[ViewVC] Diff of: cvs/libev/ev.3

Comparing libev/ev.3 (file contents):
Revision 1.7 by root, Fri Nov 23 08:36:35 2007 UTC vs.
Revision 1.9 by root, Fri Nov 23 16:17:12 2007 UTC

…		…
173	.IX Header "TIME REPRESENTATION"	173	.IX Header "TIME REPRESENTATION"
174	Libev represents time as a single floating point number, representing the	174	Libev represents time as a single floating point number, representing the
175	(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near	175	(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near
176	the beginning of 1970, details are complicated, don't ask). This type is	176	the beginning of 1970, details are complicated, don't ask). This type is
177	called \f(CW\(C`ev_tstamp\(C'\fR, which is what you should use too. It usually aliases	177	called \f(CW\(C`ev_tstamp\(C'\fR, which is what you should use too. It usually aliases
178	to the double type in C.	178	to the \f(CW\(C`double\(C'\fR type in C, and when you need to do any calculations on
		179	it, you should treat it as such.
179	.SH "GLOBAL FUNCTIONS"	180	.SH "GLOBAL FUNCTIONS"
180	.IX Header "GLOBAL FUNCTIONS"	181	.IX Header "GLOBAL FUNCTIONS"
181	These functions can be called anytime, even before initialising the	182	These functions can be called anytime, even before initialising the
182	library in any way.	183	library in any way.
183	.IP "ev_tstamp ev_time ()" 4	184	.IP "ev_tstamp ev_time ()" 4
…		…
199	.Sp	200	.Sp
200	Usually, it's a good idea to terminate if the major versions mismatch,	201	Usually, it's a good idea to terminate if the major versions mismatch,
201	as this indicates an incompatible change. Minor versions are usually	202	as this indicates an incompatible change. Minor versions are usually
202	compatible to older versions, so a larger minor version alone is usually	203	compatible to older versions, so a larger minor version alone is usually
203	not a problem.	204	not a problem.
		205	.Sp
		206	Example: make sure we haven't accidentally been linked against the wrong
		207	version:
		208	.Sp
		209	.Vb 3
		210	\& assert (("libev version mismatch",
		211	\& ev_version_major () == EV_VERSION_MAJOR
		212	\& && ev_version_minor () >= EV_VERSION_MINOR));
		213	.Ve
204	.IP "unsigned int ev_supported_backends ()" 4	214	.IP "unsigned int ev_supported_backends ()" 4
205	.IX Item "unsigned int ev_supported_backends ()"	215	.IX Item "unsigned int ev_supported_backends ()"
206	Return the set of all backends (i.e. their corresponding \f(CW\(C`EV_BACKEND_\*(C'\fR	216	Return the set of all backends (i.e. their corresponding \f(CW\(C`EV_BACKEND_\*(C'\fR
207	value) compiled into this binary of libev (independent of their	217	value) compiled into this binary of libev (independent of their
208	availability on the system you are running on). See \f(CW\(C`ev_default_loop\(C'\fR for	218	availability on the system you are running on). See \f(CW\(C`ev_default_loop\(C'\fR for
209	a description of the set values.	219	a description of the set values.
		220	.Sp
		221	Example: make sure we have the epoll method, because yeah this is cool and
		222	a must have and can we have a torrent of it please!!!11
		223	.Sp
		224	.Vb 2
		225	\& assert (("sorry, no epoll, no sex",
		226	\& ev_supported_backends () & EVBACKEND_EPOLL));
		227	.Ve
210	.IP "unsigned int ev_recommended_backends ()" 4	228	.IP "unsigned int ev_recommended_backends ()" 4
211	.IX Item "unsigned int ev_recommended_backends ()"	229	.IX Item "unsigned int ev_recommended_backends ()"
212	Return the set of all backends compiled into this binary of libev and also	230	Return the set of all backends compiled into this binary of libev and also
213	recommended for this platform. This set is often smaller than the one	231	recommended for this platform. This set is often smaller than the one
214	returned by \f(CW\(C`ev_supported_backends\(C'\fR, as for example kqueue is broken on	232	returned by \f(CW\(C`ev_supported_backends\(C'\fR, as for example kqueue is broken on
215	most BSDs and will not be autodetected unless you explicitly request it	233	most BSDs and will not be autodetected unless you explicitly request it
216	(assuming you know what you are doing). This is the set of backends that	234	(assuming you know what you are doing). This is the set of backends that
217	\&\f(CW\(C`EVFLAG_AUTO\(C'\fR will probe for.	235	libev will probe for if you specify no backends explicitly.
