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

Comparing libev/ev.pod (file contents):
Revision 1.112 by root, Wed Dec 26 08:06:09 2007 UTC vs.
Revision 1.134 by root, Sat Mar 8 07:04:56 2008 UTC

…		…
260	flags. If that is troubling you, check C<ev_backend ()> afterwards).	260	flags. If that is troubling you, check C<ev_backend ()> afterwards).
261		261
262	If you don't know what event loop to use, use the one returned from this	262	If you don't know what event loop to use, use the one returned from this
263	function.	263	function.
264		264
		265	The default loop is the only loop that can handle C<ev_signal> and
		266	C<ev_child> watchers, and to do this, it always registers a handler
		267	for C<SIGCHLD>. If this is a problem for your app you can either
		268	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you
		269	can simply overwrite the C<SIGCHLD> signal handler I<after> calling
		270	C<ev_default_init>.
		271
265	The flags argument can be used to specify special behaviour or specific	272	The flags argument can be used to specify special behaviour or specific
266	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	273	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
267		274
268	The following flags are supported:	275	The following flags are supported:
269		276
…		…
403	While this backend scales well, it requires one system call per active	410	While this backend scales well, it requires one system call per active
404	file descriptor per loop iteration. For small and medium numbers of file	411	file descriptor per loop iteration. For small and medium numbers of file
405	descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend	412	descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend
406	might perform better.	413	might perform better.
407		414
		415	On the positive side, ignoring the spurious readyness notifications, this
		416	backend actually performed to specification in all tests and is fully
		417	embeddable, which is a rare feat among the OS-specific backends.
		418
408	=item C<EVBACKEND_ALL>	419	=item C<EVBACKEND_ALL>
409		420
410	Try all backends (even potentially broken ones that wouldn't be tried	421	Try all backends (even potentially broken ones that wouldn't be tried
411	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as	422	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
412	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.	423	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
…		…
414	It is definitely not recommended to use this flag.	425	It is definitely not recommended to use this flag.
415		426
416	=back	427	=back
417		428
418	If one or more of these are ored into the flags value, then only these	429	If one or more of these are ored into the flags value, then only these
419	backends will be tried (in the reverse order as given here). If none are	430	backends will be tried (in the reverse order as listed here). If none are
420	specified, most compiled-in backend will be tried, usually in reverse	431	specified, all backends in C<ev_recommended_backends ()> will be tried.
421	order of their flag values :)
422		432
423	The most typical usage is like this:	433	The most typical usage is like this:
424		434
425	if (!ev_default_loop (0))	435	if (!ev_default_loop (0))
426	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");	436	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
…		…
473	Like C<ev_default_destroy>, but destroys an event loop created by an	483	Like C<ev_default_destroy>, but destroys an event loop created by an
474	earlier call to C<ev_loop_new>.	484	earlier call to C<ev_loop_new>.
475		485
476	=item ev_default_fork ()	486	=item ev_default_fork ()
477		487
		488	This function sets a flag that causes subsequent C<ev_loop> iterations
478	This function reinitialises the kernel state for backends that have	489	to reinitialise the kernel state for backends that have one. Despite the
479	one. Despite the name, you can call it anytime, but it makes most sense	490	name, you can call it anytime, but it makes most sense after forking, in
480	after forking, in either the parent or child process (or both, but that	491	the child process (or both child and parent, but that again makes little
481	again makes little sense).	492	sense). You I<must> call it in the child before using any of the libev
		493	functions, and it will only take effect at the next C<ev_loop> iteration.
482		494
483	You I<must> call this function in the child process after forking if and	495	On the other hand, you only need to call this function in the child
484	only if you want to use the event library in both processes. If you just	496	process if and only if you want to use the event library in the child. If
485	fork+exec, you don't have to call it.	497	you just fork+exec, you don't have to call it at all.
