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

Comparing libev/ev.pod (file contents):
Revision 1.299 by sf-exg, Sat Aug 28 21:42:12 2010 UTC vs.
Revision 1.311 by root, Thu Oct 21 14:40:07 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
…		…
439	of course I<doesn't>, and epoll just loves to report events for totally	439	of course I<doesn't>, and epoll just loves to report events for totally
440	I<different> file descriptors (even already closed ones, so one cannot	440	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	441	even remove them from the set) than registered in the set (especially
442	on SMP systems). Libev tries to counter these spurious notifications by	442	on SMP systems). Libev tries to counter these spurious notifications by
443	employing an additional generation counter and comparing that against the	443	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required.	444	events to filter out spurious ones, recreating the set when required. Last
		445	not least, it also refuses to work with some file descriptors which work
		446	perfectly fine with C<select> (files, many character devices...).
445		447
446	While stopping, setting and starting an I/O watcher in the same iteration	448	While stopping, setting and starting an I/O watcher in the same iteration
447	will result in some caching, there is still a system call per such	449	will result in some caching, there is still a system call per such
448	incident (because the same I<file descriptor> could point to a different	450	incident (because the same I<file descriptor> could point to a different
449	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	451	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
604	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
605	earlier call to C<ev_loop_new>.	607	earlier call to C<ev_loop_new>.
606		608
607	=item ev_default_fork ()	609	=item ev_default_fork ()
608		610
609	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
610	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
611	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
612	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
613	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
614	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.
615		617
616	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
617	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
618	because some kernel interfaces cough I<kqueue> cough do funny things	620	because some kernel interfaces cough I<kqueue> cough do funny things
619	during fork.	621	during fork.
620		622
621	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
622	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
623	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
624	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).
625		629
626	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
627	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
628	quite nicely into a call to C<pthread_atfork>:	632	quite nicely into a call to C<pthread_atfork>:
629		633
…		…
641	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
642	otherwise.	646	otherwise.
643		647
644	=item unsigned int ev_iteration (loop)	648	=item unsigned int ev_iteration (loop)
645		649
646	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
647	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>
648	happily wraps around with enough iterations.	652	and happily wraps around with enough iterations.
649		653
650	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
651	"ticks" the number of loop iterations), as it roughly corresponds with	655	"ticks" the number of loop iterations), as it roughly corresponds with
652	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
653	prepare and check phases.	657	prepare and check phases.
654		658
655	=item unsigned int ev_depth (loop)	659	=item unsigned int ev_depth (loop)
656		660
657	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
658	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.
659		663
660	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
661	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),
662	in which case it is higher.	666	in which case it is higher.
663		667
664	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	668	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
665	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
666	ungentleman behaviour unless it's really convenient.	670	ungentleman-like behaviour unless it's really convenient.
667		671
668	=item unsigned int ev_backend (loop)	672	=item unsigned int ev_backend (loop)
669		673
670	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
671	use.	675	use.
…		…
680		684
681	=item ev_now_update (loop)	685	=item ev_now_update (loop)
682		686
683	Establishes the current time by querying the kernel, updating the time	687	Establishes the current time by querying the kernel, updating the time
684	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
685	is usually done automatically within C<ev_loop ()>.	689	is usually done automatically within C<ev_run ()>.
686		690
687	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
688	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
689	the current time is a good idea.	693	the current time is a good idea.
690		694
…		…
692		696
693	=item ev_suspend (loop)	697	=item ev_suspend (loop)
694		698
695	=item ev_resume (loop)	699	=item ev_resume (loop)
696		700
697	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
698	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.
699		703
700	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
701	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
702	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
703	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>
…		…
714	without a previous call to C<ev_suspend>.	718	without a previous call to C<ev_suspend>.
715		719
716	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
717	event loop time (see C<ev_now_update>).	721	event loop time (see C<ev_now_update>).
718		722
719	=item ev_loop (loop, int flags)	723	=item ev_run (loop, int flags)
720		724
721	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
722	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
723	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>.
724		730
725	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
726	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.
727		734
728	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
729	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
730	finished (especially in interactive programs), but having a program	737	finished (especially in interactive programs), but having a program
731	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
732	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
733	beauty.	740	beauty.
734		741
735	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
736	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
737	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
738	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.
739		747
740	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
741	necessary) and will handle those and any already outstanding ones. It	749	necessary) and will handle those and any already outstanding ones. It
742	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
743	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
744	user-registered callback will be called), and will return after one	752	user-registered callback will be called), and will return after one
745	iteration of the loop.	753	iteration of the loop.
746		754
747	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
748	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
749	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
750	usually a better approach for this kind of thing.	758	usually a better approach for this kind of thing.
751		759
752	Here are the gory details of what C<ev_loop> does:	760	Here are the gory details of what C<ev_run> does:
753		761
		762	- Increment loop depth.
		763	- Reset the ev_break status.
754	- Before the first iteration, call any pending watchers.	764	- Before the first iteration, call any pending watchers.
		765	LOOP:
755	* If EVFLAG_FORKCHECK was used, check for a fork.	766	- If EVFLAG_FORKCHECK was used, check for a fork.
756	- 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.
757	- Queue and call all prepare watchers.	768	- Queue and call all prepare watchers.
		769	- If ev_break was called, goto FINISH.
758	- If we have been forked, detach and recreate the kernel state	770	- If we have been forked, detach and recreate the kernel state
759	as to not disturb the other process.	771	as to not disturb the other process.
760	- Update the kernel state with all outstanding changes.	772	- Update the kernel state with all outstanding changes.
761	- Update the "event loop time" (ev_now ()).	773	- Update the "event loop time" (ev_now ()).
762	- Calculate for how long to sleep or block, if at all	774	- Calculate for how long to sleep or block, if at all
763	(active idle watchers, EVLOOP_NONBLOCK or not having	775	(active idle watchers, EVRUN_NOWAIT or not having
764	any active watchers at all will result in not sleeping).	776	any active watchers at all will result in not sleeping).
765	- 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.
766	- Block the process, waiting for any events.	779	- Block the process, waiting for any events.
767	- Queue all outstanding I/O (fd) events.	780	- Queue all outstanding I/O (fd) events.
768	- 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.
769	- Queue all expired timers.	782	- Queue all expired timers.
770	- Queue all expired periodics.	783	- Queue all expired periodics.
771	- Unless any events are pending now, queue all idle watchers.	784	- Queue all idle watchers with priority higher than that of pending events.
