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

Comparing libev/ev.pod (file contents):
Revision 1.187 by root, Mon Sep 29 03:31:14 2008 UTC vs.
Revision 1.195 by root, Mon Oct 20 17:50:48 2008 UTC

…		…
685	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	685	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
686	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	686	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
687		687
688	This "unloop state" will be cleared when entering C<ev_loop> again.	688	This "unloop state" will be cleared when entering C<ev_loop> again.
689		689
		690	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.
		691
690	=item ev_ref (loop)	692	=item ev_ref (loop)
691		693
692	=item ev_unref (loop)	694	=item ev_unref (loop)
693		695
694	Ref/unref can be used to add or remove a reference count on the event	696	Ref/unref can be used to add or remove a reference count on the event
…		…
967		969
968	ev_io_start (EV_DEFAULT_UC, &w);	970	ev_io_start (EV_DEFAULT_UC, &w);
969		971
970	=item C<ev_TYPE_stop> (loop , ev_TYPE watcher)	972	=item C<ev_TYPE_stop> (loop , ev_TYPE watcher)
971		973
972	Stops the given watcher again (if active) and clears the pending	974	Stops the given watcher if active, and clears the pending status (whether
		975	the watcher was active or not).
		976
973	status. It is possible that stopped watchers are pending (for example,	977	It is possible that stopped watchers are pending - for example,
974	non-repeating timers are being stopped when they become pending), but	978	non-repeating timers are being stopped when they become pending - but
975	C<ev_TYPE_stop> ensures that the watcher is neither active nor pending. If	979	calling C<ev_TYPE_stop> ensures that the watcher is neither active nor
976	you want to free or reuse the memory used by the watcher it is therefore a	980	pending. If you want to free or reuse the memory used by the watcher it is
977	good idea to always call its C<ev_TYPE_stop> function.	981	therefore a good idea to always call its C<ev_TYPE_stop> function.
978		982
979	=item bool ev_is_active (ev_TYPE *watcher)	983	=item bool ev_is_active (ev_TYPE *watcher)
980		984
981	Returns a true value iff the watcher is active (i.e. it has been started	985	Returns a true value iff the watcher is active (i.e. it has been started
982	and not yet been stopped). As long as a watcher is active you must not modify	986	and not yet been stopped). As long as a watcher is active you must not modify
…		…
1625		1629
1626	=back	1630	=back
1627		1631
1628	=head3 Examples	1632	=head3 Examples
1629		1633
1630	Example: Try to exit cleanly on SIGINT and SIGTERM.	1634	Example: Try to exit cleanly on SIGINT.
1631		1635
1632	static void	1636	static void
1633	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1637	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1634	{	1638	{
1635	ev_unloop (loop, EVUNLOOP_ALL);	1639	ev_unloop (loop, EVUNLOOP_ALL);
1636	}	1640	}
1637		1641
1638	struct ev_signal signal_watcher;	1642	struct ev_signal signal_watcher;
1639	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1643	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1640	ev_signal_start (loop, &sigint_cb);	1644	ev_signal_start (loop, &signal_watcher);
1641		1645
1642		1646
1643	=head2 C<ev_child> - watch out for process status changes	1647	=head2 C<ev_child> - watch out for process status changes
1644		1648
1645	Child watchers trigger when your process receives a SIGCHLD in response to	1649	Child watchers trigger when your process receives a SIGCHLD in response to
…		…
2384	=over 4	2388	=over 4
2385		2389
2386	=item queueing from a signal handler context	2390	=item queueing from a signal handler context
2387		2391
2388	To implement race-free queueing, you simply add to the queue in the signal	2392	To implement race-free queueing, you simply add to the queue in the signal
2389	handler but you block the signal handler in the watcher callback. Here is an example that does that for	2393	handler but you block the signal handler in the watcher callback. Here is
2390	some fictitious SIGUSR1 handler:	2394	an example that does that for some fictitious SIGUSR1 handler:
2391		2395
2392	static ev_async mysig;	2396	static ev_async mysig;
2393		2397
2394	static void	2398	static void
2395	sigusr1_handler (void)	2399	sigusr1_handler (void)
…		…
2502	=over 4	2506	=over 4
2503		2507
2504	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)	2508	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)
2505		2509
2506	This function combines a simple timer and an I/O watcher, calls your	2510	This function combines a simple timer and an I/O watcher, calls your
2507	callback on whichever event happens first and automatically stop both	2511	callback on whichever event happens first and automatically stops both
2508	watchers. This is useful if you want to wait for a single event on an fd	2512	watchers. This is useful if you want to wait for a single event on an fd
2509	or timeout without having to allocate/configure/start/stop/free one or	2513	or timeout without having to allocate/configure/start/stop/free one or
2510	more watchers yourself.	2514	more watchers yourself.