218	.IP "ev_set_allocator (void (cb)(void *ptr, long size))" 4	236	.IP "ev_set_allocator (void (cb)(void *ptr, long size))" 4
219	.IX Item "ev_set_allocator (void (cb)(void *ptr, long size))"	237	.IX Item "ev_set_allocator (void (cb)(void *ptr, long size))"
220	Sets the allocation function to use (the prototype is similar to the	238	Sets the allocation function to use (the prototype is similar to the
221	realloc C function, the semantics are identical). It is used to allocate	239	realloc C function, the semantics are identical). It is used to allocate
222	and free memory (no surprises here). If it returns zero when memory	240	and free memory (no surprises here). If it returns zero when memory
…		…
224	destructive action. The default is your system realloc function.	242	destructive action. The default is your system realloc function.
225	.Sp	243	.Sp
226	You could override this function in high-availability programs to, say,	244	You could override this function in high-availability programs to, say,
227	free some memory if it cannot allocate memory, to use a special allocator,	245	free some memory if it cannot allocate memory, to use a special allocator,
228	or even to sleep a while and retry until some memory is available.	246	or even to sleep a while and retry until some memory is available.
		247	.Sp
		248	Example: replace the libev allocator with one that waits a bit and then
		249	retries: better than mine).
		250	.Sp
		251	.Vb 6
		252	\& static void *
		253	\& persistent_realloc (void *ptr, long size)
		254	\& {
		255	\& for (;;)
		256	\& {
		257	\& void *newptr = realloc (ptr, size);
		258	.Ve
		259	.Sp
		260	.Vb 2
		261	\& if (newptr)
		262	\& return newptr;
		263	.Ve
		264	.Sp
		265	.Vb 3
		266	\& sleep (60);
		267	\& }
		268	\& }
		269	.Ve
		270	.Sp
		271	.Vb 2
		272	\& ...
		273	\& ev_set_allocator (persistent_realloc);
		274	.Ve
229	.IP "ev_set_syserr_cb (void (cb)(const char msg));" 4	275	.IP "ev_set_syserr_cb (void (cb)(const char msg));" 4
230	.IX Item "ev_set_syserr_cb (void (cb)(const char msg));"	276	.IX Item "ev_set_syserr_cb (void (cb)(const char msg));"
231	Set the callback function to call on a retryable syscall error (such	277	Set the callback function to call on a retryable syscall error (such
232	as failed select, poll, epoll_wait). The message is a printable string	278	as failed select, poll, epoll_wait). The message is a printable string
233	indicating the system call or subsystem causing the problem. If this	279	indicating the system call or subsystem causing the problem. If this
234	callback is set, then libev will expect it to remedy the sitution, no	280	callback is set, then libev will expect it to remedy the sitution, no
235	matter what, when it returns. That is, libev will generally retry the	281	matter what, when it returns. That is, libev will generally retry the
236	requested operation, or, if the condition doesn't go away, do bad stuff	282	requested operation, or, if the condition doesn't go away, do bad stuff
237	(such as abort).	283	(such as abort).
		284	.Sp
		285	Example: do the same thing as libev does internally:
		286	.Sp
		287	.Vb 6
		288	\& static void
		289	\& fatal_error (const char *msg)
		290	\& {
		291	\& perror (msg);
		292	\& abort ();
		293	\& }
		294	.Ve
		295	.Sp
		296	.Vb 2
		297	\& ...
		298	\& ev_set_syserr_cb (fatal_error);
		299	.Ve
238	.SH "FUNCTIONS CONTROLLING THE EVENT LOOP"	300	.SH "FUNCTIONS CONTROLLING THE EVENT LOOP"
239	.IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP"	301	.IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP"
240	An event loop is described by a \f(CW\(C`struct ev_loop \*(C'\fR. The library knows two	302	An event loop is described by a \f(CW\(C`struct ev_loop \*(C'\fR. The library knows two
241	types of such loops, the \fIdefault\fR loop, which supports signals and child	303	types of such loops, the \fIdefault\fR loop, which supports signals and child
242	events, and dynamically created loops which do not.	304	events, and dynamically created loops which do not.
