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Comparing libev/ev.pod (file contents):
Revision 1.266 by root, Wed Aug 26 17:15:05 2009 UTC vs.
Revision 1.303 by root, Thu Oct 14 04:29:34 2010 UTC

…		…
75	While this document tries to be as complete as possible in documenting	75	While this document tries to be as complete as possible in documenting
76	libev, its usage and the rationale behind its design, it is not a tutorial	76	libev, its usage and the rationale behind its design, it is not a tutorial
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
82		82
83	=head1 ABOUT LIBEV	83	=head1 ABOUT LIBEV
84		84
85	Libev is an event loop: you register interest in certain events (such as a	85	Libev is an event loop: you register interest in certain events (such as a
…		…
118	Libev is very configurable. In this manual the default (and most common)	118	Libev is very configurable. In this manual the default (and most common)
119	configuration will be described, which supports multiple event loops. For	119	configuration will be described, which supports multiple event loops. For
120	more info about various configuration options please have a look at	120	more info about various configuration options please have a look at
121	B<EMBED> section in this manual. If libev was configured without support	121	B<EMBED> section in this manual. If libev was configured without support
122	for multiple event loops, then all functions taking an initial argument of	122	for multiple event loops, then all functions taking an initial argument of
123	name C<loop> (which is always of type C<ev_loop *>) will not have	123	name C<loop> (which is always of type C<struct ev_loop *>) will not have
124	this argument.	124	this argument.
125		125
126	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
127		127
128	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (somewhere	129	the (fractional) number of seconds since the (POSIX) epoch (in practise
130	near the beginning of 1970, details are complicated, don't ask). This	130	somewhere near the beginning of 1970, details are complicated, don't
131	type is called C<ev_tstamp>, which is what you should use too. It usually	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	aliases to the C<double> type in C. When you need to do any calculations	132	too. It usually aliases to the C<double> type in C. When you need to do
133	on it, you should treat it as some floating point value. Unlike the name	133	any calculations on it, you should treat it as some floating point value.
		134
134	component C<stamp> might indicate, it is also used for time differences	135	Unlike the name component C<stamp> might indicate, it is also used for
135	throughout libev.	136	time differences (e.g. delays) throughout libev.
136		137
137	=head1 ERROR HANDLING	138	=head1 ERROR HANDLING
138		139
139	Libev knows three classes of errors: operating system errors, usage errors	140	Libev knows three classes of errors: operating system errors, usage errors
140	and internal errors (bugs).	141	and internal errors (bugs).
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191	as this indicates an incompatible change. Minor versions are usually	192	as this indicates an incompatible change. Minor versions are usually
192	compatible to older versions, so a larger minor version alone is usually	193	compatible to older versions, so a larger minor version alone is usually
193	not a problem.	194	not a problem.
194		195
195	Example: Make sure we haven't accidentally been linked against the wrong	196	Example: Make sure we haven't accidentally been linked against the wrong
196	version.	197	version (note, however, that this will not detect ABI mismatches :).
197		198
198	assert (("libev version mismatch",	199	assert (("libev version mismatch",
199	ev_version_major () == EV_VERSION_MAJOR	200	ev_version_major () == EV_VERSION_MAJOR
200	&& ev_version_minor () >= EV_VERSION_MINOR));	201	&& ev_version_minor () >= EV_VERSION_MINOR));
201		202
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345	useful to try out specific backends to test their performance, or to work	346	useful to try out specific backends to test their performance, or to work
346	around bugs.	347	around bugs.
347		348
348	=item C<EVFLAG_FORKCHECK>	349	=item C<EVFLAG_FORKCHECK>
349		350
350	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	351	Instead of calling C<ev_loop_fork> manually after a fork, you can also
351	a fork, you can also make libev check for a fork in each iteration by	352	make libev check for a fork in each iteration by enabling this flag.
352	enabling this flag.
353		353
354	This works by calling C<getpid ()> on every iteration of the loop,	354	This works by calling C<getpid ()> on every iteration of the loop,
355	and thus this might slow down your event loop if you do a lot of loop	355	and thus this might slow down your event loop if you do a lot of loop
356	iterations and little real work, but is usually not noticeable (on my	356	iterations and little real work, but is usually not noticeable (on my
357	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	357	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
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370	When this flag is specified, then libev will not attempt to use the	370	When this flag is specified, then libev will not attempt to use the
371	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and	371	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and
372	testing, this flag can be useful to conserve inotify file descriptors, as	372	testing, this flag can be useful to conserve inotify file descriptors, as
373	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.	373	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
374		374
375	=item C<EVFLAG_NOSIGNALFD>	375	=item C<EVFLAG_SIGNALFD>
376		376
377	When this flag is specified, then libev will not attempt to use the	377	When this flag is specified, then libev will attempt to use the
378	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This is	378	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API
379	probably only useful to work around any bugs in libev. Consequently, this	379	delivers signals synchronously, which makes it both faster and might make
380	flag might go away once the signalfd functionality is considered stable,	380	it possible to get the queued signal data. It can also simplify signal
381	so it's useful mostly in environment variables and not in program code.	381	handling with threads, as long as you properly block signals in your
		382	threads that are not interested in handling them.
		383
		384	Signalfd will not be used by default as this changes your signal mask, and
		385	there are a lot of shoddy libraries and programs (glib's threadpool for
		386	example) that can't properly initialise their signal masks.
382		387
383	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	388	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
384		389
385	This is your standard select(2) backend. Not I<completely> standard, as	390	This is your standard select(2) backend. Not I<completely> standard, as
386	libev tries to roll its own fd_set with no limits on the number of fds,	391	libev tries to roll its own fd_set with no limits on the number of fds,
…		…
410		415
411	This backend maps C<EV_READ> to C<POLLIN \| POLLERR \| POLLHUP>, and	416	This backend maps C<EV_READ> to C<POLLIN \| POLLERR \| POLLHUP>, and
412	C<EV_WRITE> to C<POLLOUT \| POLLERR \| POLLHUP>.	417	C<EV_WRITE> to C<POLLOUT \| POLLERR \| POLLHUP>.
413		418
414	=item C<EVBACKEND_EPOLL> (value 4, Linux)	419	=item C<EVBACKEND_EPOLL> (value 4, Linux)
		420
		421	Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9
		422	kernels).
415		423
416	For few fds, this backend is a bit little slower than poll and select,	424	For few fds, this backend is a bit little slower than poll and select,
417	but it scales phenomenally better. While poll and select usually scale	425	but it scales phenomenally better. While poll and select usually scale
418	like O(total_fds) where n is the total number of fds (or the highest fd),	426	like O(total_fds) where n is the total number of fds (or the highest fd),
419	epoll scales either O(1) or O(active_fds).	427	epoll scales either O(1) or O(active_fds).
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559	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);	567	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
560		568
561	=item struct ev_loop *ev_loop_new (unsigned int flags)	569	=item struct ev_loop *ev_loop_new (unsigned int flags)
562		570
563	Similar to C<ev_default_loop>, but always creates a new event loop that is	571	Similar to C<ev_default_loop>, but always creates a new event loop that is
564	always distinct from the default loop. Unlike the default loop, it cannot	572	always distinct from the default loop.
565	handle signal and child watchers, and attempts to do so will be greeted by
566	undefined behaviour (or a failed assertion if assertions are enabled).
567		573
568	Note that this function I<is> thread-safe, and the recommended way to use	574	Note that this function I<is> thread-safe, and one common way to use
569	libev with threads is indeed to create one loop per thread, and using the	575	libev with threads is indeed to create one loop per thread, and using the
570	default loop in the "main" or "initial" thread.	576	default loop in the "main" or "initial" thread.
571		577
572	Example: Try to create a event loop that uses epoll and nothing else.	578	Example: Try to create a event loop that uses epoll and nothing else.
573		579
…		…
575	if (!epoller)	581	if (!epoller)
576	fatal ("no epoll found here, maybe it hides under your chair");	582	fatal ("no epoll found here, maybe it hides under your chair");
577		583
578	=item ev_default_destroy ()	584	=item ev_default_destroy ()
579		585
580	Destroys the default loop again (frees all memory and kernel state	586	Destroys the default loop (frees all memory and kernel state etc.). None
581	etc.). None of the active event watchers will be stopped in the normal	587	of the active event watchers will be stopped in the normal sense, so
582	sense, so e.g. C<ev_is_active> might still return true. It is your	588	e.g. C<ev_is_active> might still return true. It is your responsibility to
583	responsibility to either stop all watchers cleanly yourself I<before>	589	either stop all watchers cleanly yourself I<before> calling this function,
584	calling this function, or cope with the fact afterwards (which is usually	590	or cope with the fact afterwards (which is usually the easiest thing, you
585	the easiest thing, you can just ignore the watchers and/or C<free ()> them	591	can just ignore the watchers and/or C<free ()> them for example).