2511		2515
2512	If C<fd> is less than 0, then no I/O watcher will be started and events	2516	If C<fd> is less than 0, then no I/O watcher will be started and the
2513	is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and	2517	C<events> argument is being ignored. Otherwise, an C<ev_io> watcher for
2514	C<events> set will be created and started.	2518	the given C<fd> and C<events> set will be created and started.
2515		2519
2516	If C<timeout> is less than 0, then no timeout watcher will be	2520	If C<timeout> is less than 0, then no timeout watcher will be
2517	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	2521	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
2518	repeat = 0) will be started. While C<0> is a valid timeout, it is of	2522	repeat = 0) will be started. C<0> is a valid timeout.
2519	dubious value.
2520		2523
2521	The callback has the type C<void (cb)(int revents, void arg)> and gets	2524	The callback has the type C<void (cb)(int revents, void arg)> and gets
2522	passed an C<revents> set like normal event callbacks (a combination of	2525	passed an C<revents> set like normal event callbacks (a combination of
2523	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	2526	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2524	value passed to C<ev_once>:	2527	value passed to C<ev_once>. Note that it is possible to receive I<both>
		2528	a timeout and an io event at the same time - you probably should give io
		2529	events precedence.
		2530
		2531	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
2525		2532
2526	static void stdin_ready (int revents, void *arg)	2533	static void stdin_ready (int revents, void *arg)
2527	{	2534	{
		2535	if (revents & EV_READ)
		2536	/* stdin might have data for us, joy! */;
2528	if (revents & EV_TIMEOUT)	2537	else if (revents & EV_TIMEOUT)
2529	/* doh, nothing entered */;	2538	/* doh, nothing entered */;
2530	else if (revents & EV_READ)
2531	/* stdin might have data for us, joy! */;
2532	}	2539	}
2533		2540
2534	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2541	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2535		2542
2536	=item ev_feed_event (ev_loop , watcher , int revents)	2543	=item ev_feed_event (ev_loop , watcher , int revents)
…		…
3306	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	3313	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3307		3314
3308	#include "ev_cpp.h"	3315	#include "ev_cpp.h"
3309	#include "ev.c"	3316	#include "ev.c"
3310		3317
		3318	=head1 INTERACTION WITH OTHER PROGRAMS OR LIBRARIES
3311		3319
3312	=head1 THREADS AND COROUTINES	3320	=head2 THREADS AND COROUTINES
3313		3321
3314	=head2 THREADS	3322	=head3 THREADS
3315		3323
3316	All libev functions are reentrant and thread-safe unless explicitly	3324	All libev functions are reentrant and thread-safe unless explicitly
3317	documented otherwise, but it uses no locking itself. This means that you	3325	documented otherwise, but libev implements no locking itself. This means
3318	can use as many loops as you want in parallel, as long as there are no	3326	that you can use as many loops as you want in parallel, as long as there
3319	concurrent calls into any libev function with the same loop parameter	3327	are no concurrent calls into any libev function with the same loop
3320	(C<ev_default_*> calls have an implicit default loop parameter, of	3328	parameter (C<ev_default_*> calls have an implicit default loop parameter,
3321	course): libev guarantees that different event loops share no data	3329	of course): libev guarantees that different event loops share no data
3322	structures that need any locking.	3330	structures that need any locking.
