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Revision 1.303 by root, Thu Oct 14 04:29:34 2010 UTC vs.
Revision 1.323 by root, Sun Oct 24 18:01:26 2010 UTC

26 puts ("stdin ready"); 26 puts ("stdin ready");
27 // for one-shot events, one must manually stop the watcher 27 // for one-shot events, one must manually stop the watcher
28 // with its corresponding stop function. 28 // with its corresponding stop function.
29 ev_io_stop (EV_A_ w); 29 ev_io_stop (EV_A_ w);
30 30
31 // this causes all nested ev_loop's to stop iterating 31 // this causes all nested ev_run's to stop iterating
32 ev_unloop (EV_A_ EVUNLOOP_ALL); 32 ev_break (EV_A_ EVBREAK_ALL);
33 } 33 }
34 34
35 // another callback, this time for a time-out 35 // another callback, this time for a time-out
36 static void 36 static void
37 timeout_cb (EV_P_ ev_timer *w, int revents) 37 timeout_cb (EV_P_ ev_timer *w, int revents)
38 { 38 {
39 puts ("timeout"); 39 puts ("timeout");
40 // this causes the innermost ev_loop to stop iterating 40 // this causes the innermost ev_run to stop iterating
41 ev_unloop (EV_A_ EVUNLOOP_ONE); 41 ev_break (EV_A_ EVBREAK_ONE);
42 } 42 }
43 43
44 int 44 int
45 main (void) 45 main (void)
46 { 46 {
47 // use the default event loop unless you have special needs 47 // use the default event loop unless you have special needs
48 struct ev_loop *loop = ev_default_loop (0); 48 struct ev_loop *loop = EV_DEFAULT;
49 49
50 // initialise an io watcher, then start it 50 // initialise an io watcher, then start it
51 // this one will watch for stdin to become readable 51 // this one will watch for stdin to become readable
52 ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); 52 ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
53 ev_io_start (loop, &stdin_watcher); 53 ev_io_start (loop, &stdin_watcher);
56 // simple non-repeating 5.5 second timeout 56 // simple non-repeating 5.5 second timeout
57 ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); 57 ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58 ev_timer_start (loop, &timeout_watcher); 58 ev_timer_start (loop, &timeout_watcher);
59 59
60 // now wait for events to arrive 60 // now wait for events to arrive
61 ev_loop (loop, 0); 61 ev_run (loop, 0);
62 62
63 // unloop was called, so exit 63 // unloop was called, so exit
64 return 0; 64 return 0;
65 } 65 }
66 66
124this argument. 124this argument.
125 125
126=head2 TIME REPRESENTATION 126=head2 TIME REPRESENTATION
127 127
128Libev represents time as a single floating point number, representing 128Libev represents time as a single floating point number, representing
129the (fractional) number of seconds since the (POSIX) epoch (in practise 129the (fractional) number of seconds since the (POSIX) epoch (in practice
130somewhere near the beginning of 1970, details are complicated, don't 130somewhere near the beginning of 1970, details are complicated, don't
131ask). This type is called C<ev_tstamp>, which is what you should use 131ask). This type is called C<ev_tstamp>, which is what you should use
132too. It usually aliases to the C<double> type in C. When you need to do 132too. It usually aliases to the C<double> type in C. When you need to do
133any calculations on it, you should treat it as some floating point value. 133any calculations on it, you should treat it as some floating point value.
134 134
165 165
166=item ev_tstamp ev_time () 166=item ev_tstamp ev_time ()
167 167
168Returns the current time as libev would use it. Please note that the 168Returns the current time as libev would use it. Please note that the
169C<ev_now> function is usually faster and also often returns the timestamp 169C<ev_now> function is usually faster and also often returns the timestamp
170you actually want to know. 170you actually want to know. Also interesting is the combination of
171C<ev_update_now> and C<ev_now>.
171 172
172=item ev_sleep (ev_tstamp interval) 173=item ev_sleep (ev_tstamp interval)
173 174
174Sleep for the given interval: The current thread will be blocked until 175Sleep for the given interval: The current thread will be blocked until
175either it is interrupted or the given time interval has passed. Basically 176either it is interrupted or the given time interval has passed. Basically
192as this indicates an incompatible change. Minor versions are usually 193as this indicates an incompatible change. Minor versions are usually
193compatible to older versions, so a larger minor version alone is usually 194compatible to older versions, so a larger minor version alone is usually
194not a problem. 195not a problem.
195 196
196Example: Make sure we haven't accidentally been linked against the wrong 197Example: Make sure we haven't accidentally been linked against the wrong
197version (note, however, that this will not detect ABI mismatches :). 198version (note, however, that this will not detect other ABI mismatches,
199such as LFS or reentrancy).
198 200
199 assert (("libev version mismatch", 201 assert (("libev version mismatch",
200 ev_version_major () == EV_VERSION_MAJOR 202 ev_version_major () == EV_VERSION_MAJOR
201 && ev_version_minor () >= EV_VERSION_MINOR)); 203 && ev_version_minor () >= EV_VERSION_MINOR));
202 204
213 assert (("sorry, no epoll, no sex", 215 assert (("sorry, no epoll, no sex",
214 ev_supported_backends () & EVBACKEND_EPOLL)); 216 ev_supported_backends () & EVBACKEND_EPOLL));
215 217
216=item unsigned int ev_recommended_backends () 218=item unsigned int ev_recommended_backends ()
217 219
218Return the set of all backends compiled into this binary of libev and also 220Return the set of all backends compiled into this binary of libev and
219recommended for this platform. This set is often smaller than the one 221also recommended for this platform, meaning it will work for most file
222descriptor types. This set is often smaller than the one returned by
220returned by C<ev_supported_backends>, as for example kqueue is broken on 223C<ev_supported_backends>, as for example kqueue is broken on most BSDs
221most BSDs and will not be auto-detected unless you explicitly request it 224and will not be auto-detected unless you explicitly request it (assuming
222(assuming you know what you are doing). This is the set of backends that 225you know what you are doing). This is the set of backends that libev will
223libev will probe for if you specify no backends explicitly. 226probe for if you specify no backends explicitly.
224 227
225=item unsigned int ev_embeddable_backends () 228=item unsigned int ev_embeddable_backends ()
226 229
227Returns the set of backends that are embeddable in other event loops. This 230Returns the set of backends that are embeddable in other event loops. This
228is the theoretical, all-platform, value. To find which backends 231value is platform-specific but can include backends not available on the
229might be supported on the current system, you would need to look at 232current system. To find which embeddable backends might be supported on
230C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for 233the current system, you would need to look at C<ev_embeddable_backends ()
231recommended ones. 234& ev_supported_backends ()>, likewise for recommended ones.
232 235
233See the description of C<ev_embed> watchers for more info. 236See the description of C<ev_embed> watchers for more info.
234 237
235=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT] 238=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]
236 239
290 ... 293 ...
291 ev_set_syserr_cb (fatal_error); 294 ev_set_syserr_cb (fatal_error);
292 295
293=back 296=back
294 297
295=head1 FUNCTIONS CONTROLLING THE EVENT LOOP 298=head1 FUNCTIONS CONTROLLING EVENT LOOPS
296 299
297An event loop is described by a C<struct ev_loop *> (the C<struct> 300An event loop is described by a C<struct ev_loop *> (the C<struct> is
298is I<not> optional in this case, as there is also an C<ev_loop> 301I<not> optional in this case unless libev 3 compatibility is disabled, as
299I<function>). 302libev 3 had an C<ev_loop> function colliding with the struct name).
300 303
301The library knows two types of such loops, the I<default> loop, which 304The library knows two types of such loops, the I<default> loop, which
302supports signals and child events, and dynamically created loops which do 305supports signals and child events, and dynamically created event loops
303not. 306which do not.
304 307
305=over 4 308=over 4
306 309
307=item struct ev_loop *ev_default_loop (unsigned int flags) 310=item struct ev_loop *ev_default_loop (unsigned int flags)
308 311
309This will initialise the default event loop if it hasn't been initialised 312This returns the "default" event loop object, which is what you should
310yet and return it. If the default loop could not be initialised, returns 313normally use when you just need "the event loop". Event loop objects and
311false. If it already was initialised it simply returns it (and ignores the 314the C<flags> parameter are described in more detail in the entry for
312flags. If that is troubling you, check C<ev_backend ()> afterwards). 315C<ev_loop_new>.
316
317If the default loop is already initialised then this function simply
318returns it (and ignores the flags. If that is troubling you, check
319C<ev_backend ()> afterwards). Otherwise it will create it with the given
320flags, which should almost always be C<0>, unless the caller is also the
321one calling C<ev_run> or otherwise qualifies as "the main program".
313 322
314If you don't know what event loop to use, use the one returned from this 323If you don't know what event loop to use, use the one returned from this
315function. 324function (or via the C<EV_DEFAULT> macro).
