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

Comparing libev/ev.pod (file contents):
Revision 1.185 by root, Tue Sep 23 09:13:59 2008 UTC vs.
Revision 1.193 by root, Wed Oct 1 04:25:25 2008 UTC

…		…
214	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	214	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for
215	recommended ones.	215	recommended ones.
216		216
217	See the description of C<ev_embed> watchers for more info.	217	See the description of C<ev_embed> watchers for more info.
218		218
219	=item ev_set_allocator (void (cb)(void *ptr, long size))	219	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]
220		220
221	Sets the allocation function to use (the prototype is similar - the	221	Sets the allocation function to use (the prototype is similar - the
222	semantics are identical to the C<realloc> C89/SuS/POSIX function). It is	222	semantics are identical to the C<realloc> C89/SuS/POSIX function). It is
223	used to allocate and free memory (no surprises here). If it returns zero	223	used to allocate and free memory (no surprises here). If it returns zero
224	when memory needs to be allocated (C<size != 0>), the library might abort	224	when memory needs to be allocated (C<size != 0>), the library might abort
…		…
250	}	250	}
251		251
252	...	252	...
253	ev_set_allocator (persistent_realloc);	253	ev_set_allocator (persistent_realloc);
254		254
255	=item ev_set_syserr_cb (void (cb)(const char msg));	255	=item ev_set_syserr_cb (void (cb)(const char msg)); [NOT REENTRANT]
256		256
257	Set the callback function to call on a retryable system call error (such	257	Set the callback function to call on a retryable system call error (such
258	as failed select, poll, epoll_wait). The message is a printable string	258	as failed select, poll, epoll_wait). The message is a printable string
259	indicating the system call or subsystem causing the problem. If this	259	indicating the system call or subsystem causing the problem. If this
260	callback is set, then libev will expect it to remedy the situation, no	260	callback is set, then libev will expect it to remedy the situation, no
…		…
1625		1625
1626	=back	1626	=back
1627		1627
1628	=head3 Examples	1628	=head3 Examples
1629		1629
1630	Example: Try to exit cleanly on SIGINT and SIGTERM.	1630	Example: Try to exit cleanly on SIGINT.
1631		1631
1632	static void	1632	static void
1633	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1633	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1634	{	1634	{
1635	ev_unloop (loop, EVUNLOOP_ALL);	1635	ev_unloop (loop, EVUNLOOP_ALL);
1636	}	1636	}
1637		1637
1638	struct ev_signal signal_watcher;	1638	struct ev_signal signal_watcher;
1639	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1639	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1640	ev_signal_start (loop, &sigint_cb);	1640	ev_signal_start (loop, &signal_watcher);
1641		1641
1642		1642
1643	=head2 C<ev_child> - watch out for process status changes	1643	=head2 C<ev_child> - watch out for process status changes
1644		1644
1645	Child watchers trigger when your process receives a SIGCHLD in response to	1645	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	2242	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	2243	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	2244	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.	2245	create it, and if that fails, use the normal loop for everything.
2246		2246
		2247	=head3 C<ev_embed> and fork
		2248
		2249	While the C<ev_embed> watcher is running, forks in the embedding loop will
		2250	automatically be applied to the embedded loop as well, so no special
		2251	fork handling is required in that case. When the watcher is not running,
		2252	however, it is still the task of the libev user to call C<ev_loop_fork ()>
		2253	as applicable.
		2254
2247	=head3 Watcher-Specific Functions and Data Members	2255	=head3 Watcher-Specific Functions and Data Members
2248		2256
2249	=over 4	2257	=over 4
2250		2258
2251	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)	2259	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)
…		…
2376	=over 4	2384	=over 4
2377		2385
2378	=item queueing from a signal handler context	2386	=item queueing from a signal handler context
2379		2387
2380	To implement race-free queueing, you simply add to the queue in the signal	2388	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	2389	handler but you block the signal handler in the watcher callback. Here is
2382	some fictitious SIGUSR1 handler:	2390	an example that does that for some fictitious SIGUSR1 handler:
2383		2391
2384	static ev_async mysig;	2392	static ev_async mysig;
2385		2393
2386	static void	2394	static void
2387	sigusr1_handler (void)	2395	sigusr1_handler (void)
…		…
2494	=over 4	2502	=over 4
2495		2503
2496	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)	2504	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)
2497		2505
2498	This function combines a simple timer and an I/O watcher, calls your	2506	This function combines a simple timer and an I/O watcher, calls your
2499	callback on whichever event happens first and automatically stop both	2507	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	2508	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	2509	or timeout without having to allocate/configure/start/stop/free one or
2502	more watchers yourself.	2510	more watchers yourself.