3323		3331
3324	Or to put it differently: calls with different loop parameters can be done	3332	Or to put it differently: calls with different loop parameters can be done
3325	concurrently from multiple threads, calls with the same loop parameter	3333	concurrently from multiple threads, calls with the same loop parameter
3326	must be done serially (but can be done from different threads, as long as	3334	must be done serially (but can be done from different threads, as long as
…		…
3366	default loop and triggering an C<ev_async> watcher from the default loop	3374	default loop and triggering an C<ev_async> watcher from the default loop
3367	watcher callback into the event loop interested in the signal.	3375	watcher callback into the event loop interested in the signal.
3368		3376
3369	=back	3377	=back
3370		3378
3371	=head2 COROUTINES	3379	=head3 COROUTINES
3372		3380
3373	Libev is much more accommodating to coroutines ("cooperative threads"):	3381	Libev is very accommodating to coroutines ("cooperative threads"):
3374	libev fully supports nesting calls to it's functions from different	3382	libev fully supports nesting calls to its functions from different
3375	coroutines (e.g. you can call C<ev_loop> on the same loop from two	3383	coroutines (e.g. you can call C<ev_loop> on the same loop from two
3376	different coroutines and switch freely between both coroutines running the	3384	different coroutines, and switch freely between both coroutines running the
3377	loop, as long as you don't confuse yourself). The only exception is that	3385	loop, as long as you don't confuse yourself). The only exception is that
3378	you must not do this from C<ev_periodic> reschedule callbacks.	3386	you must not do this from C<ev_periodic> reschedule callbacks.
3379		3387
3380	Care has been taken to ensure that libev does not keep local state inside	3388	Care has been taken to ensure that libev does not keep local state inside
3381	C<ev_loop>, and other calls do not usually allow coroutine switches.	3389	C<ev_loop>, and other calls do not usually allow for coroutine switches as
		3390	they do not clal any callbacks.
3382		3391
		3392	=head2 COMPILER WARNINGS
3383		3393
3384	=head1 COMPLEXITIES	3394	Depending on your compiler and compiler settings, you might get no or a
		3395	lot of warnings when compiling libev code. Some people are apparently
		3396	scared by this.
3385		3397
3386	In this section the complexities of (many of) the algorithms used inside	3398	However, these are unavoidable for many reasons. For one, each compiler
3387	libev will be explained. For complexity discussions about backends see the	3399	has different warnings, and each user has different tastes regarding
3388	documentation for C<ev_default_init>.	3400	warning options. "Warn-free" code therefore cannot be a goal except when
		3401	targeting a specific compiler and compiler-version.
3389		3402
3390	All of the following are about amortised time: If an array needs to be	3403	Another reason is that some compiler warnings require elaborate
3391	extended, libev needs to realloc and move the whole array, but this	3404	workarounds, or other changes to the code that make it less clear and less
3392	happens asymptotically never with higher number of elements, so O(1) might	3405	maintainable.
3393	mean it might do a lengthy realloc operation in rare cases, but on average
3394	it is much faster and asymptotically approaches constant time.
3395		3406
3396	=over 4	3407	And of course, some compiler warnings are just plain stupid, or simply
		3408	wrong (because they don't actually warn about the condition their message
		3409	seems to warn about). For example, certain older gcc versions had some
		3410	warnings that resulted an extreme number of false positives. These have
		3411	been fixed, but some people still insist on making code warn-free with
		3412	such buggy versions.
3397		3413
3398	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	3414	While libev is written to generate as few warnings as possible,
		3415	"warn-free" code is not a goal, and it is recommended not to build libev
		3416	with any compiler warnings enabled unless you are prepared to cope with
		3417	them (e.g. by ignoring them). Remember that warnings are just that:
		3418	warnings, not errors, or proof of bugs.