586	for example).
587		592
588	Note that certain global state, such as signal state (and installed signal	593	Note that certain global state, such as signal state (and installed signal
589	handlers), will not be freed by this function, and related watchers (such	594	handlers), will not be freed by this function, and related watchers (such
590	as signal and child watchers) would need to be stopped manually.	595	as signal and child watchers) would need to be stopped manually.
591		596
592	In general it is not advisable to call this function except in the	597	In general it is not advisable to call this function except in the
593	rare occasion where you really need to free e.g. the signal handling	598	rare occasion where you really need to free e.g. the signal handling
594	pipe fds. If you need dynamically allocated loops it is better to use	599	pipe fds. If you need dynamically allocated loops it is better to use
595	C<ev_loop_new> and C<ev_loop_destroy>).	600	C<ev_loop_new> and C<ev_loop_destroy>.
596		601
597	=item ev_loop_destroy (loop)	602	=item ev_loop_destroy (loop)
598		603
599	Like C<ev_default_destroy>, but destroys an event loop created by an	604	Like C<ev_default_destroy>, but destroys an event loop created by an
600	earlier call to C<ev_loop_new>.	605	earlier call to C<ev_loop_new>.
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606	name, you can call it anytime, but it makes most sense after forking, in	611	name, you can call it anytime, but it makes most sense after forking, in
607	the child process (or both child and parent, but that again makes little	612	the child process (or both child and parent, but that again makes little
608	sense). You I<must> call it in the child before using any of the libev	613	sense). You I<must> call it in the child before using any of the libev
609	functions, and it will only take effect at the next C<ev_loop> iteration.	614	functions, and it will only take effect at the next C<ev_loop> iteration.
610		615
		616	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
		618	because some kernel interfaces cough I<kqueue> cough do funny things
		619	during fork.
		620
611	On the other hand, you only need to call this function in the child	621	On the other hand, you only need to call this function in the child
612	process if and only if you want to use the event library in the child. If	622	process if and only if you want to use the event loop in the child. If you
613	you just fork+exec, you don't have to call it at all.	623	just fork+exec or create a new loop in the child, you don't have to call
		624	it at all.
614		625
615	The function itself is quite fast and it's usually not a problem to call	626	The function itself is quite fast and it's usually not a problem to call
616	it just in case after a fork. To make this easy, the function will fit in	627	it just in case after a fork. To make this easy, the function will fit in
617	quite nicely into a call to C<pthread_atfork>:	628	quite nicely into a call to C<pthread_atfork>:
618		629
…		…
620		631
621	=item ev_loop_fork (loop)	632	=item ev_loop_fork (loop)
622		633
623	Like C<ev_default_fork>, but acts on an event loop created by	634	Like C<ev_default_fork>, but acts on an event loop created by
624	C<ev_loop_new>. Yes, you have to call this on every allocated event loop	635	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
625	after fork that you want to re-use in the child, and how you do this is	636	after fork that you want to re-use in the child, and how you keep track of
626	entirely your own problem.	637	them is entirely your own problem.
627		638
628	=item int ev_is_default_loop (loop)	639	=item int ev_is_default_loop (loop)
629		640
630	Returns true when the given loop is, in fact, the default loop, and false	641	Returns true when the given loop is, in fact, the default loop, and false
631	otherwise.	642	otherwise.
632		643
633	=item unsigned int ev_loop_count (loop)	644	=item unsigned int ev_iteration (loop)
634		645
635	Returns the count of loop iterations for the loop, which is identical to	646	Returns the current iteration count for the loop, which is identical to
636	the number of times libev did poll for new events. It starts at C<0> and	647	the number of times libev did poll for new events. It starts at C<0> and
637	happily wraps around with enough iterations.	648	happily wraps around with enough iterations.
638		649
639	This value can sometimes be useful as a generation counter of sorts (it	650	This value can sometimes be useful as a generation counter of sorts (it
640	"ticks" the number of loop iterations), as it roughly corresponds with	651	"ticks" the number of loop iterations), as it roughly corresponds with
641	C<ev_prepare> and C<ev_check> calls.	652	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		653	prepare and check phases.
642		654
643	=item unsigned int ev_loop_depth (loop)	655	=item unsigned int ev_depth (loop)
644		656
645	Returns the number of times C<ev_loop> was entered minus the number of	657	Returns the number of times C<ev_loop> was entered minus the number of
646	times C<ev_loop> was exited, in other words, the recursion depth.	658	times C<ev_loop> was exited, in other words, the recursion depth.
647		659
648	Outside C<ev_loop>, this number is zero. In a callback, this number is	660	Outside C<ev_loop>, this number is zero. In a callback, this number is
649	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	661	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),
650	in which case it is higher.	662	in which case it is higher.
651		663
652	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	664	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread
653	etc.), doesn't count as exit.	665	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		666	ungentleman behaviour unless it's really convenient.
654		667
655	=item unsigned int ev_backend (loop)	668	=item unsigned int ev_backend (loop)
656		669
657	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	670	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
658	use.	671	use.
…		…
692	C<ev_resume> directly afterwards to resume timer processing.	705	C<ev_resume> directly afterwards to resume timer processing.
693		706
694	Effectively, all C<ev_timer> watchers will be delayed by the time spend	707	Effectively, all C<ev_timer> watchers will be delayed by the time spend
695	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	708	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
696	will be rescheduled (that is, they will lose any events that would have	709	will be rescheduled (that is, they will lose any events that would have
697	occured while suspended).	710	occurred while suspended).
698		711
699	After calling C<ev_suspend> you B<must not> call I<any> function on the	712	After calling C<ev_suspend> you B<must not> call I<any> function on the
700	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	713	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
701	without a previous call to C<ev_suspend>.	714	without a previous call to C<ev_suspend>.
702		715
…		…
704	event loop time (see C<ev_now_update>).	717	event loop time (see C<ev_now_update>).
705		718
706	=item ev_loop (loop, int flags)	719	=item ev_loop (loop, int flags)
707		720
708	Finally, this is it, the event handler. This function usually is called	721	Finally, this is it, the event handler. This function usually is called
709	after you initialised all your watchers and you want to start handling	722	after you have initialised all your watchers and you want to start
710	events.	723	handling events.
711		724
712	If the flags argument is specified as C<0>, it will not return until	725	If the flags argument is specified as C<0>, it will not return until
713	either no event watchers are active anymore or C<ev_unloop> was called.	726	either no event watchers are active anymore or C<ev_unloop> was called.
714		727
715	Please note that an explicit C<ev_unloop> is usually better than	728	Please note that an explicit C<ev_unloop> is usually better than
…		…
779	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	792	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
780	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	793	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
781		794
782	This "unloop state" will be cleared when entering C<ev_loop> again.	795	This "unloop state" will be cleared when entering C<ev_loop> again.
783		796
784	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	797	It is safe to call C<ev_unloop> from outside any C<ev_loop> calls.
785		798
786	=item ev_ref (loop)	799	=item ev_ref (loop)
787		800
788	=item ev_unref (loop)	801	=item ev_unref (loop)
789		802
790	Ref/unref can be used to add or remove a reference count on the event	803	Ref/unref can be used to add or remove a reference count on the event
791	loop: Every watcher keeps one reference, and as long as the reference	804	loop: Every watcher keeps one reference, and as long as the reference
792	count is nonzero, C<ev_loop> will not return on its own.	805	count is nonzero, C<ev_loop> will not return on its own.
793		806
794	If you have a watcher you never unregister that should not keep C<ev_loop>	807	This is useful when you have a watcher that you never intend to
795	from returning, call ev_unref() after starting, and ev_ref() before	808	unregister, but that nevertheless should not keep C<ev_loop> from
		809	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
796	stopping it.	810	before stopping it.
797		811
798	As an example, libev itself uses this for its internal signal pipe: It	812	As an example, libev itself uses this for its internal signal pipe: It
799	is not visible to the libev user and should not keep C<ev_loop> from	813	is not visible to the libev user and should not keep C<ev_loop> from
800	exiting if no event watchers registered by it are active. It is also an	814	exiting if no event watchers registered by it are active. It is also an
801	excellent way to do this for generic recurring timers or from within	815	excellent way to do this for generic recurring timers or from within
…		…
858	usually doesn't make much sense to set it to a lower value than C<0.01>,	872	usually doesn't make much sense to set it to a lower value than C<0.01>,
859	as this approaches the timing granularity of most systems. Note that if	873	as this approaches the timing granularity of most systems. Note that if
860	you do transactions with the outside world and you can't increase the	874	you do transactions with the outside world and you can't increase the
861	parallelity, then this setting will limit your transaction rate (if you	875	parallelity, then this setting will limit your transaction rate (if you
862	need to poll once per transaction and the I/O collect interval is 0.01,	876	need to poll once per transaction and the I/O collect interval is 0.01,
863	then you can't do more than 100 transations per second).	877	then you can't do more than 100 transactions per second).