486		498
487	The function itself is quite fast and it's usually not a problem to call	499	The function itself is quite fast and it's usually not a problem to call
488	it just in case after a fork. To make this easy, the function will fit in	500	it just in case after a fork. To make this easy, the function will fit in
489	quite nicely into a call to C<pthread_atfork>:	501	quite nicely into a call to C<pthread_atfork>:
490		502
491	pthread_atfork (0, 0, ev_default_fork);	503	pthread_atfork (0, 0, ev_default_fork);
492		504
493	At the moment, C<EVBACKEND_SELECT> and C<EVBACKEND_POLL> are safe to use
494	without calling this function, so if you force one of those backends you
495	do not need to care.
496
497	=item ev_loop_fork (loop)	505	=item ev_loop_fork (loop)
498		506
499	Like C<ev_default_fork>, but acts on an event loop created by	507	Like C<ev_default_fork>, but acts on an event loop created by
500	C<ev_loop_new>. Yes, you have to call this on every allocated event loop	508	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
501	after fork, and how you do this is entirely your own problem.	509	after fork, and how you do this is entirely your own problem.
		510
		511	=item int ev_is_default_loop (loop)
		512
		513	Returns true when the given loop actually is the default loop, false otherwise.
502		514
503	=item unsigned int ev_loop_count (loop)	515	=item unsigned int ev_loop_count (loop)
504		516
505	Returns the count of loop iterations for the loop, which is identical to	517	Returns the count of loop iterations for the loop, which is identical to
506	the number of times libev did poll for new events. It starts at C<0> and	518	the number of times libev did poll for new events. It starts at C<0> and
…		…
551	usually a better approach for this kind of thing.	563	usually a better approach for this kind of thing.
552		564
553	Here are the gory details of what C<ev_loop> does:	565	Here are the gory details of what C<ev_loop> does:
554		566
555	- Before the first iteration, call any pending watchers.	567	- Before the first iteration, call any pending watchers.
556	* If there are no active watchers (reference count is zero), return.	568	* If EVFLAG_FORKCHECK was used, check for a fork.
557	- Queue all prepare watchers and then call all outstanding watchers.	569	- If a fork was detected, queue and call all fork watchers.
		570	- Queue and call all prepare watchers.
558	- If we have been forked, recreate the kernel state.	571	- If we have been forked, recreate the kernel state.
559	- Update the kernel state with all outstanding changes.	572	- Update the kernel state with all outstanding changes.
560	- Update the "event loop time".	573	- Update the "event loop time".
561	- Calculate for how long to block.	574	- Calculate for how long to sleep or block, if at all
		575	(active idle watchers, EVLOOP_NONBLOCK or not having
		576	any active watchers at all will result in not sleeping).
		577	- Sleep if the I/O and timer collect interval say so.
562	- Block the process, waiting for any events.	578	- Block the process, waiting for any events.
563	- Queue all outstanding I/O (fd) events.	579	- Queue all outstanding I/O (fd) events.
564	- Update the "event loop time" and do time jump handling.	580	- Update the "event loop time" and do time jump handling.
565	- Queue all outstanding timers.	581	- Queue all outstanding timers.
566	- Queue all outstanding periodics.	582	- Queue all outstanding periodics.
567	- If no events are pending now, queue all idle watchers.	583	- If no events are pending now, queue all idle watchers.
568	- Queue all check watchers.	584	- Queue all check watchers.
569	- Call all queued watchers in reverse order (i.e. check watchers first).	585	- Call all queued watchers in reverse order (i.e. check watchers first).
570	Signals and child watchers are implemented as I/O watchers, and will	586	Signals and child watchers are implemented as I/O watchers, and will
571	be handled here by queueing them when their watcher gets executed.	587	be handled here by queueing them when their watcher gets executed.
572	- If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	588	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
573	were used, return, otherwise continue with step *.	589	were used, or there are no active watchers, return, otherwise
		590	continue with step *.
574		591
575	Example: Queue some jobs and then loop until no events are outsanding	592	Example: Queue some jobs and then loop until no events are outstanding
576	anymore.	593	anymore.
