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

Comparing libev/ev.pod (file contents):
Revision 1.306 by root, Mon Oct 18 07:36:05 2010 UTC vs.
Revision 1.316 by root, Fri Oct 22 09:34:01 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
…		…
292		292
293	=back	293	=back
294		294
295	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	295	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP
296		296
297	An event loop is described by a C<struct ev_loop *> (the C<struct>	297	An event loop is described by a C<struct ev_loop *> (the C<struct> is
298	is I<not> optional in this case, as there is also an C<ev_loop>	298	I<not> optional in this case unless libev 3 compatibility is disabled, as
299	I<function>).	299	libev 3 had an C<ev_loop> function colliding with the struct name).
300		300
301	The library knows two types of such loops, the I<default> loop, which	301	The library knows two types of such loops, the I<default> loop, which
302	supports signals and child events, and dynamically created loops which do	302	supports signals and child events, and dynamically created event loops
303	not.	303	which do not.
304		304
305	=over 4	305	=over 4
306		306
307	=item struct ev_loop *ev_default_loop (unsigned int flags)	307	=item struct ev_loop *ev_default_loop (unsigned int flags)
308		308
…		…
606	Like C<ev_default_destroy>, but destroys an event loop created by an	606	Like C<ev_default_destroy>, but destroys an event loop created by an
607	earlier call to C<ev_loop_new>.	607	earlier call to C<ev_loop_new>.
608		608
609	=item ev_default_fork ()	609	=item ev_default_fork ()
610		610
611	This function sets a flag that causes subsequent C<ev_loop> iterations	611	This function sets a flag that causes subsequent C<ev_run> iterations
612	to reinitialise the kernel state for backends that have one. Despite the	612	to reinitialise the kernel state for backends that have one. Despite the
613	name, you can call it anytime, but it makes most sense after forking, in	613	name, you can call it anytime, but it makes most sense after forking, in
614	the child process (or both child and parent, but that again makes little	614	the child process (or both child and parent, but that again makes little
615	sense). You I<must> call it in the child before using any of the libev	615	sense). You I<must> call it in the child before using any of the libev
616	functions, and it will only take effect at the next C<ev_loop> iteration.	616	functions, and it will only take effect at the next C<ev_run> iteration.
617		617
618	Again, you I<have> to call it on I<any> loop that you want to re-use after	618	Again, you I<have> to call it on I<any> loop that you want to re-use after
619	a fork, I<even if you do not plan to use the loop in the parent>. This is	619	a fork, I<even if you do not plan to use the loop in the parent>. This is
620	because some kernel interfaces cough I<kqueue> cough do funny things	620	because some kernel interfaces cough I<kqueue> cough do funny things
621	during fork.	621	during fork.
622		622
623	On the other hand, you only need to call this function in the child	623	On the other hand, you only need to call this function in the child
624	process if and only if you want to use the event loop in the child. If you	624	process if and only if you want to use the event loop in the child. If
625	just fork+exec or create a new loop in the child, you don't have to call	625	you just fork+exec or create a new loop in the child, you don't have to
626	it at all.	626	call it at all (in fact, C<epoll> is so badly broken that it makes a
		627	difference, but libev will usually detect this case on its own and do a
		628	costly reset of the backend).
627		629
628	The function itself is quite fast and it's usually not a problem to call	630	The function itself is quite fast and it's usually not a problem to call
629	it just in case after a fork. To make this easy, the function will fit in	631	it just in case after a fork. To make this easy, the function will fit in
630	quite nicely into a call to C<pthread_atfork>:	632	quite nicely into a call to C<pthread_atfork>:
631		633
…		…
643	Returns true when the given loop is, in fact, the default loop, and false	645	Returns true when the given loop is, in fact, the default loop, and false
644	otherwise.	646	otherwise.
645		647
646	=item unsigned int ev_iteration (loop)	648	=item unsigned int ev_iteration (loop)
647		649
648	Returns the current iteration count for the loop, which is identical to	650	Returns the current iteration count for the event loop, which is identical
649	the number of times libev did poll for new events. It starts at C<0> and	651	to the number of times libev did poll for new events. It starts at C<0>
650	happily wraps around with enough iterations.	652	and happily wraps around with enough iterations.
651		653
652	This value can sometimes be useful as a generation counter of sorts (it	654	This value can sometimes be useful as a generation counter of sorts (it
653	"ticks" the number of loop iterations), as it roughly corresponds with	655	"ticks" the number of loop iterations), as it roughly corresponds with
654	C<ev_prepare> and C<ev_check> calls - and is incremented between the	656	C<ev_prepare> and C<ev_check> calls - and is incremented between the
655	prepare and check phases.	657	prepare and check phases.
656		658
657	=item unsigned int ev_depth (loop)	659	=item unsigned int ev_depth (loop)
658		660
659	Returns the number of times C<ev_loop> was entered minus the number of	661	Returns the number of times C<ev_run> was entered minus the number of
660	times C<ev_loop> was exited, in other words, the recursion depth.	662	times C<ev_run> was exited, in other words, the recursion depth.
661		663
662	Outside C<ev_loop>, this number is zero. In a callback, this number is	664	Outside C<ev_run>, this number is zero. In a callback, this number is
663	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	665	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
664	in which case it is higher.	666	in which case it is higher.
665		667
666	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	668	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
667	etc.), doesn't count as "exit" - consider this as a hint to avoid such	669	etc.), doesn't count as "exit" - consider this as a hint to avoid such
668	ungentleman behaviour unless it's really convenient.	670	ungentleman-like behaviour unless it's really convenient.
669		671
670	=item unsigned int ev_backend (loop)	672	=item unsigned int ev_backend (loop)
671		673
672	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	674	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
673	use.	675	use.
…		…
682		684
683	=item ev_now_update (loop)	685	=item ev_now_update (loop)
684		686
685	Establishes the current time by querying the kernel, updating the time	687	Establishes the current time by querying the kernel, updating the time
686	returned by C<ev_now ()> in the progress. This is a costly operation and	688	returned by C<ev_now ()> in the progress. This is a costly operation and
687	is usually done automatically within C<ev_loop ()>.	689	is usually done automatically within C<ev_run ()>.
688		690
689	This function is rarely useful, but when some event callback runs for a	691	This function is rarely useful, but when some event callback runs for a
690	very long time without entering the event loop, updating libev's idea of	692	very long time without entering the event loop, updating libev's idea of
691	the current time is a good idea.	693	the current time is a good idea.
