… | |
… | |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | #include <ev.h> |
7 | #include <ev.h> |
8 | |
8 | |
|
|
9 | =head1 EXAMPLE PROGRAM |
|
|
10 | |
|
|
11 | #include <ev.h> |
|
|
12 | |
|
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13 | ev_io stdin_watcher; |
|
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14 | ev_timer timeout_watcher; |
|
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15 | |
|
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16 | /* called when data readable on stdin */ |
|
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17 | static void |
|
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18 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
|
|
19 | { |
|
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20 | /* puts ("stdin ready"); */ |
|
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21 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
|
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22 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
|
|
23 | } |
|
|
24 | |
|
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25 | static void |
|
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26 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
27 | { |
|
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28 | /* puts ("timeout"); */ |
|
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29 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
|
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30 | } |
|
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31 | |
|
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32 | int |
|
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33 | main (void) |
|
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34 | { |
|
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35 | struct ev_loop *loop = ev_default_loop (0); |
|
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36 | |
|
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37 | /* initialise an io watcher, then start it */ |
|
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38 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
|
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39 | ev_io_start (loop, &stdin_watcher); |
|
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40 | |
|
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41 | /* simple non-repeating 5.5 second timeout */ |
|
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42 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
|
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43 | ev_timer_start (loop, &timeout_watcher); |
|
|
44 | |
|
|
45 | /* loop till timeout or data ready */ |
|
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46 | ev_loop (loop, 0); |
|
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47 | |
|
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48 | return 0; |
|
|
49 | } |
|
|
50 | |
9 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
|
|
52 | |
|
|
53 | The newest version of this document is also available as a html-formatted |
|
|
54 | web page you might find easier to navigate when reading it for the first |
|
|
55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
10 | |
56 | |
11 | Libev is an event loop: you register interest in certain events (such as a |
57 | Libev is an event loop: you register interest in certain events (such as a |
12 | file descriptor being readable or a timeout occuring), and it will manage |
58 | file descriptor being readable or a timeout occuring), and it will manage |
13 | these event sources and provide your program with events. |
59 | these event sources and provide your program with events. |
14 | |
60 | |
… | |
… | |
21 | details of the event, and then hand it over to libev by I<starting> the |
67 | details of the event, and then hand it over to libev by I<starting> the |
22 | watcher. |
68 | watcher. |
23 | |
69 | |
24 | =head1 FEATURES |
70 | =head1 FEATURES |
25 | |
71 | |
26 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
72 | Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the |
27 | kqueue mechanisms for file descriptor events, relative timers, absolute |
73 | BSD-specific C<kqueue> and the Solaris-specific event port mechanisms |
28 | timers with customised rescheduling, signal events, process status change |
74 | for file descriptor events (C<ev_io>), the Linux C<inotify> interface |
29 | events (related to SIGCHLD), and event watchers dealing with the event |
75 | (for C<ev_stat>), relative timers (C<ev_timer>), absolute timers |
30 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
76 | with customised rescheduling (C<ev_periodic>), synchronous signals |
|
|
77 | (C<ev_signal>), process status change events (C<ev_child>), and event |
|
|
78 | watchers dealing with the event loop mechanism itself (C<ev_idle>, |
|
|
79 | C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as |
|
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80 | file watchers (C<ev_stat>) and even limited support for fork events |
|
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81 | (C<ev_fork>). |
|
|
82 | |
|
|
83 | It also is quite fast (see this |
31 | fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing |
84 | L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent |
32 | it to libevent for example). |
85 | for example). |