864		878
865	Setting the I<timeout collect interval> can improve the opportunity for	879	Setting the I<timeout collect interval> can improve the opportunity for
866	saving power, as the program will "bundle" timer callback invocations that	880	saving power, as the program will "bundle" timer callback invocations that
867	are "near" in time together, by delaying some, thus reducing the number of	881	are "near" in time together, by delaying some, thus reducing the number of
868	times the process sleeps and wakes up again. Another useful technique to	882	times the process sleeps and wakes up again. Another useful technique to
…		…
916		930
917	While event loop modifications are allowed between invocations of	931	While event loop modifications are allowed between invocations of
918	C<release> and C<acquire> (that's their only purpose after all), no	932	C<release> and C<acquire> (that's their only purpose after all), no
919	modifications done will affect the event loop, i.e. adding watchers will	933	modifications done will affect the event loop, i.e. adding watchers will
920	have no effect on the set of file descriptors being watched, or the time	934	have no effect on the set of file descriptors being watched, or the time
921	waited. USe an C<ev_async> watcher to wake up C<ev_loop> when you want it	935	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it
922	to take note of any changes you made.	936	to take note of any changes you made.
923		937
924	In theory, threads executing C<ev_loop> will be async-cancel safe between	938	In theory, threads executing C<ev_loop> will be async-cancel safe between
925	invocations of C<release> and C<acquire>.	939	invocations of C<release> and C<acquire>.
926		940
…		…
1023	=item C<EV_WRITE>	1037	=item C<EV_WRITE>
1024		1038
1025	The file descriptor in the C<ev_io> watcher has become readable and/or	1039	The file descriptor in the C<ev_io> watcher has become readable and/or
1026	writable.	1040	writable.
1027		1041
1028	=item C<EV_TIMEOUT>	1042	=item C<EV_TIMER>
1029		1043
1030	The C<ev_timer> watcher has timed out.	1044	The C<ev_timer> watcher has timed out.
1031		1045
1032	=item C<EV_PERIODIC>	1046	=item C<EV_PERIODIC>
1033		1047
…		…
1123		1137
1124	ev_io w;	1138	ev_io w;
1125	ev_init (&w, my_cb);	1139	ev_init (&w, my_cb);
1126	ev_io_set (&w, STDIN_FILENO, EV_READ);	1140	ev_io_set (&w, STDIN_FILENO, EV_READ);
1127		1141
1128	=item C<ev_TYPE_set> (ev_TYPE *, [args])	1142	=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
1129		1143
1130	This macro initialises the type-specific parts of a watcher. You need to	1144	This macro initialises the type-specific parts of a watcher. You need to
1131	call C<ev_init> at least once before you call this macro, but you can	1145	call C<ev_init> at least once before you call this macro, but you can
1132	call C<ev_TYPE_set> any number of times. You must not, however, call this	1146	call C<ev_TYPE_set> any number of times. You must not, however, call this
1133	macro on a watcher that is active (it can be pending, however, which is a	1147	macro on a watcher that is active (it can be pending, however, which is a
…		…
1146		1160
1147	Example: Initialise and set an C<ev_io> watcher in one step.	1161	Example: Initialise and set an C<ev_io> watcher in one step.
1148		1162
1149	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);	1163	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
1150		1164
1151	=item C<ev_TYPE_start> (loop , ev_TYPE watcher)	1165	=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
1152		1166
1153	Starts (activates) the given watcher. Only active watchers will receive	1167	Starts (activates) the given watcher. Only active watchers will receive
1154	events. If the watcher is already active nothing will happen.	1168	events. If the watcher is already active nothing will happen.
1155		1169
1156	Example: Start the C<ev_io> watcher that is being abused as example in this	1170	Example: Start the C<ev_io> watcher that is being abused as example in this
1157	whole section.	1171	whole section.
1158		1172
1159	ev_io_start (EV_DEFAULT_UC, &w);	1173	ev_io_start (EV_DEFAULT_UC, &w);
1160		1174
1161	=item C<ev_TYPE_stop> (loop , ev_TYPE watcher)	1175	=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
1162		1176
1163	Stops the given watcher if active, and clears the pending status (whether	1177	Stops the given watcher if active, and clears the pending status (whether
1164	the watcher was active or not).	1178	the watcher was active or not).
1165		1179
1166	It is possible that stopped watchers are pending - for example,	1180	It is possible that stopped watchers are pending - for example,
…		…
1191	=item ev_cb_set (ev_TYPE *watcher, callback)	1205	=item ev_cb_set (ev_TYPE *watcher, callback)
1192		1206
1193	Change the callback. You can change the callback at virtually any time	1207	Change the callback. You can change the callback at virtually any time
1194	(modulo threads).	1208	(modulo threads).
1195		1209
1196	=item ev_set_priority (ev_TYPE *watcher, priority)	1210	=item ev_set_priority (ev_TYPE *watcher, int priority)
1197		1211
1198	=item int ev_priority (ev_TYPE *watcher)	1212	=item int ev_priority (ev_TYPE *watcher)
1199		1213
1200	Set and query the priority of the watcher. The priority is a small	1214	Set and query the priority of the watcher. The priority is a small
1201	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>	1215	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
…		…
1232	returns its C<revents> bitset (as if its callback was invoked). If the	1246	returns its C<revents> bitset (as if its callback was invoked). If the
1233	watcher isn't pending it does nothing and returns C<0>.	1247	watcher isn't pending it does nothing and returns C<0>.
1234		1248
1235	Sometimes it can be useful to "poll" a watcher instead of waiting for its	1249	Sometimes it can be useful to "poll" a watcher instead of waiting for its
1236	callback to be invoked, which can be accomplished with this function.	1250	callback to be invoked, which can be accomplished with this function.
		1251
		1252	=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
		1253
		1254	Feeds the given event set into the event loop, as if the specified event
		1255	had happened for the specified watcher (which must be a pointer to an
		1256	initialised but not necessarily started event watcher). Obviously you must
		1257	not free the watcher as long as it has pending events.
		1258
		1259	Stopping the watcher, letting libev invoke it, or calling
		1260	C<ev_clear_pending> will clear the pending event, even if the watcher was
		1261	not started in the first place.
		1262
		1263	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
		1264	functions that do not need a watcher.
1237		1265
1238	=back	1266	=back
1239		1267
1240		1268
1241	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1269	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
1352		1380
1353	For example, to emulate how many other event libraries handle priorities,	1381	For example, to emulate how many other event libraries handle priorities,
1354	you can associate an C<ev_idle> watcher to each such watcher, and in	1382	you can associate an C<ev_idle> watcher to each such watcher, and in
1355	the normal watcher callback, you just start the idle watcher. The real	1383	the normal watcher callback, you just start the idle watcher. The real
1356	processing is done in the idle watcher callback. This causes libev to	1384	processing is done in the idle watcher callback. This causes libev to
1357	continously poll and process kernel event data for the watcher, but when	1385	continuously poll and process kernel event data for the watcher, but when
1358	the lock-out case is known to be rare (which in turn is rare :), this is	1386	the lock-out case is known to be rare (which in turn is rare :), this is
1359	workable.	1387	workable.
1360		1388
1361	Usually, however, the lock-out model implemented that way will perform	1389	Usually, however, the lock-out model implemented that way will perform
1362	miserably under the type of load it was designed to handle. In that case,	1390	miserably under the type of load it was designed to handle. In that case,
…		…
1376	{	1404	{
1377	// stop the I/O watcher, we received the event, but	1405	// stop the I/O watcher, we received the event, but
1378	// are not yet ready to handle it.	1406	// are not yet ready to handle it.
1379	ev_io_stop (EV_A_ w);	1407	ev_io_stop (EV_A_ w);
1380		1408
1381	// start the idle watcher to ahndle the actual event.	1409	// start the idle watcher to handle the actual event.
1382	// it will not be executed as long as other watchers	1410	// it will not be executed as long as other watchers
1383	// with the default priority are receiving events.	1411	// with the default priority are receiving events.
1384	ev_idle_start (EV_A_ &idle);	1412	ev_idle_start (EV_A_ &idle);
1385	}	1413	}
1386		1414
…		…
1440		1468
1441	If you cannot use non-blocking mode, then force the use of a	1469	If you cannot use non-blocking mode, then force the use of a
1442	known-to-be-good backend (at the time of this writing, this includes only	1470	known-to-be-good backend (at the time of this writing, this includes only
1443	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1471	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1444	descriptors for which non-blocking operation makes no sense (such as	1472	descriptors for which non-blocking operation makes no sense (such as
1445	files) - libev doesn't guarentee any specific behaviour in that case.	1473	files) - libev doesn't guarantee any specific behaviour in that case.