316 325
317Note that this function is I<not> thread-safe, so if you want to use it 326Note that this function is I<not> thread-safe, so if you want to use it
318from multiple threads, you have to lock (note also that this is unlikely, 327from multiple threads, you have to employ some kind of mutex (note also
319as loops cannot be shared easily between threads anyway). 328that this case is unlikely, as loops cannot be shared easily between
329threads anyway).
320 330
321The default loop is the only loop that can handle C<ev_signal> and 331The default loop is the only loop that can handle C<ev_child> watchers,
322C<ev_child> watchers, and to do this, it always registers a handler 332and to do this, it always registers a handler for C<SIGCHLD>. If this is
323for C<SIGCHLD>. If this is a problem for your application you can either 333a problem for your application you can either create a dynamic loop with
324create a dynamic loop with C<ev_loop_new> that doesn't do that, or you 334C<ev_loop_new> which doesn't do that, or you can simply overwrite the
325can simply overwrite the C<SIGCHLD> signal handler I<after> calling 335C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
326C<ev_default_init>. 336
337Example: This is the most typical usage.
338
339 if (!ev_default_loop (0))
340 fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
341
342Example: Restrict libev to the select and poll backends, and do not allow
343environment settings to be taken into account:
344
345 ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
346
347=item struct ev_loop *ev_loop_new (unsigned int flags)
348
349This will create and initialise a new event loop object. If the loop
350could not be initialised, returns false.
351
352Note that this function I<is> thread-safe, and one common way to use
353libev with threads is indeed to create one loop per thread, and using the
354default loop in the "main" or "initial" thread.
327 355
328The flags argument can be used to specify special behaviour or specific 356The flags argument can be used to specify special behaviour or specific
329backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). 357backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
330 358
331The following flags are supported: 359The following flags are supported:
439of course I<doesn't>, and epoll just loves to report events for totally 467of course I<doesn't>, and epoll just loves to report events for totally
440I<different> file descriptors (even already closed ones, so one cannot 468I<different> file descriptors (even already closed ones, so one cannot
441even remove them from the set) than registered in the set (especially 469even remove them from the set) than registered in the set (especially
442on SMP systems). Libev tries to counter these spurious notifications by 470on SMP systems). Libev tries to counter these spurious notifications by
443employing an additional generation counter and comparing that against the 471employing an additional generation counter and comparing that against the
444events to filter out spurious ones, recreating the set when required. 472events to filter out spurious ones, recreating the set when required. Last
473not least, it also refuses to work with some file descriptors which work
474perfectly fine with C<select> (files, many character devices...).
445 475
446While stopping, setting and starting an I/O watcher in the same iteration 476While stopping, setting and starting an I/O watcher in the same iteration
447will result in some caching, there is still a system call per such 477will result in some caching, there is still a system call per such
448incident (because the same I<file descriptor> could point to a different 478incident (because the same I<file descriptor> could point to a different
449I<file description> now), so its best to avoid that. Also, C<dup ()>'ed 479I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
547If one or more of the backend flags are or'ed into the flags value, 577If one or more of the backend flags are or'ed into the flags value,
548then only these backends will be tried (in the reverse order as listed 578then only these backends will be tried (in the reverse order as listed
549here). If none are specified, all backends in C<ev_recommended_backends 579here). If none are specified, all backends in C<ev_recommended_backends
550()> will be tried. 580()> will be tried.
551 581
552Example: This is the most typical usage.
553
554 if (!ev_default_loop (0))
555 fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
556
557Example: Restrict libev to the select and poll backends, and do not allow
558environment settings to be taken into account:
559
560 ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
561
562Example: Use whatever libev has to offer, but make sure that kqueue is
563used if available (warning, breaks stuff, best use only with your own
564private event loop and only if you know the OS supports your types of
565fds):
566
567 ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
568
569=item struct ev_loop *ev_loop_new (unsigned int flags)
570
571Similar to C<ev_default_loop>, but always creates a new event loop that is
572always distinct from the default loop.
573
574Note that this function I<is> thread-safe, and one common way to use
575libev with threads is indeed to create one loop per thread, and using the
576default loop in the "main" or "initial" thread.
577
578Example: Try to create a event loop that uses epoll and nothing else. 582Example: Try to create a event loop that uses epoll and nothing else.
579 583
580 struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); 584 struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
581 if (!epoller) 585 if (!epoller)
582 fatal ("no epoll found here, maybe it hides under your chair"); 586 fatal ("no epoll found here, maybe it hides under your chair");
583 587
588Example: Use whatever libev has to offer, but make sure that kqueue is
589used if available.
590
591 struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
592
584=item ev_default_destroy () 593=item ev_loop_destroy (loop)
585 594
586Destroys the default loop (frees all memory and kernel state etc.). None 595Destroys an event loop object (frees all memory and kernel state
587of the active event watchers will be stopped in the normal sense, so 596etc.). None of the active event watchers will be stopped in the normal
588e.g. C<ev_is_active> might still return true. It is your responsibility to 597sense, so e.g. C<ev_is_active> might still return true. It is your
589either stop all watchers cleanly yourself I<before> calling this function, 598responsibility to either stop all watchers cleanly yourself I<before>
590or cope with the fact afterwards (which is usually the easiest thing, you 599calling this function, or cope with the fact afterwards (which is usually
591can just ignore the watchers and/or C<free ()> them for example). 600the easiest thing, you can just ignore the watchers and/or C<free ()> them
601for example).
592 602
593Note that certain global state, such as signal state (and installed signal 603Note that certain global state, such as signal state (and installed signal
594handlers), will not be freed by this function, and related watchers (such 604handlers), will not be freed by this function, and related watchers (such
595as signal and child watchers) would need to be stopped manually. 605as signal and child watchers) would need to be stopped manually.
596 606
597In general it is not advisable to call this function except in the 607This function is normally used on loop objects allocated by
598rare occasion where you really need to free e.g. the signal handling 608C<ev_loop_new>, but it can also be used on the default loop returned by
609C<ev_default_loop>, in which case it is not thread-safe.
610
611Note that it is not advisable to call this function on the default loop
612except in the rare occasion where you really need to free it's resources.
599pipe fds. If you need dynamically allocated loops it is better to use 613If you need dynamically allocated loops it is better to use C<ev_loop_new>
600C<ev_loop_new> and C<ev_loop_destroy>. 614and C<ev_loop_destroy>.
601 615
602=item ev_loop_destroy (loop) 616=item ev_loop_fork (loop)
603 617
604Like C<ev_default_destroy>, but destroys an event loop created by an
605earlier call to C<ev_loop_new>.
606
607=item ev_default_fork ()
608
609This function sets a flag that causes subsequent C<ev_loop> iterations 618This function sets a flag that causes subsequent C<ev_run> iterations to
610to reinitialise the kernel state for backends that have one. Despite the 619reinitialise the kernel state for backends that have one. Despite the
611name, you can call it anytime, but it makes most sense after forking, in 620name, you can call it anytime, but it makes most sense after forking, in
612the child process (or both child and parent, but that again makes little 621the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
613sense). You I<must> call it in the child before using any of the libev 622child before resuming or calling C<ev_run>.
614functions, and it will only take effect at the next C<ev_loop> iteration.
615 623
616Again, you I<have> to call it on I<any> loop that you want to re-use after 624Again, you I<have> to call it on I<any> loop that you want to re-use after
617a fork, I<even if you do not plan to use the loop in the parent>. This is 625a fork, I<even if you do not plan to use the loop in the parent>. This is
618because some kernel interfaces *cough* I<kqueue> *cough* do funny things 626because some kernel interfaces *cough* I<kqueue> *cough* do funny things
619during fork. 627during fork.
620 628
621On the other hand, you only need to call this function in the child 629On the other hand, you only need to call this function in the child
622process if and only if you want to use the event loop in the child. If you 630process if and only if you want to use the event loop in the child. If
623just fork+exec or create a new loop in the child, you don't have to call 631you just fork+exec or create a new loop in the child, you don't have to
624it at all. 632call it at all (in fact, C<epoll> is so badly broken that it makes a
633difference, but libev will usually detect this case on its own and do a
634costly reset of the backend).
625 635
626The function itself is quite fast and it's usually not a problem to call 636The function itself is quite fast and it's usually not a problem to call
627it just in case after a fork. To make this easy, the function will fit in 637it just in case after a fork.
628quite nicely into a call to C<pthread_atfork>:
629 638
639Example: Automate calling C<ev_loop_fork> on the default loop when
640using pthreads.
641
642 static void
643 post_fork_child (void)
644 {
645 ev_loop_fork (EV_DEFAULT);
646 }
647
648 ...
630 pthread_atfork (0, 0, ev_default_fork); 649 pthread_atfork (0, 0, post_fork_child);
631
632=item ev_loop_fork (loop)
633
634Like C<ev_default_fork>, but acts on an event loop created by
635C<ev_loop_new>. Yes, you have to call this on every allocated event loop
636after fork that you want to re-use in the child, and how you keep track of
637them is entirely your own problem.