33 | |
86 | |
34 | =head1 CONVENTIONS |
87 | =head1 CONVENTIONS |
35 | |
88 | |
36 | Libev is very configurable. In this manual the default configuration |
89 | Libev is very configurable. In this manual the default configuration will |
37 | will be described, which supports multiple event loops. For more info |
90 | be described, which supports multiple event loops. For more info about |
38 | about various configuration options please have a look at the file |
91 | various configuration options please have a look at B<EMBED> section in |
39 | F<README.embed> in the libev distribution. If libev was configured without |
92 | this manual. If libev was configured without support for multiple event |
40 | support for multiple event loops, then all functions taking an initial |
93 | loops, then all functions taking an initial argument of name C<loop> |
41 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
94 | (which is always of type C<struct ev_loop *>) will not have this argument. |
42 | will not have this argument. |
|
|
43 | |
95 | |
44 | =head1 TIME REPRESENTATION |
96 | =head1 TIME REPRESENTATION |
45 | |
97 | |
46 | Libev represents time as a single floating point number, representing the |
98 | Libev represents time as a single floating point number, representing the |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
100 | the beginning of 1970, details are complicated, don't ask). This type is |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
101 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
50 | to the C<double> type in C, and when you need to do any calculations on |
102 | to the C<double> type in C, and when you need to do any calculations on |
51 | it, you should treat it as such. |
103 | it, you should treat it as such. |
52 | |
104 | |
53 | |
|
|
54 | =head1 GLOBAL FUNCTIONS |
105 | =head1 GLOBAL FUNCTIONS |
55 | |
106 | |
56 | These functions can be called anytime, even before initialising the |
107 | These functions can be called anytime, even before initialising the |
57 | library in any way. |
108 | library in any way. |
58 | |
109 | |
… | |
… | |
77 | Usually, it's a good idea to terminate if the major versions mismatch, |
128 | Usually, it's a good idea to terminate if the major versions mismatch, |
78 | as this indicates an incompatible change. Minor versions are usually |
129 | as this indicates an incompatible change. Minor versions are usually |
79 | compatible to older versions, so a larger minor version alone is usually |
130 | compatible to older versions, so a larger minor version alone is usually |
80 | not a problem. |
131 | not a problem. |
81 | |
132 | |
82 | Example: make sure we haven't accidentally been linked against the wrong |
133 | Example: Make sure we haven't accidentally been linked against the wrong |
83 | version: |
134 | version. |
84 | |
135 | |
85 | assert (("libev version mismatch", |
136 | assert (("libev version mismatch", |
86 | ev_version_major () == EV_VERSION_MAJOR |
137 | ev_version_major () == EV_VERSION_MAJOR |
87 | && ev_version_minor () >= EV_VERSION_MINOR)); |
138 | && ev_version_minor () >= EV_VERSION_MINOR)); |
88 | |
139 | |
… | |
… | |
118 | |
169 | |
119 | See the description of C<ev_embed> watchers for more info. |
170 | See the description of C<ev_embed> watchers for more info. |
120 | |
171 | |
121 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
172 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
122 | |
173 | |
123 | Sets the allocation function to use (the prototype is similar to the |
174 | Sets the allocation function to use (the prototype is similar - the |
124 | realloc C function, the semantics are identical). It is used to allocate |
175 | semantics is identical - to the realloc C function). It is used to |
125 | and free memory (no surprises here). If it returns zero when memory |
176 | allocate and free memory (no surprises here). If it returns zero when |
126 | needs to be allocated, the library might abort or take some potentially |
177 | memory needs to be allocated, the library might abort or take some |
127 | destructive action. The default is your system realloc function. |
178 | potentially destructive action. The default is your system realloc |
|
|
179 | function. |
128 | |
180 | |
129 | You could override this function in high-availability programs to, say, |
181 | You could override this function in high-availability programs to, say, |
130 | free some memory if it cannot allocate memory, to use a special allocator, |
182 | free some memory if it cannot allocate memory, to use a special allocator, |
131 | or even to sleep a while and retry until some memory is available. |
183 | or even to sleep a while and retry until some memory is available. |
132 | |
184 | |
133 | Example: replace the libev allocator with one that waits a bit and then |
185 | Example: Replace the libev allocator with one that waits a bit and then |
134 | retries: better than mine). |
186 | retries). |
135 | |
187 | |
136 | static void * |
188 | static void * |
137 | persistent_realloc (void *ptr, long size) |
189 | persistent_realloc (void *ptr, size_t size) |
138 | { |
190 | { |
139 | for (;;) |
191 | for (;;) |
140 | { |
192 | { |
141 | void *newptr = realloc (ptr, size); |
193 | void *newptr = realloc (ptr, size); |
142 | |
194 | |
… | |
… | |
158 | callback is set, then libev will expect it to remedy the sitution, no |