1446		1474
1447	Another thing you have to watch out for is that it is quite easy to	1475	Another thing you have to watch out for is that it is quite easy to
1448	receive "spurious" readiness notifications, that is your callback might	1476	receive "spurious" readiness notifications, that is your callback might
1449	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1477	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1450	because there is no data. Not only are some backends known to create a	1478	because there is no data. Not only are some backends known to create a
…		…
1515		1543
1516	So when you encounter spurious, unexplained daemon exits, make sure you	1544	So when you encounter spurious, unexplained daemon exits, make sure you
1517	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1545	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1518	somewhere, as that would have given you a big clue).	1546	somewhere, as that would have given you a big clue).
1519		1547
		1548	=head3 The special problem of accept()ing when you can't
		1549
		1550	Many implementations of the POSIX C<accept> function (for example,
		1551	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1552	connection from the pending queue in all error cases.
		1553
		1554	For example, larger servers often run out of file descriptors (because
		1555	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1556	rejecting the connection, leading to libev signalling readiness on
		1557	the next iteration again (the connection still exists after all), and
		1558	typically causing the program to loop at 100% CPU usage.
		1559
		1560	Unfortunately, the set of errors that cause this issue differs between
		1561	operating systems, there is usually little the app can do to remedy the
		1562	situation, and no known thread-safe method of removing the connection to
		1563	cope with overload is known (to me).
		1564
		1565	One of the easiest ways to handle this situation is to just ignore it
		1566	- when the program encounters an overload, it will just loop until the
		1567	situation is over. While this is a form of busy waiting, no OS offers an
		1568	event-based way to handle this situation, so it's the best one can do.
		1569
		1570	A better way to handle the situation is to log any errors other than
		1571	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1572	messages, and continue as usual, which at least gives the user an idea of
		1573	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1574	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1575	usage.
		1576
		1577	If your program is single-threaded, then you could also keep a dummy file
		1578	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1579	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1580	close that fd, and create a new dummy fd. This will gracefully refuse
		1581	clients under typical overload conditions.
		1582
		1583	The last way to handle it is to simply log the error and C<exit>, as
		1584	is often done with C<malloc> failures, but this results in an easy
		1585	opportunity for a DoS attack.
1520		1586
1521	=head3 Watcher-Specific Functions	1587	=head3 Watcher-Specific Functions
1522		1588
1523	=over 4	1589	=over 4
1524		1590
…		…
1671	ev_tstamp timeout = last_activity + 60.;	1737	ev_tstamp timeout = last_activity + 60.;
1672		1738
1673	// if last_activity + 60. is older than now, we did time out	1739	// if last_activity + 60. is older than now, we did time out
1674	if (timeout < now)	1740	if (timeout < now)
1675	{	1741	{
1676	// timeout occured, take action	1742	// timeout occurred, take action
1677	}	1743	}
1678	else	1744	else
1679	{	1745	{
1680	// callback was invoked, but there was some activity, re-arm	1746	// callback was invoked, but there was some activity, re-arm
1681	// the watcher to fire in last_activity + 60, which is	1747	// the watcher to fire in last_activity + 60, which is
…		…
1703	to the current time (meaning we just have some activity :), then call the	1769	to the current time (meaning we just have some activity :), then call the
1704	callback, which will "do the right thing" and start the timer:	1770	callback, which will "do the right thing" and start the timer:
1705		1771
1706	ev_init (timer, callback);	1772	ev_init (timer, callback);
1707	last_activity = ev_now (loop);	1773	last_activity = ev_now (loop);
1708	callback (loop, timer, EV_TIMEOUT);	1774	callback (loop, timer, EV_TIMER);
1709		1775
1710	And when there is some activity, simply store the current time in	1776	And when there is some activity, simply store the current time in
1711	C<last_activity>, no libev calls at all:	1777	C<last_activity>, no libev calls at all:
1712		1778
1713	last_actiivty = ev_now (loop);	1779	last_activity = ev_now (loop);
1714		1780
1715	This technique is slightly more complex, but in most cases where the	1781	This technique is slightly more complex, but in most cases where the
1716	time-out is unlikely to be triggered, much more efficient.	1782	time-out is unlikely to be triggered, much more efficient.
1717		1783
1718	Changing the timeout is trivial as well (if it isn't hard-coded in the	1784	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1837	C<repeat> value), or reset the running timer to the C<repeat> value.	1903	C<repeat> value), or reset the running timer to the C<repeat> value.
1838		1904
1839	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a	1905	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a
1840	usage example.	1906	usage example.
1841		1907
1842	=item ev_timer_remaining (loop, ev_timer *)	1908	=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
1843		1909
1844	Returns the remaining time until a timer fires. If the timer is active,	1910	Returns the remaining time until a timer fires. If the timer is active,
1845	then this time is relative to the current event loop time, otherwise it's	1911	then this time is relative to the current event loop time, otherwise it's
1846	the timeout value currently configured.	1912	the timeout value currently configured.
1847		1913
1848	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns	1914	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
1849	C<5>. When the timer is started and one second passes, C<ev_timer_remain>	1915	C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
1850	will return C<4>. When the timer expires and is restarted, it will return	1916	will return C<4>. When the timer expires and is restarted, it will return
1851	roughly C<7> (likely slightly less as callback invocation takes some time,	1917	roughly C<7> (likely slightly less as callback invocation takes some time,
1852	too), and so on.	1918	too), and so on.
1853		1919
1854	=item ev_tstamp repeat [read-write]	1920	=item ev_tstamp repeat [read-write]
…		…
2057	Example: Call a callback every hour, or, more precisely, whenever the	2123	Example: Call a callback every hour, or, more precisely, whenever the
2058	system time is divisible by 3600. The callback invocation times have	2124	system time is divisible by 3600. The callback invocation times have
2059	potentially a lot of jitter, but good long-term stability.	2125	potentially a lot of jitter, but good long-term stability.
2060		2126
2061	static void	2127	static void
2062	clock_cb (struct ev_loop loop, ev_io w, int revents)	2128	clock_cb (struct ev_loop loop, ev_periodic w, int revents)
2063	{	2129	{
2064	... its now a full hour (UTC, or TAI or whatever your clock follows)	2130	... its now a full hour (UTC, or TAI or whatever your clock follows)
2065	}	2131	}
2066		2132
2067	ev_periodic hourly_tick;	2133	ev_periodic hourly_tick;
…		…
2114	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should	2180	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2115	not be unduly interrupted. If you have a problem with system calls getting	2181	not be unduly interrupted. If you have a problem with system calls getting
2116	interrupted by signals you can block all signals in an C<ev_check> watcher	2182	interrupted by signals you can block all signals in an C<ev_check> watcher
2117	and unblock them in an C<ev_prepare> watcher.	2183	and unblock them in an C<ev_prepare> watcher.
2118		2184
2119	=head3 The special problem of inheritance over execve	2185	=head3 The special problem of inheritance over fork/execve/pthread_create
2120		2186
2121	Both the signal mask (C<sigprocmask>) and the signal disposition	2187	Both the signal mask (C<sigprocmask>) and the signal disposition
2122	(C<sigaction>) are unspecified after starting a signal watcher (and after	2188	(C<sigaction>) are unspecified after starting a signal watcher (and after
2123	stopping it again), that is, libev might or might not block the signal,	2189	stopping it again), that is, libev might or might not block the signal,
2124	and might or might not set or restore the installed signal handler.	2190	and might or might not set or restore the installed signal handler.
…		…
2130		2196
2131	This means that before calling C<exec> (from the child) you should reset	2197	This means that before calling C<exec> (from the child) you should reset
2132	the signal mask to whatever "default" you expect (all clear is a good	2198	the signal mask to whatever "default" you expect (all clear is a good
2133	choice usually).	2199	choice usually).
2134		2200
2135	In current versions of libev, you can ensure that the signal mask is not	2201	The simplest way to ensure that the signal mask is reset in the child is
2136	blocking any signals (except temporarily, so thread users watch out) by	2202	to install a fork handler with C<pthread_atfork> that resets it. That will
2137	specifying the C<EVFLAG_NOSIGNALFD> when creating the event loop. This is	2203	catch fork calls done by libraries (such as the libc) as well.