772	- Queue all check watchers.	785	- Queue all check watchers.
773	- 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).
774	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
775	be handled here by queueing them when their watcher gets executed.	788	be handled here by queueing them when their watcher gets executed.
776	- 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
777	were used, or there are no active watchers, return, otherwise	790	were used, or there are no active watchers, goto FINISH, otherwise
778	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.
779		796
780	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
781	anymore.	798	anymore.
782		799
783	... queue jobs here, make sure they register event watchers as long	800	... queue jobs here, make sure they register event watchers as long
784	... 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..)
785	ev_loop (my_loop, 0);	802	ev_run (my_loop, 0);
786	... jobs done or somebody called unloop. yeah!	803	... jobs done or somebody called unloop. yeah!
787		804
788	=item ev_unloop (loop, how)	805	=item ev_break (loop, how)
789		806
790	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
791	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
792	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
793	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.
794		811
795	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.
796		813
797	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##
798		815
799	=item ev_ref (loop)	816	=item ev_ref (loop)
800		817
801	=item ev_unref (loop)	818	=item ev_unref (loop)
802		819
803	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
804	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
805	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.
806		823
807	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
808	unregister, but that nevertheless should not keep C<ev_loop> from	825	unregister, but that nevertheless should not keep C<ev_run> from
809	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>
810	before stopping it.	827	before stopping it.
811		828
812	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
813	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
814	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
815	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
816	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
817	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
818	before, respectively. Note also that libev might stop watchers itself	835	before, respectively. Note also that libev might stop watchers itself
819	(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>
820	in the callback).	837	in the callback).
821		838
822	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>
823	running when nothing else is active.	840	running when nothing else is active.
824		841
825	ev_signal exitsig;	842	ev_signal exitsig;
826	ev_signal_init (&exitsig, sig_cb, SIGINT);	843	ev_signal_init (&exitsig, sig_cb, SIGINT);
827	ev_signal_start (loop, &exitsig);	844	ev_signal_start (loop, &exitsig);
…		…
890	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	907	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
891		908
892	=item ev_invoke_pending (loop)	909	=item ev_invoke_pending (loop)
893		910
894	This call will simply invoke all pending watchers while resetting their	911	This call will simply invoke all pending watchers while resetting their
895	pending state. Normally, C<ev_loop> does this automatically when required,	912	pending state. Normally, C<ev_run> does this automatically when required,
896	but when overriding the invoke callback this call comes handy.	913	but when overriding the invoke callback this call comes handy.
897		914
898	=item int ev_pending_count (loop)	915	=item int ev_pending_count (loop)
899		916
900	Returns the number of pending watchers - zero indicates that no watchers	917	Returns the number of pending watchers - zero indicates that no watchers
901	are pending.	918	are pending.
902		919
903	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	920	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
904		921
905	This overrides the invoke pending functionality of the loop: Instead of	922	This overrides the invoke pending functionality of the loop: Instead of
906	invoking all pending watchers when there are any, C<ev_loop> will call	923	invoking all pending watchers when there are any, C<ev_run> will call
907	this callback instead. This is useful, for example, when you want to	924	this callback instead. This is useful, for example, when you want to
908	invoke the actual watchers inside another context (another thread etc.).	925	invoke the actual watchers inside another context (another thread etc.).
909		926
910	If you want to reset the callback, use C<ev_invoke_pending> as new	927	If you want to reset the callback, use C<ev_invoke_pending> as new
911	callback.	928	callback.
…		…
914		931
915	Sometimes you want to share the same loop between multiple threads. This	932	Sometimes you want to share the same loop between multiple threads. This
916	can be done relatively simply by putting mutex_lock/unlock calls around	933	can be done relatively simply by putting mutex_lock/unlock calls around
917	each call to a libev function.	934	each call to a libev function.
918		935
919	However, C<ev_loop> can run an indefinite time, so it is not feasible to	936	However, C<ev_run> can run an indefinite time, so it is not feasible
920	wait for it to return. One way around this is to wake up the loop via	937	to wait for it to return. One way around this is to wake up the event
921	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	938	loop via C<ev_break> and C<av_async_send>, another way is to set these
922	and I<acquire> callbacks on the loop.	939	I<release> and I<acquire> callbacks on the loop.
923		940
924	When set, then C<release> will be called just before the thread is	941	When set, then C<release> will be called just before the thread is
925	suspended waiting for new events, and C<acquire> is called just	942	suspended waiting for new events, and C<acquire> is called just
926	afterwards.	943	afterwards.
927		944
…		…
930		947
931	While event loop modifications are allowed between invocations of	948	While event loop modifications are allowed between invocations of
932	C<release> and C<acquire> (that's their only purpose after all), no	949	C<release> and C<acquire> (that's their only purpose after all), no
933	modifications done will affect the event loop, i.e. adding watchers will	950	modifications done will affect the event loop, i.e. adding watchers will
934	have no effect on the set of file descriptors being watched, or the time	951	have no effect on the set of file descriptors being watched, or the time
935	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	952	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
936	to take note of any changes you made.	953	to take note of any changes you made.
937		954
938	In theory, threads executing C<ev_loop> will be async-cancel safe between	955	In theory, threads executing C<ev_run> will be async-cancel safe between
939	invocations of C<release> and C<acquire>.	956	invocations of C<release> and C<acquire>.
940		957
941	See also the locking example in the C<THREADS> section later in this	958	See also the locking example in the C<THREADS> section later in this
942	document.	959	document.
943		960
…		…
952	These two functions can be used to associate arbitrary data with a loop,	969	These two functions can be used to associate arbitrary data with a loop,
953	and are intended solely for the C<invoke_pending_cb>, C<release> and	970	and are intended solely for the C<invoke_pending_cb>, C<release> and
954	C<acquire> callbacks described above, but of course can be (ab-)used for	971	C<acquire> callbacks described above, but of course can be (ab-)used for
955	any other purpose as well.	972	any other purpose as well.
956		973
957	=item ev_loop_verify (loop)	974	=item ev_verify (loop)
958		975
959	This function only does something when C<EV_VERIFY> support has been	976	This function only does something when C<EV_VERIFY> support has been
960	compiled in, which is the default for non-minimal builds. It tries to go	977	compiled in, which is the default for non-minimal builds. It tries to go
961	through all internal structures and checks them for validity. If anything	978	through all internal structures and checks them for validity. If anything
962	is found to be inconsistent, it will print an error message to standard	979	is found to be inconsistent, it will print an error message to standard
…		…
973		990
974	In the following description, uppercase C<TYPE> in names stands for the	991	In the following description, uppercase C<TYPE> in names stands for the
975	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	992	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
976	watchers and C<ev_io_start> for I/O watchers.	993	watchers and C<ev_io_start> for I/O watchers.