3399		3419
3400	This means that, when you have a watcher that triggers in one hour and
3401	there are 100 watchers that would trigger before that then inserting will
3402	have to skip roughly seven (C<ld 100>) of these watchers.
3403		3420
3404	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)	3421	=head2 VALGRIND
3405		3422
3406	That means that changing a timer costs less than removing/adding them	3423	Valgrind has a special section here because it is a popular tool that is
3407	as only the relative motion in the event queue has to be paid for.	3424	highly useful. Unfortunately, valgrind reports are very hard to interpret.
3408		3425
3409	=item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)	3426	If you think you found a bug (memory leak, uninitialised data access etc.)
		3427	in libev, then check twice: If valgrind reports something like:
3410		3428
3411	These just add the watcher into an array or at the head of a list.	3429	==2274== definitely lost: 0 bytes in 0 blocks.
		3430	==2274== possibly lost: 0 bytes in 0 blocks.
		3431	==2274== still reachable: 256 bytes in 1 blocks.
3412		3432
3413	=item Stopping check/prepare/idle/fork/async watchers: O(1)	3433	Then there is no memory leak, just as memory accounted to global variables
		3434	is not a memleak - the memory is still being refernced, and didn't leak.
3414		3435
3415	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	3436	Similarly, under some circumstances, valgrind might report kernel bugs
		3437	as if it were a bug in libev (e.g. in realloc or in the poll backend,
		3438	although an acceptable workaround has been found here), or it might be
		3439	confused.
3416		3440
3417	These watchers are stored in lists then need to be walked to find the	3441	Keep in mind that valgrind is a very good tool, but only a tool. Don't
3418	correct watcher to remove. The lists are usually short (you don't usually	3442	make it into some kind of religion.
3419	have many watchers waiting for the same fd or signal).
3420		3443
3421	=item Finding the next timer in each loop iteration: O(1)	3444	If you are unsure about something, feel free to contact the mailing list
		3445	with the full valgrind report and an explanation on why you think this
		3446	is a bug in libev (best check the archives, too :). However, don't be
		3447	annoyed when you get a brisk "this is no bug" answer and take the chance
		3448	of learning how to interpret valgrind properly.
3422		3449
3423	By virtue of using a binary or 4-heap, the next timer is always found at a	3450	If you need, for some reason, empty reports from valgrind for your project
3424	fixed position in the storage array.	3451	I suggest using suppression lists.
3425		3452
3426	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
3427		3453
3428	A change means an I/O watcher gets started or stopped, which requires	3454	=head1 PORTABILITY NOTES
3429	libev to recalculate its status (and possibly tell the kernel, depending
3430	on backend and whether C<ev_io_set> was used).
3431		3455
3432	=item Activating one watcher (putting it into the pending state): O(1)
3433
3434	=item Priority handling: O(number_of_priorities)
3435
3436	Priorities are implemented by allocating some space for each
3437	priority. When doing priority-based operations, libev usually has to
3438	linearly search all the priorities, but starting/stopping and activating
3439	watchers becomes O(1) with respect to priority handling.
3440
3441	=item Sending an ev_async: O(1)
3442
3443	=item Processing ev_async_send: O(number_of_async_watchers)
3444
3445	=item Processing signals: O(max_signal_number)
3446
3447	Sending involves a system call I<iff> there were no other C<ev_async_send>
3448	calls in the current loop iteration. Checking for async and signal events
3449	involves iterating over all running async watchers or all signal numbers.
3450
3451	=back
3452
3453
3454	=head1 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	3456	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
3455		3457
3456	Win32 doesn't support any of the standards (e.g. POSIX) that libev	3458	Win32 doesn't support any of the standards (e.g. POSIX) that libev
3457	requires, and its I/O model is fundamentally incompatible with the POSIX	3459	requires, and its I/O model is fundamentally incompatible with the POSIX
3458	model. Libev still offers limited functionality on this platform in	3460	model. Libev still offers limited functionality on this platform in
3459	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	3461	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
…		…
3546	wrap all I/O functions and provide your own fd management, but the cost of	3548	wrap all I/O functions and provide your own fd management, but the cost of
3547	calling select (O(n²)) will likely make this unworkable.	3549	calling select (O(n²)) will likely make this unworkable.