2138	not guaranteed for future versions, however.	2204
		2205	In current versions of libev, the signal will not be blocked indefinitely
		2206	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
		2207	the window of opportunity for problems, it will not go away, as libev
		2208	I<has> to modify the signal mask, at least temporarily.
		2209
		2210	So I can't stress this enough: I<If you do not reset your signal mask when
		2211	you expect it to be empty, you have a race condition in your code>. This
		2212	is not a libev-specific thing, this is true for most event libraries.
2139		2213
2140	=head3 Watcher-Specific Functions and Data Members	2214	=head3 Watcher-Specific Functions and Data Members
2141		2215
2142	=over 4	2216	=over 4
2143		2217
…		…
2891	C<ev_default_fork> cheats and calls it in the wrong process, the fork	2965	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2892	handlers will be invoked, too, of course.	2966	handlers will be invoked, too, of course.
2893		2967
2894	=head3 The special problem of life after fork - how is it possible?	2968	=head3 The special problem of life after fork - how is it possible?
2895		2969
2896	Most uses of C<fork()> consist of forking, then some simple calls to ste	2970	Most uses of C<fork()> consist of forking, then some simple calls to set
2897	up/change the process environment, followed by a call to C<exec()>. This	2971	up/change the process environment, followed by a call to C<exec()>. This
2898	sequence should be handled by libev without any problems.	2972	sequence should be handled by libev without any problems.
2899		2973
2900	This changes when the application actually wants to do event handling	2974	This changes when the application actually wants to do event handling
2901	in the child, or both parent in child, in effect "continuing" after the	2975	in the child, or both parent in child, in effect "continuing" after the
…		…
2935	believe me.	3009	believe me.
2936		3010
2937	=back	3011	=back
2938		3012
2939		3013
2940	=head2 C<ev_async> - how to wake up another event loop	3014	=head2 C<ev_async> - how to wake up an event loop
2941		3015
2942	In general, you cannot use an C<ev_loop> from multiple threads or other	3016	In general, you cannot use an C<ev_loop> from multiple threads or other
2943	asynchronous sources such as signal handlers (as opposed to multiple event	3017	asynchronous sources such as signal handlers (as opposed to multiple event
2944	loops - those are of course safe to use in different threads).	3018	loops - those are of course safe to use in different threads).
2945		3019
2946	Sometimes, however, you need to wake up another event loop you do not	3020	Sometimes, however, you need to wake up an event loop you do not control,
2947	control, for example because it belongs to another thread. This is what	3021	for example because it belongs to another thread. This is what C<ev_async>
2948	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3022	watchers do: as long as the C<ev_async> watcher is active, you can signal
2949	can signal it by calling C<ev_async_send>, which is thread- and signal	3023	it by calling C<ev_async_send>, which is thread- and signal safe.
2950	safe.
2951		3024
2952	This functionality is very similar to C<ev_signal> watchers, as signals,	3025	This functionality is very similar to C<ev_signal> watchers, as signals,
2953	too, are asynchronous in nature, and signals, too, will be compressed	3026	too, are asynchronous in nature, and signals, too, will be compressed
2954	(i.e. the number of callback invocations may be less than the number of	3027	(i.e. the number of callback invocations may be less than the number of
2955	C<ev_async_sent> calls).	3028	C<ev_async_sent> calls).
…		…
2960	=head3 Queueing	3033	=head3 Queueing
2961		3034
2962	C<ev_async> does not support queueing of data in any way. The reason	3035	C<ev_async> does not support queueing of data in any way. The reason
2963	is that the author does not know of a simple (or any) algorithm for a	3036	is that the author does not know of a simple (or any) algorithm for a
2964	multiple-writer-single-reader queue that works in all cases and doesn't	3037	multiple-writer-single-reader queue that works in all cases and doesn't
2965	need elaborate support such as pthreads.	3038	need elaborate support such as pthreads or unportable memory access
		3039	semantics.
2966		3040
2967	That means that if you want to queue data, you have to provide your own	3041	That means that if you want to queue data, you have to provide your own
2968	queue. But at least I can tell you how to implement locking around your	3042	queue. But at least I can tell you how to implement locking around your
2969	queue:	3043	queue:
2970		3044
…		…
3109		3183
3110	If C<timeout> is less than 0, then no timeout watcher will be	3184	If C<timeout> is less than 0, then no timeout watcher will be
3111	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3185	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3112	repeat = 0) will be started. C<0> is a valid timeout.	3186	repeat = 0) will be started. C<0> is a valid timeout.
3113		3187
3114	The callback has the type C<void (cb)(int revents, void arg)> and gets	3188	The callback has the type C<void (cb)(int revents, void arg)> and is
3115	passed an C<revents> set like normal event callbacks (a combination of	3189	passed an C<revents> set like normal event callbacks (a combination of
3116	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3190	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3117	value passed to C<ev_once>. Note that it is possible to receive I<both>	3191	value passed to C<ev_once>. Note that it is possible to receive I<both>
3118	a timeout and an io event at the same time - you probably should give io	3192	a timeout and an io event at the same time - you probably should give io
3119	events precedence.	3193	events precedence.
3120		3194
3121	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3195	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3122		3196
3123	static void stdin_ready (int revents, void *arg)	3197	static void stdin_ready (int revents, void *arg)
3124	{	3198	{
3125	if (revents & EV_READ)	3199	if (revents & EV_READ)
3126	/* stdin might have data for us, joy! */;	3200	/* stdin might have data for us, joy! */;
3127	else if (revents & EV_TIMEOUT)	3201	else if (revents & EV_TIMER)
3128	/* doh, nothing entered */;	3202	/* doh, nothing entered */;
3129	}	3203	}
3130		3204
3131	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3205	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3132		3206
3133	=item ev_feed_event (struct ev_loop , watcher , int revents)
3134
3135	Feeds the given event set into the event loop, as if the specified event
3136	had happened for the specified watcher (which must be a pointer to an
3137	initialised but not necessarily started event watcher).
3138
3139	=item ev_feed_fd_event (struct ev_loop *, int fd, int revents)	3207	=item ev_feed_fd_event (loop, int fd, int revents)
3140		3208
3141	Feed an event on the given fd, as if a file descriptor backend detected	3209	Feed an event on the given fd, as if a file descriptor backend detected
3142	the given events it.	3210	the given events it.
3143		3211
3144	=item ev_feed_signal_event (struct ev_loop *loop, int signum)	3212	=item ev_feed_signal_event (loop, int signum)
3145		3213
3146	Feed an event as if the given signal occurred (C<loop> must be the default	3214	Feed an event as if the given signal occurred (C<loop> must be the default
3147	loop!).	3215	loop!).
3148		3216
3149	=back	3217	=back
…		…
3229		3297
3230	=over 4	3298	=over 4
3231		3299
3232	=item ev::TYPE::TYPE ()	3300	=item ev::TYPE::TYPE ()
3233		3301
3234	=item ev::TYPE::TYPE (struct ev_loop *)	3302	=item ev::TYPE::TYPE (loop)
3235		3303
3236	=item ev::TYPE::~TYPE	3304	=item ev::TYPE::~TYPE
3237		3305
3238	The constructor (optionally) takes an event loop to associate the watcher	3306	The constructor (optionally) takes an event loop to associate the watcher
3239	with. If it is omitted, it will use C<EV_DEFAULT>.	3307	with. If it is omitted, it will use C<EV_DEFAULT>.
…		…
3272	myclass obj;	3340	myclass obj;
3273	ev::io iow;	3341	ev::io iow;
3274	iow.set <myclass, &myclass::io_cb> (&obj);	3342	iow.set <myclass, &myclass::io_cb> (&obj);
3275		3343
3276	=item w->set (object *)	3344	=item w->set (object *)
3277
3278	This is an B<experimental> feature that might go away in a future version.
3279		3345
3280	This is a variation of a method callback - leaving out the method to call	3346	This is a variation of a method callback - leaving out the method to call
3281	will default the method to C<operator ()>, which makes it possible to use	3347	will default the method to C<operator ()>, which makes it possible to use
3282	functor objects without having to manually specify the C<operator ()> all	3348	functor objects without having to manually specify the C<operator ()> all
3283	the time. Incidentally, you can then also leave out the template argument	3349	the time. Incidentally, you can then also leave out the template argument
…		…
3316	Example: Use a plain function as callback.	3382	Example: Use a plain function as callback.
3317		3383
3318	static void io_cb (ev::io &w, int revents) { }	3384	static void io_cb (ev::io &w, int revents) { }
3319	iow.set <io_cb> ();	3385	iow.set <io_cb> ();
3320		3386
3321	=item w->set (struct ev_loop *)	3387	=item w->set (loop)
3322		3388
3323	Associates a different C<struct ev_loop> with this watcher. You can only	3389	Associates a different C<struct ev_loop> with this watcher. You can only
3324	do this when the watcher is inactive (and not pending either).	3390	do this when the watcher is inactive (and not pending either).