692		694
…		…
694		696
695	=item ev_suspend (loop)	697	=item ev_suspend (loop)
696		698
697	=item ev_resume (loop)	699	=item ev_resume (loop)
698		700
699	These two functions suspend and resume a loop, for use when the loop is	701	These two functions suspend and resume an event loop, for use when the
700	not used for a while and timeouts should not be processed.	702	loop is not used for a while and timeouts should not be processed.
701		703
702	A typical use case would be an interactive program such as a game: When	704	A typical use case would be an interactive program such as a game: When
703	the user presses C<^Z> to suspend the game and resumes it an hour later it	705	the user presses C<^Z> to suspend the game and resumes it an hour later it
704	would be best to handle timeouts as if no time had actually passed while	706	would be best to handle timeouts as if no time had actually passed while
705	the program was suspended. This can be achieved by calling C<ev_suspend>	707	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
716	without a previous call to C<ev_suspend>.	718	without a previous call to C<ev_suspend>.
717		719
718	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	720	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
719	event loop time (see C<ev_now_update>).	721	event loop time (see C<ev_now_update>).
720		722
721	=item ev_loop (loop, int flags)	723	=item ev_run (loop, int flags)
722		724
723	Finally, this is it, the event handler. This function usually is called	725	Finally, this is it, the event handler. This function usually is called
724	after you have initialised all your watchers and you want to start	726	after you have initialised all your watchers and you want to start
725	handling events.	727	handling events. It will ask the operating system for any new events, call
		728	the watcher callbacks, an then repeat the whole process indefinitely: This
		729	is why event loops are called I<loops>.
726		730
727	If the flags argument is specified as C<0>, it will not return until	731	If the flags argument is specified as C<0>, it will keep handling events
728	either no event watchers are active anymore or C<ev_unloop> was called.	732	until either no event watchers are active anymore or C<ev_break> was
		733	called.
729		734
730	Please note that an explicit C<ev_unloop> is usually better than	735	Please note that an explicit C<ev_break> is usually better than
731	relying on all watchers to be stopped when deciding when a program has	736	relying on all watchers to be stopped when deciding when a program has
732	finished (especially in interactive programs), but having a program	737	finished (especially in interactive programs), but having a program
733	that automatically loops as long as it has to and no longer by virtue	738	that automatically loops as long as it has to and no longer by virtue
734	of relying on its watchers stopping correctly, that is truly a thing of	739	of relying on its watchers stopping correctly, that is truly a thing of
735	beauty.	740	beauty.
736		741
737	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	742	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
738	those events and any already outstanding ones, but will not block your	743	those events and any already outstanding ones, but will not wait and
739	process in case there are no events and will return after one iteration of	744	block your process in case there are no events and will return after one
740	the loop.	745	iteration of the loop. This is sometimes useful to poll and handle new
		746	events while doing lengthy calculations, to keep the program responsive.
741		747
742	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	748	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
743	necessary) and will handle those and any already outstanding ones. It	749	necessary) and will handle those and any already outstanding ones. It
744	will block your process until at least one new event arrives (which could	750	will block your process until at least one new event arrives (which could
745	be an event internal to libev itself, so there is no guarantee that a	751	be an event internal to libev itself, so there is no guarantee that a
746	user-registered callback will be called), and will return after one	752	user-registered callback will be called), and will return after one
747	iteration of the loop.	753	iteration of the loop.
748		754
749	This is useful if you are waiting for some external event in conjunction	755	This is useful if you are waiting for some external event in conjunction
750	with something not expressible using other libev watchers (i.e. "roll your	756	with something not expressible using other libev watchers (i.e. "roll your
751	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	757	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
752	usually a better approach for this kind of thing.	758	usually a better approach for this kind of thing.
753		759
754	Here are the gory details of what C<ev_loop> does:	760	Here are the gory details of what C<ev_run> does:
755		761
		762	- Increment loop depth.
		763	- Reset the ev_break status.
756	- Before the first iteration, call any pending watchers.	764	- Before the first iteration, call any pending watchers.
		765	LOOP:
757	* If EVFLAG_FORKCHECK was used, check for a fork.	766	- If EVFLAG_FORKCHECK was used, check for a fork.
758	- If a fork was detected (by any means), queue and call all fork watchers.	767	- If a fork was detected (by any means), queue and call all fork watchers.
759	- Queue and call all prepare watchers.	768	- Queue and call all prepare watchers.
		769	- If ev_break was called, goto FINISH.
760	- If we have been forked, detach and recreate the kernel state	770	- If we have been forked, detach and recreate the kernel state
761	as to not disturb the other process.	771	as to not disturb the other process.
762	- Update the kernel state with all outstanding changes.	772	- Update the kernel state with all outstanding changes.
763	- Update the "event loop time" (ev_now ()).	773	- Update the "event loop time" (ev_now ()).
764	- Calculate for how long to sleep or block, if at all	774	- Calculate for how long to sleep or block, if at all
765	(active idle watchers, EVLOOP_NONBLOCK or not having	775	(active idle watchers, EVRUN_NOWAIT or not having
766	any active watchers at all will result in not sleeping).	776	any active watchers at all will result in not sleeping).
767	- Sleep if the I/O and timer collect interval say so.	777	- Sleep if the I/O and timer collect interval say so.
		778	- Increment loop iteration counter.
768	- Block the process, waiting for any events.	779	- Block the process, waiting for any events.
769	- Queue all outstanding I/O (fd) events.	780	- Queue all outstanding I/O (fd) events.
770	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	781	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
771	- Queue all expired timers.	782	- Queue all expired timers.
772	- Queue all expired periodics.	783	- Queue all expired periodics.
773	- Unless any events are pending now, queue all idle watchers.	784	- Queue all idle watchers with priority higher than that of pending events.
774	- Queue all check watchers.	785	- Queue all check watchers.
775	- Call all queued watchers in reverse order (i.e. check watchers first).	786	- Call all queued watchers in reverse order (i.e. check watchers first).
776	Signals and child watchers are implemented as I/O watchers, and will	787	Signals and child watchers are implemented as I/O watchers, and will
777	be handled here by queueing them when their watcher gets executed.	788	be handled here by queueing them when their watcher gets executed.
778	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	789	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
779	were used, or there are no active watchers, return, otherwise	790	were used, or there are no active watchers, goto FINISH, otherwise
780	continue with step *.	791	continue with step LOOP.
		792	FINISH:
		793	- Reset the ev_break status iff it was EVBREAK_ONE.
		794	- Decrement the loop depth.
		795	- Return.
781		796
782	Example: Queue some jobs and then loop until no events are outstanding	797	Example: Queue some jobs and then loop until no events are outstanding
783	anymore.	798	anymore.
784		799
785	... queue jobs here, make sure they register event watchers as long	800	... queue jobs here, make sure they register event watchers as long
786	... as they still have work to do (even an idle watcher will do..)	801	... as they still have work to do (even an idle watcher will do..)