…		…
256	.Sp	318	.Sp
257	If you don't know what event loop to use, use the one returned from this	319	If you don't know what event loop to use, use the one returned from this
258	function.	320	function.
259	.Sp	321	.Sp
260	The flags argument can be used to specify special behaviour or specific	322	The flags argument can be used to specify special behaviour or specific
261	backends to use, and is usually specified as \f(CW0\fR (or \s-1EVFLAG_AUTO\s0).	323	backends to use, and is usually specified as \f(CW0\fR (or \f(CW\(C`EVFLAG_AUTO\(C'\fR).
262	.Sp	324	.Sp
263	It supports the following flags:	325	The following flags are supported:
264	.RS 4	326	.RS 4
265	.ie n .IP """EVFLAG_AUTO""" 4	327	.ie n .IP """EVFLAG_AUTO""" 4
266	.el .IP "\f(CWEVFLAG_AUTO\fR" 4	328	.el .IP "\f(CWEVFLAG_AUTO\fR" 4
267	.IX Item "EVFLAG_AUTO"	329	.IX Item "EVFLAG_AUTO"
268	The default flags value. Use this if you have no clue (it's the right	330	The default flags value. Use this if you have no clue (it's the right
…		…
312	.el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4	374	.el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4
313	.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)"	375	.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)"
314	Kqueue deserves special mention, as at the time of this writing, it	376	Kqueue deserves special mention, as at the time of this writing, it
315	was broken on all BSDs except NetBSD (usually it doesn't work with	377	was broken on all BSDs except NetBSD (usually it doesn't work with
316	anything but sockets and pipes, except on Darwin, where of course its	378	anything but sockets and pipes, except on Darwin, where of course its
317	completely useless). For this reason its not being \(L"autodetected\(R" unless	379	completely useless). For this reason its not being \(L"autodetected\(R"
318	you explicitly specify the flags (i.e. you don't use \s-1EVFLAG_AUTO\s0).	380	unless you explicitly specify it explicitly in the flags (i.e. using
		381	\&\f(CW\(C`EVBACKEND_KQUEUE\(C'\fR).
319	.Sp	382	.Sp
320	It scales in the same way as the epoll backend, but the interface to the	383	It scales in the same way as the epoll backend, but the interface to the
321	kernel is more efficient (which says nothing about its actual speed, of	384	kernel is more efficient (which says nothing about its actual speed, of
322	course). While starting and stopping an I/O watcher does not cause an	385	course). While starting and stopping an I/O watcher does not cause an
323	extra syscall as with epoll, it still adds up to four event changes per	386	extra syscall as with epoll, it still adds up to four event changes per
…		…
346	.Sp	409	.Sp
347	If one or more of these are ored into the flags value, then only these	410	If one or more of these are ored into the flags value, then only these
348	backends will be tried (in the reverse order as given here). If none are	411	backends will be tried (in the reverse order as given here). If none are
349	specified, most compiled-in backend will be tried, usually in reverse	412	specified, most compiled-in backend will be tried, usually in reverse
350	order of their flag values :)	413	order of their flag values :)
		414	.Sp
		415	The most typical usage is like this:
		416	.Sp
		417	.Vb 2
		418	\& if (!ev_default_loop (0))
		419	\& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		420	.Ve
		421	.Sp
		422	Restrict libev to the select and poll backends, and do not allow
		423	environment settings to be taken into account:
		424	.Sp
		425	.Vb 1
		426	\& ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
		427	.Ve
		428	.Sp
		429	Use whatever libev has to offer, but make sure that kqueue is used if
		430	available (warning, breaks stuff, best use only with your own private
		431	event loop and only if you know the \s-1OS\s0 supports your types of fds):
		432	.Sp
		433	.Vb 1
		434	\& ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
		435	.Ve
351	.RE	436	.RE
352	.IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4	437	.IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4
353	.IX Item "struct ev_loop *ev_loop_new (unsigned int flags)"	438	.IX Item "struct ev_loop *ev_loop_new (unsigned int flags)"
354	Similar to \f(CW\(C`ev_default_loop\(C'\fR, but always creates a new event loop that is	439	Similar to \f(CW\(C`ev_default_loop\(C'\fR, but always creates a new event loop that is
355	always distinct from the default loop. Unlike the default loop, it cannot	440	always distinct from the default loop. Unlike the default loop, it cannot
356	handle signal and child watchers, and attempts to do so will be greeted by	441	handle signal and child watchers, and attempts to do so will be greeted by
357	undefined behaviour (or a failed assertion if assertions are enabled).	442	undefined behaviour (or a failed assertion if assertions are enabled).