577		594
578	... queue jobs here, make sure they register event watchers as long	595	... queue jobs here, make sure they register event watchers as long
579	... as they still have work to do (even an idle watcher will do..)	596	... as they still have work to do (even an idle watcher will do..)
580	ev_loop (my_loop, 0);	597	ev_loop (my_loop, 0);
…		…
584		601
585	Can be used to make a call to C<ev_loop> return early (but only after it	602	Can be used to make a call to C<ev_loop> return early (but only after it
586	has processed all outstanding events). The C<how> argument must be either	603	has processed all outstanding events). The C<how> argument must be either
587	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	604	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
588	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	605	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
		606
		607	This "unloop state" will be cleared when entering C<ev_loop> again.
589		608
590	=item ev_ref (loop)	609	=item ev_ref (loop)
591		610
592	=item ev_unref (loop)	611	=item ev_unref (loop)
593		612
…		…
598	returning, ev_unref() after starting, and ev_ref() before stopping it. For	617	returning, ev_unref() after starting, and ev_ref() before stopping it. For
599	example, libev itself uses this for its internal signal pipe: It is not	618	example, libev itself uses this for its internal signal pipe: It is not
600	visible to the libev user and should not keep C<ev_loop> from exiting if	619	visible to the libev user and should not keep C<ev_loop> from exiting if
601	no event watchers registered by it are active. It is also an excellent	620	no event watchers registered by it are active. It is also an excellent
602	way to do this for generic recurring timers or from within third-party	621	way to do this for generic recurring timers or from within third-party
603	libraries. Just remember to I<unref after start> and I<ref before stop>.	622	libraries. Just remember to I<unref after start> and I<ref before stop>
		623	(but only if the watcher wasn't active before, or was active before,
		624	respectively).
604		625
605	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	626	Example: Create a signal watcher, but keep it from keeping C<ev_loop>
606	running when nothing else is active.	627	running when nothing else is active.
607		628
608	struct ev_signal exitsig;	629	struct ev_signal exitsig;
…		…
756		777
757	=item C<EV_FORK>	778	=item C<EV_FORK>
758		779
759	The event loop has been resumed in the child process after fork (see	780	The event loop has been resumed in the child process after fork (see
760	C<ev_fork>).	781	C<ev_fork>).
		782
		783	=item C<EV_ASYNC>
		784
		785	The given async watcher has been asynchronously notified (see C<ev_async>).
761		786
762	=item C<EV_ERROR>	787	=item C<EV_ERROR>
763		788
764	An unspecified error has occured, the watcher has been stopped. This might	789	An unspecified error has occured, the watcher has been stopped. This might
765	happen because the watcher could not be properly started because libev	790	happen because the watcher could not be properly started because libev
…		…
1131	configure a timer to trigger every 10 seconds, then it will trigger at	1156	configure a timer to trigger every 10 seconds, then it will trigger at
1132	exactly 10 second intervals. If, however, your program cannot keep up with	1157	exactly 10 second intervals. If, however, your program cannot keep up with
1133	the timer (because it takes longer than those 10 seconds to do stuff) the	1158	the timer (because it takes longer than those 10 seconds to do stuff) the
1134	timer will not fire more than once per event loop iteration.	1159	timer will not fire more than once per event loop iteration.
1135		1160
1136	=item ev_timer_again (loop)	1161	=item ev_timer_again (loop, ev_timer *)
1137		1162
1138	This will act as if the timer timed out and restart it again if it is	1163	This will act as if the timer timed out and restart it again if it is
1139	repeating. The exact semantics are:	1164	repeating. The exact semantics are:
1140		1165
1141	If the timer is pending, its pending status is cleared.	1166	If the timer is pending, its pending status is cleared.
…		…
1250	In this configuration the watcher triggers an event at the wallclock time	1275	In this configuration the watcher triggers an event at the wallclock time
1251	C<at> and doesn't repeat. It will not adjust when a time jump occurs,	1276	C<at> and doesn't repeat. It will not adjust when a time jump occurs,
1252	that is, if it is to be run at January 1st 2011 then it will run when the	1277	that is, if it is to be run at January 1st 2011 then it will run when the
1253	system time reaches or surpasses this time.	1278	system time reaches or surpasses this time.