977		994
978	A watcher is a structure that you create and register to record your	995	A watcher is an opaque structure that you allocate and register to record
979	interest in some event. For instance, if you want to wait for STDIN to	996	your interest in some event. To make a concrete example, imagine you want
980	become readable, you would create an C<ev_io> watcher for that:	997	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		998	for that:
981		999
982	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1000	static void my_cb (struct ev_loop loop, ev_io w, int revents)
983	{	1001	{
984	ev_io_stop (w);	1002	ev_io_stop (w);
985	ev_unloop (loop, EVUNLOOP_ALL);	1003	ev_break (loop, EVBREAK_ALL);
986	}	1004	}
987		1005
988	struct ev_loop *loop = ev_default_loop (0);	1006	struct ev_loop *loop = ev_default_loop (0);
989		1007
990	ev_io stdin_watcher;	1008	ev_io stdin_watcher;
991		1009
992	ev_init (&stdin_watcher, my_cb);	1010	ev_init (&stdin_watcher, my_cb);
993	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1011	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
994	ev_io_start (loop, &stdin_watcher);	1012	ev_io_start (loop, &stdin_watcher);
995		1013
996	ev_loop (loop, 0);	1014	ev_run (loop, 0);
997		1015
998	As you can see, you are responsible for allocating the memory for your	1016	As you can see, you are responsible for allocating the memory for your
999	watcher structures (and it is I<usually> a bad idea to do this on the	1017	watcher structures (and it is I<usually> a bad idea to do this on the
1000	stack).	1018	stack).
1001		1019
1002	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1020	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1003	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1021	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1004		1022
1005	Each watcher structure must be initialised by a call to C<ev_init	1023	Each watcher structure must be initialised by a call to C<ev_init (watcher
1006	(watcher *, callback)>, which expects a callback to be provided. This	1024	*, callback)>, which expects a callback to be provided. This callback is
1007	callback gets invoked each time the event occurs (or, in the case of I/O	1025	invoked each time the event occurs (or, in the case of I/O watchers, each
1008	watchers, each time the event loop detects that the file descriptor given	1026	time the event loop detects that the file descriptor given is readable
1009	is readable and/or writable).	1027	and/or writable).
1010		1028
1011	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1029	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1012	macro to configure it, with arguments specific to the watcher type. There	1030	macro to configure it, with arguments specific to the watcher type. There
1013	is also a macro to combine initialisation and setting in one call: C<<	1031	is also a macro to combine initialisation and setting in one call: C<<
1014	ev_TYPE_init (watcher *, callback, ...) >>.	1032	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1065		1083
1066	=item C<EV_PREPARE>	1084	=item C<EV_PREPARE>
1067		1085
1068	=item C<EV_CHECK>	1086	=item C<EV_CHECK>
1069		1087
1070	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1088	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1071	to gather new events, and all C<ev_check> watchers are invoked just after	1089	to gather new events, and all C<ev_check> watchers are invoked just after
1072	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1090	C<ev_run> has gathered them, but before it invokes any callbacks for any
1073	received events. Callbacks of both watcher types can start and stop as	1091	received events. Callbacks of both watcher types can start and stop as
1074	many watchers as they want, and all of them will be taken into account	1092	many watchers as they want, and all of them will be taken into account
1075	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1093	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1076	C<ev_loop> from blocking).	1094	C<ev_run> from blocking).
1077		1095
1078	=item C<EV_EMBED>	1096	=item C<EV_EMBED>
1079		1097
1080	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1098	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1081		1099
…		…
1109	example it might indicate that a fd is readable or writable, and if your	1127	example it might indicate that a fd is readable or writable, and if your
1110	callbacks is well-written it can just attempt the operation and cope with	1128	callbacks is well-written it can just attempt the operation and cope with
1111	the error from read() or write(). This will not work in multi-threaded	1129	the error from read() or write(). This will not work in multi-threaded
1112	programs, though, as the fd could already be closed and reused for another	1130	programs, though, as the fd could already be closed and reused for another
1113	thing, so beware.	1131	thing, so beware.
		1132
		1133	=back
		1134
		1135	=head2 WATCHER STATES
		1136
		1137	There are various watcher states mentioned throughout this manual -
		1138	active, pending and so on. In this section these states and the rules to
		1139	transition between them will be described in more detail - and while these
		1140	rules might look complicated, they usually do "the right thing".
		1141
		1142	=over 4
		1143
		1144	=item initialiased
		1145
		1146	Before a watcher can be registered with the event looop it has to be
		1147	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1148	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1149
		1150	In this state it is simply some block of memory that is suitable for use
		1151	in an event loop. It can be moved around, freed, reused etc. at will.
		1152
		1153	=item started/running/active
		1154
		1155	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1156	property of the event loop, and is actively waiting for events. While in
		1157	this state it cannot be accessed (except in a few documented ways), moved,
		1158	freed or anything else - the only legal thing is to keep a pointer to it,
		1159	and call libev functions on it that are documented to work on active watchers.
		1160
		1161	=item pending
		1162
		1163	If a watcher is active and libev determines that an event it is interested
		1164	in has occured (such as a timer expiring), it will become pending. It will
		1165	stay in this pending state until either it is stopped or its callback is
		1166	about to be invoked, so it is not normally pending inside the watcher
		1167	callback.
		1168
		1169	The watcher might or might not be active while it is pending (for example,
		1170	an expired non-repeating timer can be pending but no longer active). If it
		1171	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1172	but it is still property of the event loop at this time, so cannot be
		1173	moved, freed or reused. And if it is active the rules described in the
		1174	previous item still apply.
		1175
		1176	It is also possible to feed an event on a watcher that is not active (e.g.
		1177	via C<ev_feed_event>), in which case it becomes pending without being
		1178	active.
		1179
		1180	=item stopped
		1181
		1182	A watcher can be stopped implicitly by libev (in which case it might still
		1183	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1184	latter will clear any pending state the watcher might be in, regardless
		1185	of whether it was active or not, so stopping a watcher explicitly before
		1186	freeing it is often a good idea.
		1187
		1188	While stopped (and not pending) the watcher is essentially in the
		1189	initialised state, that is it can be reused, moved, modified in any way
		1190	you wish.