		443	.Sp
		444	Example: try to create a event loop that uses epoll and nothing else.
		445	.Sp
		446	.Vb 3
		447	\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
		448	\& if (!epoller)
		449	\& fatal ("no epoll found here, maybe it hides under your chair");
		450	.Ve
358	.IP "ev_default_destroy ()" 4	451	.IP "ev_default_destroy ()" 4
359	.IX Item "ev_default_destroy ()"	452	.IX Item "ev_default_destroy ()"
360	Destroys the default loop again (frees all memory and kernel state	453	Destroys the default loop again (frees all memory and kernel state
361	etc.). This stops all registered event watchers (by not touching them in	454	etc.). This stops all registered event watchers (by not touching them in
362	any way whatsoever, although you cannot rely on this :).	455	any way whatsoever, although you cannot rely on this :).
…		…
396	Returns one of the \f(CW\(C`EVBACKEND_\*(C'\fR flags indicating the event backend in	489	Returns one of the \f(CW\(C`EVBACKEND_\*(C'\fR flags indicating the event backend in
397	use.	490	use.
398	.IP "ev_tstamp ev_now (loop)" 4	491	.IP "ev_tstamp ev_now (loop)" 4
399	.IX Item "ev_tstamp ev_now (loop)"	492	.IX Item "ev_tstamp ev_now (loop)"
400	Returns the current \(L"event loop time\(R", which is the time the event loop	493	Returns the current \(L"event loop time\(R", which is the time the event loop
401	got events and started processing them. This timestamp does not change	494	received events and started processing them. This timestamp does not
402	as long as callbacks are being processed, and this is also the base time	495	change as long as callbacks are being processed, and this is also the base
403	used for relative timers. You can treat it as the timestamp of the event	496	time used for relative timers. You can treat it as the timestamp of the
404	occuring (or more correctly, the mainloop finding out about it).	497	event occuring (or more correctly, libev finding out about it).
405	.IP "ev_loop (loop, int flags)" 4	498	.IP "ev_loop (loop, int flags)" 4
406	.IX Item "ev_loop (loop, int flags)"	499	.IX Item "ev_loop (loop, int flags)"
407	Finally, this is it, the event handler. This function usually is called	500	Finally, this is it, the event handler. This function usually is called
408	after you initialised all your watchers and you want to start handling	501	after you initialised all your watchers and you want to start handling
409	events.	502	events.
410	.Sp	503	.Sp
411	If the flags argument is specified as 0, it will not return until either	504	If the flags argument is specified as \f(CW0\fR, it will not return until
412	no event watchers are active anymore or \f(CW\(C`ev_unloop\(C'\fR was called.	505	either no event watchers are active anymore or \f(CW\(C`ev_unloop\(C'\fR was called.
		506	.Sp
		507	Please note that an explicit \f(CW\(C`ev_unloop\(C'\fR is usually better than
		508	relying on all watchers to be stopped when deciding when a program has
		509	finished (especially in interactive programs), but having a program that
		510	automatically loops as long as it has to and no longer by virtue of
		511	relying on its watchers stopping correctly is a thing of beauty.
413	.Sp	512	.Sp
414	A flags value of \f(CW\(C`EVLOOP_NONBLOCK\(C'\fR will look for new events, will handle	513	A flags value of \f(CW\(C`EVLOOP_NONBLOCK\(C'\fR will look for new events, will handle
415	those events and any outstanding ones, but will not block your process in	514	those events and any outstanding ones, but will not block your process in
416	case there are no events and will return after one iteration of the loop.	515	case there are no events and will return after one iteration of the loop.