787	ev_loop (my_loop, 0);	802	ev_run (my_loop, 0);
788	... jobs done or somebody called unloop. yeah!	803	... jobs done or somebody called unloop. yeah!
789		804
790	=item ev_unloop (loop, how)	805	=item ev_break (loop, how)
791		806
792	Can be used to make a call to C<ev_loop> return early (but only after it	807	Can be used to make a call to C<ev_run> return early (but only after it
793	has processed all outstanding events). The C<how> argument must be either	808	has processed all outstanding events). The C<how> argument must be either
794	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	809	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
795	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	810	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
796		811
797	This "unloop state" will be cleared when entering C<ev_loop> again.	812	This "unloop state" will be cleared when entering C<ev_run> again.
798		813
799	It is safe to call C<ev_unloop> from outside any C<ev_loop> calls.	814	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
800		815
801	=item ev_ref (loop)	816	=item ev_ref (loop)
802		817
803	=item ev_unref (loop)	818	=item ev_unref (loop)
804		819
805	Ref/unref can be used to add or remove a reference count on the event	820	Ref/unref can be used to add or remove a reference count on the event
806	loop: Every watcher keeps one reference, and as long as the reference	821	loop: Every watcher keeps one reference, and as long as the reference
807	count is nonzero, C<ev_loop> will not return on its own.	822	count is nonzero, C<ev_run> will not return on its own.
808		823
809	This is useful when you have a watcher that you never intend to	824	This is useful when you have a watcher that you never intend to
810	unregister, but that nevertheless should not keep C<ev_loop> from	825	unregister, but that nevertheless should not keep C<ev_run> from
811	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	826	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
812	before stopping it.	827	before stopping it.
813		828
814	As an example, libev itself uses this for its internal signal pipe: It	829	As an example, libev itself uses this for its internal signal pipe: It
815	is not visible to the libev user and should not keep C<ev_loop> from	830	is not visible to the libev user and should not keep C<ev_run> from
816	exiting if no event watchers registered by it are active. It is also an	831	exiting if no event watchers registered by it are active. It is also an
817	excellent way to do this for generic recurring timers or from within	832	excellent way to do this for generic recurring timers or from within
818	third-party libraries. Just remember to I<unref after start> and I<ref	833	third-party libraries. Just remember to I<unref after start> and I<ref
819	before stop> (but only if the watcher wasn't active before, or was active	834	before stop> (but only if the watcher wasn't active before, or was active
820	before, respectively. Note also that libev might stop watchers itself	835	before, respectively. Note also that libev might stop watchers itself
821	(e.g. non-repeating timers) in which case you have to C<ev_ref>	836	(e.g. non-repeating timers) in which case you have to C<ev_ref>
822	in the callback).	837	in the callback).
823		838
824	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	839	Example: Create a signal watcher, but keep it from keeping C<ev_run>
825	running when nothing else is active.	840	running when nothing else is active.
826		841
827	ev_signal exitsig;	842	ev_signal exitsig;
828	ev_signal_init (&exitsig, sig_cb, SIGINT);	843	ev_signal_init (&exitsig, sig_cb, SIGINT);
829	ev_signal_start (loop, &exitsig);	844	ev_signal_start (loop, &exitsig);
…		…
892	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	907	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
893		908
894	=item ev_invoke_pending (loop)	909	=item ev_invoke_pending (loop)
895		910
896	This call will simply invoke all pending watchers while resetting their	911	This call will simply invoke all pending watchers while resetting their
897	pending state. Normally, C<ev_loop> does this automatically when required,	912	pending state. Normally, C<ev_run> does this automatically when required,
898	but when overriding the invoke callback this call comes handy.	913	but when overriding the invoke callback this call comes handy. This
		914	function can be invoked from a watcher - this can be useful for example
		915	when you want to do some lengthy calculation and want to pass further
		916	event handling to another thread (you still have to make sure only one
		917	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
899		918
900	=item int ev_pending_count (loop)	919	=item int ev_pending_count (loop)
901		920
902	Returns the number of pending watchers - zero indicates that no watchers	921	Returns the number of pending watchers - zero indicates that no watchers
903	are pending.	922	are pending.
904		923
905	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	924	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
906		925
907	This overrides the invoke pending functionality of the loop: Instead of	926	This overrides the invoke pending functionality of the loop: Instead of
908	invoking all pending watchers when there are any, C<ev_loop> will call	927	invoking all pending watchers when there are any, C<ev_run> will call
909	this callback instead. This is useful, for example, when you want to	928	this callback instead. This is useful, for example, when you want to
910	invoke the actual watchers inside another context (another thread etc.).	929	invoke the actual watchers inside another context (another thread etc.).
911		930
912	If you want to reset the callback, use C<ev_invoke_pending> as new	931	If you want to reset the callback, use C<ev_invoke_pending> as new
913	callback.	932	callback.
…		…
916		935
917	Sometimes you want to share the same loop between multiple threads. This	936	Sometimes you want to share the same loop between multiple threads. This
918	can be done relatively simply by putting mutex_lock/unlock calls around	937	can be done relatively simply by putting mutex_lock/unlock calls around
919	each call to a libev function.	938	each call to a libev function.
920		939
921	However, C<ev_loop> can run an indefinite time, so it is not feasible to	940	However, C<ev_run> can run an indefinite time, so it is not feasible
922	wait for it to return. One way around this is to wake up the loop via	941	to wait for it to return. One way around this is to wake up the event
923	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	942	loop via C<ev_break> and C<av_async_send>, another way is to set these
924	and I<acquire> callbacks on the loop.	943	I<release> and I<acquire> callbacks on the loop.
925		944
926	When set, then C<release> will be called just before the thread is	945	When set, then C<release> will be called just before the thread is
927	suspended waiting for new events, and C<acquire> is called just	946	suspended waiting for new events, and C<acquire> is called just
928	afterwards.	947	afterwards.
929		948
…		…
932		951
933	While event loop modifications are allowed between invocations of	952	While event loop modifications are allowed between invocations of
934	C<release> and C<acquire> (that's their only purpose after all), no	953	C<release> and C<acquire> (that's their only purpose after all), no
935	modifications done will affect the event loop, i.e. adding watchers will	954	modifications done will affect the event loop, i.e. adding watchers will
936	have no effect on the set of file descriptors being watched, or the time	955	have no effect on the set of file descriptors being watched, or the time
937	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	956	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
938	to take note of any changes you made.	957	to take note of any changes you made.
939		958
940	In theory, threads executing C<ev_loop> will be async-cancel safe between	959	In theory, threads executing C<ev_run> will be async-cancel safe between
941	invocations of C<release> and C<acquire>.	960	invocations of C<release> and C<acquire>.