2503		2511
2504	If C<fd> is less than 0, then no I/O watcher will be started and events	2512	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	2513	C<events> argument is being ignored. Otherwise, an C<ev_io> watcher for
2506	C<events> set will be created and started.	2514	the given C<fd> and C<events> set will be created and started.
2507		2515
2508	If C<timeout> is less than 0, then no timeout watcher will be	2516	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	2517	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	2518	repeat = 0) will be started. C<0> is a valid timeout.
2511	dubious value.
2512		2519
2513	The callback has the type C<void (cb)(int revents, void arg)> and gets	2520	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	2521	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>	2522	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2516	value passed to C<ev_once>:	2523	value passed to C<ev_once>. Note that it is possible to receive I<both>
		2524	a timeout and an io event at the same time - you probably should give io
		2525	events precedence.
		2526
		2527	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
2517		2528
2518	static void stdin_ready (int revents, void *arg)	2529	static void stdin_ready (int revents, void *arg)
2519	{	2530	{
		2531	if (revents & EV_READ)
		2532	/* stdin might have data for us, joy! */;
2520	if (revents & EV_TIMEOUT)	2533	else if (revents & EV_TIMEOUT)
2521	/* doh, nothing entered */;	2534	/* doh, nothing entered */;
2522	else if (revents & EV_READ)
2523	/* stdin might have data for us, joy! */;
2524	}	2535	}
2525		2536
2526	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2537	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2527		2538
2528	=item ev_feed_event (ev_loop , watcher , int revents)	2539	=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:	3309	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3299		3310
3300	#include "ev_cpp.h"	3311	#include "ev_cpp.h"
3301	#include "ev.c"	3312	#include "ev.c"
3302		3313
		3314	=head1 INTERACTION WITH OTHER PROGRAMS OR LIBRARIES
3303		3315
3304	=head1 THREADS AND COROUTINES	3316	=head2 THREADS AND COROUTINES
3305		3317
3306	=head2 THREADS	3318	=head3 THREADS
3307		3319
3308	Libev itself is thread-safe (unless the opposite is specifically	3320	All libev functions are reentrant and thread-safe unless explicitly
3309	documented for a function), but it uses no locking itself. This means that	3321	documented otherwise, but libev implements no locking itself. This means
3310	you can use as many loops as you want in parallel, as long as only one	3322	that you can use as many loops as you want in parallel, as long as there
3311	thread ever calls into one libev function with the same loop parameter:	3323	are no concurrent calls into any libev function with the same loop
		3324	parameter (C<ev_default_*> calls have an implicit default loop parameter,
3312	libev guarantees that different event loops share no data structures that	3325	of course): libev guarantees that different event loops share no data
3313	need locking.	3326	structures that need any locking.
3314		3327
3315	Or to put it differently: calls with different loop parameters can be done	3328	Or to put it differently: calls with different loop parameters can be done
3316	concurrently from multiple threads, calls with the same loop parameter	3329	concurrently from multiple threads, calls with the same loop parameter
3317	must be done serially (but can be done from different threads, as long as	3330	must be done serially (but can be done from different threads, as long as
3318	only one thread ever is inside a call at any point in time, e.g. by using	3331	only one thread ever is inside a call at any point in time, e.g. by using
3319	a mutex per loop).	3332	a mutex per loop).