638 650
639=item int ev_is_default_loop (loop) 651=item int ev_is_default_loop (loop)
640 652
641Returns true when the given loop is, in fact, the default loop, and false 653Returns true when the given loop is, in fact, the default loop, and false
642otherwise. 654otherwise.
643 655
644=item unsigned int ev_iteration (loop) 656=item unsigned int ev_iteration (loop)
645 657
646Returns the current iteration count for the loop, which is identical to 658Returns the current iteration count for the event loop, which is identical
647the number of times libev did poll for new events. It starts at C<0> and 659to the number of times libev did poll for new events. It starts at C<0>
648happily wraps around with enough iterations. 660and happily wraps around with enough iterations.
649 661
650This value can sometimes be useful as a generation counter of sorts (it 662This value can sometimes be useful as a generation counter of sorts (it
651"ticks" the number of loop iterations), as it roughly corresponds with 663"ticks" the number of loop iterations), as it roughly corresponds with
652C<ev_prepare> and C<ev_check> calls - and is incremented between the 664C<ev_prepare> and C<ev_check> calls - and is incremented between the
653prepare and check phases. 665prepare and check phases.
654 666
655=item unsigned int ev_depth (loop) 667=item unsigned int ev_depth (loop)
656 668
657Returns the number of times C<ev_loop> was entered minus the number of 669Returns the number of times C<ev_run> was entered minus the number of
658times C<ev_loop> was exited, in other words, the recursion depth. 670times C<ev_run> was exited, in other words, the recursion depth.
659 671
660Outside C<ev_loop>, this number is zero. In a callback, this number is 672Outside C<ev_run>, this number is zero. In a callback, this number is
661C<1>, unless C<ev_loop> was invoked recursively (or from another thread), 673C<1>, unless C<ev_run> was invoked recursively (or from another thread),
662in which case it is higher. 674in which case it is higher.
663 675
664Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread 676Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
665etc.), doesn't count as "exit" - consider this as a hint to avoid such 677etc.), doesn't count as "exit" - consider this as a hint to avoid such
666ungentleman behaviour unless it's really convenient. 678ungentleman-like behaviour unless it's really convenient.
667 679
668=item unsigned int ev_backend (loop) 680=item unsigned int ev_backend (loop)
669 681
670Returns one of the C<EVBACKEND_*> flags indicating the event backend in 682Returns one of the C<EVBACKEND_*> flags indicating the event backend in
671use. 683use.
680 692
681=item ev_now_update (loop) 693=item ev_now_update (loop)
682 694
683Establishes the current time by querying the kernel, updating the time 695Establishes the current time by querying the kernel, updating the time
684returned by C<ev_now ()> in the progress. This is a costly operation and 696returned by C<ev_now ()> in the progress. This is a costly operation and
685is usually done automatically within C<ev_loop ()>. 697is usually done automatically within C<ev_run ()>.
686 698
687This function is rarely useful, but when some event callback runs for a 699This function is rarely useful, but when some event callback runs for a
688very long time without entering the event loop, updating libev's idea of 700very long time without entering the event loop, updating libev's idea of
689the current time is a good idea. 701the current time is a good idea.
690 702
692 704
693=item ev_suspend (loop) 705=item ev_suspend (loop)
694 706
695=item ev_resume (loop) 707=item ev_resume (loop)
696 708
697These two functions suspend and resume a loop, for use when the loop is 709These two functions suspend and resume an event loop, for use when the
698not used for a while and timeouts should not be processed. 710loop is not used for a while and timeouts should not be processed.
699 711
700A typical use case would be an interactive program such as a game: When 712A typical use case would be an interactive program such as a game: When
701the user presses C<^Z> to suspend the game and resumes it an hour later it 713the user presses C<^Z> to suspend the game and resumes it an hour later it
702would be best to handle timeouts as if no time had actually passed while 714would be best to handle timeouts as if no time had actually passed while
703the program was suspended. This can be achieved by calling C<ev_suspend> 715the program was suspended. This can be achieved by calling C<ev_suspend>
714without a previous call to C<ev_suspend>. 726without a previous call to C<ev_suspend>.
715 727
716Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the 728Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
717event loop time (see C<ev_now_update>). 729event loop time (see C<ev_now_update>).
718 730
719=item ev_loop (loop, int flags) 731=item ev_run (loop, int flags)
720 732
721Finally, this is it, the event handler. This function usually is called 733Finally, this is it, the event handler. This function usually is called
722after you have initialised all your watchers and you want to start 734after you have initialised all your watchers and you want to start
723handling events. 735handling events. It will ask the operating system for any new events, call
736the watcher callbacks, an then repeat the whole process indefinitely: This
737is why event loops are called I<loops>.
724 738
725If the flags argument is specified as C<0>, it will not return until 739If the flags argument is specified as C<0>, it will keep handling events
726either no event watchers are active anymore or C<ev_unloop> was called. 740until either no event watchers are active anymore or C<ev_break> was
741called.
727 742
728Please note that an explicit C<ev_unloop> is usually better than 743Please note that an explicit C<ev_break> is usually better than
729relying on all watchers to be stopped when deciding when a program has 744relying on all watchers to be stopped when deciding when a program has
730finished (especially in interactive programs), but having a program 745finished (especially in interactive programs), but having a program
731that automatically loops as long as it has to and no longer by virtue 746that automatically loops as long as it has to and no longer by virtue
732of relying on its watchers stopping correctly, that is truly a thing of 747of relying on its watchers stopping correctly, that is truly a thing of
733beauty. 748beauty.
734 749
735A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle 750A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
736those events and any already outstanding ones, but will not block your 751those events and any already outstanding ones, but will not wait and
737process in case there are no events and will return after one iteration of 752block your process in case there are no events and will return after one
738the loop. 753iteration of the loop. This is sometimes useful to poll and handle new
754events while doing lengthy calculations, to keep the program responsive.
739 755
740A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if 756A flags value of C<EVRUN_ONCE> will look for new events (waiting if
741necessary) and will handle those and any already outstanding ones. It 757necessary) and will handle those and any already outstanding ones. It
742will block your process until at least one new event arrives (which could 758will block your process until at least one new event arrives (which could
743be an event internal to libev itself, so there is no guarantee that a 759be an event internal to libev itself, so there is no guarantee that a
744user-registered callback will be called), and will return after one 760user-registered callback will be called), and will return after one
745iteration of the loop. 761iteration of the loop.
746 762
747This is useful if you are waiting for some external event in conjunction 763This is useful if you are waiting for some external event in conjunction
748with something not expressible using other libev watchers (i.e. "roll your 764with something not expressible using other libev watchers (i.e. "roll your
749own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is 765own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
750usually a better approach for this kind of thing. 766usually a better approach for this kind of thing.
751 767
752Here are the gory details of what C<ev_loop> does: 768Here are the gory details of what C<ev_run> does:
753 769
770 - Increment loop depth.
771 - Reset the ev_break status.
754 - Before the first iteration, call any pending watchers. 772 - Before the first iteration, call any pending watchers.
773 LOOP:
755 * If EVFLAG_FORKCHECK was used, check for a fork. 774 - If EVFLAG_FORKCHECK was used, check for a fork.
756 - If a fork was detected (by any means), queue and call all fork watchers. 775 - If a fork was detected (by any means), queue and call all fork watchers.
757 - Queue and call all prepare watchers. 776 - Queue and call all prepare watchers.
777 - If ev_break was called, goto FINISH.
758 - If we have been forked, detach and recreate the kernel state 778 - If we have been forked, detach and recreate the kernel state
759 as to not disturb the other process. 779 as to not disturb the other process.
760 - Update the kernel state with all outstanding changes. 780 - Update the kernel state with all outstanding changes.
761 - Update the "event loop time" (ev_now ()). 781 - Update the "event loop time" (ev_now ()).
762 - Calculate for how long to sleep or block, if at all 782 - Calculate for how long to sleep or block, if at all
763 (active idle watchers, EVLOOP_NONBLOCK or not having 783 (active idle watchers, EVRUN_NOWAIT or not having
764 any active watchers at all will result in not sleeping). 784 any active watchers at all will result in not sleeping).
765 - Sleep if the I/O and timer collect interval say so. 785 - Sleep if the I/O and timer collect interval say so.
786 - Increment loop iteration counter.
766 - Block the process, waiting for any events. 787 - Block the process, waiting for any events.
767 - Queue all outstanding I/O (fd) events. 788 - Queue all outstanding I/O (fd) events.
768 - Update the "event loop time" (ev_now ()), and do time jump adjustments. 789 - Update the "event loop time" (ev_now ()), and do time jump adjustments.
769 - Queue all expired timers. 790 - Queue all expired timers.
770 - Queue all expired periodics. 791 - Queue all expired periodics.
771 - Unless any events are pending now, queue all idle watchers. 792 - Queue all idle watchers with priority higher than that of pending events.