942		961
943	See also the locking example in the C<THREADS> section later in this	962	See also the locking example in the C<THREADS> section later in this
944	document.	963	document.
945		964
…		…
954	These two functions can be used to associate arbitrary data with a loop,	973	These two functions can be used to associate arbitrary data with a loop,
955	and are intended solely for the C<invoke_pending_cb>, C<release> and	974	and are intended solely for the C<invoke_pending_cb>, C<release> and
956	C<acquire> callbacks described above, but of course can be (ab-)used for	975	C<acquire> callbacks described above, but of course can be (ab-)used for
957	any other purpose as well.	976	any other purpose as well.
958		977
959	=item ev_loop_verify (loop)	978	=item ev_verify (loop)
960		979
961	This function only does something when C<EV_VERIFY> support has been	980	This function only does something when C<EV_VERIFY> support has been
962	compiled in, which is the default for non-minimal builds. It tries to go	981	compiled in, which is the default for non-minimal builds. It tries to go
963	through all internal structures and checks them for validity. If anything	982	through all internal structures and checks them for validity. If anything
964	is found to be inconsistent, it will print an error message to standard	983	is found to be inconsistent, it will print an error message to standard
…		…
975		994
976	In the following description, uppercase C<TYPE> in names stands for the	995	In the following description, uppercase C<TYPE> in names stands for the
977	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	996	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
978	watchers and C<ev_io_start> for I/O watchers.	997	watchers and C<ev_io_start> for I/O watchers.
979		998
980	A watcher is a structure that you create and register to record your	999	A watcher is an opaque structure that you allocate and register to record
981	interest in some event. For instance, if you want to wait for STDIN to	1000	your interest in some event. To make a concrete example, imagine you want
982	become readable, you would create an C<ev_io> watcher for that:	1001	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1002	for that:
983		1003
984	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1004	static void my_cb (struct ev_loop loop, ev_io w, int revents)
985	{	1005	{
986	ev_io_stop (w);	1006	ev_io_stop (w);
987	ev_unloop (loop, EVUNLOOP_ALL);	1007	ev_break (loop, EVBREAK_ALL);
988	}	1008	}
989		1009
990	struct ev_loop *loop = ev_default_loop (0);	1010	struct ev_loop *loop = ev_default_loop (0);
991		1011
992	ev_io stdin_watcher;	1012	ev_io stdin_watcher;
993		1013
994	ev_init (&stdin_watcher, my_cb);	1014	ev_init (&stdin_watcher, my_cb);
995	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1015	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
996	ev_io_start (loop, &stdin_watcher);	1016	ev_io_start (loop, &stdin_watcher);
997		1017
998	ev_loop (loop, 0);	1018	ev_run (loop, 0);
999		1019
1000	As you can see, you are responsible for allocating the memory for your	1020	As you can see, you are responsible for allocating the memory for your
1001	watcher structures (and it is I<usually> a bad idea to do this on the	1021	watcher structures (and it is I<usually> a bad idea to do this on the
1002	stack).	1022	stack).
1003		1023
1004	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1024	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1005	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1025	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1006		1026
1007	Each watcher structure must be initialised by a call to C<ev_init	1027	Each watcher structure must be initialised by a call to C<ev_init (watcher
1008	(watcher *, callback)>, which expects a callback to be provided. This	1028	*, callback)>, which expects a callback to be provided. This callback is
1009	callback gets invoked each time the event occurs (or, in the case of I/O	1029	invoked each time the event occurs (or, in the case of I/O watchers, each
1010	watchers, each time the event loop detects that the file descriptor given	1030	time the event loop detects that the file descriptor given is readable
1011	is readable and/or writable).	1031	and/or writable).
1012		1032
1013	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1033	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1014	macro to configure it, with arguments specific to the watcher type. There	1034	macro to configure it, with arguments specific to the watcher type. There
1015	is also a macro to combine initialisation and setting in one call: C<<	1035	is also a macro to combine initialisation and setting in one call: C<<
1016	ev_TYPE_init (watcher *, callback, ...) >>.	1036	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1067		1087
1068	=item C<EV_PREPARE>	1088	=item C<EV_PREPARE>
1069		1089
1070	=item C<EV_CHECK>	1090	=item C<EV_CHECK>
1071		1091
1072	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1092	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1073	to gather new events, and all C<ev_check> watchers are invoked just after	1093	to gather new events, and all C<ev_check> watchers are invoked just after
1074	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1094	C<ev_run> has gathered them, but before it invokes any callbacks for any
1075	received events. Callbacks of both watcher types can start and stop as	1095	received events. Callbacks of both watcher types can start and stop as
1076	many watchers as they want, and all of them will be taken into account	1096	many watchers as they want, and all of them will be taken into account
1077	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1097	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1078	C<ev_loop> from blocking).	1098	C<ev_run> from blocking).
1079		1099
1080	=item C<EV_EMBED>	1100	=item C<EV_EMBED>
1081		1101
1082	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1102	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1083		1103
…		…
1111	example it might indicate that a fd is readable or writable, and if your	1131	example it might indicate that a fd is readable or writable, and if your
1112	callbacks is well-written it can just attempt the operation and cope with	1132	callbacks is well-written it can just attempt the operation and cope with
1113	the error from read() or write(). This will not work in multi-threaded	1133	the error from read() or write(). This will not work in multi-threaded
1114	programs, though, as the fd could already be closed and reused for another	1134	programs, though, as the fd could already be closed and reused for another
1115	thing, so beware.	1135	thing, so beware.
		1136
		1137	=back
		1138
		1139	=head2 WATCHER STATES
		1140
		1141	There are various watcher states mentioned throughout this manual -
		1142	active, pending and so on. In this section these states and the rules to
		1143	transition between them will be described in more detail - and while these
		1144	rules might look complicated, they usually do "the right thing".
		1145
		1146	=over 4
		1147
		1148	=item initialiased
		1149
		1150	Before a watcher can be registered with the event looop it has to be
		1151	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1152	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1153
		1154	In this state it is simply some block of memory that is suitable for use
		1155	in an event loop. It can be moved around, freed, reused etc. at will.
		1156
		1157	=item started/running/active
		1158
		1159	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1160	property of the event loop, and is actively waiting for events. While in
		1161	this state it cannot be accessed (except in a few documented ways), moved,
		1162	freed or anything else - the only legal thing is to keep a pointer to it,
		1163	and call libev functions on it that are documented to work on active watchers.