417	.Sp	516	.Sp
418	A flags value of \f(CW\(C`EVLOOP_ONESHOT\(C'\fR will look for new events (waiting if	517	A flags value of \f(CW\(C`EVLOOP_ONESHOT\(C'\fR will look for new events (waiting if
419	neccessary) and will handle those and any outstanding ones. It will block	518	neccessary) and will handle those and any outstanding ones. It will block
420	your process until at least one new event arrives, and will return after	519	your process until at least one new event arrives, and will return after
421	one iteration of the loop.	520	one iteration of the loop. This is useful if you are waiting for some
		521	external event in conjunction with something not expressible using other
		522	libev watchers. However, a pair of \f(CW\(C`ev_prepare\(C'\fR/\f(CW\(C`ev_check\(C'\fR watchers is
		523	usually a better approach for this kind of thing.
422	.Sp	524	.Sp
423	This flags value could be used to implement alternative looping
424	constructs, but the \f(CW\(C`prepare\(C'\fR and \f(CW\(C`check\(C'\fR watchers provide a better and
425	more generic mechanism.
426	.Sp
427	Here are the gory details of what ev_loop does:	525	Here are the gory details of what \f(CW\(C`ev_loop\(C'\fR does:
428	.Sp	526	.Sp
429	.Vb 15	527	.Vb 18
430	\& 1. If there are no active watchers (reference count is zero), return.	528	\& * If there are no active watchers (reference count is zero), return.
431	\& 2. Queue and immediately call all prepare watchers.	529	\& - Queue prepare watchers and then call all outstanding watchers.
432	\& 3. If we have been forked, recreate the kernel state.	530	\& - If we have been forked, recreate the kernel state.
433	\& 4. Update the kernel state with all outstanding changes.	531	\& - Update the kernel state with all outstanding changes.
434	\& 5. Update the "event loop time".	532	\& - Update the "event loop time".
435	\& 6. Calculate for how long to block.	533	\& - Calculate for how long to block.
436	\& 7. Block the process, waiting for events.	534	\& - Block the process, waiting for any events.
		535	\& - Queue all outstanding I/O (fd) events.
437	\& 8. Update the "event loop time" and do time jump handling.	536	\& - Update the "event loop time" and do time jump handling.
438	\& 9. Queue all outstanding timers.	537	\& - Queue all outstanding timers.
439	\& 10. Queue all outstanding periodics.	538	\& - Queue all outstanding periodics.
440	\& 11. If no events are pending now, queue all idle watchers.	539	\& - If no events are pending now, queue all idle watchers.
441	\& 12. Queue all check watchers.	540	\& - Queue all check watchers.
442	\& 13. Call all queued watchers in reverse order (i.e. check watchers first).	541	\& - Call all queued watchers in reverse order (i.e. check watchers first).
		542	\& Signals and child watchers are implemented as I/O watchers, and will
		543	\& be handled here by queueing them when their watcher gets executed.
443	\& 14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	544	\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
444	\& was used, return, otherwise continue with step #1.	545	\& were used, return, otherwise continue with step *.
		546	.Ve
		547	.Sp
		548	Example: queue some jobs and then loop until no events are outsanding
		549	anymore.
		550	.Sp
		551	.Vb 4
		552	\& ... queue jobs here, make sure they register event watchers as long
		553	\& ... as they still have work to do (even an idle watcher will do..)
		554	\& ev_loop (my_loop, 0);
		555	\& ... jobs done. yeah!
445	.Ve	556	.Ve
446	.IP "ev_unloop (loop, how)" 4	557	.IP "ev_unloop (loop, how)" 4
447	.IX Item "ev_unloop (loop, how)"	558	.IX Item "ev_unloop (loop, how)"
448	Can be used to make a call to \f(CW\(C`ev_loop\(C'\fR return early (but only after it	559	Can be used to make a call to \f(CW\(C`ev_loop\(C'\fR return early (but only after it
449	has processed all outstanding events). The \f(CW\(C`how\(C'\fR argument must be either	560	has processed all outstanding events). The \f(CW\(C`how\(C'\fR argument must be either
…		…
463	example, libev itself uses this for its internal signal pipe: It is not	574	example, libev itself uses this for its internal signal pipe: It is not
464	visible to the libev user and should not keep \f(CW\(C`ev_loop\(C'\fR from exiting if	575	visible to the libev user and should not keep \f(CW\(C`ev_loop\(C'\fR from exiting if
465	no event watchers registered by it are active. It is also an excellent	576	no event watchers registered by it are active. It is also an excellent
466	way to do this for generic recurring timers or from within third-party	577	way to do this for generic recurring timers or from within third-party
467	libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.	578	libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
		579	.Sp
		580	Example: create a signal watcher, but keep it from keeping \f(CW\(C`ev_loop\(C'\fR
		581	running when nothing else is active.