772 - Queue all check watchers. 793 - Queue all check watchers.
773 - Call all queued watchers in reverse order (i.e. check watchers first). 794 - Call all queued watchers in reverse order (i.e. check watchers first).
774 Signals and child watchers are implemented as I/O watchers, and will 795 Signals and child watchers are implemented as I/O watchers, and will
775 be handled here by queueing them when their watcher gets executed. 796 be handled here by queueing them when their watcher gets executed.
776 - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK 797 - If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
777 were used, or there are no active watchers, return, otherwise 798 were used, or there are no active watchers, goto FINISH, otherwise
778 continue with step *. 799 continue with step LOOP.
800 FINISH:
801 - Reset the ev_break status iff it was EVBREAK_ONE.
802 - Decrement the loop depth.
803 - Return.
779 804
780Example: Queue some jobs and then loop until no events are outstanding 805Example: Queue some jobs and then loop until no events are outstanding
781anymore. 806anymore.
782 807
783 ... queue jobs here, make sure they register event watchers as long 808 ... queue jobs here, make sure they register event watchers as long
784 ... as they still have work to do (even an idle watcher will do..) 809 ... as they still have work to do (even an idle watcher will do..)
785 ev_loop (my_loop, 0); 810 ev_run (my_loop, 0);
786 ... jobs done or somebody called unloop. yeah! 811 ... jobs done or somebody called unloop. yeah!
787 812
788=item ev_unloop (loop, how) 813=item ev_break (loop, how)
789 814
790Can be used to make a call to C<ev_loop> return early (but only after it 815Can be used to make a call to C<ev_run> return early (but only after it
791has processed all outstanding events). The C<how> argument must be either 816has processed all outstanding events). The C<how> argument must be either
792C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or 817C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
793C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. 818C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
794 819
795This "unloop state" will be cleared when entering C<ev_loop> again. 820This "unloop state" will be cleared when entering C<ev_run> again.
796 821
797It is safe to call C<ev_unloop> from outside any C<ev_loop> calls. 822It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
798 823
799=item ev_ref (loop) 824=item ev_ref (loop)
800 825
801=item ev_unref (loop) 826=item ev_unref (loop)
802 827
803Ref/unref can be used to add or remove a reference count on the event 828Ref/unref can be used to add or remove a reference count on the event
804loop: Every watcher keeps one reference, and as long as the reference 829loop: Every watcher keeps one reference, and as long as the reference
805count is nonzero, C<ev_loop> will not return on its own. 830count is nonzero, C<ev_run> will not return on its own.
806 831
807This is useful when you have a watcher that you never intend to 832This is useful when you have a watcher that you never intend to
808unregister, but that nevertheless should not keep C<ev_loop> from 833unregister, but that nevertheless should not keep C<ev_run> from
809returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> 834returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
810before stopping it. 835before stopping it.
811 836
812As an example, libev itself uses this for its internal signal pipe: It 837As an example, libev itself uses this for its internal signal pipe: It
813is not visible to the libev user and should not keep C<ev_loop> from 838is not visible to the libev user and should not keep C<ev_run> from
814exiting if no event watchers registered by it are active. It is also an 839exiting if no event watchers registered by it are active. It is also an
815excellent way to do this for generic recurring timers or from within 840excellent way to do this for generic recurring timers or from within
816third-party libraries. Just remember to I<unref after start> and I<ref 841third-party libraries. Just remember to I<unref after start> and I<ref
817before stop> (but only if the watcher wasn't active before, or was active 842before stop> (but only if the watcher wasn't active before, or was active
818before, respectively. Note also that libev might stop watchers itself 843before, respectively. Note also that libev might stop watchers itself
819(e.g. non-repeating timers) in which case you have to C<ev_ref> 844(e.g. non-repeating timers) in which case you have to C<ev_ref>
820in the callback). 845in the callback).
821 846
822Example: Create a signal watcher, but keep it from keeping C<ev_loop> 847Example: Create a signal watcher, but keep it from keeping C<ev_run>
823running when nothing else is active. 848running when nothing else is active.
824 849
825 ev_signal exitsig; 850 ev_signal exitsig;
826 ev_signal_init (&exitsig, sig_cb, SIGINT); 851 ev_signal_init (&exitsig, sig_cb, SIGINT);
827 ev_signal_start (loop, &exitsig); 852 ev_signal_start (loop, &exitsig);
890 ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); 915 ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
891 916
892=item ev_invoke_pending (loop) 917=item ev_invoke_pending (loop)
893 918
894This call will simply invoke all pending watchers while resetting their 919This call will simply invoke all pending watchers while resetting their
895pending state. Normally, C<ev_loop> does this automatically when required, 920pending state. Normally, C<ev_run> does this automatically when required,
896but when overriding the invoke callback this call comes handy. 921but when overriding the invoke callback this call comes handy. This
922function can be invoked from a watcher - this can be useful for example
923when you want to do some lengthy calculation and want to pass further
924event handling to another thread (you still have to make sure only one
925thread executes within C<ev_invoke_pending> or C<ev_run> of course).
897 926
898=item int ev_pending_count (loop) 927=item int ev_pending_count (loop)
899 928
900Returns the number of pending watchers - zero indicates that no watchers 929Returns the number of pending watchers - zero indicates that no watchers
901are pending. 930are pending.
902 931
903=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) 932=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
904 933
905This overrides the invoke pending functionality of the loop: Instead of 934This overrides the invoke pending functionality of the loop: Instead of
906invoking all pending watchers when there are any, C<ev_loop> will call 935invoking all pending watchers when there are any, C<ev_run> will call
907this callback instead. This is useful, for example, when you want to 936this callback instead. This is useful, for example, when you want to
908invoke the actual watchers inside another context (another thread etc.). 937invoke the actual watchers inside another context (another thread etc.).
909 938
910If you want to reset the callback, use C<ev_invoke_pending> as new 939If you want to reset the callback, use C<ev_invoke_pending> as new
911callback. 940callback.
914 943
915Sometimes you want to share the same loop between multiple threads. This 944Sometimes you want to share the same loop between multiple threads. This
916can be done relatively simply by putting mutex_lock/unlock calls around 945can be done relatively simply by putting mutex_lock/unlock calls around
917each call to a libev function. 946each call to a libev function.
918 947
919However, C<ev_loop> can run an indefinite time, so it is not feasible to 948However, C<ev_run> can run an indefinite time, so it is not feasible
920wait for it to return. One way around this is to wake up the loop via 949to wait for it to return. One way around this is to wake up the event
921C<ev_unloop> and C<av_async_send>, another way is to set these I<release> 950loop via C<ev_break> and C<av_async_send>, another way is to set these
922and I<acquire> callbacks on the loop. 951I<release> and I<acquire> callbacks on the loop.
923 952
924When set, then C<release> will be called just before the thread is 953When set, then C<release> will be called just before the thread is
925suspended waiting for new events, and C<acquire> is called just 954suspended waiting for new events, and C<acquire> is called just
926afterwards. 955afterwards.
927 956
930 959
931While event loop modifications are allowed between invocations of 960While event loop modifications are allowed between invocations of
932C<release> and C<acquire> (that's their only purpose after all), no 961C<release> and C<acquire> (that's their only purpose after all), no
933modifications done will affect the event loop, i.e. adding watchers will 962modifications done will affect the event loop, i.e. adding watchers will
934have no effect on the set of file descriptors being watched, or the time 963have no effect on the set of file descriptors being watched, or the time
935waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it 964waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
936to take note of any changes you made. 965to take note of any changes you made.
937 966
938In theory, threads executing C<ev_loop> will be async-cancel safe between 967In theory, threads executing C<ev_run> will be async-cancel safe between
939invocations of C<release> and C<acquire>. 968invocations of C<release> and C<acquire>.
940 969
941See also the locking example in the C<THREADS> section later in this 970See also the locking example in the C<THREADS> section later in this
942document. 971document.
943 972
952These two functions can be used to associate arbitrary data with a loop, 981These two functions can be used to associate arbitrary data with a loop,
953and are intended solely for the C<invoke_pending_cb>, C<release> and 982and are intended solely for the C<invoke_pending_cb>, C<release> and
954C<acquire> callbacks described above, but of course can be (ab-)used for 983C<acquire> callbacks described above, but of course can be (ab-)used for
955any other purpose as well. 984any other purpose as well.
956 985
957=item ev_loop_verify (loop) 986=item ev_verify (loop)
958 987
959This function only does something when C<EV_VERIFY> support has been 988This function only does something when C<EV_VERIFY> support has been
960compiled in, which is the default for non-minimal builds. It tries to go 989compiled in, which is the default for non-minimal builds. It tries to go
961through all internal structures and checks them for validity. If anything 990through all internal structures and checks them for validity. If anything
962is found to be inconsistent, it will print an error message to standard 991is found to be inconsistent, it will print an error message to standard
973 1002
974In the following description, uppercase C<TYPE> in names stands for the 1003In the following description, uppercase C<TYPE> in names stands for the
975watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer 1004watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
976watchers and C<ev_io_start> for I/O watchers. 1005watchers and C<ev_io_start> for I/O watchers.