1114		1191
1115	=back	1192	=back
1116		1193
1117	=head2 GENERIC WATCHER FUNCTIONS	1194	=head2 GENERIC WATCHER FUNCTIONS
1118		1195
…		…
1622	...	1699	...
1623	struct ev_loop *loop = ev_default_init (0);	1700	struct ev_loop *loop = ev_default_init (0);
1624	ev_io stdin_readable;	1701	ev_io stdin_readable;
1625	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1702	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1626	ev_io_start (loop, &stdin_readable);	1703	ev_io_start (loop, &stdin_readable);
1627	ev_loop (loop, 0);	1704	ev_run (loop, 0);
1628		1705
1629		1706
1630	=head2 C<ev_timer> - relative and optionally repeating timeouts	1707	=head2 C<ev_timer> - relative and optionally repeating timeouts
1631		1708
1632	Timer watchers are simple relative timers that generate an event after a	1709	Timer watchers are simple relative timers that generate an event after a
…		…
1641	The callback is guaranteed to be invoked only I<after> its timeout has	1718	The callback is guaranteed to be invoked only I<after> its timeout has
1642	passed (not I<at>, so on systems with very low-resolution clocks this	1719	passed (not I<at>, so on systems with very low-resolution clocks this
1643	might introduce a small delay). If multiple timers become ready during the	1720	might introduce a small delay). If multiple timers become ready during the
1644	same loop iteration then the ones with earlier time-out values are invoked	1721	same loop iteration then the ones with earlier time-out values are invoked
1645	before ones of the same priority with later time-out values (but this is	1722	before ones of the same priority with later time-out values (but this is
1646	no longer true when a callback calls C<ev_loop> recursively).	1723	no longer true when a callback calls C<ev_run> recursively).
1647		1724
1648	=head3 Be smart about timeouts	1725	=head3 Be smart about timeouts
1649		1726
1650	Many real-world problems involve some kind of timeout, usually for error	1727	Many real-world problems involve some kind of timeout, usually for error
1651	recovery. A typical example is an HTTP request - if the other side hangs,	1728	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1822		1899
1823	=head3 The special problem of time updates	1900	=head3 The special problem of time updates
1824		1901
1825	Establishing the current time is a costly operation (it usually takes at	1902	Establishing the current time is a costly operation (it usually takes at
1826	least two system calls): EV therefore updates its idea of the current	1903	least two system calls): EV therefore updates its idea of the current
1827	time only before and after C<ev_loop> collects new events, which causes a	1904	time only before and after C<ev_run> collects new events, which causes a
1828	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1905	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1829	lots of events in one iteration.	1906	lots of events in one iteration.
1830		1907
1831	The relative timeouts are calculated relative to the C<ev_now ()>	1908	The relative timeouts are calculated relative to the C<ev_now ()>
1832	time. This is usually the right thing as this timestamp refers to the time	1909	time. This is usually the right thing as this timestamp refers to the time
…		…
1949	}	2026	}
1950		2027
1951	ev_timer mytimer;	2028	ev_timer mytimer;
1952	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2029	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1953	ev_timer_again (&mytimer); /* start timer */	2030	ev_timer_again (&mytimer); /* start timer */
1954	ev_loop (loop, 0);	2031	ev_run (loop, 0);
1955		2032
1956	// and in some piece of code that gets executed on any "activity":	2033	// and in some piece of code that gets executed on any "activity":
1957	// reset the timeout to start ticking again at 10 seconds	2034	// reset the timeout to start ticking again at 10 seconds
1958	ev_timer_again (&mytimer);	2035	ev_timer_again (&mytimer);
1959		2036
…		…
1985		2062
1986	As with timers, the callback is guaranteed to be invoked only when the	2063	As with timers, the callback is guaranteed to be invoked only when the
1987	point in time where it is supposed to trigger has passed. If multiple	2064	point in time where it is supposed to trigger has passed. If multiple
1988	timers become ready during the same loop iteration then the ones with	2065	timers become ready during the same loop iteration then the ones with
1989	earlier time-out values are invoked before ones with later time-out values	2066	earlier time-out values are invoked before ones with later time-out values
1990	(but this is no longer true when a callback calls C<ev_loop> recursively).	2067	(but this is no longer true when a callback calls C<ev_run> recursively).
1991		2068
1992	=head3 Watcher-Specific Functions and Data Members	2069	=head3 Watcher-Specific Functions and Data Members
1993		2070
1994	=over 4	2071	=over 4
1995		2072
…		…
2123	Example: Call a callback every hour, or, more precisely, whenever the	2200	Example: Call a callback every hour, or, more precisely, whenever the
2124	system time is divisible by 3600. The callback invocation times have	2201	system time is divisible by 3600. The callback invocation times have
2125	potentially a lot of jitter, but good long-term stability.	2202	potentially a lot of jitter, but good long-term stability.
2126		2203
2127	static void	2204	static void
2128	clock_cb (struct ev_loop loop, ev_io w, int revents)	2205	clock_cb (struct ev_loop loop, ev_periodic w, int revents)
2129	{	2206	{
2130	... its now a full hour (UTC, or TAI or whatever your clock follows)	2207	... its now a full hour (UTC, or TAI or whatever your clock follows)
2131	}	2208	}
2132		2209
2133	ev_periodic hourly_tick;	2210	ev_periodic hourly_tick;
…		…
2233	Example: Try to exit cleanly on SIGINT.	2310	Example: Try to exit cleanly on SIGINT.
2234		2311
2235	static void	2312	static void
2236	sigint_cb (struct ev_loop loop, ev_signal w, int revents)	2313	sigint_cb (struct ev_loop loop, ev_signal w, int revents)
2237	{	2314	{
2238	ev_unloop (loop, EVUNLOOP_ALL);	2315	ev_break (loop, EVBREAK_ALL);
2239	}	2316	}
2240		2317
2241	ev_signal signal_watcher;	2318	ev_signal signal_watcher;
2242	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2319	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2243	ev_signal_start (loop, &signal_watcher);	2320	ev_signal_start (loop, &signal_watcher);
…		…
2629		2706
2630	Prepare and check watchers are usually (but not always) used in pairs:	2707	Prepare and check watchers are usually (but not always) used in pairs:
2631	prepare watchers get invoked before the process blocks and check watchers	2708	prepare watchers get invoked before the process blocks and check watchers
2632	afterwards.	2709	afterwards.