3320		3333
3321	Specifically to support threads (and signal handlers), libev implements	3334	Specifically to support threads (and signal handlers), libev implements
3322	so-called C<ev_async> watchers, which allow some limited form of	3335	so-called C<ev_async> watchers, which allow some limited form of
3323	concurrency on the same event loop.	3336	concurrency on the same event loop, namely waking it up "from the
		3337	outside".
3324		3338
3325	If you want to know which design (one loop, locking, or multiple loops	3339	If you want to know which design (one loop, locking, or multiple loops
3326	without or something else still) is best for your problem, then I cannot	3340	without or something else still) is best for your problem, then I cannot
3327	help you. I can give some generic advice however:	3341	help you, but here is some generic advice:
3328		3342
3329	=over 4	3343	=over 4
3330		3344
3331	=item * most applications have a main thread: use the default libev loop	3345	=item * most applications have a main thread: use the default libev loop
3332	in that thread, or create a separate thread running only the default loop.	3346	in that thread, or create a separate thread running only the default loop.
…		…
3356	default loop and triggering an C<ev_async> watcher from the default loop	3370	default loop and triggering an C<ev_async> watcher from the default loop
3357	watcher callback into the event loop interested in the signal.	3371	watcher callback into the event loop interested in the signal.
3358		3372
3359	=back	3373	=back
3360		3374
3361	=head2 COROUTINES	3375	=head3 COROUTINES
3362		3376
3363	Libev is much more accommodating to coroutines ("cooperative threads"):	3377	Libev is very accommodating to coroutines ("cooperative threads"):
3364	libev fully supports nesting calls to it's functions from different	3378	libev fully supports nesting calls to its functions from different
3365	coroutines (e.g. you can call C<ev_loop> on the same loop from two	3379	coroutines (e.g. you can call C<ev_loop> on the same loop from two
3366	different coroutines and switch freely between both coroutines running the	3380	different coroutines, and switch freely between both coroutines running the
3367	loop, as long as you don't confuse yourself). The only exception is that	3381	loop, as long as you don't confuse yourself). The only exception is that
3368	you must not do this from C<ev_periodic> reschedule callbacks.	3382	you must not do this from C<ev_periodic> reschedule callbacks.
3369		3383
3370	Care has been taken to ensure that libev does not keep local state inside	3384	Care has been taken to ensure that libev does not keep local state inside
3371	C<ev_loop>, and other calls do not usually allow coroutine switches.	3385	C<ev_loop>, and other calls do not usually allow for coroutine switches as
		3386	they do not clal any callbacks.
3372		3387
		3388	=head2 COMPILER WARNINGS
3373		3389
3374	=head1 COMPLEXITIES	3390	Depending on your compiler and compiler settings, you might get no or a
		3391	lot of warnings when compiling libev code. Some people are apparently
		3392	scared by this.
3375		3393
3376	In this section the complexities of (many of) the algorithms used inside	3394	However, these are unavoidable for many reasons. For one, each compiler
3377	libev will be explained. For complexity discussions about backends see the	3395	has different warnings, and each user has different tastes regarding
3378	documentation for C<ev_default_init>.	3396	warning options. "Warn-free" code therefore cannot be a goal except when
		3397	targeting a specific compiler and compiler-version.
3379		3398
3380	All of the following are about amortised time: If an array needs to be	3399	Another reason is that some compiler warnings require elaborate
3381	extended, libev needs to realloc and move the whole array, but this	3400	workarounds, or other changes to the code that make it less clear and less
3382	happens asymptotically never with higher number of elements, so O(1) might	3401	maintainable.
3383	mean it might do a lengthy realloc operation in rare cases, but on average
3384	it is much faster and asymptotically approaches constant time.
3385		3402
3386	=over 4	3403	And of course, some compiler warnings are just plain stupid, or simply
		3404	wrong (because they don't actually warn about the condition their message
		3405	seems to warn about). For example, certain older gcc versions had some
		3406	warnings that resulted an extreme number of false positives. These have
		3407	been fixed, but some people still insist on making code warn-free with
		3408	such buggy versions.
