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

Comparing libev/ev.pod (file contents):
Revision 1.186 by root, Wed Sep 24 07:56:14 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
…		…
2242	So when you want to use this feature you will always have to be prepared	2246	So when you want to use this feature you will always have to be prepared
2243	that you cannot get an embeddable loop. The recommended way to get around	2247	that you cannot get an embeddable loop. The recommended way to get around
2244	this is to have a separate variables for your embeddable loop, try to	2248	this is to have a separate variables for your embeddable loop, try to
2245	create it, and if that fails, use the normal loop for everything.	2249	create it, and if that fails, use the normal loop for everything.
2246		2250
		2251	=head3 C<ev_embed> and fork
		2252
		2253	While the C<ev_embed> watcher is running, forks in the embedding loop will
		2254	automatically be applied to the embedded loop as well, so no special
		2255	fork handling is required in that case. When the watcher is not running,
		2256	however, it is still the task of the libev user to call C<ev_loop_fork ()>
		2257	as applicable.
		2258
2247	=head3 Watcher-Specific Functions and Data Members	2259	=head3 Watcher-Specific Functions and Data Members
2248		2260
2249	=over 4	2261	=over 4
2250		2262
2251	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)	2263	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)
…		…
2376	=over 4	2388	=over 4
2377		2389
2378	=item queueing from a signal handler context	2390	=item queueing from a signal handler context
2379		2391
2380	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
2381	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
2382	some fictitious SIGUSR1 handler:	2394	an example that does that for some fictitious SIGUSR1 handler:
2383		2395
2384	static ev_async mysig;	2396	static ev_async mysig;
2385		2397
2386	static void	2398	static void
2387	sigusr1_handler (void)	2399	sigusr1_handler (void)
…		…
2494	=over 4	2506	=over 4
2495		2507
2496	=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)
2497		2509
2498	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
2499	callback on whichever event happens first and automatically stop both	2511	callback on whichever event happens first and automatically stops both
2500	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
2501	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
2502	more watchers yourself.	2514	more watchers yourself.
2503		2515
2504	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
2505	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
2506	C<events> set will be created and started.	2518	the given C<fd> and C<events> set will be created and started.
2507		2519
2508	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
2509	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
2510	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.
2511	dubious value.
2512		2523
2513	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
2514	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
2515	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>
2516	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.
2517		2532
2518	static void stdin_ready (int revents, void *arg)	2533	static void stdin_ready (int revents, void *arg)
2519	{	2534	{
		2535	if (revents & EV_READ)
		2536	/* stdin might have data for us, joy! */;
2520	if (revents & EV_TIMEOUT)	2537	else if (revents & EV_TIMEOUT)
2521	/* doh, nothing entered */;	2538	/* doh, nothing entered */;
2522	else if (revents & EV_READ)
2523	/* stdin might have data for us, joy! */;
2524	}	2539	}
2525		2540
2526	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2541	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2527		2542
2528	=item ev_feed_event (ev_loop , watcher , int revents)	2543	=item ev_feed_event (ev_loop , watcher , int revents)
…		…
3298	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:
3299		3314
3300	#include "ev_cpp.h"	3315	#include "ev_cpp.h"
3301	#include "ev.c"	3316	#include "ev.c"
3302		3317
		3318	=head1 INTERACTION WITH OTHER PROGRAMS OR LIBRARIES
3303		3319
3304	=head1 THREADS AND COROUTINES	3320	=head2 THREADS AND COROUTINES
3305		3321
3306	=head2 THREADS	3322	=head3 THREADS
3307		3323
3308	All libev functions are reentrant and thread-safe unless explicitly	3324	All libev functions are reentrant and thread-safe unless explicitly
3309	documented otherwise, but it uses no locking itself. This means that you	3325	documented otherwise, but libev implements no locking itself. This means
3310	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
3311	concurrent calls into any libev function with the same loop parameter	3327	are no concurrent calls into any libev function with the same loop
3312	(C<ev_default_*> calls have an implicit default loop parameter, of	3328	parameter (C<ev_default_*> calls have an implicit default loop parameter,
3313	course): libev guarantees that different event loops share no data	3329	of course): libev guarantees that different event loops share no data
3314	structures that need any locking.	3330	structures that need any locking.