210 | callback is set, then libev will expect it to remedy the sitution, no |
159 | matter what, when it returns. That is, libev will generally retry the |
211 | matter what, when it returns. That is, libev will generally retry the |
160 | requested operation, or, if the condition doesn't go away, do bad stuff |
212 | requested operation, or, if the condition doesn't go away, do bad stuff |
161 | (such as abort). |
213 | (such as abort). |
162 | |
214 | |
163 | Example: do the same thing as libev does internally: |
215 | Example: This is basically the same thing that libev does internally, too. |
164 | |
216 | |
165 | static void |
217 | static void |
166 | fatal_error (const char *msg) |
218 | fatal_error (const char *msg) |
167 | { |
219 | { |
168 | perror (msg); |
220 | perror (msg); |
… | |
… | |
218 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
270 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
219 | override the flags completely if it is found in the environment. This is |
271 | override the flags completely if it is found in the environment. This is |
220 | useful to try out specific backends to test their performance, or to work |
272 | useful to try out specific backends to test their performance, or to work |
221 | around bugs. |
273 | around bugs. |
222 | |
274 | |
|
|
275 | =item C<EVFLAG_FORKCHECK> |
|
|
276 | |
|
|
277 | Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after |
|
|
278 | a fork, you can also make libev check for a fork in each iteration by |
|
|
279 | enabling this flag. |
|
|
280 | |
|
|
281 | This works by calling C<getpid ()> on every iteration of the loop, |
|
|
282 | and thus this might slow down your event loop if you do a lot of loop |
|
|
283 | iterations and little real work, but is usually not noticeable (on my |
|
|
284 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
|
|
285 | without a syscall and thus I<very> fast, but my Linux system also has |
|
|
286 | C<pthread_atfork> which is even faster). |
|
|
287 | |
|
|
288 | The big advantage of this flag is that you can forget about fork (and |
|
|
289 | forget about forgetting to tell libev about forking) when you use this |
|
|
290 | flag. |
|
|
291 | |
|
|
292 | This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS> |
|
|
293 | environment variable. |
|
|
294 | |
223 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
295 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
224 | |
296 | |
225 | This is your standard select(2) backend. Not I<completely> standard, as |
297 | This is your standard select(2) backend. Not I<completely> standard, as |
226 | libev tries to roll its own fd_set with no limits on the number of fds, |
298 | libev tries to roll its own fd_set with no limits on the number of fds, |
227 | but if that fails, expect a fairly low limit on the number of fds when |
299 | but if that fails, expect a fairly low limit on the number of fds when |
… | |
… | |
314 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
386 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
315 | always distinct from the default loop. Unlike the default loop, it cannot |
387 | always distinct from the default loop. Unlike the default loop, it cannot |
316 | handle signal and child watchers, and attempts to do so will be greeted by |
388 | handle signal and child watchers, and attempts to do so will be greeted by |
317 | undefined behaviour (or a failed assertion if assertions are enabled). |
389 | undefined behaviour (or a failed assertion if assertions are enabled). |
318 | |
390 | |
319 | Example: try to create a event loop that uses epoll and nothing else. |
391 | Example: Try to create a event loop that uses epoll and nothing else. |
320 | |
392 | |
321 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
393 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
322 | if (!epoller) |
394 | if (!epoller) |
323 | fatal ("no epoll found here, maybe it hides under your chair"); |
395 | fatal ("no epoll found here, maybe it hides under your chair"); |
324 | |
396 | |
… | |
… | |
361 | =item ev_loop_fork (loop) |
433 | =item ev_loop_fork (loop) |
362 | |
434 | |
363 | Like C<ev_default_fork>, but acts on an event loop created by |
435 | Like C<ev_default_fork>, but acts on an event loop created by |
364 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
436 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
365 | after fork, and how you do this is entirely your own problem. |
437 | after fork, and how you do this is entirely your own problem. |
|
|
438 | |
|
|
439 | =item unsigned int ev_loop_count (loop) |
|
|
440 | |
|
|
441 | Returns the count of loop iterations for the loop, which is identical to |
|
|
442 | the number of times libev did poll for new events. It starts at C<0> and |
|
|
443 | happily wraps around with enough iterations. |
|
|
444 | |
|
|
445 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
446 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
447 | C<ev_prepare> and C<ev_check> calls. |
366 | |
448 | |
367 | =item unsigned int ev_backend (loop) |
449 | =item unsigned int ev_backend (loop) |
368 | |
450 | |
369 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
451 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
370 | use. |
452 | use. |
… | |
… | |
423 | Signals and child watchers are implemented as I/O watchers, and will |