2633		2710
2634	You I<must not> call C<ev_loop> or similar functions that enter	2711	You I<must not> call C<ev_run> or similar functions that enter
2635	the current event loop from either C<ev_prepare> or C<ev_check>	2712	the current event loop from either C<ev_prepare> or C<ev_check>
2636	watchers. Other loops than the current one are fine, however. The	2713	watchers. Other loops than the current one are fine, however. The
2637	rationale behind this is that you do not need to check for recursion in	2714	rationale behind this is that you do not need to check for recursion in
2638	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2715	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2639	C<ev_check> so if you have one watcher of each kind they will always be	2716	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2807		2884
2808	if (timeout >= 0)	2885	if (timeout >= 0)
2809	// create/start timer	2886	// create/start timer
2810		2887
2811	// poll	2888	// poll
2812	ev_loop (EV_A_ 0);	2889	ev_run (EV_A_ 0);
2813		2890
2814	// stop timer again	2891	// stop timer again
2815	if (timeout >= 0)	2892	if (timeout >= 0)
2816	ev_timer_stop (EV_A_ &to);	2893	ev_timer_stop (EV_A_ &to);
2817		2894
…		…
2895	if you do not want that, you need to temporarily stop the embed watcher).	2972	if you do not want that, you need to temporarily stop the embed watcher).
2896		2973
2897	=item ev_embed_sweep (loop, ev_embed *)	2974	=item ev_embed_sweep (loop, ev_embed *)
2898		2975
2899	Make a single, non-blocking sweep over the embedded loop. This works	2976	Make a single, non-blocking sweep over the embedded loop. This works
2900	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2977	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2901	appropriate way for embedded loops.	2978	appropriate way for embedded loops.
2902		2979
2903	=item struct ev_loop *other [read-only]	2980	=item struct ev_loop *other [read-only]
2904		2981
2905	The embedded event loop.	2982	The embedded event loop.
…		…
2965	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3042	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2966	handlers will be invoked, too, of course.	3043	handlers will be invoked, too, of course.
2967		3044
2968	=head3 The special problem of life after fork - how is it possible?	3045	=head3 The special problem of life after fork - how is it possible?
2969		3046
2970	Most uses of C<fork()> consist of forking, then some simple calls to ste	3047	Most uses of C<fork()> consist of forking, then some simple calls to set
2971	up/change the process environment, followed by a call to C<exec()>. This	3048	up/change the process environment, followed by a call to C<exec()>. This
2972	sequence should be handled by libev without any problems.	3049	sequence should be handled by libev without any problems.
2973		3050
2974	This changes when the application actually wants to do event handling	3051	This changes when the application actually wants to do event handling
2975	in the child, or both parent in child, in effect "continuing" after the	3052	in the child, or both parent in child, in effect "continuing" after the
…		…
3009	believe me.	3086	believe me.
3010		3087
3011	=back	3088	=back
3012		3089
3013		3090
3014	=head2 C<ev_async> - how to wake up another event loop	3091	=head2 C<ev_async> - how to wake up an event loop
3015		3092
3016	In general, you cannot use an C<ev_loop> from multiple threads or other	3093	In general, you cannot use an C<ev_run> from multiple threads or other
3017	asynchronous sources such as signal handlers (as opposed to multiple event	3094	asynchronous sources such as signal handlers (as opposed to multiple event
3018	loops - those are of course safe to use in different threads).	3095	loops - those are of course safe to use in different threads).
3019		3096
3020	Sometimes, however, you need to wake up another event loop you do not	3097	Sometimes, however, you need to wake up an event loop you do not control,
3021	control, for example because it belongs to another thread. This is what	3098	for example because it belongs to another thread. This is what C<ev_async>
3022	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3099	watchers do: as long as the C<ev_async> watcher is active, you can signal
3023	can signal it by calling C<ev_async_send>, which is thread- and signal	3100	it by calling C<ev_async_send>, which is thread- and signal safe.
3024	safe.
3025		3101
3026	This functionality is very similar to C<ev_signal> watchers, as signals,	3102	This functionality is very similar to C<ev_signal> watchers, as signals,
3027	too, are asynchronous in nature, and signals, too, will be compressed	3103	too, are asynchronous in nature, and signals, too, will be compressed
3028	(i.e. the number of callback invocations may be less than the number of	3104	(i.e. the number of callback invocations may be less than the number of
3029	C<ev_async_sent> calls).	3105	C<ev_async_sent> calls).
…		…
3390	Associates a different C<struct ev_loop> with this watcher. You can only	3466	Associates a different C<struct ev_loop> with this watcher. You can only
3391	do this when the watcher is inactive (and not pending either).	3467	do this when the watcher is inactive (and not pending either).
3392		3468
3393	=item w->set ([arguments])	3469	=item w->set ([arguments])
3394		3470
3395	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3471	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3396	called at least once. Unlike the C counterpart, an active watcher gets	3472	method or a suitable start method must be called at least once. Unlike the
3397	automatically stopped and restarted when reconfiguring it with this	3473	C counterpart, an active watcher gets automatically stopped and restarted
3398	method.	3474	when reconfiguring it with this method.
3399		3475
3400	=item w->start ()	3476	=item w->start ()
3401		3477
3402	Starts the watcher. Note that there is no C<loop> argument, as the	3478	Starts the watcher. Note that there is no C<loop> argument, as the
3403	constructor already stores the event loop.	3479	constructor already stores the event loop.
3404		3480
		3481	=item w->start ([arguments])
		3482
		3483	Instead of calling C<set> and C<start> methods separately, it is often
		3484	convenient to wrap them in one call. Uses the same type of arguments as
		3485	the configure C<set> method of the watcher.
		3486
3405	=item w->stop ()	3487	=item w->stop ()
3406		3488
3407	Stops the watcher if it is active. Again, no C<loop> argument.	3489	Stops the watcher if it is active. Again, no C<loop> argument.
3408		3490
3409	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3491	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3421		3503
3422	=back	3504	=back
3423		3505
3424	=back	3506	=back
3425		3507
3426	Example: Define a class with an IO and idle watcher, start one of them in	3508	Example: Define a class with two I/O and idle watchers, start the I/O
3427	the constructor.	3509	watchers in the constructor.