1254		1279
1255	=item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)	1280	=item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)
1256		1281
1257	In this mode the watcher will always be scheduled to time out at the next	1282	In this mode the watcher will always be scheduled to time out at the next
1258	C<at + N * interval> time (for some integer N, which can also be negative)	1283	C<at + N * interval> time (for some integer N, which can also be negative)
1259	and then repeat, regardless of any time jumps.	1284	and then repeat, regardless of any time jumps.
1260		1285
…		…
1411		1436
1412	The signal the watcher watches out for.	1437	The signal the watcher watches out for.
1413		1438
1414	=back	1439	=back
1415		1440
		1441	=head3 Examples
		1442
		1443	Example: Try to exit cleanly on SIGINT and SIGTERM.
		1444
		1445	static void
		1446	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
		1447	{
		1448	ev_unloop (loop, EVUNLOOP_ALL);
		1449	}
		1450
		1451	struct ev_signal signal_watcher;
		1452	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
		1453	ev_signal_start (loop, &sigint_cb);
		1454
1416		1455
1417	=head2 C<ev_child> - watch out for process status changes	1456	=head2 C<ev_child> - watch out for process status changes
1418		1457
1419	Child watchers trigger when your process receives a SIGCHLD in response to	1458	Child watchers trigger when your process receives a SIGCHLD in response to
1420	some child status changes (most typically when a child of yours dies).	1459	some child status changes (most typically when a child of yours dies). It
		1460	is permissible to install a child watcher I<after> the child has been
		1461	forked (which implies it might have already exited), as long as the event
		1462	loop isn't entered (or is continued from a watcher).
		1463
		1464	Only the default event loop is capable of handling signals, and therefore
		1465	you can only rgeister child watchers in the default event loop.
		1466
		1467	=head3 Process Interaction
		1468
		1469	Libev grabs C<SIGCHLD> as soon as the default event loop is
		1470	initialised. This is necessary to guarantee proper behaviour even if
		1471	the first child watcher is started after the child exits. The occurance
		1472	of C<SIGCHLD> is recorded asynchronously, but child reaping is done
		1473	synchronously as part of the event loop processing. Libev always reaps all
		1474	children, even ones not watched.
		1475
		1476	=head3 Overriding the Built-In Processing
		1477
		1478	Libev offers no special support for overriding the built-in child
		1479	processing, but if your application collides with libev's default child
		1480	handler, you can override it easily by installing your own handler for
		1481	C<SIGCHLD> after initialising the default loop, and making sure the
		1482	default loop never gets destroyed. You are encouraged, however, to use an
		1483	event-based approach to child reaping and thus use libev's support for
		1484	that, so other libev users can use C<ev_child> watchers freely.
1421		1485
1422	=head3 Watcher-Specific Functions and Data Members	1486	=head3 Watcher-Specific Functions and Data Members
1423		1487
1424	=over 4	1488	=over 4
1425		1489
1426	=item ev_child_init (ev_child *, callback, int pid)	1490	=item ev_child_init (ev_child *, callback, int pid, int trace)
1427		1491
1428	=item ev_child_set (ev_child *, int pid)	1492	=item ev_child_set (ev_child *, int pid, int trace)
1429		1493
1430	Configures the watcher to wait for status changes of process C<pid> (or	1494	Configures the watcher to wait for status changes of process C<pid> (or
1431	I<any> process if C<pid> is specified as C<0>). The callback can look	1495	I<any> process if C<pid> is specified as C<0>). The callback can look
1432	at the C<rstatus> member of the C<ev_child> watcher structure to see	1496	at the C<rstatus> member of the C<ev_child> watcher structure to see
1433	the status word (use the macros from C<sys/wait.h> and see your systems	1497	the status word (use the macros from C<sys/wait.h> and see your systems
1434	C<waitpid> documentation). The C<rpid> member contains the pid of the	1498	C<waitpid> documentation). The C<rpid> member contains the pid of the
1435	process causing the status change.	1499	process causing the status change. C<trace> must be either C<0> (only
		1500	activate the watcher when the process terminates) or C<1> (additionally
		1501	activate the watcher when the process is stopped or continued).