977 1006
978A watcher is a structure that you create and register to record your 1007A watcher is an opaque structure that you allocate and register to record
979interest in some event. For instance, if you want to wait for STDIN to 1008your interest in some event. To make a concrete example, imagine you want
980become readable, you would create an C<ev_io> watcher for that: 1009to wait for STDIN to become readable, you would create an C<ev_io> watcher
1010for that:
981 1011
982 static void my_cb (struct ev_loop *loop, ev_io *w, int revents) 1012 static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
983 { 1013 {
984 ev_io_stop (w); 1014 ev_io_stop (w);
985 ev_unloop (loop, EVUNLOOP_ALL); 1015 ev_break (loop, EVBREAK_ALL);
986 } 1016 }
987 1017
988 struct ev_loop *loop = ev_default_loop (0); 1018 struct ev_loop *loop = ev_default_loop (0);
989 1019
990 ev_io stdin_watcher; 1020 ev_io stdin_watcher;
991 1021
992 ev_init (&stdin_watcher, my_cb); 1022 ev_init (&stdin_watcher, my_cb);
993 ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); 1023 ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
994 ev_io_start (loop, &stdin_watcher); 1024 ev_io_start (loop, &stdin_watcher);
995 1025
996 ev_loop (loop, 0); 1026 ev_run (loop, 0);
997 1027
998As you can see, you are responsible for allocating the memory for your 1028As you can see, you are responsible for allocating the memory for your
999watcher structures (and it is I<usually> a bad idea to do this on the 1029watcher structures (and it is I<usually> a bad idea to do this on the
1000stack). 1030stack).
1001 1031
1002Each watcher has an associated watcher structure (called C<struct ev_TYPE> 1032Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1003or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). 1033or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1004 1034
1005Each watcher structure must be initialised by a call to C<ev_init 1035Each watcher structure must be initialised by a call to C<ev_init (watcher
1006(watcher *, callback)>, which expects a callback to be provided. This 1036*, callback)>, which expects a callback to be provided. This callback is
1007callback gets invoked each time the event occurs (or, in the case of I/O 1037invoked each time the event occurs (or, in the case of I/O watchers, each
1008watchers, each time the event loop detects that the file descriptor given 1038time the event loop detects that the file descriptor given is readable
1009is readable and/or writable). 1039and/or writable).
1010 1040
1011Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> 1041Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1012macro to configure it, with arguments specific to the watcher type. There 1042macro to configure it, with arguments specific to the watcher type. There
1013is also a macro to combine initialisation and setting in one call: C<< 1043is also a macro to combine initialisation and setting in one call: C<<
1014ev_TYPE_init (watcher *, callback, ...) >>. 1044ev_TYPE_init (watcher *, callback, ...) >>.
1065 1095
1066=item C<EV_PREPARE> 1096=item C<EV_PREPARE>
1067 1097
1068=item C<EV_CHECK> 1098=item C<EV_CHECK>
1069 1099
1070All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts 1100All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1071to gather new events, and all C<ev_check> watchers are invoked just after 1101to gather new events, and all C<ev_check> watchers are invoked just after
1072C<ev_loop> has gathered them, but before it invokes any callbacks for any 1102C<ev_run> has gathered them, but before it invokes any callbacks for any
1073received events. Callbacks of both watcher types can start and stop as 1103received events. Callbacks of both watcher types can start and stop as
1074many watchers as they want, and all of them will be taken into account 1104many watchers as they want, and all of them will be taken into account
1075(for example, a C<ev_prepare> watcher might start an idle watcher to keep 1105(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1076C<ev_loop> from blocking). 1106C<ev_run> from blocking).
1077 1107
1078=item C<EV_EMBED> 1108=item C<EV_EMBED>
1079 1109
1080The embedded event loop specified in the C<ev_embed> watcher needs attention. 1110The embedded event loop specified in the C<ev_embed> watcher needs attention.
1081 1111
1109example it might indicate that a fd is readable or writable, and if your 1139example it might indicate that a fd is readable or writable, and if your
1110callbacks is well-written it can just attempt the operation and cope with 1140callbacks is well-written it can just attempt the operation and cope with
1111the error from read() or write(). This will not work in multi-threaded 1141the error from read() or write(). This will not work in multi-threaded
1112programs, though, as the fd could already be closed and reused for another 1142programs, though, as the fd could already be closed and reused for another
1113thing, so beware. 1143thing, so beware.
1144
1145=back
1146
1147=head2 WATCHER STATES
1148
1149There are various watcher states mentioned throughout this manual -
1150active, pending and so on. In this section these states and the rules to
1151transition between them will be described in more detail - and while these
1152rules might look complicated, they usually do "the right thing".
1153
1154=over 4
1155
1156=item initialiased
1157
1158Before a watcher can be registered with the event looop it has to be
1159initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
1160C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
1161
1162In this state it is simply some block of memory that is suitable for use
1163in an event loop. It can be moved around, freed, reused etc. at will.
1164
1165=item started/running/active
1166
1167Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
1168property of the event loop, and is actively waiting for events. While in
1169this state it cannot be accessed (except in a few documented ways), moved,
1170freed or anything else - the only legal thing is to keep a pointer to it,
1171and call libev functions on it that are documented to work on active watchers.
1172
1173=item pending
1174
1175If a watcher is active and libev determines that an event it is interested
1176in has occurred (such as a timer expiring), it will become pending. It will
1177stay in this pending state until either it is stopped or its callback is
1178about to be invoked, so it is not normally pending inside the watcher
1179callback.
1180
1181The watcher might or might not be active while it is pending (for example,
1182an expired non-repeating timer can be pending but no longer active). If it
1183is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
1184but it is still property of the event loop at this time, so cannot be
1185moved, freed or reused. And if it is active the rules described in the
1186previous item still apply.
1187
1188It is also possible to feed an event on a watcher that is not active (e.g.
1189via C<ev_feed_event>), in which case it becomes pending without being
1190active.
1191
1192=item stopped
1193
1194A watcher can be stopped implicitly by libev (in which case it might still
1195be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
1196latter will clear any pending state the watcher might be in, regardless
1197of whether it was active or not, so stopping a watcher explicitly before
1198freeing it is often a good idea.
1199
1200While stopped (and not pending) the watcher is essentially in the
1201initialised state, that is it can be reused, moved, modified in any way
1202you wish.
1114 1203
1115=back 1204=back
1116 1205
1117=head2 GENERIC WATCHER FUNCTIONS 1206=head2 GENERIC WATCHER FUNCTIONS
1118 1207
1622 ... 1711 ...
1623 struct ev_loop *loop = ev_default_init (0); 1712 struct ev_loop *loop = ev_default_init (0);
1624 ev_io stdin_readable; 1713 ev_io stdin_readable;
1625 ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); 1714 ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1626 ev_io_start (loop, &stdin_readable); 1715 ev_io_start (loop, &stdin_readable);
1627 ev_loop (loop, 0); 1716 ev_run (loop, 0);
1628 1717
1629 1718
1630=head2 C<ev_timer> - relative and optionally repeating timeouts 1719=head2 C<ev_timer> - relative and optionally repeating timeouts
1631 1720
1632Timer watchers are simple relative timers that generate an event after a 1721Timer watchers are simple relative timers that generate an event after a
1641The callback is guaranteed to be invoked only I<after> its timeout has 1730The callback is guaranteed to be invoked only I<after> its timeout has
1642passed (not I<at>, so on systems with very low-resolution clocks this 1731passed (not I<at>, so on systems with very low-resolution clocks this
1643might introduce a small delay). If multiple timers become ready during the 1732might introduce a small delay). If multiple timers become ready during the
1644same loop iteration then the ones with earlier time-out values are invoked 1733same loop iteration then the ones with earlier time-out values are invoked
1645before ones of the same priority with later time-out values (but this is 1734before ones of the same priority with later time-out values (but this is
1646no longer true when a callback calls C<ev_loop> recursively). 1735no longer true when a callback calls C<ev_run> recursively).
1647 1736
1648=head3 Be smart about timeouts 1737=head3 Be smart about timeouts
1649 1738
1650Many real-world problems involve some kind of timeout, usually for error 1739Many real-world problems involve some kind of timeout, usually for error
1651recovery. A typical example is an HTTP request - if the other side hangs, 1740recovery. A typical example is an HTTP request - if the other side hangs,
1822 1911
1823=head3 The special problem of time updates 1912=head3 The special problem of time updates
1824 1913
1825Establishing the current time is a costly operation (it usually takes at 1914Establishing the current time is a costly operation (it usually takes at
1826least two system calls): EV therefore updates its idea of the current 1915least two system calls): EV therefore updates its idea of the current
1827time only before and after C<ev_loop> collects new events, which causes a 1916time only before and after C<ev_run> collects new events, which causes a
1828growing difference between C<ev_now ()> and C<ev_time ()> when handling 1917growing difference between C<ev_now ()> and C<ev_time ()> when handling
1829lots of events in one iteration. 1918lots of events in one iteration.