		1164
		1165	=item pending
		1166
		1167	If a watcher is active and libev determines that an event it is interested
		1168	in has occurred (such as a timer expiring), it will become pending. It will
		1169	stay in this pending state until either it is stopped or its callback is
		1170	about to be invoked, so it is not normally pending inside the watcher
		1171	callback.
		1172
		1173	The watcher might or might not be active while it is pending (for example,
		1174	an expired non-repeating timer can be pending but no longer active). If it
		1175	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1176	but it is still property of the event loop at this time, so cannot be
		1177	moved, freed or reused. And if it is active the rules described in the
		1178	previous item still apply.
		1179
		1180	It is also possible to feed an event on a watcher that is not active (e.g.
		1181	via C<ev_feed_event>), in which case it becomes pending without being
		1182	active.
		1183
		1184	=item stopped
		1185
		1186	A watcher can be stopped implicitly by libev (in which case it might still
		1187	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1188	latter will clear any pending state the watcher might be in, regardless
		1189	of whether it was active or not, so stopping a watcher explicitly before
		1190	freeing it is often a good idea.
		1191
		1192	While stopped (and not pending) the watcher is essentially in the
		1193	initialised state, that is it can be reused, moved, modified in any way
		1194	you wish.
1116		1195
1117	=back	1196	=back
1118		1197
1119	=head2 GENERIC WATCHER FUNCTIONS	1198	=head2 GENERIC WATCHER FUNCTIONS
1120		1199
…		…
1624	...	1703	...
1625	struct ev_loop *loop = ev_default_init (0);	1704	struct ev_loop *loop = ev_default_init (0);
1626	ev_io stdin_readable;	1705	ev_io stdin_readable;
1627	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1706	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1628	ev_io_start (loop, &stdin_readable);	1707	ev_io_start (loop, &stdin_readable);
1629	ev_loop (loop, 0);	1708	ev_run (loop, 0);
1630		1709
1631		1710
1632	=head2 C<ev_timer> - relative and optionally repeating timeouts	1711	=head2 C<ev_timer> - relative and optionally repeating timeouts
1633		1712
1634	Timer watchers are simple relative timers that generate an event after a	1713	Timer watchers are simple relative timers that generate an event after a
…		…
1643	The callback is guaranteed to be invoked only I<after> its timeout has	1722	The callback is guaranteed to be invoked only I<after> its timeout has
1644	passed (not I<at>, so on systems with very low-resolution clocks this	1723	passed (not I<at>, so on systems with very low-resolution clocks this
1645	might introduce a small delay). If multiple timers become ready during the	1724	might introduce a small delay). If multiple timers become ready during the
1646	same loop iteration then the ones with earlier time-out values are invoked	1725	same loop iteration then the ones with earlier time-out values are invoked
1647	before ones of the same priority with later time-out values (but this is	1726	before ones of the same priority with later time-out values (but this is
1648	no longer true when a callback calls C<ev_loop> recursively).	1727	no longer true when a callback calls C<ev_run> recursively).
1649		1728
1650	=head3 Be smart about timeouts	1729	=head3 Be smart about timeouts
1651		1730
1652	Many real-world problems involve some kind of timeout, usually for error	1731	Many real-world problems involve some kind of timeout, usually for error
1653	recovery. A typical example is an HTTP request - if the other side hangs,	1732	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1824		1903
1825	=head3 The special problem of time updates	1904	=head3 The special problem of time updates
1826		1905
1827	Establishing the current time is a costly operation (it usually takes at	1906	Establishing the current time is a costly operation (it usually takes at
1828	least two system calls): EV therefore updates its idea of the current	1907	least two system calls): EV therefore updates its idea of the current
1829	time only before and after C<ev_loop> collects new events, which causes a	1908	time only before and after C<ev_run> collects new events, which causes a
1830	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1909	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1831	lots of events in one iteration.	1910	lots of events in one iteration.
1832		1911
1833	The relative timeouts are calculated relative to the C<ev_now ()>	1912	The relative timeouts are calculated relative to the C<ev_now ()>
1834	time. This is usually the right thing as this timestamp refers to the time	1913	time. This is usually the right thing as this timestamp refers to the time
…		…
1951	}	2030	}
1952		2031
1953	ev_timer mytimer;	2032	ev_timer mytimer;
1954	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2033	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1955	ev_timer_again (&mytimer); /* start timer */	2034	ev_timer_again (&mytimer); /* start timer */
1956	ev_loop (loop, 0);	2035	ev_run (loop, 0);
1957		2036
1958	// and in some piece of code that gets executed on any "activity":	2037	// and in some piece of code that gets executed on any "activity":
1959	// reset the timeout to start ticking again at 10 seconds	2038	// reset the timeout to start ticking again at 10 seconds
1960	ev_timer_again (&mytimer);	2039	ev_timer_again (&mytimer);
1961		2040
…		…
1987		2066
1988	As with timers, the callback is guaranteed to be invoked only when the	2067	As with timers, the callback is guaranteed to be invoked only when the
1989	point in time where it is supposed to trigger has passed. If multiple	2068	point in time where it is supposed to trigger has passed. If multiple
1990	timers become ready during the same loop iteration then the ones with	2069	timers become ready during the same loop iteration then the ones with
1991	earlier time-out values are invoked before ones with later time-out values	2070	earlier time-out values are invoked before ones with later time-out values
1992	(but this is no longer true when a callback calls C<ev_loop> recursively).	2071	(but this is no longer true when a callback calls C<ev_run> recursively).
1993		2072
1994	=head3 Watcher-Specific Functions and Data Members	2073	=head3 Watcher-Specific Functions and Data Members
1995		2074
1996	=over 4	2075	=over 4
1997		2076
…		…
2235	Example: Try to exit cleanly on SIGINT.	2314	Example: Try to exit cleanly on SIGINT.
2236		2315
2237	static void	2316	static void
2238	sigint_cb (struct ev_loop loop, ev_signal w, int revents)	2317	sigint_cb (struct ev_loop loop, ev_signal w, int revents)
2239	{	2318	{
2240	ev_unloop (loop, EVUNLOOP_ALL);	2319	ev_break (loop, EVBREAK_ALL);
2241	}	2320	}
2242		2321
2243	ev_signal signal_watcher;	2322	ev_signal signal_watcher;
2244	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2323	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2245	ev_signal_start (loop, &signal_watcher);	2324	ev_signal_start (loop, &signal_watcher);
…		…
2631		2710
2632	Prepare and check watchers are usually (but not always) used in pairs:	2711	Prepare and check watchers are usually (but not always) used in pairs:
2633	prepare watchers get invoked before the process blocks and check watchers	2712	prepare watchers get invoked before the process blocks and check watchers
2634	afterwards.	2713	afterwards.