1436		1502
1437	=item int pid [read-only]	1503	=item int pid [read-only]
1438		1504
1439	The process id this watcher watches out for, or C<0>, meaning any process id.	1505	The process id this watcher watches out for, or C<0>, meaning any process id.
1440		1506
…		…
1449		1515
1450	=back	1516	=back
1451		1517
1452	=head3 Examples	1518	=head3 Examples
1453		1519
1454	Example: Try to exit cleanly on SIGINT and SIGTERM.	1520	Example: C<fork()> a new process and install a child handler to wait for
		1521	its completion.
		1522
		1523	ev_child cw;
1455		1524
1456	static void	1525	static void
1457	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1526	child_cb (EV_P_ struct ev_child *w, int revents)
1458	{	1527	{
1459	ev_unloop (loop, EVUNLOOP_ALL);	1528	ev_child_stop (EV_A_ w);
		1529	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1460	}	1530	}
1461		1531
1462	struct ev_signal signal_watcher;	1532	pid_t pid = fork ();
1463	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1533
1464	ev_signal_start (loop, &sigint_cb);	1534	if (pid < 0)
		1535	// error
		1536	else if (pid == 0)
		1537	{
		1538	// the forked child executes here
		1539	exit (1);
		1540	}
		1541	else
		1542	{
		1543	ev_child_init (&cw, child_cb, pid, 0);
		1544	ev_child_start (EV_DEFAULT_ &cw);
		1545	}
1465		1546
1466		1547
1467	=head2 C<ev_stat> - did the file attributes just change?	1548	=head2 C<ev_stat> - did the file attributes just change?
1468		1549
1469	This watches a filesystem path for attribute changes. That is, it calls	1550	This watches a filesystem path for attribute changes. That is, it calls
…		…
1549		1630
1550	The callback will be receive C<EV_STAT> when a change was detected,	1631	The callback will be receive C<EV_STAT> when a change was detected,
1551	relative to the attributes at the time the watcher was started (or the	1632	relative to the attributes at the time the watcher was started (or the
1552	last change was detected).	1633	last change was detected).
1553		1634
1554	=item ev_stat_stat (ev_stat *)	1635	=item ev_stat_stat (loop, ev_stat *)
1555		1636
1556	Updates the stat buffer immediately with new values. If you change the	1637	Updates the stat buffer immediately with new values. If you change the
1557	watched path in your callback, you could call this fucntion to avoid	1638	watched path in your callback, you could call this fucntion to avoid
1558	detecting this change (while introducing a race condition). Can also be	1639	detecting this change (while introducing a race condition). Can also be
1559	useful simply to find out the new values.	1640	useful simply to find out the new values.
…		…
1676	static void	1757	static void
1677	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1758	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1678	{	1759	{
1679	free (w);	1760	free (w);
1680	// now do something you wanted to do when the program has	1761	// now do something you wanted to do when the program has
1681	// no longer asnything immediate to do.	1762	// no longer anything immediate to do.
1682	}	1763	}
1683		1764
1684	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1765	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1685	ev_idle_init (idle_watcher, idle_cb);	1766	ev_idle_init (idle_watcher, idle_cb);
1686	ev_idle_start (loop, idle_cb);	1767	ev_idle_start (loop, idle_cb);
…		…
2027	believe me.	2108	believe me.
2028		2109
2029	=back	2110	=back
2030		2111
2031		2112
		2113	=head2 C<ev_async> - how to wake up another event loop
		2114
		2115	In general, you cannot use an C<ev_loop> from multiple threads or other
		2116	asynchronous sources such as signal handlers (as opposed to multiple event
		2117	loops - those are of course safe to use in different threads).