3315		3331
3316	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
3317	concurrently from multiple threads, calls with the same loop parameter	3333	concurrently from multiple threads, calls with the same loop parameter
3318	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
…		…
3358	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
3359	watcher callback into the event loop interested in the signal.	3375	watcher callback into the event loop interested in the signal.
3360		3376
3361	=back	3377	=back
3362		3378
3363	=head2 COROUTINES	3379	=head3 COROUTINES
3364		3380
3365	Libev is much more accommodating to coroutines ("cooperative threads"):	3381	Libev is very accommodating to coroutines ("cooperative threads"):
3366	libev fully supports nesting calls to it's functions from different	3382	libev fully supports nesting calls to its functions from different
3367	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
3368	different coroutines and switch freely between both coroutines running the	3384	different coroutines, and switch freely between both coroutines running the
3369	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
3370	you must not do this from C<ev_periodic> reschedule callbacks.	3386	you must not do this from C<ev_periodic> reschedule callbacks.
3371		3387
3372	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
3373	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.
3374		3391
		3392	=head2 COMPILER WARNINGS
3375		3393
3376	=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.
3377		3397
3378	In this section the complexities of (many of) the algorithms used inside	3398	However, these are unavoidable for many reasons. For one, each compiler
3379	libev will be explained. For complexity discussions about backends see the	3399	has different warnings, and each user has different tastes regarding
3380	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.
3381		3402
3382	All of the following are about amortised time: If an array needs to be	3403	Another reason is that some compiler warnings require elaborate
3383	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
3384	happens asymptotically never with higher number of elements, so O(1) might	3405	maintainable.
3385	mean it might do a lengthy realloc operation in rare cases, but on average
3386	it is much faster and asymptotically approaches constant time.
3387		3406
3388	=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.
3389		3413
3390	=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.
3391		3419
3392	This means that, when you have a watcher that triggers in one hour and
3393	there are 100 watchers that would trigger before that then inserting will
3394	have to skip roughly seven (C<ld 100>) of these watchers.
3395		3420
3396	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)	3421	=head2 VALGRIND
3397		3422
3398	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
3399	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.
3400		3425
3401	=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:
3402		3428
3403	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.
3404		3432
3405	=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.
3406		3435
3407	=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.
3408		3440
3409	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
3410	correct watcher to remove. The lists are usually short (you don't usually	3442	make it into some kind of religion.
3411	have many watchers waiting for the same fd or signal).
3412		3443
3413	=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.
3414		3449
3415	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
3416	fixed position in the storage array.	3451	I suggest using suppression lists.
3417		3452
3418	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
3419		3453
3420	A change means an I/O watcher gets started or stopped, which requires	3454	=head1 PORTABILITY NOTES
3421	libev to recalculate its status (and possibly tell the kernel, depending
3422	on backend and whether C<ev_io_set> was used).
3423		3455
3424	=item Activating one watcher (putting it into the pending state): O(1)
3425
3426	=item Priority handling: O(number_of_priorities)
3427
3428	Priorities are implemented by allocating some space for each
3429	priority. When doing priority-based operations, libev usually has to
3430	linearly search all the priorities, but starting/stopping and activating
3431	watchers becomes O(1) with respect to priority handling.
3432
3433	=item Sending an ev_async: O(1)
3434
3435	=item Processing ev_async_send: O(number_of_async_watchers)
3436
3437	=item Processing signals: O(max_signal_number)
3438
3439	Sending involves a system call I<iff> there were no other C<ev_async_send>
3440	calls in the current loop iteration. Checking for async and signal events
3441	involves iterating over all running async watchers or all signal numbers.