1830 1919
1831The relative timeouts are calculated relative to the C<ev_now ()> 1920The relative timeouts are calculated relative to the C<ev_now ()>
1832time. This is usually the right thing as this timestamp refers to the time 1921time. This is usually the right thing as this timestamp refers to the time
1949 } 2038 }
1950 2039
1951 ev_timer mytimer; 2040 ev_timer mytimer;
1952 ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ 2041 ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1953 ev_timer_again (&mytimer); /* start timer */ 2042 ev_timer_again (&mytimer); /* start timer */
1954 ev_loop (loop, 0); 2043 ev_run (loop, 0);
1955 2044
1956 // and in some piece of code that gets executed on any "activity": 2045 // and in some piece of code that gets executed on any "activity":
1957 // reset the timeout to start ticking again at 10 seconds 2046 // reset the timeout to start ticking again at 10 seconds
1958 ev_timer_again (&mytimer); 2047 ev_timer_again (&mytimer);
1959 2048
1985 2074
1986As with timers, the callback is guaranteed to be invoked only when the 2075As with timers, the callback is guaranteed to be invoked only when the
1987point in time where it is supposed to trigger has passed. If multiple 2076point in time where it is supposed to trigger has passed. If multiple
1988timers become ready during the same loop iteration then the ones with 2077timers become ready during the same loop iteration then the ones with
1989earlier time-out values are invoked before ones with later time-out values 2078earlier time-out values are invoked before ones with later time-out values
1990(but this is no longer true when a callback calls C<ev_loop> recursively). 2079(but this is no longer true when a callback calls C<ev_run> recursively).
1991 2080
1992=head3 Watcher-Specific Functions and Data Members 2081=head3 Watcher-Specific Functions and Data Members
1993 2082
1994=over 4 2083=over 4
1995 2084
2233Example: Try to exit cleanly on SIGINT. 2322Example: Try to exit cleanly on SIGINT.
2234 2323
2235 static void 2324 static void
2236 sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) 2325 sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2237 { 2326 {
2238 ev_unloop (loop, EVUNLOOP_ALL); 2327 ev_break (loop, EVBREAK_ALL);
2239 } 2328 }
2240 2329
2241 ev_signal signal_watcher; 2330 ev_signal signal_watcher;
2242 ev_signal_init (&signal_watcher, sigint_cb, SIGINT); 2331 ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2243 ev_signal_start (loop, &signal_watcher); 2332 ev_signal_start (loop, &signal_watcher);
2629 2718
2630Prepare and check watchers are usually (but not always) used in pairs: 2719Prepare and check watchers are usually (but not always) used in pairs:
2631prepare watchers get invoked before the process blocks and check watchers 2720prepare watchers get invoked before the process blocks and check watchers
2632afterwards. 2721afterwards.
2633 2722
2634You I<must not> call C<ev_loop> or similar functions that enter 2723You I<must not> call C<ev_run> or similar functions that enter
2635the current event loop from either C<ev_prepare> or C<ev_check> 2724the current event loop from either C<ev_prepare> or C<ev_check>
2636watchers. Other loops than the current one are fine, however. The 2725watchers. Other loops than the current one are fine, however. The
2637rationale behind this is that you do not need to check for recursion in 2726rationale behind this is that you do not need to check for recursion in
2638those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, 2727those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2639C<ev_check> so if you have one watcher of each kind they will always be 2728C<ev_check> so if you have one watcher of each kind they will always be
2807 2896
2808 if (timeout >= 0) 2897 if (timeout >= 0)
2809 // create/start timer 2898 // create/start timer
2810 2899
2811 // poll 2900 // poll
2812 ev_loop (EV_A_ 0); 2901 ev_run (EV_A_ 0);
2813 2902
2814 // stop timer again 2903 // stop timer again
2815 if (timeout >= 0) 2904 if (timeout >= 0)
2816 ev_timer_stop (EV_A_ &to); 2905 ev_timer_stop (EV_A_ &to);
2817 2906
2895if you do not want that, you need to temporarily stop the embed watcher). 2984if you do not want that, you need to temporarily stop the embed watcher).
2896 2985
2897=item ev_embed_sweep (loop, ev_embed *) 2986=item ev_embed_sweep (loop, ev_embed *)
2898 2987
2899Make a single, non-blocking sweep over the embedded loop. This works 2988Make a single, non-blocking sweep over the embedded loop. This works
2900similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most 2989similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2901appropriate way for embedded loops. 2990appropriate way for embedded loops.
2902 2991
2903=item struct ev_loop *other [read-only] 2992=item struct ev_loop *other [read-only]
2904 2993
2905The embedded event loop. 2994The embedded event loop.
2991disadvantage of having to use multiple event loops (which do not support 3080disadvantage of having to use multiple event loops (which do not support
2992signal watchers). 3081signal watchers).
2993 3082
2994When this is not possible, or you want to use the default loop for 3083When this is not possible, or you want to use the default loop for
2995other reasons, then in the process that wants to start "fresh", call 3084other reasons, then in the process that wants to start "fresh", call
2996C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying 3085C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2997the default loop will "orphan" (not stop) all registered watchers, so you 3086Destroying the default loop will "orphan" (not stop) all registered
2998have to be careful not to execute code that modifies those watchers. Note 3087watchers, so you have to be careful not to execute code that modifies
2999also that in that case, you have to re-register any signal watchers. 3088those watchers. Note also that in that case, you have to re-register any
3089signal watchers.
3000 3090
3001=head3 Watcher-Specific Functions and Data Members 3091=head3 Watcher-Specific Functions and Data Members
3002 3092
3003=over 4 3093=over 4
3004 3094
3011=back 3101=back
3012 3102
3013 3103
3014=head2 C<ev_async> - how to wake up an event loop 3104=head2 C<ev_async> - how to wake up an event loop
3015 3105
3016In general, you cannot use an C<ev_loop> from multiple threads or other 3106In general, you cannot use an C<ev_run> from multiple threads or other
3017asynchronous sources such as signal handlers (as opposed to multiple event 3107asynchronous sources such as signal handlers (as opposed to multiple event
3018loops - those are of course safe to use in different threads). 3108loops - those are of course safe to use in different threads).
3019 3109
3020Sometimes, however, you need to wake up an event loop you do not control, 3110Sometimes, however, you need to wake up an event loop you do not control,
3021for example because it belongs to another thread. This is what C<ev_async> 3111for example because it belongs to another thread. This is what C<ev_async>
3389Associates a different C<struct ev_loop> with this watcher. You can only 3479Associates a different C<struct ev_loop> with this watcher. You can only
3390do this when the watcher is inactive (and not pending either). 3480do this when the watcher is inactive (and not pending either).
3391 3481
3392=item w->set ([arguments]) 3482=item w->set ([arguments])
3393 3483
3394Basically the same as C<ev_TYPE_set>, with the same arguments. Must be 3484Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3395called at least once. Unlike the C counterpart, an active watcher gets 3485method or a suitable start method must be called at least once. Unlike the
3396automatically stopped and restarted when reconfiguring it with this 3486C counterpart, an active watcher gets automatically stopped and restarted
3397method. 3487when reconfiguring it with this method.
3398 3488
3399=item w->start () 3489=item w->start ()
3400 3490
3401Starts the watcher. Note that there is no C<loop> argument, as the 3491Starts the watcher. Note that there is no C<loop> argument, as the
3402constructor already stores the event loop. 3492constructor already stores the event loop.
3403 3493
3494=item w->start ([arguments])
3495
3496Instead of calling C<set> and C<start> methods separately, it is often
3497convenient to wrap them in one call. Uses the same type of arguments as
3498the configure C<set> method of the watcher.
3499
3404=item w->stop () 3500=item w->stop ()
3405 3501
3406Stops the watcher if it is active. Again, no C<loop> argument. 3502Stops the watcher if it is active. Again, no C<loop> argument.
3407 3503
3408=item w->again () (C<ev::timer>, C<ev::periodic> only) 3504=item w->again () (C<ev::timer>, C<ev::periodic> only)
3420 3516
3421=back 3517=back
3422 3518
3423=back 3519=back
3424 3520
3425Example: Define a class with an IO and idle watcher, start one of them in 3521Example: Define a class with two I/O and idle watchers, start the I/O
3426the constructor. 3522watchers in the constructor.