3325		3391
3326	=item w->set ([arguments])	3392	=item w->set ([arguments])
…		…
3425	Erkki Seppala has written Ocaml bindings for libev, to be found at	3491	Erkki Seppala has written Ocaml bindings for libev, to be found at
3426	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.	3492	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3427		3493
3428	=item Lua	3494	=item Lua
3429		3495
3430	Brian Maher has written a partial interface to libev	3496	Brian Maher has written a partial interface to libev for lua (at the
3431	for lua (only C<ev_io> and C<ev_timer>), to be found at	3497	time of this writing, only C<ev_io> and C<ev_timer>), to be found at
3432	L<http://github.com/brimworks/lua-ev>.	3498	L<http://github.com/brimworks/lua-ev>.
3433		3499
3434	=back	3500	=back
3435		3501
3436		3502
…		…
3591	libev.m4	3657	libev.m4
3592		3658
3593	=head2 PREPROCESSOR SYMBOLS/MACROS	3659	=head2 PREPROCESSOR SYMBOLS/MACROS
3594		3660
3595	Libev can be configured via a variety of preprocessor symbols you have to	3661	Libev can be configured via a variety of preprocessor symbols you have to
3596	define before including any of its files. The default in the absence of	3662	define before including (or compiling) any of its files. The default in
3597	autoconf is documented for every option.	3663	the absence of autoconf is documented for every option.
		3664
		3665	Symbols marked with "(h)" do not change the ABI, and can have different
		3666	values when compiling libev vs. including F<ev.h>, so it is permissible
		3667	to redefine them before including F<ev.h> without breaking compatibility
		3668	to a compiled library. All other symbols change the ABI, which means all
		3669	users of libev and the libev code itself must be compiled with compatible
		3670	settings.
3598		3671
3599	=over 4	3672	=over 4
3600		3673
3601	=item EV_STANDALONE	3674	=item EV_STANDALONE (h)
3602		3675
3603	Must always be C<1> if you do not use autoconf configuration, which	3676	Must always be C<1> if you do not use autoconf configuration, which
3604	keeps libev from including F<config.h>, and it also defines dummy	3677	keeps libev from including F<config.h>, and it also defines dummy
3605	implementations for some libevent functions (such as logging, which is not	3678	implementations for some libevent functions (such as logging, which is not
3606	supported). It will also not define any of the structs usually found in	3679	supported). It will also not define any of the structs usually found in
…		…
3756	as well as for signal and thread safety in C<ev_async> watchers.	3829	as well as for signal and thread safety in C<ev_async> watchers.
3757		3830
3758	In the absence of this define, libev will use C<sig_atomic_t volatile>	3831	In the absence of this define, libev will use C<sig_atomic_t volatile>
3759	(from F<signal.h>), which is usually good enough on most platforms.	3832	(from F<signal.h>), which is usually good enough on most platforms.
3760		3833
3761	=item EV_H	3834	=item EV_H (h)
3762		3835
3763	The name of the F<ev.h> header file used to include it. The default if	3836	The name of the F<ev.h> header file used to include it. The default if
3764	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be	3837	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
3765	used to virtually rename the F<ev.h> header file in case of conflicts.	3838	used to virtually rename the F<ev.h> header file in case of conflicts.
3766		3839
3767	=item EV_CONFIG_H	3840	=item EV_CONFIG_H (h)
3768		3841
3769	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	3842	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
3770	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	3843	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
3771	C<EV_H>, above.	3844	C<EV_H>, above.
3772		3845
3773	=item EV_EVENT_H	3846	=item EV_EVENT_H (h)
3774		3847
3775	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	3848	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
3776	of how the F<event.h> header can be found, the default is C<"event.h">.	3849	of how the F<event.h> header can be found, the default is C<"event.h">.
3777		3850
3778	=item EV_PROTOTYPES	3851	=item EV_PROTOTYPES (h)
3779		3852
3780	If defined to be C<0>, then F<ev.h> will not define any function	3853	If defined to be C<0>, then F<ev.h> will not define any function
3781	prototypes, but still define all the structs and other symbols. This is	3854	prototypes, but still define all the structs and other symbols. This is
3782	occasionally useful if you want to provide your own wrapper functions	3855	occasionally useful if you want to provide your own wrapper functions
3783	around libev functions.	3856	around libev functions.
…		…
3805	fine.	3878	fine.
3806		3879
3807	If your embedding application does not need any priorities, defining these	3880	If your embedding application does not need any priorities, defining these
3808	both to C<0> will save some memory and CPU.	3881	both to C<0> will save some memory and CPU.
3809		3882
3810	=item EV_PERIODIC_ENABLE	3883	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		3884	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		3885	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3811		3886
3812	If undefined or defined to be C<1>, then periodic timers are supported. If	3887	If undefined or defined to be C<1> (and the platform supports it), then
3813	defined to be C<0>, then they are not. Disabling them saves a few kB of	3888	the respective watcher type is supported. If defined to be C<0>, then it
3814	code.	3889	is not. Disabling watcher types mainly saves code size.
3815		3890
3816	=item EV_IDLE_ENABLE	3891	=item EV_FEATURES
3817
3818	If undefined or defined to be C<1>, then idle watchers are supported. If
3819	defined to be C<0>, then they are not. Disabling them saves a few kB of
3820	code.
3821
3822	=item EV_EMBED_ENABLE
3823
3824	If undefined or defined to be C<1>, then embed watchers are supported. If
3825	defined to be C<0>, then they are not. Embed watchers rely on most other
3826	watcher types, which therefore must not be disabled.
3827
3828	=item EV_STAT_ENABLE
3829
3830	If undefined or defined to be C<1>, then stat watchers are supported. If
3831	defined to be C<0>, then they are not.
3832
3833	=item EV_FORK_ENABLE
3834
3835	If undefined or defined to be C<1>, then fork watchers are supported. If
3836	defined to be C<0>, then they are not.
3837
3838	=item EV_ASYNC_ENABLE
3839
3840	If undefined or defined to be C<1>, then async watchers are supported. If
3841	defined to be C<0>, then they are not.
3842
3843	=item EV_MINIMAL
3844		3892
3845	If you need to shave off some kilobytes of code at the expense of some	3893	If you need to shave off some kilobytes of code at the expense of some
3846	speed (but with the full API), define this symbol to C<1>. Currently this	3894	speed (but with the full API), you can define this symbol to request
3847	is used to override some inlining decisions, saves roughly 30% code size	3895	certain subsets of functionality. The default is to enable all features
3848	on amd64. It also selects a much smaller 2-heap for timer management over	3896	that can be enabled on the platform.
3849	the default 4-heap.
3850		3897
3851	You can save even more by disabling watcher types you do not need	3898	A typical way to use this symbol is to define it to C<0> (or to a bitset
3852	and setting C<EV_MAXPRI> == C<EV_MINPRI>. Also, disabling C<assert>	3899	with some broad features you want) and then selectively re-enable
3853	(C<-DNDEBUG>) will usually reduce code size a lot.	3900	additional parts you want, for example if you want everything minimal,
		3901	but multiple event loop support, async and child watchers and the poll
		3902	backend, use this:
3854		3903
3855	Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to	3904	#define EV_FEATURES 0
3856	provide a bare-bones event library. See C<ev.h> for details on what parts	3905	#define EV_MULTIPLICITY 1
3857	of the API are still available, and do not complain if this subset changes	3906	#define EV_USE_POLL 1
3858	over time.	3907	#define EV_CHILD_ENABLE 1
		3908	#define EV_ASYNC_ENABLE 1
		3909
		3910	The actual value is a bitset, it can be a combination of the following
		3911	values:
		3912
		3913	=over 4
		3914
		3915	=item C<1> - faster/larger code
		3916
		3917	Use larger code to speed up some operations.
		3918
		3919	Currently this is used to override some inlining decisions (enlarging the
		3920	code size by roughly 30% on amd64).
		3921
		3922	When optimising for size, use of compiler flags such as C<-Os> with
		3923	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		3924	assertions.
		3925
		3926	=item C<2> - faster/larger data structures
		3927
		3928	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		3929	hash table sizes and so on. This will usually further increase code size
		3930	and can additionally have an effect on the size of data structures at
		3931	runtime.
		3932
		3933	=item C<4> - full API configuration
		3934
		3935	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		3936	enables multiplicity (C<EV_MULTIPLICITY>=1).
		3937
		3938	=item C<8> - full API
		3939
		3940	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		3941	details on which parts of the API are still available without this
		3942	feature, and do not complain if this subset changes over time.