3442
3443	=back
3444
3445
3446	=head1 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	3456	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
3447		3457
3448	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
3449	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
3450	model. Libev still offers limited functionality on this platform in	3460	model. Libev still offers limited functionality on this platform in
3451	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
…		…
3538	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
3539	calling select (O(n²)) will likely make this unworkable.	3549	calling select (O(n²)) will likely make this unworkable.
3540		3550
3541	=back	3551	=back
3542		3552
3543
3544	=head1 PORTABILITY REQUIREMENTS	3553	=head2 PORTABILITY REQUIREMENTS
3545		3554
3546	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
3547	additional extensions:	3556	backend-specific APIs, libev relies on a few additional extensions:
3548		3557
3549	=over 4	3558	=over 4
3550		3559
3551	=item C<void ()(ev_watcher_type , int revents)> must have compatible	3560	=item C<void ()(ev_watcher_type , int revents)> must have compatible
3552	calling conventions regardless of C<ev_watcher_type *>.	3561	calling conventions regardless of C<ev_watcher_type *>.
…		…
3577	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
3578	well.	3587	well.
3579		3588
3580	=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
3581		3590
3582	To improve portability and simplify using libev, libev uses C<long>	3591	To improve portability and simplify its API, libev uses C<long> internally
3583	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
3584	non-POSIX systems (Microsoft...) this might be unexpectedly low, but	3593	systems (Microsoft...) this might be unexpectedly low, but is still at
3585	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
3586	millions of watchers.	3595	watchers.
3587		3596
3588	=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
3589		3598
3590	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
3591	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
…		…
3595	=back	3604	=back
3596		3605
3597	If you know of other additional requirements drop me a note.	3606	If you know of other additional requirements drop me a note.
3598		3607
3599		3608
3600	=head1 COMPILER WARNINGS	3609	=head1 ALGORITHMIC COMPLEXITIES
3601		3610
3602	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
3603	lot of warnings when compiling libev code. Some people are apparently	3612	libev will be documented. For complexity discussions about backends see
3604	scared by this.	3613	the documentation for C<ev_default_init>.
3605		3614
3606	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
3607	has different warnings, and each user has different tastes regarding	3616	extended, libev needs to realloc and move the whole array, but this
3608	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
3609	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.
3610		3620
3611	Another reason is that some compiler warnings require elaborate	3621	=over 4
3612	workarounds, or other changes to the code that make it less clear and less
3613	maintainable.
3614		3622
3615	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)
3616	wrong (because they don't actually warn about the condition their message
3617	seems to warn about).
3618		3624
3619	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
3620	"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
3621	with any compiler warnings enabled unless you are prepared to cope with	3627	have to skip roughly seven (C<ld 100>) of these watchers.
3622	them (e.g. by ignoring them). Remember that warnings are just that:
3623	warnings, not errors, or proof of bugs.
3624		3628
		3629	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
3625		3630
3626	=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.
3627		3633
3628	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)
3629	highly useful, but valgrind reports are very hard to interpret.
3630		3635
3631	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.
3632	in libev, then check twice: If valgrind reports something like:
3633		3637
3634	==2274== definitely lost: 0 bytes in 0 blocks.	3638	=item Stopping check/prepare/idle/fork/async watchers: O(1)
3635	==2274== possibly lost: 0 bytes in 0 blocks.
3636	==2274== still reachable: 256 bytes in 1 blocks.
3637		3639
3638	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))
3639	valgrind might report kernel bugs as if it were a bug in libev, or it
3640	might be confused (it is a very good tool, but only a tool).
3641		3641
3642	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
3643	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
3644	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
3645	no bug" answer and take the chance of learning how to interpret valgrind	3645	is rare).
3646	properly.
3647		3646
3648	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)
3649	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
3650		3678
3651		3679
3652	=head1 AUTHOR	3680	=head1 AUTHOR
3653		3681
3654	Marc Lehmann <libev@schmorp.de>.	3682	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.pod (file contents): Revision 1.186 by root, Wed Sep 24 07:56:14 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 1.186 by root, Wed Sep 24 07:56:14 2008 UTC vs.
Revision 1.195 by root, Mon Oct 20 17:50:48 2008 UTC