		582	.Sp
		583	.Vb 4
		584	\& struct dv_signal exitsig;
		585	\& ev_signal_init (&exitsig, sig_cb, SIGINT);
		586	\& ev_signal_start (myloop, &exitsig);
		587	\& evf_unref (myloop);
		588	.Ve
		589	.Sp
		590	Example: for some weird reason, unregister the above signal handler again.
		591	.Sp
		592	.Vb 2
		593	\& ev_ref (myloop);
		594	\& ev_signal_stop (myloop, &exitsig);
		595	.Ve
468	.SH "ANATOMY OF A WATCHER"	596	.SH "ANATOMY OF A WATCHER"
469	.IX Header "ANATOMY OF A WATCHER"	597	.IX Header "ANATOMY OF A WATCHER"
470	A watcher is a structure that you create and register to record your	598	A watcher is a structure that you create and register to record your
471	interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to	599	interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to
472	become readable, you would create an \f(CW\(C`ev_io\(C'\fR watcher for that:	600	become readable, you would create an \f(CW\(C`ev_io\(C'\fR watcher for that:
…		…
660	\&\f(CW\(C`EVBACKEND_SELECT\(C'\fR or \f(CW\(C`EVBACKEND_POLL\(C'\fR, which don't suffer from this	788	\&\f(CW\(C`EVBACKEND_SELECT\(C'\fR or \f(CW\(C`EVBACKEND_POLL\(C'\fR, which don't suffer from this
661	problem. Also note that it is quite easy to have your callback invoked	789	problem. Also note that it is quite easy to have your callback invoked
662	when the readyness condition is no longer valid even when employing	790	when the readyness condition is no longer valid even when employing
663	typical ways of handling events, so its a good idea to use non-blocking	791	typical ways of handling events, so its a good idea to use non-blocking
664	I/O unconditionally.	792	I/O unconditionally.
		793	.PP
		794	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well
		795	readable, but only once. Since it is likely line\-buffered, you could
		796	attempt to read a whole line in the callback:
		797	.PP
		798	.Vb 6
		799	\& static void
		800	\& stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
		801	\& {
		802	\& ev_io_stop (loop, w);
		803	\& .. read from stdin here (or from w->fd) and haqndle any I/O errors
		804	\& }
		805	.Ve
		806	.PP
		807	.Vb 6
		808	\& ...
		809	\& struct ev_loop *loop = ev_default_init (0);
		810	\& struct ev_io stdin_readable;
		811	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
		812	\& ev_io_start (loop, &stdin_readable);
		813	\& ev_loop (loop, 0);
		814	.Ve
665	.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts"	815	.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts"
666	.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts"	816	.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts"
667	.IX Subsection "ev_timer - relative and optionally recurring timeouts"	817	.IX Subsection "ev_timer - relative and optionally recurring timeouts"
668	Timer watchers are simple relative timers that generate an event after a	818	Timer watchers are simple relative timers that generate an event after a
669	given time, and optionally repeating in regular intervals after that.	819	given time, and optionally repeating in regular intervals after that.
…		…
719	seconds of inactivity on the socket. The easiest way to do this is to	869	seconds of inactivity on the socket. The easiest way to do this is to
720	configure an \f(CW\(C`ev_timer\(C'\fR with after=repeat=60 and calling ev_timer_again each	870	configure an \f(CW\(C`ev_timer\(C'\fR with after=repeat=60 and calling ev_timer_again each
721	time you successfully read or write some data. If you go into an idle	871	time you successfully read or write some data. If you go into an idle
722	state where you do not expect data to travel on the socket, you can stop	872	state where you do not expect data to travel on the socket, you can stop
723	the timer, and again will automatically restart it if need be.	873	the timer, and again will automatically restart it if need be.
		874	.PP
		875	Example: create a timer that fires after 60 seconds.
		876	.PP
		877	.Vb 5
		878	\& static void
		879	\& one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
		880	\& {
		881	\& .. one minute over, w is actually stopped right here
		882	\& }
		883	.Ve
		884	.PP
		885	.Vb 3
		886	\& struct ev_timer mytimer;
		887	\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
		888	\& ev_timer_start (loop, &mytimer);
		889	.Ve
		890	.PP
		891	Example: create a timeout timer that times out after 10 seconds of
		892	inactivity.