2635		2714
2636	You I<must not> call C<ev_loop> or similar functions that enter	2715	You I<must not> call C<ev_run> or similar functions that enter
2637	the current event loop from either C<ev_prepare> or C<ev_check>	2716	the current event loop from either C<ev_prepare> or C<ev_check>
2638	watchers. Other loops than the current one are fine, however. The	2717	watchers. Other loops than the current one are fine, however. The
2639	rationale behind this is that you do not need to check for recursion in	2718	rationale behind this is that you do not need to check for recursion in
2640	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2719	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2641	C<ev_check> so if you have one watcher of each kind they will always be	2720	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2809		2888
2810	if (timeout >= 0)	2889	if (timeout >= 0)
2811	// create/start timer	2890	// create/start timer
2812		2891
2813	// poll	2892	// poll
2814	ev_loop (EV_A_ 0);	2893	ev_run (EV_A_ 0);
2815		2894
2816	// stop timer again	2895	// stop timer again
2817	if (timeout >= 0)	2896	if (timeout >= 0)
2818	ev_timer_stop (EV_A_ &to);	2897	ev_timer_stop (EV_A_ &to);
2819		2898
…		…
2897	if you do not want that, you need to temporarily stop the embed watcher).	2976	if you do not want that, you need to temporarily stop the embed watcher).
2898		2977
2899	=item ev_embed_sweep (loop, ev_embed *)	2978	=item ev_embed_sweep (loop, ev_embed *)
2900		2979
2901	Make a single, non-blocking sweep over the embedded loop. This works	2980	Make a single, non-blocking sweep over the embedded loop. This works
2902	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2981	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2903	appropriate way for embedded loops.	2982	appropriate way for embedded loops.
2904		2983
2905	=item struct ev_loop *other [read-only]	2984	=item struct ev_loop *other [read-only]
2906		2985
2907	The embedded event loop.	2986	The embedded event loop.
…		…
3013	=back	3092	=back
3014		3093
3015		3094
3016	=head2 C<ev_async> - how to wake up an event loop	3095	=head2 C<ev_async> - how to wake up an event loop
3017		3096
3018	In general, you cannot use an C<ev_loop> from multiple threads or other	3097	In general, you cannot use an C<ev_run> from multiple threads or other
3019	asynchronous sources such as signal handlers (as opposed to multiple event	3098	asynchronous sources such as signal handlers (as opposed to multiple event
3020	loops - those are of course safe to use in different threads).	3099	loops - those are of course safe to use in different threads).
3021		3100
3022	Sometimes, however, you need to wake up an event loop you do not control,	3101	Sometimes, however, you need to wake up an event loop you do not control,
3023	for example because it belongs to another thread. This is what C<ev_async>	3102	for example because it belongs to another thread. This is what C<ev_async>
…		…
3391	Associates a different C<struct ev_loop> with this watcher. You can only	3470	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).	3471	do this when the watcher is inactive (and not pending either).
3393		3472
3394	=item w->set ([arguments])	3473	=item w->set ([arguments])
3395		3474
3396	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3475	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	3476	method or a suitable start method must be called at least once. Unlike the
3398	automatically stopped and restarted when reconfiguring it with this	3477	C counterpart, an active watcher gets automatically stopped and restarted
3399	method.	3478	when reconfiguring it with this method.
3400		3479
3401	=item w->start ()	3480	=item w->start ()
3402		3481
3403	Starts the watcher. Note that there is no C<loop> argument, as the	3482	Starts the watcher. Note that there is no C<loop> argument, as the
3404	constructor already stores the event loop.	3483	constructor already stores the event loop.
3405		3484
		3485	=item w->start ([arguments])
		3486
		3487	Instead of calling C<set> and C<start> methods separately, it is often
		3488	convenient to wrap them in one call. Uses the same type of arguments as
		3489	the configure C<set> method of the watcher.
		3490
3406	=item w->stop ()	3491	=item w->stop ()
3407		3492
3408	Stops the watcher if it is active. Again, no C<loop> argument.	3493	Stops the watcher if it is active. Again, no C<loop> argument.
3409		3494
3410	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3495	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3422		3507
3423	=back	3508	=back
3424		3509
3425	=back	3510	=back
3426		3511
3427	Example: Define a class with an IO and idle watcher, start one of them in	3512	Example: Define a class with two I/O and idle watchers, start the I/O
3428	the constructor.	3513	watchers in the constructor.
3429		3514
3430	class myclass	3515	class myclass
3431	{	3516	{
3432	ev::io io ; void io_cb (ev::io &w, int revents);	3517	ev::io io ; void io_cb (ev::io &w, int revents);
		3518	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3433	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3519	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3434		3520
3435	myclass (int fd)	3521	myclass (int fd)
3436	{	3522	{
3437	io .set <myclass, &myclass::io_cb > (this);	3523	io .set <myclass, &myclass::io_cb > (this);
		3524	io2 .set <myclass, &myclass::io2_cb > (this);
3438	idle.set <myclass, &myclass::idle_cb> (this);	3525	idle.set <myclass, &myclass::idle_cb> (this);
3439		3526
3440	io.start (fd, ev::READ);	3527	io.set (fd, ev::WRITE); // configure the watcher
		3528	io.start (); // start it whenever convenient
		3529
		3530	io2.start (fd, ev::READ); // set + start in one call
3441	}	3531	}
3442	};	3532	};
3443		3533
3444		3534
3445	=head1 OTHER LANGUAGE BINDINGS	3535	=head1 OTHER LANGUAGE BINDINGS
…		…
3519	loop argument"). The C<EV_A> form is used when this is the sole argument,	3609	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:	3610	C<EV_A_> is used when other arguments are following. Example:
3521		3611
3522	ev_unref (EV_A);	3612	ev_unref (EV_A);
3523	ev_timer_add (EV_A_ watcher);	3613	ev_timer_add (EV_A_ watcher);
3524	ev_loop (EV_A_ 0);	3614	ev_run (EV_A_ 0);
3525		3615
3526	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3616	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3527	which is often provided by the following macro.	3617	which is often provided by the following macro.
3528		3618
3529	=item C<EV_P>, C<EV_P_>	3619	=item C<EV_P>, C<EV_P_>
…		…
3569	}	3659	}
3570		3660
3571	ev_check check;	3661	ev_check check;
3572	ev_check_init (&check, check_cb);	3662	ev_check_init (&check, check_cb);
3573	ev_check_start (EV_DEFAULT_ &check);	3663	ev_check_start (EV_DEFAULT_ &check);
3574	ev_loop (EV_DEFAULT_ 0);	3664	ev_run (EV_DEFAULT_ 0);
3575		3665
3576	=head1 EMBEDDING	3666	=head1 EMBEDDING
3577		3667
3578	Libev can (and often is) directly embedded into host	3668	Libev can (and often is) directly embedded into host
3579	applications. Examples of applications that embed it include the Deliantra	3669	applications. Examples of applications that embed it include the Deliantra
…		…
3670	to a compiled library. All other symbols change the ABI, which means all	3760	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	3761	users of libev and the libev code itself must be compiled with compatible
3672	settings.	3762	settings.