3387		3409
3388	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	3410	While libev is written to generate as few warnings as possible,
		3411	"warn-free" code is not a goal, and it is recommended not to build libev
		3412	with any compiler warnings enabled unless you are prepared to cope with
		3413	them (e.g. by ignoring them). Remember that warnings are just that:
		3414	warnings, not errors, or proof of bugs.
3389		3415
3390	This means that, when you have a watcher that triggers in one hour and
3391	there are 100 watchers that would trigger before that then inserting will
3392	have to skip roughly seven (C<ld 100>) of these watchers.
3393		3416
3394	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)	3417	=head2 VALGRIND
3395		3418
3396	That means that changing a timer costs less than removing/adding them	3419	Valgrind has a special section here because it is a popular tool that is
3397	as only the relative motion in the event queue has to be paid for.	3420	highly useful. Unfortunately, valgrind reports are very hard to interpret.
3398		3421
3399	=item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)	3422	If you think you found a bug (memory leak, uninitialised data access etc.)
		3423	in libev, then check twice: If valgrind reports something like:
3400		3424
3401	These just add the watcher into an array or at the head of a list.	3425	==2274== definitely lost: 0 bytes in 0 blocks.
		3426	==2274== possibly lost: 0 bytes in 0 blocks.
		3427	==2274== still reachable: 256 bytes in 1 blocks.
3402		3428
3403	=item Stopping check/prepare/idle/fork/async watchers: O(1)	3429	Then there is no memory leak, just as memory accounted to global variables
		3430	is not a memleak - the memory is still being refernced, and didn't leak.
3404		3431
3405	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	3432	Similarly, under some circumstances, valgrind might report kernel bugs
		3433	as if it were a bug in libev (e.g. in realloc or in the poll backend,
		3434	although an acceptable workaround has been found here), or it might be
		3435	confused.
3406		3436
3407	These watchers are stored in lists then need to be walked to find the	3437	Keep in mind that valgrind is a very good tool, but only a tool. Don't
3408	correct watcher to remove. The lists are usually short (you don't usually	3438	make it into some kind of religion.
3409	have many watchers waiting for the same fd or signal).
3410		3439
3411	=item Finding the next timer in each loop iteration: O(1)	3440	If you are unsure about something, feel free to contact the mailing list
		3441	with the full valgrind report and an explanation on why you think this
		3442	is a bug in libev (best check the archives, too :). However, don't be
		3443	annoyed when you get a brisk "this is no bug" answer and take the chance
		3444	of learning how to interpret valgrind properly.
3412		3445
3413	By virtue of using a binary or 4-heap, the next timer is always found at a	3446	If you need, for some reason, empty reports from valgrind for your project
3414	fixed position in the storage array.	3447	I suggest using suppression lists.
3415		3448
3416	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
3417		3449
3418	A change means an I/O watcher gets started or stopped, which requires	3450	=head1 PORTABILITY NOTES
3419	libev to recalculate its status (and possibly tell the kernel, depending
3420	on backend and whether C<ev_io_set> was used).
3421		3451
3422	=item Activating one watcher (putting it into the pending state): O(1)
3423
3424	=item Priority handling: O(number_of_priorities)
3425
3426	Priorities are implemented by allocating some space for each
3427	priority. When doing priority-based operations, libev usually has to
3428	linearly search all the priorities, but starting/stopping and activating
3429	watchers becomes O(1) with respect to priority handling.
3430
3431	=item Sending an ev_async: O(1)
3432
3433	=item Processing ev_async_send: O(number_of_async_watchers)
3434
3435	=item Processing signals: O(max_signal_number)
3436
3437	Sending involves a system call I<iff> there were no other C<ev_async_send>
3438	calls in the current loop iteration. Checking for async and signal events
3439	involves iterating over all running async watchers or all signal numbers.