		893	.PP
		894	.Vb 5
		895	\& static void
		896	\& timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
		897	\& {
		898	\& .. ten seconds without any activity
		899	\& }
		900	.Ve
		901	.PP
		902	.Vb 4
		903	\& struct ev_timer mytimer;
		904	\& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
		905	\& ev_timer_again (&mytimer); /* start timer */
		906	\& ev_loop (loop, 0);
		907	.Ve
		908	.PP
		909	.Vb 3
		910	\& // and in some piece of code that gets executed on any "activity":
		911	\& // reset the timeout to start ticking again at 10 seconds
		912	\& ev_timer_again (&mytimer);
		913	.Ve
724	.ie n .Sh """ev_periodic"" \- to cron or not to cron"	914	.ie n .Sh """ev_periodic"" \- to cron or not to cron"
725	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron"	915	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron"
726	.IX Subsection "ev_periodic - to cron or not to cron"	916	.IX Subsection "ev_periodic - to cron or not to cron"
727	Periodic watchers are also timers of a kind, but they are very versatile	917	Periodic watchers are also timers of a kind, but they are very versatile
728	(and unfortunately a bit complex).	918	(and unfortunately a bit complex).
…		…
820	.IX Item "ev_periodic_again (loop, ev_periodic *)"	1010	.IX Item "ev_periodic_again (loop, ev_periodic *)"
821	Simply stops and restarts the periodic watcher again. This is only useful	1011	Simply stops and restarts the periodic watcher again. This is only useful
822	when you changed some parameters or the reschedule callback would return	1012	when you changed some parameters or the reschedule callback would return
823	a different time than the last time it was called (e.g. in a crond like	1013	a different time than the last time it was called (e.g. in a crond like
824	program when the crontabs have changed).	1014	program when the crontabs have changed).
		1015	.PP
		1016	Example: call a callback every hour, or, more precisely, whenever the
		1017	system clock is divisible by 3600. The callback invocation times have
		1018	potentially a lot of jittering, but good long-term stability.
		1019	.PP
		1020	.Vb 5
		1021	\& static void
		1022	\& clock_cb (struct ev_loop loop, struct ev_io w, int revents)
		1023	\& {
		1024	\& ... its now a full hour (UTC, or TAI or whatever your clock follows)
		1025	\& }
		1026	.Ve
		1027	.PP
		1028	.Vb 3
		1029	\& struct ev_periodic hourly_tick;
		1030	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
		1031	\& ev_periodic_start (loop, &hourly_tick);
		1032	.Ve
		1033	.PP
		1034	Example: the same as above, but use a reschedule callback to do it:
		1035	.PP
		1036	.Vb 1
		1037	\& #include <math.h>
		1038	.Ve
		1039	.PP
		1040	.Vb 5
		1041	\& static ev_tstamp
		1042	\& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
		1043	\& {
		1044	\& return fmod (now, 3600.) + 3600.;
		1045	\& }
		1046	.Ve
		1047	.PP
		1048	.Vb 1
		1049	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
		1050	.Ve
		1051	.PP
		1052	Example: call a callback every hour, starting now:
		1053	.PP
		1054	.Vb 4
		1055	\& struct ev_periodic hourly_tick;
		1056	\& ev_periodic_init (&hourly_tick, clock_cb,
		1057	\& fmod (ev_now (loop), 3600.), 3600., 0);
		1058	\& ev_periodic_start (loop, &hourly_tick);
		1059	.Ve
825	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled"	1060	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled"
826	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled"	1061	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled"
827	.IX Subsection "ev_signal - signal me when a signal gets signalled"	1062	.IX Subsection "ev_signal - signal me when a signal gets signalled"
828	Signal watchers will trigger an event when the process receives a specific	1063	Signal watchers will trigger an event when the process receives a specific
829	signal one or more times. Even though signals are very asynchronous, libev	1064	signal one or more times. Even though signals are very asynchronous, libev
…		…
859	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look	1094	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look
860	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see	1095	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see
861	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems	1096	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems
862	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the	1097	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the
863	process causing the status change.	1098	process causing the status change.