3428		3510
3429	class myclass	3511	class myclass
3430	{	3512	{
3431	ev::io io ; void io_cb (ev::io &w, int revents);	3513	ev::io io ; void io_cb (ev::io &w, int revents);
		3514	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3432	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3515	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3433		3516
3434	myclass (int fd)	3517	myclass (int fd)
3435	{	3518	{
3436	io .set <myclass, &myclass::io_cb > (this);	3519	io .set <myclass, &myclass::io_cb > (this);
		3520	io2 .set <myclass, &myclass::io2_cb > (this);
3437	idle.set <myclass, &myclass::idle_cb> (this);	3521	idle.set <myclass, &myclass::idle_cb> (this);
3438		3522
3439	io.start (fd, ev::READ);	3523	io.set (fd, ev::WRITE); // configure the watcher
		3524	io.start (); // start it whenever convenient
		3525
		3526	io2.start (fd, ev::READ); // set + start in one call
3440	}	3527	}
3441	};	3528	};
3442		3529
3443		3530
3444	=head1 OTHER LANGUAGE BINDINGS	3531	=head1 OTHER LANGUAGE BINDINGS
…		…
3518	loop argument"). The C<EV_A> form is used when this is the sole argument,	3605	loop argument"). The C<EV_A> form is used when this is the sole argument,
3519	C<EV_A_> is used when other arguments are following. Example:	3606	C<EV_A_> is used when other arguments are following. Example:
3520		3607
3521	ev_unref (EV_A);	3608	ev_unref (EV_A);
3522	ev_timer_add (EV_A_ watcher);	3609	ev_timer_add (EV_A_ watcher);
3523	ev_loop (EV_A_ 0);	3610	ev_run (EV_A_ 0);
3524		3611
3525	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3612	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3526	which is often provided by the following macro.	3613	which is often provided by the following macro.
3527		3614
3528	=item C<EV_P>, C<EV_P_>	3615	=item C<EV_P>, C<EV_P_>
…		…
3568	}	3655	}
3569		3656
3570	ev_check check;	3657	ev_check check;
3571	ev_check_init (&check, check_cb);	3658	ev_check_init (&check, check_cb);
3572	ev_check_start (EV_DEFAULT_ &check);	3659	ev_check_start (EV_DEFAULT_ &check);
3573	ev_loop (EV_DEFAULT_ 0);	3660	ev_run (EV_DEFAULT_ 0);
3574		3661
3575	=head1 EMBEDDING	3662	=head1 EMBEDDING
3576		3663
3577	Libev can (and often is) directly embedded into host	3664	Libev can (and often is) directly embedded into host
3578	applications. Examples of applications that embed it include the Deliantra	3665	applications. Examples of applications that embed it include the Deliantra
…		…
3669	to a compiled library. All other symbols change the ABI, which means all	3756	to a compiled library. All other symbols change the ABI, which means all
3670	users of libev and the libev code itself must be compiled with compatible	3757	users of libev and the libev code itself must be compiled with compatible
3671	settings.	3758	settings.
3672		3759
3673	=over 4	3760	=over 4
		3761
		3762	=item EV_COMPAT3 (h)
		3763
		3764	Backwards compatibility is a major concern for libev. This is why this
		3765	release of libev comes with wrappers for the functions and symbols that
		3766	have been renamed between libev version 3 and 4.
		3767
		3768	You can disable these wrappers (to test compatibility with future
		3769	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3770	sources. This has the additional advantage that you can drop the C<struct>
		3771	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3772	typedef in that case.
		3773
		3774	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3775	and in some even more future version the compatibility code will be
		3776	removed completely.
3674		3777
3675	=item EV_STANDALONE (h)	3778	=item EV_STANDALONE (h)
3676		3779
3677	Must always be C<1> if you do not use autoconf configuration, which	3780	Must always be C<1> if you do not use autoconf configuration, which
3678	keeps libev from including F<config.h>, and it also defines dummy	3781	keeps libev from including F<config.h>, and it also defines dummy
…		…
4028	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4131	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4029	will be C<0>.	4132	will be C<0>.
4030		4133
4031	=item EV_VERIFY	4134	=item EV_VERIFY
4032		4135
4033	Controls how much internal verification (see C<ev_loop_verify ()>) will	4136	Controls how much internal verification (see C<ev_verify ()>) will
4034	be done: If set to C<0>, no internal verification code will be compiled	4137	be done: If set to C<0>, no internal verification code will be compiled
4035	in. If set to C<1>, then verification code will be compiled in, but not	4138	in. If set to C<1>, then verification code will be compiled in, but not
4036	called. If set to C<2>, then the internal verification code will be	4139	called. If set to C<2>, then the internal verification code will be
4037	called once per loop, which can slow down libev. If set to C<3>, then the	4140	called once per loop, which can slow down libev. If set to C<3>, then the
4038	verification code will be called very frequently, which will slow down	4141	verification code will be called very frequently, which will slow down
…		…
4042	will be C<0>.	4145	will be C<0>.
4043		4146
4044	=item EV_COMMON	4147	=item EV_COMMON
4045		4148
4046	By default, all watchers have a C<void *data> member. By redefining	4149	By default, all watchers have a C<void *data> member. By redefining
4047	this macro to a something else you can include more and other types of	4150	this macro to something else you can include more and other types of
4048	members. You have to define it each time you include one of the files,	4151	members. You have to define it each time you include one of the files,
4049	though, and it must be identical each time.	4152	though, and it must be identical each time.
4050		4153
4051	For example, the perl EV module uses something like this:	4154	For example, the perl EV module uses something like this:
4052		4155
…		…
4253	userdata *u = ev_userdata (EV_A);	4356	userdata *u = ev_userdata (EV_A);
4254	pthread_mutex_lock (&u->lock);	4357	pthread_mutex_lock (&u->lock);
4255	}	4358	}
4256		4359
4257	The event loop thread first acquires the mutex, and then jumps straight	4360	The event loop thread first acquires the mutex, and then jumps straight
4258	into C<ev_loop>:	4361	into C<ev_run>:
4259		4362
4260	void *	4363	void *
4261	l_run (void *thr_arg)	4364	l_run (void *thr_arg)
4262	{	4365	{
4263	struct ev_loop loop = (struct ev_loop )thr_arg;	4366	struct ev_loop loop = (struct ev_loop )thr_arg;
4264		4367
4265	l_acquire (EV_A);	4368	l_acquire (EV_A);
4266	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4369	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4267	ev_loop (EV_A_ 0);	4370	ev_run (EV_A_ 0);
4268	l_release (EV_A);	4371	l_release (EV_A);
4269		4372
4270	return 0;	4373	return 0;
4271	}	4374	}
4272		4375
…		…
4324		4427
4325	=head3 COROUTINES	4428	=head3 COROUTINES
4326		4429
4327	Libev is very accommodating to coroutines ("cooperative threads"):	4430	Libev is very accommodating to coroutines ("cooperative threads"):
4328	libev fully supports nesting calls to its functions from different	4431	libev fully supports nesting calls to its functions from different
4329	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4432	coroutines (e.g. you can call C<ev_run> on the same loop from two
4330	different coroutines, and switch freely between both coroutines running	4433	different coroutines, and switch freely between both coroutines running
4331	the loop, as long as you don't confuse yourself). The only exception is	4434	the loop, as long as you don't confuse yourself). The only exception is
4332	that you must not do this from C<ev_periodic> reschedule callbacks.	4435	that you must not do this from C<ev_periodic> reschedule callbacks.