		2118
		2119	Sometimes, however, you need to wake up another event loop you do not
		2120	control, for example because it belongs to another thread. This is what
		2121	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you
		2122	can signal it by calling C<ev_async_send>, which is thread- and signal
		2123	safe.
		2124
		2125	This functionality is very similar to C<ev_signal> watchers, as signals,
		2126	too, are asynchronous in nature, and signals, too, will be compressed
		2127	(i.e. the number of callback invocations may be less than the number of
		2128	C<ev_async_sent> calls).
		2129
		2130	Unlike C<ev_signal> watchers, C<ev_async> works with any event loop, not
		2131	just the default loop.
		2132
		2133	=head3 Queueing
		2134
		2135	C<ev_async> does not support queueing of data in any way. The reason
		2136	is that the author does not know of a simple (or any) algorithm for a
		2137	multiple-writer-single-reader queue that works in all cases and doesn't
		2138	need elaborate support such as pthreads.
		2139
		2140	That means that if you want to queue data, you have to provide your own
		2141	queue. But at least I can tell you would implement locking around your
		2142	queue:
		2143
		2144	=over 4
		2145
		2146	=item queueing from a signal handler context
		2147
		2148	To implement race-free queueing, you simply add to the queue in the signal
		2149	handler but you block the signal handler in the watcher callback. Here is an example that does that for
		2150	some fictitiuous SIGUSR1 handler:
		2151
		2152	static ev_async mysig;
		2153
		2154	static void
		2155	sigusr1_handler (void)
		2156	{
		2157	sometype data;
		2158
		2159	// no locking etc.
		2160	queue_put (data);
		2161	ev_async_send (EV_DEFAULT_ &mysig);
		2162	}
		2163
		2164	static void
		2165	mysig_cb (EV_P_ ev_async *w, int revents)
		2166	{
		2167	sometype data;
		2168	sigset_t block, prev;
		2169
		2170	sigemptyset (&block);
		2171	sigaddset (&block, SIGUSR1);
		2172	sigprocmask (SIG_BLOCK, &block, &prev);
		2173
		2174	while (queue_get (&data))
		2175	process (data);
		2176
		2177	if (sigismember (&prev, SIGUSR1)
		2178	sigprocmask (SIG_UNBLOCK, &block, 0);
		2179	}
		2180
		2181	(Note: pthreads in theory requires you to use C<pthread_setmask>
		2182	instead of C<sigprocmask> when you use threads, but libev doesn't do it
		2183	either...).
		2184
		2185	=item queueing from a thread context
		2186
		2187	The strategy for threads is different, as you cannot (easily) block
		2188	threads but you can easily preempt them, so to queue safely you need to
		2189	employ a traditional mutex lock, such as in this pthread example:
		2190
		2191	static ev_async mysig;
		2192	static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER;
		2193
		2194	static void
		2195	otherthread (void)
		2196	{
		2197	// only need to lock the actual queueing operation
		2198	pthread_mutex_lock (&mymutex);
		2199	queue_put (data);
		2200	pthread_mutex_unlock (&mymutex);
		2201
		2202	ev_async_send (EV_DEFAULT_ &mysig);
		2203	}
		2204
		2205	static void
		2206	mysig_cb (EV_P_ ev_async *w, int revents)
		2207	{
		2208	pthread_mutex_lock (&mymutex);
		2209
		2210	while (queue_get (&data))
		2211	process (data);
		2212
		2213	pthread_mutex_unlock (&mymutex);
		2214	}
		2215
		2216	=back
		2217
		2218
		2219	=head3 Watcher-Specific Functions and Data Members
		2220
		2221	=over 4
		2222
		2223	=item ev_async_init (ev_async *, callback)
		2224
		2225	Initialises and configures the async watcher - it has no parameters of any
		2226	kind. There is a C<ev_asynd_set> macro, but using it is utterly pointless,
		2227	believe me.