3427 3523
3428 class myclass 3524 class myclass
3429 { 3525 {
3430 ev::io io ; void io_cb (ev::io &w, int revents); 3526 ev::io io ; void io_cb (ev::io &w, int revents);
3527 ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3431 ev::idle idle; void idle_cb (ev::idle &w, int revents); 3528 ev::idle idle; void idle_cb (ev::idle &w, int revents);
3432 3529
3433 myclass (int fd) 3530 myclass (int fd)
3434 { 3531 {
3435 io .set <myclass, &myclass::io_cb > (this); 3532 io .set <myclass, &myclass::io_cb > (this);
3533 io2 .set <myclass, &myclass::io2_cb > (this);
3436 idle.set <myclass, &myclass::idle_cb> (this); 3534 idle.set <myclass, &myclass::idle_cb> (this);
3437 3535
3438 io.start (fd, ev::READ); 3536 io.set (fd, ev::WRITE); // configure the watcher
3537 io.start (); // start it whenever convenient
3538
3539 io2.start (fd, ev::READ); // set + start in one call
3439 } 3540 }
3440 }; 3541 };
3441 3542
3442 3543
3443=head1 OTHER LANGUAGE BINDINGS 3544=head1 OTHER LANGUAGE BINDINGS
3517loop argument"). The C<EV_A> form is used when this is the sole argument, 3618loop argument"). The C<EV_A> form is used when this is the sole argument,
3518C<EV_A_> is used when other arguments are following. Example: 3619C<EV_A_> is used when other arguments are following. Example:
3519 3620
3520 ev_unref (EV_A); 3621 ev_unref (EV_A);
3521 ev_timer_add (EV_A_ watcher); 3622 ev_timer_add (EV_A_ watcher);
3522 ev_loop (EV_A_ 0); 3623 ev_run (EV_A_ 0);
3523 3624
3524It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, 3625It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3525which is often provided by the following macro. 3626which is often provided by the following macro.
3526 3627
3527=item C<EV_P>, C<EV_P_> 3628=item C<EV_P>, C<EV_P_>
3567 } 3668 }
3568 3669
3569 ev_check check; 3670 ev_check check;
3570 ev_check_init (&check, check_cb); 3671 ev_check_init (&check, check_cb);
3571 ev_check_start (EV_DEFAULT_ &check); 3672 ev_check_start (EV_DEFAULT_ &check);
3572 ev_loop (EV_DEFAULT_ 0); 3673 ev_run (EV_DEFAULT_ 0);
3573 3674
3574=head1 EMBEDDING 3675=head1 EMBEDDING
3575 3676
3576Libev can (and often is) directly embedded into host 3677Libev can (and often is) directly embedded into host
3577applications. Examples of applications that embed it include the Deliantra 3678applications. Examples of applications that embed it include the Deliantra
3668to a compiled library. All other symbols change the ABI, which means all 3769to a compiled library. All other symbols change the ABI, which means all
3669users of libev and the libev code itself must be compiled with compatible 3770users of libev and the libev code itself must be compiled with compatible
3670settings. 3771settings.
3671 3772
3672=over 4 3773=over 4
3774
3775=item EV_COMPAT3 (h)
3776
3777Backwards compatibility is a major concern for libev. This is why this
3778release of libev comes with wrappers for the functions and symbols that
3779have been renamed between libev version 3 and 4.
3780
3781You can disable these wrappers (to test compatibility with future
3782versions) by defining C<EV_COMPAT3> to C<0> when compiling your
3783sources. This has the additional advantage that you can drop the C<struct>
3784from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
3785typedef in that case.
3786
3787In some future version, the default for C<EV_COMPAT3> will become C<0>,
3788and in some even more future version the compatibility code will be
3789removed completely.
3673 3790
3674=item EV_STANDALONE (h) 3791=item EV_STANDALONE (h)
3675 3792
3676Must always be C<1> if you do not use autoconf configuration, which 3793Must always be C<1> if you do not use autoconf configuration, which
3677keeps libev from including F<config.h>, and it also defines dummy 3794keeps libev from including F<config.h>, and it also defines dummy
4027The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it 4144The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4028will be C<0>. 4145will be C<0>.
4029 4146
4030=item EV_VERIFY 4147=item EV_VERIFY
4031 4148
4032Controls how much internal verification (see C<ev_loop_verify ()>) will 4149Controls how much internal verification (see C<ev_verify ()>) will
4033be done: If set to C<0>, no internal verification code will be compiled 4150be done: If set to C<0>, no internal verification code will be compiled
4034in. If set to C<1>, then verification code will be compiled in, but not 4151in. If set to C<1>, then verification code will be compiled in, but not
4035called. If set to C<2>, then the internal verification code will be 4152called. If set to C<2>, then the internal verification code will be
4036called once per loop, which can slow down libev. If set to C<3>, then the 4153called once per loop, which can slow down libev. If set to C<3>, then the
4037verification code will be called very frequently, which will slow down 4154verification code will be called very frequently, which will slow down
4252 userdata *u = ev_userdata (EV_A); 4369 userdata *u = ev_userdata (EV_A);
4253 pthread_mutex_lock (&u->lock); 4370 pthread_mutex_lock (&u->lock);
4254 } 4371 }
4255 4372
4256The event loop thread first acquires the mutex, and then jumps straight 4373The event loop thread first acquires the mutex, and then jumps straight
4257into C<ev_loop>: 4374into C<ev_run>:
4258 4375
4259 void * 4376 void *
4260 l_run (void *thr_arg) 4377 l_run (void *thr_arg)
4261 { 4378 {
4262 struct ev_loop *loop = (struct ev_loop *)thr_arg; 4379 struct ev_loop *loop = (struct ev_loop *)thr_arg;
4263 4380
4264 l_acquire (EV_A); 4381 l_acquire (EV_A);
4265 pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); 4382 pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4266 ev_loop (EV_A_ 0); 4383 ev_run (EV_A_ 0);
4267 l_release (EV_A); 4384 l_release (EV_A);
4268 4385
4269 return 0; 4386 return 0;
4270 } 4387 }
4271 4388
4323 4440
4324=head3 COROUTINES 4441=head3 COROUTINES
4325 4442
4326Libev is very accommodating to coroutines ("cooperative threads"): 4443Libev is very accommodating to coroutines ("cooperative threads"):
4327libev fully supports nesting calls to its functions from different 4444libev fully supports nesting calls to its functions from different
4328coroutines (e.g. you can call C<ev_loop> on the same loop from two 4445coroutines (e.g. you can call C<ev_run> on the same loop from two
4329different coroutines, and switch freely between both coroutines running 4446different coroutines, and switch freely between both coroutines running
4330the loop, as long as you don't confuse yourself). The only exception is 4447the loop, as long as you don't confuse yourself). The only exception is
4331that you must not do this from C<ev_periodic> reschedule callbacks. 4448that you must not do this from C<ev_periodic> reschedule callbacks.
4332 4449
4333Care has been taken to ensure that libev does not keep local state inside 4450Care has been taken to ensure that libev does not keep local state inside
4334C<ev_loop>, and other calls do not usually allow for coroutine switches as 4451C<ev_run>, and other calls do not usually allow for coroutine switches as
4335they do not call any callbacks. 4452they do not call any callbacks.
4336 4453
4337=head2 COMPILER WARNINGS 4454=head2 COMPILER WARNINGS
4338 4455
4339Depending on your compiler and compiler settings, you might get no or a 4456Depending on your compiler and compiler settings, you might get no or a
4423=head3 C<kqueue> is buggy 4540=head3 C<kqueue> is buggy
4424 4541
4425The kqueue syscall is broken in all known versions - most versions support 4542The kqueue syscall is broken in all known versions - most versions support
4426only sockets, many support pipes. 4543only sockets, many support pipes.
4427 4544
4545Libev tries to work around this by not using C<kqueue> by default on this
4546rotten platform, but of course you can still ask for it when creating a
4547loop - embedding a socket-only kqueue loop into a select-based one is
4548probably going to work well.
4549
4428=head3 C<poll> is buggy 4550=head3 C<poll> is buggy
4429 4551
4430Instead of fixing C<kqueue>, Apple replaced their (working) C<poll> 4552Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
4431implementation by something calling C<kqueue> internally around the 10.5.6 4553implementation by something calling C<kqueue> internally around the 10.5.6
4432release, so now C<kqueue> I<and> C<poll> are broken. 4554release, so now C<kqueue> I<and> C<poll> are broken.
4433 4555
4434Libev tries to work around this by neither using C<kqueue> nor C<poll> by 4556Libev tries to work around this by not using C<poll> by default on
4435default on this rotten platform, but of course you cna still ask for them 4557this rotten platform, but of course you can still ask for it when creating
4436when creating a loop. 4558a loop.
4437 4559
4438=head3 C<select> is buggy 4560=head3 C<select> is buggy
4439 4561
4440All that's left is C<select>, and of course Apple found a way to fuck this 4562All that's left is C<select>, and of course Apple found a way to fuck this
4441one up as well: On OS/X, C<select> actively limits the number of file 4563one up as well: On OS/X, C<select> actively limits the number of file
4442descriptors you can pass in to 1024 - your program suddenyl crashes when 4564descriptors you can pass in to 1024 - your program suddenly crashes when
4443you use more. 4565you use more.