		3943
		3944	=item C<16> - enable all optional watcher types
		3945
		3946	Enables all optional watcher types. If you want to selectively enable
		3947	only some watcher types other than I/O and timers (e.g. prepare,
		3948	embed, async, child...) you can enable them manually by defining
		3949	C<EV_watchertype_ENABLE> to C<1> instead.
		3950
		3951	=item C<32> - enable all backends
		3952
		3953	This enables all backends - without this feature, you need to enable at
		3954	least one backend manually (C<EV_USE_SELECT> is a good choice).
		3955
		3956	=item C<64> - enable OS-specific "helper" APIs
		3957
		3958	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		3959	default.
		3960
		3961	=back
		3962
		3963	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		3964	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		3965	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		3966	watchers, timers and monotonic clock support.
		3967
		3968	With an intelligent-enough linker (gcc+binutils are intelligent enough
		3969	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		3970	your program might be left out as well - a binary starting a timer and an
		3971	I/O watcher then might come out at only 5Kb.
		3972
		3973	=item EV_AVOID_STDIO
		3974
		3975	If this is set to C<1> at compiletime, then libev will avoid using stdio
		3976	functions (printf, scanf, perror etc.). This will increase the code size
		3977	somewhat, but if your program doesn't otherwise depend on stdio and your
		3978	libc allows it, this avoids linking in the stdio library which is quite
		3979	big.
		3980
		3981	Note that error messages might become less precise when this option is
		3982	enabled.
3859		3983
3860	=item EV_NSIG	3984	=item EV_NSIG
3861		3985
3862	The highest supported signal number, +1 (or, the number of	3986	The highest supported signal number, +1 (or, the number of
3863	signals): Normally, libev tries to deduce the maximum number of signals	3987	signals): Normally, libev tries to deduce the maximum number of signals
3864	automatically, but sometimes this fails, in which case it can be	3988	automatically, but sometimes this fails, in which case it can be
3865	specified. Also, using a lower number than detected (C<32> should be	3989	specified. Also, using a lower number than detected (C<32> should be
3866	good for about any system in existance) can save some memory, as libev	3990	good for about any system in existence) can save some memory, as libev
3867	statically allocates some 12-24 bytes per signal number.	3991	statically allocates some 12-24 bytes per signal number.
3868		3992
3869	=item EV_PID_HASHSIZE	3993	=item EV_PID_HASHSIZE
3870		3994
3871	C<ev_child> watchers use a small hash table to distribute workload by	3995	C<ev_child> watchers use a small hash table to distribute workload by
3872	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	3996	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3873	than enough. If you need to manage thousands of children you might want to	3997	usually more than enough. If you need to manage thousands of children you
3874	increase this value (I<must> be a power of two).	3998	might want to increase this value (I<must> be a power of two).
3875		3999
3876	=item EV_INOTIFY_HASHSIZE	4000	=item EV_INOTIFY_HASHSIZE
3877		4001
3878	C<ev_stat> watchers use a small hash table to distribute workload by	4002	C<ev_stat> watchers use a small hash table to distribute workload by
3879	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4003	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3880	usually more than enough. If you need to manage thousands of C<ev_stat>	4004	disabled), usually more than enough. If you need to manage thousands of
3881	watchers you might want to increase this value (I<must> be a power of	4005	C<ev_stat> watchers you might want to increase this value (I<must> be a
3882	two).	4006	power of two).
3883		4007
3884	=item EV_USE_4HEAP	4008	=item EV_USE_4HEAP
3885		4009
3886	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4010	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3887	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4011	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3888	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4012	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3889	faster performance with many (thousands) of watchers.	4013	faster performance with many (thousands) of watchers.
3890		4014
3891	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4015	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3892	(disabled).	4016	will be C<0>.
3893		4017
3894	=item EV_HEAP_CACHE_AT	4018	=item EV_HEAP_CACHE_AT
3895		4019
3896	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4020	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3897	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4021	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3898	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4022	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3899	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4023	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3900	but avoids random read accesses on heap changes. This improves performance	4024	but avoids random read accesses on heap changes. This improves performance
3901	noticeably with many (hundreds) of watchers.	4025	noticeably with many (hundreds) of watchers.
3902		4026
3903	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4027	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3904	(disabled).	4028	will be C<0>.
3905		4029
3906	=item EV_VERIFY	4030	=item EV_VERIFY
3907		4031
3908	Controls how much internal verification (see C<ev_loop_verify ()>) will	4032	Controls how much internal verification (see C<ev_loop_verify ()>) will
3909	be done: If set to C<0>, no internal verification code will be compiled	4033	be done: If set to C<0>, no internal verification code will be compiled
…		…
3911	called. If set to C<2>, then the internal verification code will be	4035	called. If set to C<2>, then the internal verification code will be
3912	called once per loop, which can slow down libev. If set to C<3>, then the	4036	called once per loop, which can slow down libev. If set to C<3>, then the
3913	verification code will be called very frequently, which will slow down	4037	verification code will be called very frequently, which will slow down
3914	libev considerably.	4038	libev considerably.
3915		4039
3916	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4040	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3917	C<0>.	4041	will be C<0>.
3918		4042
3919	=item EV_COMMON	4043	=item EV_COMMON
3920		4044
3921	By default, all watchers have a C<void *data> member. By redefining	4045	By default, all watchers have a C<void *data> member. By redefining
3922	this macro to a something else you can include more and other types of	4046	this macro to something else you can include more and other types of
3923	members. You have to define it each time you include one of the files,	4047	members. You have to define it each time you include one of the files,
3924	though, and it must be identical each time.	4048	though, and it must be identical each time.
3925		4049
3926	For example, the perl EV module uses something like this:	4050	For example, the perl EV module uses something like this:
3927		4051
…		…
3980	file.	4104	file.
3981		4105
3982	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4106	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
3983	that everybody includes and which overrides some configure choices:	4107	that everybody includes and which overrides some configure choices:
3984		4108
3985	#define EV_MINIMAL 1	4109	#define EV_FEATURES 8
3986	#define EV_USE_POLL 0	4110	#define EV_USE_SELECT 1
3987	#define EV_MULTIPLICITY 0
3988	#define EV_PERIODIC_ENABLE 0	4111	#define EV_PREPARE_ENABLE 1
		4112	#define EV_IDLE_ENABLE 1
3989	#define EV_STAT_ENABLE 0	4113	#define EV_SIGNAL_ENABLE 1
3990	#define EV_FORK_ENABLE 0	4114	#define EV_CHILD_ENABLE 1
		4115	#define EV_USE_STDEXCEPT 0
3991	#define EV_CONFIG_H <config.h>	4116	#define EV_CONFIG_H <config.h>
3992	#define EV_MINPRI 0
3993	#define EV_MAXPRI 0
3994		4117
3995	#include "ev++.h"	4118	#include "ev++.h"
3996		4119
3997	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4120	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3998		4121
…		…
4227	maintainable.	4350	maintainable.
4228		4351
4229	And of course, some compiler warnings are just plain stupid, or simply	4352	And of course, some compiler warnings are just plain stupid, or simply
4230	wrong (because they don't actually warn about the condition their message	4353	wrong (because they don't actually warn about the condition their message
4231	seems to warn about). For example, certain older gcc versions had some	4354	seems to warn about). For example, certain older gcc versions had some
4232	warnings that resulted an extreme number of false positives. These have	4355	warnings that resulted in an extreme number of false positives. These have
4233	been fixed, but some people still insist on making code warn-free with	4356	been fixed, but some people still insist on making code warn-free with
4234	such buggy versions.	4357	such buggy versions.
4235		4358
4236	While libev is written to generate as few warnings as possible,	4359	While libev is written to generate as few warnings as possible,
4237	"warn-free" code is not a goal, and it is recommended not to build libev	4360	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4273	I suggest using suppression lists.	4396	I suggest using suppression lists.
4274		4397
4275		4398
4276	=head1 PORTABILITY NOTES	4399	=head1 PORTABILITY NOTES
4277		4400
		4401	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4402
		4403	GNU/Linux is the only common platform that supports 64 bit file/large file
		4404	interfaces but I<disables> them by default.
		4405
		4406	That means that libev compiled in the default environment doesn't support
		4407	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4408
		4409	Unfortunately, many programs try to work around this GNU/Linux issue
		4410	by enabling the large file API, which makes them incompatible with the
		4411	standard libev compiled for their system.
		4412
		4413	Likewise, libev cannot enable the large file API itself as this would
		4414	suddenly make it incompatible to the default compile time environment,
		4415	i.e. all programs not using special compile switches.
		4416
		4417	=head2 OS/X AND DARWIN BUGS
		4418
		4419	The whole thing is a bug if you ask me - basically any system interface
		4420	you touch is broken, whether it is locales, poll, kqueue or even the
		4421	OpenGL drivers.
		4422
		4423	=head3 C<kqueue> is buggy
		4424
		4425	The kqueue syscall is broken in all known versions - most versions support
		4426	only sockets, many support pipes.