		2228
		2229	=item ev_async_send (loop, ev_async *)
		2230
		2231	Sends/signals/activates the given C<ev_async> watcher, that is, feeds
		2232	an C<EV_ASYNC> event on the watcher into the event loop. Unlike
		2233	C<ev_feed_event>, this call is safe to do in other threads, signal or
		2234	similar contexts (see the dicusssion of C<EV_ATOMIC_T> in the embedding
		2235	section below on what exactly this means).
		2236
		2237	This call incurs the overhead of a syscall only once per loop iteration,
		2238	so while the overhead might be noticable, it doesn't apply to repeated
		2239	calls to C<ev_async_send>.
		2240
		2241	=back
		2242
		2243
2032	=head1 OTHER FUNCTIONS	2244	=head1 OTHER FUNCTIONS
2033		2245
2034	There are some other functions of possible interest. Described. Here. Now.	2246	There are some other functions of possible interest. Described. Here. Now.
2035		2247
2036	=over 4	2248	=over 4
…		…
2263	Example: Define a class with an IO and idle watcher, start one of them in	2475	Example: Define a class with an IO and idle watcher, start one of them in
2264	the constructor.	2476	the constructor.
2265		2477
2266	class myclass	2478	class myclass
2267	{	2479	{
2268	ev_io io; void io_cb (ev::io &w, int revents);	2480	ev::io io; void io_cb (ev::io &w, int revents);
2269	ev_idle idle void idle_cb (ev::idle &w, int revents);	2481	ev:idle idle void idle_cb (ev::idle &w, int revents);
2270		2482
2271	myclass ();	2483	myclass (int fd)
2272	}
2273
2274	myclass::myclass (int fd)
2275	{	2484	{
2276	io .set <myclass, &myclass::io_cb > (this);	2485	io .set <myclass, &myclass::io_cb > (this);
2277	idle.set <myclass, &myclass::idle_cb> (this);	2486	idle.set <myclass, &myclass::idle_cb> (this);
2278		2487
2279	io.start (fd, ev::READ);	2488	io.start (fd, ev::READ);
		2489	}
2280	}	2490	};
2281		2491
2282		2492
2283	=head1 MACRO MAGIC	2493	=head1 MACRO MAGIC
2284		2494
2285	Libev can be compiled with a variety of options, the most fundamantal	2495	Libev can be compiled with a variety of options, the most fundamantal
…		…
2541		2751
2542	If defined to be C<1>, libev will compile in support for the Linux inotify	2752	If defined to be C<1>, libev will compile in support for the Linux inotify
2543	interface to speed up C<ev_stat> watchers. Its actual availability will	2753	interface to speed up C<ev_stat> watchers. Its actual availability will
2544	be detected at runtime.	2754	be detected at runtime.
2545		2755
		2756	=item EV_ATOMIC_T
		2757
		2758	Libev requires an integer type (suitable for storing C<0> or C<1>) whose
		2759	access is atomic with respect to other threads or signal contexts. No such
		2760	type is easily found in the C language, so you can provide your own type
		2761	that you know is safe for your purposes. It is used both for signal handler "locking"
		2762	as well as for signal and thread safety in C<ev_async> watchers.
		2763
		2764	In the absense of this define, libev will use C<sig_atomic_t volatile>
		2765	(from F<signal.h>), which is usually good enough on most platforms.
		2766
2546	=item EV_H	2767	=item EV_H
2547		2768
2548	The name of the F<ev.h> header file used to include it. The default if	2769	The name of the F<ev.h> header file used to include it. The default if
2549	undefined is C<"ev.h"> in F<event.h> and F<ev.c>. This can be used to	2770	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
2550	virtually rename the F<ev.h> header file in case of conflicts.	2771	used to virtually rename the F<ev.h> header file in case of conflicts.
2551		2772
2552	=item EV_CONFIG_H	2773	=item EV_CONFIG_H
2553		2774
2554	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	2775	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
2555	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	2776	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
2556	C<EV_H>, above.	2777	C<EV_H>, above.
2557		2778
2558	=item EV_EVENT_H	2779	=item EV_EVENT_H
2559		2780
2560	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	2781	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
2561	of how the F<event.h> header can be found, the dfeault is C<"event.h">.	2782	of how the F<event.h> header can be found, the default is C<"event.h">.