		1099	.PP
		1100	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
		1101	.PP
		1102	.Vb 5
		1103	\& static void
		1104	\& sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
		1105	\& {
		1106	\& ev_unloop (loop, EVUNLOOP_ALL);
		1107	\& }
		1108	.Ve
		1109	.PP
		1110	.Vb 3
		1111	\& struct ev_signal signal_watcher;
		1112	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
		1113	\& ev_signal_start (loop, &sigint_cb);
		1114	.Ve
864	.ie n .Sh """ev_idle"" \- when you've got nothing better to do"	1115	.ie n .Sh """ev_idle"" \- when you've got nothing better to do"
865	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do"	1116	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do"
866	.IX Subsection "ev_idle - when you've got nothing better to do"	1117	.IX Subsection "ev_idle - when you've got nothing better to do"
867	Idle watchers trigger events when there are no other events are pending	1118	Idle watchers trigger events when there are no other events are pending
868	(prepare, check and other idle watchers do not count). That is, as long	1119	(prepare, check and other idle watchers do not count). That is, as long
…		…
882	.IP "ev_idle_init (ev_signal *, callback)" 4	1133	.IP "ev_idle_init (ev_signal *, callback)" 4
883	.IX Item "ev_idle_init (ev_signal *, callback)"	1134	.IX Item "ev_idle_init (ev_signal *, callback)"
884	Initialises and configures the idle watcher \- it has no parameters of any	1135	Initialises and configures the idle watcher \- it has no parameters of any
885	kind. There is a \f(CW\(C`ev_idle_set\(C'\fR macro, but using it is utterly pointless,	1136	kind. There is a \f(CW\(C`ev_idle_set\(C'\fR macro, but using it is utterly pointless,
886	believe me.	1137	believe me.
		1138	.PP
		1139	Example: dynamically allocate an \f(CW\(C`ev_idle\(C'\fR, start it, and in the
		1140	callback, free it. Alos, use no error checking, as usual.
		1141	.PP
		1142	.Vb 7
		1143	\& static void
		1144	\& idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
		1145	\& {
		1146	\& free (w);
		1147	\& // now do something you wanted to do when the program has
		1148	\& // no longer asnything immediate to do.
		1149	\& }
		1150	.Ve
		1151	.PP
		1152	.Vb 3
		1153	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
		1154	\& ev_idle_init (idle_watcher, idle_cb);
		1155	\& ev_idle_start (loop, idle_cb);
		1156	.Ve
887	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop"	1157	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop"
888	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop"	1158	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop"
889	.IX Subsection "ev_prepare and ev_check - customise your event loop"	1159	.IX Subsection "ev_prepare and ev_check - customise your event loop"
890	Prepare and check watchers are usually (but not always) used in tandem:	1160	Prepare and check watchers are usually (but not always) used in tandem:
891	prepare watchers get invoked before the process blocks and check watchers	1161	prepare watchers get invoked before the process blocks and check watchers
…		…
919	.IX Item "ev_check_init (ev_check *, callback)"	1189	.IX Item "ev_check_init (ev_check *, callback)"
920	.PD	1190	.PD
921	Initialises and configures the prepare or check watcher \- they have no	1191	Initialises and configures the prepare or check watcher \- they have no
922	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR	1192	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR
923	macros, but using them is utterly, utterly and completely pointless.	1193	macros, but using them is utterly, utterly and completely pointless.
		1194	.PP
		1195	Example: TODO.
924	.SH "OTHER FUNCTIONS"	1196	.SH "OTHER FUNCTIONS"
925	.IX Header "OTHER FUNCTIONS"	1197	.IX Header "OTHER FUNCTIONS"
926	There are some other functions of possible interest. Described. Here. Now.	1198	There are some other functions of possible interest. Described. Here. Now.
927	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4	1199	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
928	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"	1200	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"

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Comparing libev/ev.3 (file contents): Revision 1.7 by root, Fri Nov 23 08:36:35 2007 UTC vs. Revision 1.9 by root, Fri Nov 23 16:17:12 2007 UTC

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Comparing libev/ev.3 (file contents):
Revision 1.7 by root, Fri Nov 23 08:36:35 2007 UTC vs.
Revision 1.9 by root, Fri Nov 23 16:17:12 2007 UTC