4444 4566
4445There is an undocumented "workaround" for this - defining 4567There is an undocumented "workaround" for this - defining
4446C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should> 4568C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
4447work on OS/X. 4569work on OS/X.
4450 4572
4451=head3 C<errno> reentrancy 4573=head3 C<errno> reentrancy
4452 4574
4453The default compile environment on Solaris is unfortunately so 4575The default compile environment on Solaris is unfortunately so
4454thread-unsafe that you can't even use components/libraries compiled 4576thread-unsafe that you can't even use components/libraries compiled
4455without C<-D_REENTRANT> (as long as they use C<errno>), which, of course, 4577without C<-D_REENTRANT> in a threaded program, which, of course, isn't
4456isn't defined by default. 4578defined by default. A valid, if stupid, implementation choice.
4457 4579
4458If you want to use libev in threaded environments you have to make sure 4580If you want to use libev in threaded environments you have to make sure
4459it's compiled with C<_REENTRANT> defined. 4581it's compiled with C<_REENTRANT> defined.
4460 4582
4461=head3 Event port backend 4583=head3 Event port backend
4462 4584
4463The scalable event interface for Solaris is called "event ports". Unfortunately, 4585The scalable event interface for Solaris is called "event
4464this mechanism is very buggy. If you run into high CPU usage, your program 4586ports". Unfortunately, this mechanism is very buggy in all major
4587releases. If you run into high CPU usage, your program freezes or you get
4465freezes or you get a large number of spurious wakeups, make sure you have 4588a large number of spurious wakeups, make sure you have all the relevant
4466all the relevant and latest kernel patches applied. No, I don't know which 4589and latest kernel patches applied. No, I don't know which ones, but there
4467ones, but there are multiple ones. 4590are multiple ones to apply, and afterwards, event ports actually work
4591great.
4468 4592
4469If you can't get it to work, you can try running the program with 4593If you can't get it to work, you can try running the program by setting
4470C<LIBEV_FLAGS=3> to only allow C<poll> and C<select> backends. 4594the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
4595C<select> backends.
4471 4596
4472=head2 AIX POLL BUG 4597=head2 AIX POLL BUG
4473 4598
4474AIX unfortunately has a broken C<poll.h> header. Libev works around 4599AIX unfortunately has a broken C<poll.h> header. Libev works around
4475this by trying to avoid the poll backend altogether (i.e. it's not even 4600this by trying to avoid the poll backend altogether (i.e. it's not even
4476compiled in), which normally isn't a big problem as C<select> works fine 4601compiled in), which normally isn't a big problem as C<select> works fine
4477with large bitsets, and AIX is dead anyway. 4602with large bitsets on AIX, and AIX is dead anyway.
4478 4603
4479=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS 4604=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
4480 4605
4481=head3 General issues 4606=head3 General issues
4482 4607
4619watchers. 4744watchers.
4620 4745
4621=item C<double> must hold a time value in seconds with enough accuracy 4746=item C<double> must hold a time value in seconds with enough accuracy
4622 4747
4623The type C<double> is used to represent timestamps. It is required to 4748The type C<double> is used to represent timestamps. It is required to
4624have at least 51 bits of mantissa (and 9 bits of exponent), which is good 4749have at least 51 bits of mantissa (and 9 bits of exponent), which is
4625enough for at least into the year 4000. This requirement is fulfilled by 4750good enough for at least into the year 4000 with millisecond accuracy
4751(the design goal for libev). This requirement is overfulfilled by
4626implementations implementing IEEE 754, which is basically all existing 4752implementations using IEEE 754, which is basically all existing ones. With
4627ones. With IEEE 754 doubles, you get microsecond accuracy until at least 4753IEEE 754 doubles, you get microsecond accuracy until at least 2200.
46282200.
4629 4754
4630=back 4755=back
4631 4756
4632If you know of other additional requirements drop me a note. 4757If you know of other additional requirements drop me a note.
4633 4758
4711compatibility, so most programs should still compile. Those might be 4836compatibility, so most programs should still compile. Those might be
4712removed in later versions of libev, so better update early than late. 4837removed in later versions of libev, so better update early than late.
4713 4838
4714=over 4 4839=over 4
4715 4840
4716=item C<ev_loop_count> renamed to C<ev_iteration> 4841=item C<ev_default_destroy> and C<ev_default_fork> have been removed
4717 4842
4718=item C<ev_loop_depth> renamed to C<ev_depth> 4843These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
4719 4844
4720=item C<ev_loop_verify> renamed to C<ev_verify> 4845 ev_loop_destroy (EV_DEFAULT);
4846 ev_loop_fork (EV_DEFAULT);
4847
4848=item function/symbol renames
4849
4850A number of functions and symbols have been renamed:
4851
4852 ev_loop => ev_run
4853 EVLOOP_NONBLOCK => EVRUN_NOWAIT
4854 EVLOOP_ONESHOT => EVRUN_ONCE
4855
4856 ev_unloop => ev_break
4857 EVUNLOOP_CANCEL => EVBREAK_CANCEL
4858 EVUNLOOP_ONE => EVBREAK_ONE
4859 EVUNLOOP_ALL => EVBREAK_ALL
4860
4861 EV_TIMEOUT => EV_TIMER
4862
4863 ev_loop_count => ev_iteration
4864 ev_loop_depth => ev_depth
4865 ev_loop_verify => ev_verify
4721 4866
4722Most functions working on C<struct ev_loop> objects don't have an 4867Most functions working on C<struct ev_loop> objects don't have an
4723C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is 4868C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
4869associated constants have been renamed to not collide with the C<struct
4870ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
4871as all other watcher types. Note that C<ev_loop_fork> is still called
4724still called C<ev_loop_fork> because it would otherwise clash with the 4872C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4725C<ev_fork> typedef. 4873typedef.
4726 4874
4727=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents> 4875=item C<EV_COMPAT3> backwards compatibility mechanism
4728 4876
4729This is a simple rename - all other watcher types use their name 4877The backward compatibility mechanism can be controlled by
4730as revents flag, and now C<ev_timer> does, too. 4878C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4731 4879section.
4732Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4733and continue to be present for the foreseeable future, so this is mostly a
4734documentation change.
4735 4880
4736=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> 4881=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4737 4882
4738The preprocessor symbol C<EV_MINIMAL> has been replaced by a different 4883The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4739mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile 4884mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
4746 4891
4747=over 4 4892=over 4
4748 4893
4749=item active 4894=item active
4750 4895
4751A watcher is active as long as it has been started (has been attached to 4896A watcher is active as long as it has been started and not yet stopped.
4752an event loop) but not yet stopped (disassociated from the event loop). 4897See L<WATCHER STATES> for details.
4753 4898
4754=item application 4899=item application
4755 4900
4756In this document, an application is whatever is using libev. 4901In this document, an application is whatever is using libev.
4902
4903=item backend
4904
4905The part of the code dealing with the operating system interfaces.
4757 4906
4758=item callback 4907=item callback
4759 4908
4760The address of a function that is called when some event has been 4909The address of a function that is called when some event has been
4761detected. Callbacks are being passed the event loop, the watcher that 4910detected. Callbacks are being passed the event loop, the watcher that
4762received the event, and the actual event bitset. 4911received the event, and the actual event bitset.
4763 4912
4764=item callback invocation 4913=item callback/watcher invocation
4765 4914
4766The act of calling the callback associated with a watcher. 4915The act of calling the callback associated with a watcher.
4767 4916
4768=item event 4917=item event
4769 4918
4788The model used to describe how an event loop handles and processes 4937The model used to describe how an event loop handles and processes
4789watchers and events. 4938watchers and events.
4790 4939
4791=item pending 4940=item pending
4792 4941
4793A watcher is pending as soon as the corresponding event has been detected, 4942A watcher is pending as soon as the corresponding event has been
4794and stops being pending as soon as the watcher will be invoked or its 4943detected. See L<WATCHER STATES> for details.
4795pending status is explicitly cleared by the application.
4796
4797A watcher can be pending, but not active. Stopping a watcher also clears
4798its pending status.
4799 4944
4800=item real time 4945=item real time
4801 4946
4802The physical time that is observed. It is apparently strictly monotonic :) 4947The physical time that is observed. It is apparently strictly monotonic :)
4803 4948
4810=item watcher 4955=item watcher
4811 4956
4812A data structure that describes interest in certain events. Watchers need 4957A data structure that describes interest in certain events. Watchers need
4813to be started (attached to an event loop) before they can receive events. 4958to be started (attached to an event loop) before they can receive events.
4814 4959
4815=item watcher invocation
4816
4817The act of calling the callback associated with a watcher.
4818
4819=back 4960=back
4820 4961
4821=head1 AUTHOR 4962=head1 AUTHOR
4822 4963
4823Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. 4964Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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