3440
3441	=back
3442
3443
3444	=head1 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	3452	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
3445		3453
3446	Win32 doesn't support any of the standards (e.g. POSIX) that libev	3454	Win32 doesn't support any of the standards (e.g. POSIX) that libev
3447	requires, and its I/O model is fundamentally incompatible with the POSIX	3455	requires, and its I/O model is fundamentally incompatible with the POSIX
3448	model. Libev still offers limited functionality on this platform in	3456	model. Libev still offers limited functionality on this platform in
3449	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	3457	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
…		…
3536	wrap all I/O functions and provide your own fd management, but the cost of	3544	wrap all I/O functions and provide your own fd management, but the cost of
3537	calling select (O(n²)) will likely make this unworkable.	3545	calling select (O(n²)) will likely make this unworkable.
3538		3546
3539	=back	3547	=back
3540		3548
3541
3542	=head1 PORTABILITY REQUIREMENTS	3549	=head2 PORTABILITY REQUIREMENTS
3543		3550
3544	In addition to a working ISO-C implementation, libev relies on a few	3551	In addition to a working ISO-C implementation and of course the
3545	additional extensions:	3552	backend-specific APIs, libev relies on a few additional extensions:
3546		3553
3547	=over 4	3554	=over 4
3548		3555
3549	=item C<void ()(ev_watcher_type , int revents)> must have compatible	3556	=item C<void ()(ev_watcher_type , int revents)> must have compatible
3550	calling conventions regardless of C<ev_watcher_type *>.	3557	calling conventions regardless of C<ev_watcher_type *>.
…		…
3575	except the initial one, and run the default loop in the initial thread as	3582	except the initial one, and run the default loop in the initial thread as
3576	well.	3583	well.
3577		3584
3578	=item C<long> must be large enough for common memory allocation sizes	3585	=item C<long> must be large enough for common memory allocation sizes
3579		3586
3580	To improve portability and simplify using libev, libev uses C<long>	3587	To improve portability and simplify its API, libev uses C<long> internally
3581	internally instead of C<size_t> when allocating its data structures. On	3588	instead of C<size_t> when allocating its data structures. On non-POSIX
3582	non-POSIX systems (Microsoft...) this might be unexpectedly low, but	3589	systems (Microsoft...) this might be unexpectedly low, but is still at
3583	is still at least 31 bits everywhere, which is enough for hundreds of	3590	least 31 bits everywhere, which is enough for hundreds of millions of
3584	millions of watchers.	3591	watchers.
3585		3592
3586	=item C<double> must hold a time value in seconds with enough accuracy	3593	=item C<double> must hold a time value in seconds with enough accuracy
3587		3594
3588	The type C<double> is used to represent timestamps. It is required to	3595	The type C<double> is used to represent timestamps. It is required to
3589	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	3596	have at least 51 bits of mantissa (and 9 bits of exponent), which is good
…		…
3593	=back	3600	=back
3594		3601
3595	If you know of other additional requirements drop me a note.	3602	If you know of other additional requirements drop me a note.
3596		3603
3597		3604
3598	=head1 COMPILER WARNINGS	3605	=head1 ALGORITHMIC COMPLEXITIES
3599		3606
3600	Depending on your compiler and compiler settings, you might get no or a	3607	In this section the complexities of (many of) the algorithms used inside
3601	lot of warnings when compiling libev code. Some people are apparently	3608	libev will be documented. For complexity discussions about backends see
3602	scared by this.	3609	the documentation for C<ev_default_init>.
3603		3610
3604	However, these are unavoidable for many reasons. For one, each compiler	3611	All of the following are about amortised time: If an array needs to be
3605	has different warnings, and each user has different tastes regarding	3612	extended, libev needs to realloc and move the whole array, but this
3606	warning options. "Warn-free" code therefore cannot be a goal except when	3613	happens asymptotically rarer with higher number of elements, so O(1) might
3607	targeting a specific compiler and compiler-version.	3614	mean that libev does a lengthy realloc operation in rare cases, but on
		3615	average it is much faster and asymptotically approaches constant time.
3608		3616
3609	Another reason is that some compiler warnings require elaborate	3617	=over 4
3610	workarounds, or other changes to the code that make it less clear and less
3611	maintainable.
3612		3618
3613	And of course, some compiler warnings are just plain stupid, or simply	3619	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
3614	wrong (because they don't actually warn about the condition their message
3615	seems to warn about).