3548		3550
3549	=back	3551	=back
3550		3552
3551
3552	=head1 PORTABILITY REQUIREMENTS	3553	=head2 PORTABILITY REQUIREMENTS
3553		3554
3554	In addition to a working ISO-C implementation, libev relies on a few	3555	In addition to a working ISO-C implementation and of course the
3555	additional extensions:	3556	backend-specific APIs, libev relies on a few additional extensions:
3556		3557
3557	=over 4	3558	=over 4
3558		3559
3559	=item C<void ()(ev_watcher_type , int revents)> must have compatible	3560	=item C<void ()(ev_watcher_type , int revents)> must have compatible
3560	calling conventions regardless of C<ev_watcher_type *>.	3561	calling conventions regardless of C<ev_watcher_type *>.
…		…
3585	except the initial one, and run the default loop in the initial thread as	3586	except the initial one, and run the default loop in the initial thread as
3586	well.	3587	well.
3587		3588
3588	=item C<long> must be large enough for common memory allocation sizes	3589	=item C<long> must be large enough for common memory allocation sizes
3589		3590
3590	To improve portability and simplify using libev, libev uses C<long>	3591	To improve portability and simplify its API, libev uses C<long> internally
3591	internally instead of C<size_t> when allocating its data structures. On	3592	instead of C<size_t> when allocating its data structures. On non-POSIX
3592	non-POSIX systems (Microsoft...) this might be unexpectedly low, but	3593	systems (Microsoft...) this might be unexpectedly low, but is still at
3593	is still at least 31 bits everywhere, which is enough for hundreds of	3594	least 31 bits everywhere, which is enough for hundreds of millions of
3594	millions of watchers.	3595	watchers.
3595		3596
3596	=item C<double> must hold a time value in seconds with enough accuracy	3597	=item C<double> must hold a time value in seconds with enough accuracy
3597		3598
3598	The type C<double> is used to represent timestamps. It is required to	3599	The type C<double> is used to represent timestamps. It is required to
3599	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	3600	have at least 51 bits of mantissa (and 9 bits of exponent), which is good
…		…
3603	=back	3604	=back
3604		3605
3605	If you know of other additional requirements drop me a note.	3606	If you know of other additional requirements drop me a note.
3606		3607
3607		3608
3608	=head1 COMPILER WARNINGS	3609	=head1 ALGORITHMIC COMPLEXITIES
3609		3610
3610	Depending on your compiler and compiler settings, you might get no or a	3611	In this section the complexities of (many of) the algorithms used inside
3611	lot of warnings when compiling libev code. Some people are apparently	3612	libev will be documented. For complexity discussions about backends see
3612	scared by this.	3613	the documentation for C<ev_default_init>.
3613		3614
3614	However, these are unavoidable for many reasons. For one, each compiler	3615	All of the following are about amortised time: If an array needs to be
3615	has different warnings, and each user has different tastes regarding	3616	extended, libev needs to realloc and move the whole array, but this
3616	warning options. "Warn-free" code therefore cannot be a goal except when	3617	happens asymptotically rarer with higher number of elements, so O(1) might
3617	targeting a specific compiler and compiler-version.	3618	mean that libev does a lengthy realloc operation in rare cases, but on
		3619	average it is much faster and asymptotically approaches constant time.
3618		3620
3619	Another reason is that some compiler warnings require elaborate	3621	=over 4
3620	workarounds, or other changes to the code that make it less clear and less
3621	maintainable.
3622		3622
3623	And of course, some compiler warnings are just plain stupid, or simply	3623	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
3624	wrong (because they don't actually warn about the condition their message
3625	seems to warn about).
