limited functionality on this platform in	4603	model. Libev still offers limited functionality on this platform in
4408	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4604	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4409	descriptors. This only applies when using Win32 natively, not when using	4605	descriptors. This only applies when using Win32 natively, not when using
4410	e.g. cygwin.	4606	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4607	as every compielr comes with a slightly differently broken/incompatible
		4608	environment.
4411		4609
4412	Lifting these limitations would basically require the full	4610	Lifting these limitations would basically require the full
4413	re-implementation of the I/O system. If you are into these kinds of	4611	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	4612	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).	4613	also that glib is the slowest event library known to man).
4416		4614
4417	There is no supported compilation method available on windows except	4615	There is no supported compilation method available on windows except
4418	embedding it into other applications.	4616	embedding it into other applications.
4419		4617
4420	Sensible signal handling is officially unsupported by Microsoft - libev	4618	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!):	4646	you do I<not> compile the F<ev.c> or any other embedded source files!):
4449		4647
4450	#include "evwrap.h"	4648	#include "evwrap.h"
4451	#include "ev.c"	4649	#include "ev.c"
4452		4650
4453	=over 4
4454
4455	=item The winsocket select function	4651	=head3 The winsocket C<select> function
4456		4652
4457	The winsocket C<select> function doesn't follow POSIX in that it	4653	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	4654	requires socket I<handles> and not socket I<file descriptors> (it is
4459	also extremely buggy). This makes select very inefficient, and also	4655	also extremely buggy). This makes select very inefficient, and also
4460	requires a mapping from file descriptors to socket handles (the Microsoft	4656	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 */	4665	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4470		4666
4471	Note that winsockets handling of fd sets is O(n), so you can easily get a	4667	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.	4668	complexity in the O(n²) range when using win32.
4473		4669
4474	=item Limited number of file descriptors	4670	=head3 Limited number of file descriptors
4475		4671
4476	Windows has numerous arbitrary (and low) limits on things.	4672	Windows has numerous arbitrary (and low) limits on things.
4477		4673
4478	Early versions of winsocket's select only supported waiting for a maximum	4674	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	4675	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	4690	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,	4691	(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	4692	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.	4693	the cost of calling select (O(n²)) will likely make this unworkable.
4498		4694
4499	=back
4500
4501	=head2 PORTABILITY REQUIREMENTS	4695	=head2 PORTABILITY REQUIREMENTS
4502		4696
4503	In addition to a working ISO-C implementation and of course the	4697	In addition to a working ISO-C implementation and of course the
4504	backend-specific APIs, libev relies on a few additional extensions:	4698	backend-specific APIs, libev relies on a few additional extensions:
4505		4699
…		…
4543	watchers.	4737	watchers.
4544		4738
4545	=item C<double> must hold a time value in seconds with enough accuracy	4739	=item C<double> must hold a time value in seconds with enough accuracy
4546		4740
4547	The type C<double> is used to represent timestamps. It is required to	4741	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	4742	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	4743	good enough for at least into the year 4000 with millisecond accuracy
		4744	(the design goal for libev). This requirement is overfulfilled by
4550	implementations implementing IEEE 754, which is basically all existing	4745	implementations using IEEE 754, which is basically all existing ones. With
4551	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4746	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4552	2200.
4553		4747
4554	=back	4748	=back
4555		4749
4556	If you know of other additional requirements drop me a note.	4750	If you know of other additional requirements drop me a note.
4557		4751
…		…
4635	compatibility, so most programs should still compile. Those might be	4829	compatibility, so most programs should still compile. Those might be
4636	removed in later versions of libev, so better update early than late.	4830	removed in later versions of libev, so better update early than late.
4637		4831
4638	=over 4	4832	=over 4
4639		4833
4640	=item C<ev_loop_count> renamed to C<ev_iteration>	4834	=item function/symbol renames
4641		4835
4642	=item C<ev_loop_depth> renamed to C<ev_depth>	4836	A number of functions and symbols have been renamed:
4643		4837
4644	=item C<ev_loop_verify> renamed to C<ev_verify>	4838	ev_loop => ev_run
		4839	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4840	EVLOOP_ONESHOT => EVRUN_ONCE
		4841
		4842	ev_unloop => ev_break
		4843	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4844	EVUNLOOP_ONE => EVBREAK_ONE
		4845	EVUNLOOP_ALL => EVBREAK_ALL
		4846
		4847	EV_TIMEOUT => EV_TIMER
		4848
		4849	ev_loop_count => ev_iteration
		4850	ev_loop_depth => ev_depth
		4851	ev_loop_verify => ev_verify
4645		4852
4646	Most functions working on C<struct ev_loop> objects don't have an	4853	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	4854	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4855	associated constants have been renamed to not collide with the C<struct
		4856	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4857	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	4858	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4649	C<ev_fork> typedef.	4859	typedef.
4650		4860
4651	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>	4861	=item C<EV_COMPAT3> backwards compatibility mechanism
4652		4862
4653	This is a simple rename - all other watcher types use their name	4863	The backward compatibility mechanism can be controlled by
4654	as revents flag, and now C<ev_timer> does, too.	4864	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4655		4865	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		4866
4660	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4867	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4661		4868
4662	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4869	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4663	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4870	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4670		4877
4671	=over 4	4878	=over 4
4672		4879
4673	=item active	4880	=item active
4674		4881
4675	A watcher is active as long as it has been started (has been attached to	4882	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).	4883	See L<WATCHER STATES> for details.
4677		4884
4678	=item application	4885	=item application
4679		4886
4680	In this document, an application is whatever is using libev.	4887	In this document, an application is whatever is using libev.
		4888
		4889	=item backend
		4890
		4891	The part of the code dealing with the operating system interfaces.
4681		4892
4682	=item callback	4893	=item callback
4683		4894
4684	The address of a function that is called when some event has been	4895	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	4896	detected. Callbacks are being passed the event loop, the watcher that
4686	received the event, and the actual event bitset.	4897	received the event, and the actual event bitset.
4687		4898
4688	=item callback invocation	4899	=item callback/watcher invocation
4689		4900
4690	The act of calling the callback associated with a watcher.	4901	The act of calling the callback associated with a watcher.
4691		4902
4692	=item event	4903	=item event
4693		4904
…		…
4712	The model used to describe how an event loop handles and processes	4923	The model used to describe how an event loop handles and processes
4713	watchers and events.	4924	watchers and events.
4714		4925
4715	=item pending	4926	=item pending
4716		4927
4717	A watcher is pending as soon as the corresponding event has been detected,	4928	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	4929	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		4930
4724	=item real time	4931	=item real time
4725		4932
4726	The physical time that is observed. It is apparently strictly monotonic :)	4933	The physical time that is observed. It is apparently strictly monotonic :)
4727		4934
…		…
4734	=item watcher	4941	=item watcher
4735		4942
4736	A data structure that describes interest in certain events. Watchers need	4943	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.	4944	to be started (attached to an event loop) before they can receive events.
4738		4945
4739	=item watcher invocation
4740
4741	The act of calling the callback associated with a watcher.
4742
4743	=back	4946	=back
4744		4947
4745	=head1 AUTHOR	4948	=head1 AUTHOR
4746		4949
4747	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4950	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 1.318 by root, Fri Oct 22 09:40:22 2010 UTC

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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 1.318 by root, Fri Oct 22 09:40:22 2010 UTC