		4427
		4428	=head3 C<poll> is buggy
		4429
		4430	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4431	implementation by something calling C<kqueue> internally around the 10.5.6
		4432	release, so now C<kqueue> I<and> C<poll> are broken.
		4433
		4434	Libev tries to work around this by neither using C<kqueue> nor C<poll> by
		4435	default on this rotten platform, but of course you cna still ask for them
		4436	when creating a loop.
		4437
		4438	=head3 C<select> is buggy
		4439
		4440	All that's left is C<select>, and of course Apple found a way to fuck this
		4441	one up as well: On OS/X, C<select> actively limits the number of file
		4442	descriptors you can pass in to 1024 - your program suddenyl crashes when
		4443	you use more.
		4444
		4445	There is an undocumented "workaround" for this - defining
		4446	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4447	work on OS/X.
		4448
		4449	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4450
		4451	=head3 C<errno> reentrancy
		4452
		4453	The default compile environment on Solaris is unfortunately so
		4454	thread-unsafe that you can't even use components/libraries compiled
		4455	without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,
		4456	isn't defined by default.
		4457
		4458	If you want to use libev in threaded environments you have to make sure
		4459	it's compiled with C<_REENTRANT> defined.
		4460
		4461	=head3 Event port backend
		4462
		4463	The scalable event interface for Solaris is called "event ports". Unfortunately,
		4464	this mechanism is very buggy. If you run into high CPU usage, your program
		4465	freezes or you get a large number of spurious wakeups, make sure you have
		4466	all the relevant and latest kernel patches applied. No, I don't know which
		4467	ones, but there are multiple ones.
		4468
		4469	If you can't get it to work, you can try running the program with
		4470	C<LIBEV_FLAGS=3> to only allow C<poll> and C<select> backends.
		4471
		4472	=head2 AIX POLL BUG
		4473
		4474	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4475	this by trying to avoid the poll backend altogether (i.e. it's not even
		4476	compiled in), which normally isn't a big problem as C<select> works fine
		4477	with large bitsets, and AIX is dead anyway.
		4478
4278	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4479	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4480
		4481	=head3 General issues
4279		4482
4280	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4483	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4281	requires, and its I/O model is fundamentally incompatible with the POSIX	4484	requires, and its I/O model is fundamentally incompatible with the POSIX
4282	model. Libev still offers limited functionality on this platform in	4485	model. Libev still offers limited functionality on this platform in
4283	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4486	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4284	descriptors. This only applies when using Win32 natively, not when using	4487	descriptors. This only applies when using Win32 natively, not when using
4285	e.g. cygwin.	4488	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4489	as every compielr comes with a slightly differently broken/incompatible
		4490	environment.
4286		4491
4287	Lifting these limitations would basically require the full	4492	Lifting these limitations would basically require the full
4288	re-implementation of the I/O system. If you are into these kinds of	4493	re-implementation of the I/O system. If you are into this kind of thing,
4289	things, then note that glib does exactly that for you in a very portable	4494	then note that glib does exactly that for you in a very portable way (note
4290	way (note also that glib is the slowest event library known to man).	4495	also that glib is the slowest event library known to man).
4291		4496
4292	There is no supported compilation method available on windows except	4497	There is no supported compilation method available on windows except
4293	embedding it into other applications.	4498	embedding it into other applications.
4294		4499
4295	Sensible signal handling is officially unsupported by Microsoft - libev	4500	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4323	you do I<not> compile the F<ev.c> or any other embedded source files!):	4528	you do I<not> compile the F<ev.c> or any other embedded source files!):
4324		4529
4325	#include "evwrap.h"	4530	#include "evwrap.h"
4326	#include "ev.c"	4531	#include "ev.c"
4327		4532
4328	=over 4
4329
4330	=item The winsocket select function	4533	=head3 The winsocket C<select> function
4331		4534
4332	The winsocket C<select> function doesn't follow POSIX in that it	4535	The winsocket C<select> function doesn't follow POSIX in that it
4333	requires socket I<handles> and not socket I<file descriptors> (it is	4536	requires socket I<handles> and not socket I<file descriptors> (it is
4334	also extremely buggy). This makes select very inefficient, and also	4537	also extremely buggy). This makes select very inefficient, and also
4335	requires a mapping from file descriptors to socket handles (the Microsoft	4538	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4344	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4547	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4345		4548
4346	Note that winsockets handling of fd sets is O(n), so you can easily get a	4549	Note that winsockets handling of fd sets is O(n), so you can easily get a
4347	complexity in the O(n²) range when using win32.	4550	complexity in the O(n²) range when using win32.
4348		4551
4349	=item Limited number of file descriptors	4552	=head3 Limited number of file descriptors
4350		4553
4351	Windows has numerous arbitrary (and low) limits on things.	4554	Windows has numerous arbitrary (and low) limits on things.
4352		4555
4353	Early versions of winsocket's select only supported waiting for a maximum	4556	Early versions of winsocket's select only supported waiting for a maximum
4354	of C<64> handles (probably owning to the fact that all windows kernels	4557	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4369	runtime libraries. This might get you to about C<512> or C<2048> sockets	4572	runtime libraries. This might get you to about C<512> or C<2048> sockets
4370	(depending on windows version and/or the phase of the moon). To get more,	4573	(depending on windows version and/or the phase of the moon). To get more,
4371	you need to wrap all I/O functions and provide your own fd management, but	4574	you need to wrap all I/O functions and provide your own fd management, but
4372	the cost of calling select (O(n²)) will likely make this unworkable.	4575	the cost of calling select (O(n²)) will likely make this unworkable.
4373		4576
4374	=back
4375
4376	=head2 PORTABILITY REQUIREMENTS	4577	=head2 PORTABILITY REQUIREMENTS
4377		4578
4378	In addition to a working ISO-C implementation and of course the	4579	In addition to a working ISO-C implementation and of course the
4379	backend-specific APIs, libev relies on a few additional extensions:	4580	backend-specific APIs, libev relies on a few additional extensions:
4380		4581
…		…
4500	involves iterating over all running async watchers or all signal numbers.	4701	involves iterating over all running async watchers or all signal numbers.
4501		4702
4502	=back	4703	=back
4503		4704
4504		4705
		4706	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4707
		4708	The major version 4 introduced some minor incompatible changes to the API.
		4709
		4710	At the moment, the C<ev.h> header file tries to implement superficial
		4711	compatibility, so most programs should still compile. Those might be
		4712	removed in later versions of libev, so better update early than late.
		4713
		4714	=over 4
		4715
		4716	=item C<ev_loop_count> renamed to C<ev_iteration>
		4717
		4718	=item C<ev_loop_depth> renamed to C<ev_depth>
		4719
		4720	=item C<ev_loop_verify> renamed to C<ev_verify>
		4721
		4722	Most functions working on C<struct ev_loop> objects don't have an
		4723	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is
		4724	still called C<ev_loop_fork> because it would otherwise clash with the
		4725	C<ev_fork> typedef.
		4726
		4727	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>
		4728
		4729	This is a simple rename - all other watcher types use their name
		4730	as revents flag, and now C<ev_timer> does, too.
		4731
		4732	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
		4733	and continue to be present for the foreseeable future, so this is mostly a
		4734	documentation change.
		4735
		4736	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4737
		4738	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4739	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4740	and work, but the library code will of course be larger.
		4741
		4742	=back
		4743
		4744
4505	=head1 GLOSSARY	4745	=head1 GLOSSARY
4506		4746
4507	=over 4	4747	=over 4
4508		4748
4509	=item active	4749	=item active
…		…
4530	A change of state of some external event, such as data now being available	4770	A change of state of some external event, such as data now being available
4531	for reading on a file descriptor, time having passed or simply not having	4771	for reading on a file descriptor, time having passed or simply not having
4532	any other events happening anymore.	4772	any other events happening anymore.
4533		4773
4534	In libev, events are represented as single bits (such as C<EV_READ> or	4774	In libev, events are represented as single bits (such as C<EV_READ> or
4535	C<EV_TIMEOUT>).	4775	C<EV_TIMER>).
4536		4776
4537	=item event library	4777	=item event library
4538		4778
4539	A software package implementing an event model and loop.	4779	A software package implementing an event model and loop.
4540		4780

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Comparing libev/ev.pod (file contents): Revision 1.266 by root, Wed Aug 26 17:15:05 2009 UTC vs. Revision 1.303 by root, Thu Oct 14 04:29:34 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.266 by root, Wed Aug 26 17:15:05 2009 UTC vs.
Revision 1.303 by root, Thu Oct 14 04:29:34 2010 UTC