4333		4436
4334	Care has been taken to ensure that libev does not keep local state inside	4437	Care has been taken to ensure that libev does not keep local state inside
4335	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4438	C<ev_run>, and other calls do not usually allow for coroutine switches as
4336	they do not call any callbacks.	4439	they do not call any callbacks.
4337		4440
4338	=head2 COMPILER WARNINGS	4441	=head2 COMPILER WARNINGS
4339		4442
4340	Depending on your compiler and compiler settings, you might get no or a	4443	Depending on your compiler and compiler settings, you might get no or a
…		…
4351	maintainable.	4454	maintainable.
4352		4455
4353	And of course, some compiler warnings are just plain stupid, or simply	4456	And of course, some compiler warnings are just plain stupid, or simply
4354	wrong (because they don't actually warn about the condition their message	4457	wrong (because they don't actually warn about the condition their message
4355	seems to warn about). For example, certain older gcc versions had some	4458	seems to warn about). For example, certain older gcc versions had some
4356	warnings that resulted an extreme number of false positives. These have	4459	warnings that resulted in an extreme number of false positives. These have
4357	been fixed, but some people still insist on making code warn-free with	4460	been fixed, but some people still insist on making code warn-free with
4358	such buggy versions.	4461	such buggy versions.
4359		4462
4360	While libev is written to generate as few warnings as possible,	4463	While libev is written to generate as few warnings as possible,
4361	"warn-free" code is not a goal, and it is recommended not to build libev	4464	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4397	I suggest using suppression lists.	4500	I suggest using suppression lists.
4398		4501
4399		4502
4400	=head1 PORTABILITY NOTES	4503	=head1 PORTABILITY NOTES
4401		4504
		4505	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4506
		4507	GNU/Linux is the only common platform that supports 64 bit file/large file
		4508	interfaces but I<disables> them by default.
		4509
		4510	That means that libev compiled in the default environment doesn't support
		4511	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4512
		4513	Unfortunately, many programs try to work around this GNU/Linux issue
		4514	by enabling the large file API, which makes them incompatible with the
		4515	standard libev compiled for their system.
		4516
		4517	Likewise, libev cannot enable the large file API itself as this would
		4518	suddenly make it incompatible to the default compile time environment,
		4519	i.e. all programs not using special compile switches.
		4520
		4521	=head2 OS/X AND DARWIN BUGS
		4522
		4523	The whole thing is a bug if you ask me - basically any system interface
		4524	you touch is broken, whether it is locales, poll, kqueue or even the
		4525	OpenGL drivers.
		4526
		4527	=head3 C<kqueue> is buggy
		4528
		4529	The kqueue syscall is broken in all known versions - most versions support
		4530	only sockets, many support pipes.
		4531
		4532	Libev tries to work around this by not using C<kqueue> by default on
		4533	this rotten platform, but of course you can still ask for it when creating
		4534	a loop.
		4535
		4536	=head3 C<poll> is buggy
		4537
		4538	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4539	implementation by something calling C<kqueue> internally around the 10.5.6
		4540	release, so now C<kqueue> I<and> C<poll> are broken.
		4541
		4542	Libev tries to work around this by not using C<poll> by default on
		4543	this rotten platform, but of course you can still ask for it when creating
		4544	a loop.
		4545
		4546	=head3 C<select> is buggy
		4547
		4548	All that's left is C<select>, and of course Apple found a way to fuck this
		4549	one up as well: On OS/X, C<select> actively limits the number of file
		4550	descriptors you can pass in to 1024 - your program suddenly crashes when
		4551	you use more.
		4552
		4553	There is an undocumented "workaround" for this - defining
		4554	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4555	work on OS/X.
		4556
		4557	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4558
		4559	=head3 C<errno> reentrancy
		4560
		4561	The default compile environment on Solaris is unfortunately so
		4562	thread-unsafe that you can't even use components/libraries compiled
		4563	without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,
		4564	isn't defined by default.
		4565
		4566	If you want to use libev in threaded environments you have to make sure
		4567	it's compiled with C<_REENTRANT> defined.
		4568
		4569	=head3 Event port backend
		4570
		4571	The scalable event interface for Solaris is called "event ports". Unfortunately,
		4572	this mechanism is very buggy. If you run into high CPU usage, your program
		4573	freezes or you get a large number of spurious wakeups, make sure you have
		4574	all the relevant and latest kernel patches applied. No, I don't know which
		4575	ones, but there are multiple ones.
		4576
		4577	If you can't get it to work, you can try running the program by setting
		4578	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4579	C<select> backends.
		4580
		4581	=head2 AIX POLL BUG
		4582
		4583	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4584	this by trying to avoid the poll backend altogether (i.e. it's not even
		4585	compiled in), which normally isn't a big problem as C<select> works fine
		4586	with large bitsets, and AIX is dead anyway.
		4587
4402	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4588	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4589
		4590	=head3 General issues
4403		4591
4404	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4592	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4405	requires, and its I/O model is fundamentally incompatible with the POSIX	4593	requires, and its I/O model is fundamentally incompatible with the POSIX
4406	model. Libev still offers limited functionality on this platform in	4594	model. Libev still offers limited functionality on this platform in
4407	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4595	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4408	descriptors. This only applies when using Win32 natively, not when using	4596	descriptors. This only applies when using Win32 natively, not when using
4409	e.g. cygwin.	4597	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4598	as every compielr comes with a slightly differently broken/incompatible
		4599	environment.
4410		4600
4411	Lifting these limitations would basically require the full	4601	Lifting these limitations would basically require the full
4412	re-implementation of the I/O system. If you are into these kinds of	4602	re-implementation of the I/O system. If you are into this kind of thing,
4413	things, then note that glib does exactly that for you in a very portable	4603	then note that glib does exactly that for you in a very portable way (note
4414	way (note also that glib is the slowest event library known to man).	4604	also that glib is the slowest event library known to man).