505 | Signals and child watchers are implemented as I/O watchers, and will |
424 | be handled here by queueing them when their watcher gets executed. |
506 | be handled here by queueing them when their watcher gets executed. |
425 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
507 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
426 | were used, return, otherwise continue with step *. |
508 | were used, return, otherwise continue with step *. |
427 | |
509 | |
428 | Example: queue some jobs and then loop until no events are outsanding |
510 | Example: Queue some jobs and then loop until no events are outsanding |
429 | anymore. |
511 | anymore. |
430 | |
512 | |
431 | ... queue jobs here, make sure they register event watchers as long |
513 | ... queue jobs here, make sure they register event watchers as long |
432 | ... as they still have work to do (even an idle watcher will do..) |
514 | ... as they still have work to do (even an idle watcher will do..) |
433 | ev_loop (my_loop, 0); |
515 | ev_loop (my_loop, 0); |
… | |
… | |
453 | visible to the libev user and should not keep C<ev_loop> from exiting if |
535 | visible to the libev user and should not keep C<ev_loop> from exiting if |
454 | no event watchers registered by it are active. It is also an excellent |
536 | no event watchers registered by it are active. It is also an excellent |
455 | way to do this for generic recurring timers or from within third-party |
537 | way to do this for generic recurring timers or from within third-party |
456 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
538 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
457 | |
539 | |
458 | Example: create a signal watcher, but keep it from keeping C<ev_loop> |
540 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
459 | running when nothing else is active. |
541 | running when nothing else is active. |
460 | |
542 | |
461 | struct dv_signal exitsig; |
543 | struct ev_signal exitsig; |
462 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
544 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
463 | ev_signal_start (myloop, &exitsig); |
545 | ev_signal_start (loop, &exitsig); |
464 | evf_unref (myloop); |
546 | evf_unref (loop); |
465 | |
547 | |
466 | Example: for some weird reason, unregister the above signal handler again. |
548 | Example: For some weird reason, unregister the above signal handler again. |
467 | |
549 | |
468 | ev_ref (myloop); |
550 | ev_ref (loop); |
469 | ev_signal_stop (myloop, &exitsig); |
551 | ev_signal_stop (loop, &exitsig); |
470 | |
552 | |
471 | =back |
553 | =back |
472 | |
554 | |
473 | |
555 | |
474 | =head1 ANATOMY OF A WATCHER |
556 | =head1 ANATOMY OF A WATCHER |
… | |
… | |
544 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
626 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
545 | |
627 | |
546 | =item C<EV_CHILD> |
628 | =item C<EV_CHILD> |
547 | |
629 | |
548 | The pid specified in the C<ev_child> watcher has received a status change. |
630 | The pid specified in the C<ev_child> watcher has received a status change. |
|
|
631 | |
|
|
632 | =item C<EV_STAT> |
|
|
633 | |
|
|
634 | The path specified in the C<ev_stat> watcher changed its attributes somehow. |
549 | |
635 | |
550 | =item C<EV_IDLE> |
636 | =item C<EV_IDLE> |
551 | |
637 | |
552 | The C<ev_idle> watcher has determined that you have nothing better to do. |
638 | The C<ev_idle> watcher has determined that you have nothing better to do. |
553 | |
639 | |
… | |
… | |
561 | received events. Callbacks of both watcher types can start and stop as |
647 | received events. Callbacks of both watcher types can start and stop as |
562 | many watchers as they want, and all of them will be taken into account |
648 | many watchers as they want, and all of them will be taken into account |
563 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
649 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
564 | C<ev_loop> from blocking). |
650 | C<ev_loop> from blocking). |
565 | |
651 | |
|
|
652 | =item C<EV_EMBED> |
|
|
653 | |
|
|
654 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
|
|
655 | |
|
|
656 | =item C<EV_FORK> |
|
|
657 | |
|
|
658 | The event loop has been resumed in the child process after fork (see |
|
|
659 | C<ev_fork>). |
|
|
660 | |
566 | =item C<EV_ERROR> |
661 | =item C<EV_ERROR> |
567 | |
662 | |
568 | An unspecified error has occured, the watcher has been stopped. This might |
663 | An unspecified error has occured, the watcher has been stopped. This might |
569 | happen because the watcher could not be properly started because libev |
664 | happen because the watcher could not be properly started because libev |
570 | ran out of memory, a file descriptor was found to be closed or any other |
665 | ran out of memory, a file descriptor was found to be closed or any other |
… | |
… | |
644 | events but its callback has not yet been invoked). As long as a watcher |
739 | events but its callback has not yet been invoked). As long as a watcher |
645 | is pending (but not active) you must not call an init function on it (but |
740 | is pending (but not active) you must not call an init function on it (but |
646 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
741 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
647 | libev (e.g. you cnanot C<free ()> it). |
742 | libev (e.g. you cnanot C<free ()> it). |
648 | |