2562		2783
2563	=item EV_PROTOTYPES	2784	=item EV_PROTOTYPES
2564		2785
2565	If defined to be C<0>, then F<ev.h> will not define any function	2786	If defined to be C<0>, then F<ev.h> will not define any function
2566	prototypes, but still define all the structs and other symbols. This is	2787	prototypes, but still define all the structs and other symbols. This is
…		…
2615	defined to be C<0>, then they are not.	2836	defined to be C<0>, then they are not.
2616		2837
2617	=item EV_FORK_ENABLE	2838	=item EV_FORK_ENABLE
2618		2839
2619	If undefined or defined to be C<1>, then fork watchers are supported. If	2840	If undefined or defined to be C<1>, then fork watchers are supported. If
		2841	defined to be C<0>, then they are not.
		2842
		2843	=item EV_ASYNC_ENABLE
		2844
		2845	If undefined or defined to be C<1>, then async watchers are supported. If
2620	defined to be C<0>, then they are not.	2846	defined to be C<0>, then they are not.
2621		2847
2622	=item EV_MINIMAL	2848	=item EV_MINIMAL
2623		2849
2624	If you need to shave off some kilobytes of code at the expense of some	2850	If you need to shave off some kilobytes of code at the expense of some
…		…
2745	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)	2971	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
2746		2972
2747	That means that changing a timer costs less than removing/adding them	2973	That means that changing a timer costs less than removing/adding them
2748	as only the relative motion in the event queue has to be paid for.	2974	as only the relative motion in the event queue has to be paid for.
2749		2975
2750	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2976	=item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)
2751		2977
2752	These just add the watcher into an array or at the head of a list.	2978	These just add the watcher into an array or at the head of a list.
2753		2979
2754	=item Stopping check/prepare/idle watchers: O(1)	2980	=item Stopping check/prepare/idle/fork/async watchers: O(1)
2755		2981
2756	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	2982	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2757		2983
2758	These watchers are stored in lists then need to be walked to find the	2984	These watchers are stored in lists then need to be walked to find the
2759	correct watcher to remove. The lists are usually short (you don't usually	2985	correct watcher to remove. The lists are usually short (you don't usually
…		…
2775	=item Priority handling: O(number_of_priorities)	3001	=item Priority handling: O(number_of_priorities)
2776		3002
2777	Priorities are implemented by allocating some space for each	3003	Priorities are implemented by allocating some space for each
2778	priority. When doing priority-based operations, libev usually has to	3004	priority. When doing priority-based operations, libev usually has to
2779	linearly search all the priorities, but starting/stopping and activating	3005	linearly search all the priorities, but starting/stopping and activating
2780	watchers becomes O(1) w.r.t. prioritiy handling.	3006	watchers becomes O(1) w.r.t. priority handling.
		3007
		3008	=item Sending an ev_async: O(1)
		3009
		3010	=item Processing ev_async_send: O(number_of_async_watchers)
		3011
		3012	=item Processing signals: O(max_signal_number)
		3013
		3014	Sending involves a syscall I<iff> there were no other C<ev_async_send>
		3015	calls in the current loop iteration. Checking for async and signal events
		3016	involves iterating over all running async watchers or all signal numbers.
2781		3017
2782	=back	3018	=back
2783		3019
2784		3020
2785	=head1 Win32 platform limitations and workarounds	3021	=head1 Win32 platform limitations and workarounds

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Comparing libev/ev.pod (file contents): Revision 1.112 by root, Wed Dec 26 08:06:09 2007 UTC vs. Revision 1.134 by root, Sat Mar 8 07:04:56 2008 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.112 by root, Wed Dec 26 08:06:09 2007 UTC vs.
Revision 1.134 by root, Sat Mar 8 07:04:56 2008 UTC