4415		4605
4416	There is no supported compilation method available on windows except	4606	There is no supported compilation method available on windows except
4417	embedding it into other applications.	4607	embedding it into other applications.
4418		4608
4419	Sensible signal handling is officially unsupported by Microsoft - libev	4609	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4447	you do I<not> compile the F<ev.c> or any other embedded source files!):	4637	you do I<not> compile the F<ev.c> or any other embedded source files!):
4448		4638
4449	#include "evwrap.h"	4639	#include "evwrap.h"
4450	#include "ev.c"	4640	#include "ev.c"
4451		4641
4452	=over 4
4453
4454	=item The winsocket select function	4642	=head3 The winsocket C<select> function
4455		4643
4456	The winsocket C<select> function doesn't follow POSIX in that it	4644	The winsocket C<select> function doesn't follow POSIX in that it
4457	requires socket I<handles> and not socket I<file descriptors> (it is	4645	requires socket I<handles> and not socket I<file descriptors> (it is
4458	also extremely buggy). This makes select very inefficient, and also	4646	also extremely buggy). This makes select very inefficient, and also
4459	requires a mapping from file descriptors to socket handles (the Microsoft	4647	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4468	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4656	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4469		4657
4470	Note that winsockets handling of fd sets is O(n), so you can easily get a	4658	Note that winsockets handling of fd sets is O(n), so you can easily get a
4471	complexity in the O(n²) range when using win32.	4659	complexity in the O(n²) range when using win32.
4472		4660
4473	=item Limited number of file descriptors	4661	=head3 Limited number of file descriptors
4474		4662
4475	Windows has numerous arbitrary (and low) limits on things.	4663	Windows has numerous arbitrary (and low) limits on things.
4476		4664
4477	Early versions of winsocket's select only supported waiting for a maximum	4665	Early versions of winsocket's select only supported waiting for a maximum
4478	of C<64> handles (probably owning to the fact that all windows kernels	4666	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4493	runtime libraries. This might get you to about C<512> or C<2048> sockets	4681	runtime libraries. This might get you to about C<512> or C<2048> sockets
4494	(depending on windows version and/or the phase of the moon). To get more,	4682	(depending on windows version and/or the phase of the moon). To get more,
4495	you need to wrap all I/O functions and provide your own fd management, but	4683	you need to wrap all I/O functions and provide your own fd management, but
4496	the cost of calling select (O(n²)) will likely make this unworkable.	4684	the cost of calling select (O(n²)) will likely make this unworkable.
4497		4685
4498	=back
4499
4500	=head2 PORTABILITY REQUIREMENTS	4686	=head2 PORTABILITY REQUIREMENTS
4501		4687
4502	In addition to a working ISO-C implementation and of course the	4688	In addition to a working ISO-C implementation and of course the
4503	backend-specific APIs, libev relies on a few additional extensions:	4689	backend-specific APIs, libev relies on a few additional extensions:
4504		4690
…		…
4542	watchers.	4728	watchers.
4543		4729
4544	=item C<double> must hold a time value in seconds with enough accuracy	4730	=item C<double> must hold a time value in seconds with enough accuracy
4545		4731
4546	The type C<double> is used to represent timestamps. It is required to	4732	The type C<double> is used to represent timestamps. It is required to
4547	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4733	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4548	enough for at least into the year 4000. This requirement is fulfilled by	4734	good enough for at least into the year 4000 with millisecond accuracy
		4735	(the design goal for libev). This requirement is overfulfilled by
4549	implementations implementing IEEE 754, which is basically all existing	4736	implementations using IEEE 754, which is basically all existing ones. With
4550	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4737	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4551	2200.
4552		4738
4553	=back	4739	=back
4554		4740
4555	If you know of other additional requirements drop me a note.	4741	If you know of other additional requirements drop me a note.
4556		4742
…		…
4634	compatibility, so most programs should still compile. Those might be	4820	compatibility, so most programs should still compile. Those might be
4635	removed in later versions of libev, so better update early than late.	4821	removed in later versions of libev, so better update early than late.
4636		4822
4637	=over 4	4823	=over 4
4638		4824
4639	=item C<ev_loop_count> renamed to C<ev_iteration>	4825	=item function/symbol renames
4640		4826
4641	=item C<ev_loop_depth> renamed to C<ev_depth>	4827	A number of functions and symbols have been renamed:
4642		4828
4643	=item C<ev_loop_verify> renamed to C<ev_verify>	4829	ev_loop => ev_run
		4830	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4831	EVLOOP_ONESHOT => EVRUN_ONCE
		4832
		4833	ev_unloop => ev_break
		4834	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4835	EVUNLOOP_ONE => EVBREAK_ONE
		4836	EVUNLOOP_ALL => EVBREAK_ALL
		4837
		4838	EV_TIMEOUT => EV_TIMER
		4839
		4840	ev_loop_count => ev_iteration
		4841	ev_loop_depth => ev_depth
		4842	ev_loop_verify => ev_verify
4644		4843
4645	Most functions working on C<struct ev_loop> objects don't have an	4844	Most functions working on C<struct ev_loop> objects don't have an
4646	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is	4845	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4846	associated constants have been renamed to not collide with the C<struct
		4847	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4848	as all other watcher types. Note that C<ev_loop_fork> is still called
4647	still called C<ev_loop_fork> because it would otherwise clash with the	4849	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4648	C<ev_fork> typedef.	4850	typedef.
4649		4851
4650	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>	4852	=item C<EV_COMPAT3> backwards compatibility mechanism
4651		4853
4652	This is a simple rename - all other watcher types use their name	4854	The backward compatibility mechanism can be controlled by
4653	as revents flag, and now C<ev_timer> does, too.	4855	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4654		4856	section.
4655	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4656	and continue to be present for the foreseeable future, so this is mostly a
4657	documentation change.
4658		4857
4659	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4858	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4660		4859
4661	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4860	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4662	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4861	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile

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Comparing libev/ev.pod (file contents): Revision 1.299 by sf-exg, Sat Aug 28 21:42:12 2010 UTC vs. Revision 1.311 by root, Thu Oct 21 14:40:07 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.299 by sf-exg, Sat Aug 28 21:42:12 2010 UTC vs.
Revision 1.311 by root, Thu Oct 21 14:40:07 2010 UTC