3626		3624
3627	While libev is written to generate as few warnings as possible,	3625	This means that, when you have a watcher that triggers in one hour and
3628	"warn-free" code is not a goal, and it is recommended not to build libev	3626	there are 100 watchers that would trigger before that, then inserting will
3629	with any compiler warnings enabled unless you are prepared to cope with	3627	have to skip roughly seven (C<ld 100>) of these watchers.
3630	them (e.g. by ignoring them). Remember that warnings are just that:
3631	warnings, not errors, or proof of bugs.
3632		3628
		3629	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
3633		3630
3634	=head1 VALGRIND	3631	That means that changing a timer costs less than removing/adding them,
		3632	as only the relative motion in the event queue has to be paid for.
3635		3633
3636	Valgrind has a special section here because it is a popular tool that is	3634	=item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)
3637	highly useful, but valgrind reports are very hard to interpret.
3638		3635
3639	If you think you found a bug (memory leak, uninitialised data access etc.)	3636	These just add the watcher into an array or at the head of a list.
3640	in libev, then check twice: If valgrind reports something like:
3641		3637
3642	==2274== definitely lost: 0 bytes in 0 blocks.	3638	=item Stopping check/prepare/idle/fork/async watchers: O(1)
3643	==2274== possibly lost: 0 bytes in 0 blocks.
3644	==2274== still reachable: 256 bytes in 1 blocks.
3645		3639
3646	Then there is no memory leak. Similarly, under some circumstances,	3640	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
3647	valgrind might report kernel bugs as if it were a bug in libev, or it
3648	might be confused (it is a very good tool, but only a tool).
3649		3641
3650	If you are unsure about something, feel free to contact the mailing list	3642	These watchers are stored in lists, so they need to be walked to find the
3651	with the full valgrind report and an explanation on why you think this is	3643	correct watcher to remove. The lists are usually short (you don't usually
3652	a bug in libev. However, don't be annoyed when you get a brisk "this is	3644	have many watchers waiting for the same fd or signal: one is typical, two
3653	no bug" answer and take the chance of learning how to interpret valgrind	3645	is rare).
3654	properly.
3655		3646
3656	If you need, for some reason, empty reports from valgrind for your project	3647	=item Finding the next timer in each loop iteration: O(1)
3657	I suggest using suppression lists.	3648
		3649	By virtue of using a binary or 4-heap, the next timer is always found at a
		3650	fixed position in the storage array.
		3651
		3652	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
		3653
		3654	A change means an I/O watcher gets started or stopped, which requires
		3655	libev to recalculate its status (and possibly tell the kernel, depending
		3656	on backend and whether C<ev_io_set> was used).
		3657
		3658	=item Activating one watcher (putting it into the pending state): O(1)
		3659
		3660	=item Priority handling: O(number_of_priorities)
		3661
		3662	Priorities are implemented by allocating some space for each
		3663	priority. When doing priority-based operations, libev usually has to
		3664	linearly search all the priorities, but starting/stopping and activating
		3665	watchers becomes O(1) with respect to priority handling.
		3666
		3667	=item Sending an ev_async: O(1)
		3668
		3669	=item Processing ev_async_send: O(number_of_async_watchers)
		3670
		3671	=item Processing signals: O(max_signal_number)
		3672
		3673	Sending involves a system call I<iff> there were no other C<ev_async_send>
		3674	calls in the current loop iteration. Checking for async and signal events
		3675	involves iterating over all running async watchers or all signal numbers.
		3676
		3677	=back
3658		3678
3659		3679
3660	=head1 AUTHOR	3680	=head1 AUTHOR
3661		3681
3662	Marc Lehmann <libev@schmorp.de>.	3682	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.pod (file contents): Revision 1.187 by root, Mon Sep 29 03:31:14 2008 UTC vs. Revision 1.195 by root, Mon Oct 20 17:50:48 2008 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.187 by root, Mon Sep 29 03:31:14 2008 UTC vs.
Revision 1.195 by root, Mon Oct 20 17:50:48 2008 UTC