3616		3620
3617	While libev is written to generate as few warnings as possible,	3621	This means that, when you have a watcher that triggers in one hour and
3618	"warn-free" code is not a goal, and it is recommended not to build libev	3622	there are 100 watchers that would trigger before that, then inserting will
3619	with any compiler warnings enabled unless you are prepared to cope with	3623	have to skip roughly seven (C<ld 100>) of these watchers.
3620	them (e.g. by ignoring them). Remember that warnings are just that:
3621	warnings, not errors, or proof of bugs.
3622		3624
		3625	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
3623		3626
3624	=head1 VALGRIND	3627	That means that changing a timer costs less than removing/adding them,
		3628	as only the relative motion in the event queue has to be paid for.
3625		3629
3626	Valgrind has a special section here because it is a popular tool that is	3630	=item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)
3627	highly useful, but valgrind reports are very hard to interpret.
3628		3631
3629	If you think you found a bug (memory leak, uninitialised data access etc.)	3632	These just add the watcher into an array or at the head of a list.
3630	in libev, then check twice: If valgrind reports something like:
3631		3633
3632	==2274== definitely lost: 0 bytes in 0 blocks.	3634	=item Stopping check/prepare/idle/fork/async watchers: O(1)
3633	==2274== possibly lost: 0 bytes in 0 blocks.
3634	==2274== still reachable: 256 bytes in 1 blocks.
3635		3635
3636	Then there is no memory leak. Similarly, under some circumstances,	3636	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
3637	valgrind might report kernel bugs as if it were a bug in libev, or it
3638	might be confused (it is a very good tool, but only a tool).
3639		3637
3640	If you are unsure about something, feel free to contact the mailing list	3638	These watchers are stored in lists, so they need to be walked to find the
3641	with the full valgrind report and an explanation on why you think this is	3639	correct watcher to remove. The lists are usually short (you don't usually
3642	a bug in libev. However, don't be annoyed when you get a brisk "this is	3640	have many watchers waiting for the same fd or signal: one is typical, two
3643	no bug" answer and take the chance of learning how to interpret valgrind	3641	is rare).
3644	properly.
3645		3642
3646	If you need, for some reason, empty reports from valgrind for your project	3643	=item Finding the next timer in each loop iteration: O(1)
3647	I suggest using suppression lists.	3644
		3645	By virtue of using a binary or 4-heap, the next timer is always found at a
		3646	fixed position in the storage array.
		3647
		3648	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
		3649
		3650	A change means an I/O watcher gets started or stopped, which requires
		3651	libev to recalculate its status (and possibly tell the kernel, depending
		3652	on backend and whether C<ev_io_set> was used).
		3653
		3654	=item Activating one watcher (putting it into the pending state): O(1)
		3655
		3656	=item Priority handling: O(number_of_priorities)
		3657
		3658	Priorities are implemented by allocating some space for each
		3659	priority. When doing priority-based operations, libev usually has to
		3660	linearly search all the priorities, but starting/stopping and activating
		3661	watchers becomes O(1) with respect to priority handling.
		3662
		3663	=item Sending an ev_async: O(1)
		3664
		3665	=item Processing ev_async_send: O(number_of_async_watchers)
		3666
		3667	=item Processing signals: O(max_signal_number)
		3668
		3669	Sending involves a system call I<iff> there were no other C<ev_async_send>
		3670	calls in the current loop iteration. Checking for async and signal events
		3671	involves iterating over all running async watchers or all signal numbers.
		3672
		3673	=back
3648		3674
3649		3675
3650	=head1 AUTHOR	3676	=head1 AUTHOR
3651		3677
3652	Marc Lehmann <libev@schmorp.de>.	3678	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.pod (file contents): Revision 1.185 by root, Tue Sep 23 09:13:59 2008 UTC vs. Revision 1.193 by root, Wed Oct 1 04:25:25 2008 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.185 by root, Tue Sep 23 09:13:59 2008 UTC vs.
Revision 1.193 by root, Wed Oct 1 04:25:25 2008 UTC