3673		3763
3674	=over 4	3764	=over 4
		3765
		3766	=item EV_COMPAT3 (h)
		3767
		3768	Backwards compatibility is a major concern for libev. This is why this
		3769	release of libev comes with wrappers for the functions and symbols that
		3770	have been renamed between libev version 3 and 4.
		3771
		3772	You can disable these wrappers (to test compatibility with future
		3773	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3774	sources. This has the additional advantage that you can drop the C<struct>
		3775	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3776	typedef in that case.
		3777
		3778	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3779	and in some even more future version the compatibility code will be
		3780	removed completely.
3675		3781
3676	=item EV_STANDALONE (h)	3782	=item EV_STANDALONE (h)
3677		3783
3678	Must always be C<1> if you do not use autoconf configuration, which	3784	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	3785	keeps libev from including F<config.h>, and it also defines dummy
…		…
4029	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4135	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4030	will be C<0>.	4136	will be C<0>.
4031		4137
4032	=item EV_VERIFY	4138	=item EV_VERIFY
4033		4139
4034	Controls how much internal verification (see C<ev_loop_verify ()>) will	4140	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	4141	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	4142	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	4143	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	4144	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	4145	verification code will be called very frequently, which will slow down
…		…
4254	userdata *u = ev_userdata (EV_A);	4360	userdata *u = ev_userdata (EV_A);
4255	pthread_mutex_lock (&u->lock);	4361	pthread_mutex_lock (&u->lock);
4256	}	4362	}
4257		4363
4258	The event loop thread first acquires the mutex, and then jumps straight	4364	The event loop thread first acquires the mutex, and then jumps straight
4259	into C<ev_loop>:	4365	into C<ev_run>:
4260		4366
4261	void *	4367	void *
4262	l_run (void *thr_arg)	4368	l_run (void *thr_arg)
4263	{	4369	{
4264	struct ev_loop loop = (struct ev_loop )thr_arg;	4370	struct ev_loop loop = (struct ev_loop )thr_arg;
4265		4371
4266	l_acquire (EV_A);	4372	l_acquire (EV_A);
4267	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4373	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4268	ev_loop (EV_A_ 0);	4374	ev_run (EV_A_ 0);
4269	l_release (EV_A);	4375	l_release (EV_A);
4270		4376
4271	return 0;	4377	return 0;
4272	}	4378	}
4273		4379
…		…
4325		4431
4326	=head3 COROUTINES	4432	=head3 COROUTINES
4327		4433
4328	Libev is very accommodating to coroutines ("cooperative threads"):	4434	Libev is very accommodating to coroutines ("cooperative threads"):
4329	libev fully supports nesting calls to its functions from different	4435	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	4436	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	4437	different coroutines, and switch freely between both coroutines running
4332	the loop, as long as you don't confuse yourself). The only exception is	4438	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.	4439	that you must not do this from C<ev_periodic> reschedule callbacks.
4334		4440
4335	Care has been taken to ensure that libev does not keep local state inside	4441	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	4442	C<ev_run>, and other calls do not usually allow for coroutine switches as
4337	they do not call any callbacks.	4443	they do not call any callbacks.
4338		4444
4339	=head2 COMPILER WARNINGS	4445	=head2 COMPILER WARNINGS
4340		4446
4341	Depending on your compiler and compiler settings, you might get no or a	4447	Depending on your compiler and compiler settings, you might get no or a
…		…
4425	=head3 C<kqueue> is buggy	4531	=head3 C<kqueue> is buggy
4426		4532
4427	The kqueue syscall is broken in all known versions - most versions support	4533	The kqueue syscall is broken in all known versions - most versions support
4428	only sockets, many support pipes.	4534	only sockets, many support pipes.
4429		4535
4430	Libev tries to work around this by not using C<kqueue> by default on	4536	Libev tries to work around this by not using C<kqueue> by default on this
4431	this rotten platform, but of course you can still ask for it when creating	4537	rotten platform, but of course you can still ask for it when creating a
4432	a loop.	4538	loop - embedding a socket-only kqueue loop into a select-based one is
		4539	probably going to work well.
4433		4540
4434	=head3 C<poll> is buggy	4541	=head3 C<poll> is buggy
4435		4542
4436	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>	4543	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
4437	implementation by something calling C<kqueue> internally around the 10.5.6	4544	implementation by something calling C<kqueue> internally around the 10.5.6
…		…
4456		4563
4457	=head3 C<errno> reentrancy	4564	=head3 C<errno> reentrancy
4458		4565
4459	The default compile environment on Solaris is unfortunately so	4566	The default compile environment on Solaris is unfortunately so
4460	thread-unsafe that you can't even use components/libraries compiled	4567	thread-unsafe that you can't even use components/libraries compiled
4461	without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,	4568	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
4462	isn't defined by default.	4569	defined by default. A valid, if stupid, implementation choice.
4463		4570
4464	If you want to use libev in threaded environments you have to make sure	4571	If you want to use libev in threaded environments you have to make sure
4465	it's compiled with C<_REENTRANT> defined.	4572	it's compiled with C<_REENTRANT> defined.
4466		4573
4467	=head3 Event port backend	4574	=head3 Event port backend
4468		4575
4469	The scalable event interface for Solaris is called "event ports". Unfortunately,	4576	The scalable event interface for Solaris is called "event
4470	this mechanism is very buggy. If you run into high CPU usage, your program	4577	ports". Unfortunately, this mechanism is very buggy in all major
		4578	releases. If you run into high CPU usage, your program freezes or you get
4471	freezes or you get a large number of spurious wakeups, make sure you have	4579	a large number of spurious wakeups, make sure you have all the relevant
4472	all the relevant and latest kernel patches applied. No, I don't know which	4580	and latest kernel patches applied. No, I don't know which ones, but there
4473	ones, but there are multiple ones.	4581	are multiple ones to apply, and afterwards, event ports actually work
		4582	great.
4474		4583
4475	If you can't get it to work, you can try running the program by setting	4584	If you can't get it to work, you can try running the program by setting
4476	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and	4585	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
4477	C<select> backends.	4586	C<select> backends.
4478		4587
4479	=head2 AIX POLL BUG	4588	=head2 AIX POLL BUG
4480		4589
4481	AIX unfortunately has a broken C<poll.h> header. Libev works around	4590	AIX unfortunately has a broken C<poll.h> header. Libev works around
4482	this by trying to avoid the poll backend altogether (i.e. it's not even	4591	this by trying to avoid the poll backend altogether (i.e. it's not even
4483	compiled in), which normally isn't a big problem as C<select> works fine	4592	compiled in), which normally isn't a big problem as C<select> works fine
4484	with large bitsets, and AIX is dead anyway.	4593	with large bitsets on AIX, and AIX is dead anyway.
4485		4594
4486	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4595	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
4487		4596
4488	=head3 General issues	4597	=head3 General issues
4489		4598
…		…
4626	watchers.	4735	watchers.
4627		4736
4628	=item C<double> must hold a time value in seconds with enough accuracy	4737	=item C<double> must hold a time value in seconds with enough accuracy
4629		4738
4630	The type C<double> is used to represent timestamps. It is required to	4739	The type C<double> is used to represent timestamps. It is required to
4631	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4740	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4632	enough for at least into the year 4000. This requirement is fulfilled by	4741	good enough for at least into the year 4000 with millisecond accuracy
		4742	(the design goal for libev). This requirement is overfulfilled by
4633	implementations implementing IEEE 754, which is basically all existing	4743	implementations using IEEE 754, which is basically all existing ones. With
4634	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4744	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4635	2200.
4636		4745
4637	=back	4746	=back
4638		4747
4639	If you know of other additional requirements drop me a note.	4748	If you know of other additional requirements drop me a note.
4640		4749
…		…
4718	compatibility, so most programs should still compile. Those might be	4827	compatibility, so most programs should still compile. Those might be
4719	removed in later versions of libev, so better update early than late.	4828	removed in later versions of libev, so better update early than late.
4720		4829
4721	=over 4	4830	=over 4
4722		4831
4723	=item C<ev_loop_count> renamed to C<ev_iteration>	4832	=item function/symbol renames
4724		4833
4725	=item C<ev_loop_depth> renamed to C<ev_depth>	4834	A number of functions and symbols have been renamed:
4726		4835
4727	=item C<ev_loop_verify> renamed to C<ev_verify>	4836	ev_loop => ev_run
		4837	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4838	EVLOOP_ONESHOT => EVRUN_ONCE
		4839
		4840	ev_unloop => ev_break
		4841	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4842	EVUNLOOP_ONE => EVBREAK_ONE
		4843	EVUNLOOP_ALL => EVBREAK_ALL
		4844
		4845	EV_TIMEOUT => EV_TIMER
		4846
		4847	ev_loop_count => ev_iteration
		4848	ev_loop_depth => ev_depth
		4849	ev_loop_verify => ev_verify
4728		4850
4729	Most functions working on C<struct ev_loop> objects don't have an	4851	Most functions working on C<struct ev_loop> objects don't have an
4730	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is	4852	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4853	associated constants have been renamed to not collide with the C<struct
		4854	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4855	as all other watcher types. Note that C<ev_loop_fork> is still called
4731	still called C<ev_loop_fork> because it would otherwise clash with the	4856	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4732	C<ev_fork> typedef.	4857	typedef.
4733		4858
4734	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>	4859	=item C<EV_COMPAT3> backwards compatibility mechanism
4735		4860
4736	This is a simple rename - all other watcher types use their name	4861	The backward compatibility mechanism can be controlled by
4737	as revents flag, and now C<ev_timer> does, too.	4862	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4738		4863	section.
4739	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4740	and continue to be present for the foreseeable future, so this is mostly a
4741	documentation change.
4742		4864
4743	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4865	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4744		4866
4745	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4867	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4746	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4868	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4753		4875
4754	=over 4	4876	=over 4
4755		4877
4756	=item active	4878	=item active
4757		4879
4758	A watcher is active as long as it has been started (has been attached to	4880	A watcher is active as long as it has been started and not yet stopped.
4759	an event loop) but not yet stopped (disassociated from the event loop).	4881	See L<WATCHER STATES> for details.
4760		4882
4761	=item application	4883	=item application
4762		4884
4763	In this document, an application is whatever is using libev.	4885	In this document, an application is whatever is using libev.
		4886
		4887	=item backend
		4888
		4889	The part of the code dealing with the operating system interfaces.
4764		4890
4765	=item callback	4891	=item callback
4766		4892
4767	The address of a function that is called when some event has been	4893	The address of a function that is called when some event has been
4768	detected. Callbacks are being passed the event loop, the watcher that	4894	detected. Callbacks are being passed the event loop, the watcher that
4769	received the event, and the actual event bitset.	4895	received the event, and the actual event bitset.
4770		4896
4771	=item callback invocation	4897	=item callback/watcher invocation
4772		4898
4773	The act of calling the callback associated with a watcher.	4899	The act of calling the callback associated with a watcher.
4774		4900
4775	=item event	4901	=item event
4776		4902
…		…
4795	The model used to describe how an event loop handles and processes	4921	The model used to describe how an event loop handles and processes
4796	watchers and events.	4922	watchers and events.
4797		4923
4798	=item pending	4924	=item pending
4799		4925
4800	A watcher is pending as soon as the corresponding event has been detected,	4926	A watcher is pending as soon as the corresponding event has been
4801	and stops being pending as soon as the watcher will be invoked or its	4927	detected. See L<WATCHER STATES> for details.
4802	pending status is explicitly cleared by the application.
4803
4804	A watcher can be pending, but not active. Stopping a watcher also clears
4805	its pending status.
4806		4928
4807	=item real time	4929	=item real time
4808		4930
4809	The physical time that is observed. It is apparently strictly monotonic :)	4931	The physical time that is observed. It is apparently strictly monotonic :)
4810		4932
…		…
4817	=item watcher	4939	=item watcher
4818		4940
4819	A data structure that describes interest in certain events. Watchers need	4941	A data structure that describes interest in certain events. Watchers need
4820	to be started (attached to an event loop) before they can receive events.	4942	to be started (attached to an event loop) before they can receive events.
4821		4943
4822	=item watcher invocation
4823
4824	The act of calling the callback associated with a watcher.
4825
4826	=back	4944	=back
4827		4945
4828	=head1 AUTHOR	4946	=head1 AUTHOR
4829		4947
4830	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4948	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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Comparing libev/ev.pod (file contents): Revision 1.306 by root, Mon Oct 18 07:36:05 2010 UTC vs. Revision 1.316 by root, Fri Oct 22 09:34:01 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.306 by root, Mon Oct 18 07:36:05 2010 UTC vs.
Revision 1.316 by root, Fri Oct 22 09:34:01 2010 UTC