743 | |
649 | =item callback = ev_cb (ev_TYPE *watcher) |
744 | =item callback ev_cb (ev_TYPE *watcher) |
650 | |
745 | |
651 | Returns the callback currently set on the watcher. |
746 | Returns the callback currently set on the watcher. |
652 | |
747 | |
653 | =item ev_cb_set (ev_TYPE *watcher, callback) |
748 | =item ev_cb_set (ev_TYPE *watcher, callback) |
654 | |
749 | |
655 | Change the callback. You can change the callback at virtually any time |
750 | Change the callback. You can change the callback at virtually any time |
656 | (modulo threads). |
751 | (modulo threads). |
|
|
752 | |
|
|
753 | =item ev_set_priority (ev_TYPE *watcher, priority) |
|
|
754 | |
|
|
755 | =item int ev_priority (ev_TYPE *watcher) |
|
|
756 | |
|
|
757 | Set and query the priority of the watcher. The priority is a small |
|
|
758 | integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> |
|
|
759 | (default: C<-2>). Pending watchers with higher priority will be invoked |
|
|
760 | before watchers with lower priority, but priority will not keep watchers |
|
|
761 | from being executed (except for C<ev_idle> watchers). |
|
|
762 | |
|
|
763 | This means that priorities are I<only> used for ordering callback |
|
|
764 | invocation after new events have been received. This is useful, for |
|
|
765 | example, to reduce latency after idling, or more often, to bind two |
|
|
766 | watchers on the same event and make sure one is called first. |
|
|
767 | |
|
|
768 | If you need to suppress invocation when higher priority events are pending |
|
|
769 | you need to look at C<ev_idle> watchers, which provide this functionality. |
|
|
770 | |
|
|
771 | The default priority used by watchers when no priority has been set is |
|
|
772 | always C<0>, which is supposed to not be too high and not be too low :). |
|
|
773 | |
|
|
774 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
|
|
775 | fine, as long as you do not mind that the priority value you query might |
|
|
776 | or might not have been adjusted to be within valid range. |
657 | |
777 | |
658 | =back |
778 | =back |
659 | |
779 | |
660 | |
780 | |
661 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
781 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
682 | { |
802 | { |
683 | struct my_io *w = (struct my_io *)w_; |
803 | struct my_io *w = (struct my_io *)w_; |
684 | ... |
804 | ... |
685 | } |
805 | } |
686 | |
806 | |
687 | More interesting and less C-conformant ways of catsing your callback type |
807 | More interesting and less C-conformant ways of casting your callback type |
688 | have been omitted.... |
808 | instead have been omitted. |
|
|
809 | |
|
|
810 | Another common scenario is having some data structure with multiple |
|
|
811 | watchers: |
|
|
812 | |
|
|
813 | struct my_biggy |
|
|
814 | { |
|
|
815 | int some_data; |
|
|
816 | ev_timer t1; |
|
|
817 | ev_timer t2; |
|
|
818 | } |
|
|
819 | |
|
|
820 | In this case getting the pointer to C<my_biggy> is a bit more complicated, |
|
|
821 | you need to use C<offsetof>: |
|
|
822 | |
|
|
823 | #include <stddef.h> |
|
|
824 | |
|
|
825 | static void |
|
|
826 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
827 | { |
|
|
828 | struct my_biggy big = (struct my_biggy * |
|
|
829 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
830 | } |
|
|
831 | |
|
|
832 | static void |
|
|
833 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
834 | { |
|
|
835 | struct my_biggy big = (struct my_biggy * |
|
|
836 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
837 | } |
689 | |
838 | |
690 | |
839 | |
691 | =head1 WATCHER TYPES |
840 | =head1 WATCHER TYPES |
692 | |
841 | |
693 | This section describes each watcher in detail, but will not repeat |
842 | This section describes each watcher in detail, but will not repeat |
694 | information given in the last section. |
843 | information given in the last section. Any initialisation/set macros, |
|
|
844 | functions and members specific to the watcher type are explained. |
|
|
845 | |
|
|
846 | Members are additionally marked with either I<[read-only]>, meaning that, |
|
|
847 | while the watcher is active, you can look at the member and expect some |
|
|
848 | sensible content, but you must not modify it (you can modify it while the |
|
|
849 | watcher is stopped to your hearts content), or I<[read-write]>, which |
|
|
850 | means you can expect it to have some sensible content while the watcher |
|
|
851 | is active, but you can also modify it. Modifying it may not do something |
|
|
852 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
853 | not crash or malfunction in any way. |
695 | |
854 | |
696 | |
855 | |
697 | =head2 C<ev_io> - is this file descriptor readable or writable? |
856 | =head2 C<ev_io> - is this file descriptor readable or writable? |
698 | |
857 | |
699 | I/O watchers check whether a file descriptor is readable or writable |
858 | I/O watchers check whether a file descriptor is readable or writable |
… | |
… | |
728 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
887 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
729 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
888 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
730 | |
889 | |
731 | If you cannot run the fd in non-blocking mode (for example you should not |
890 | If you cannot run the fd in non-blocking mode (for example you should not |
732 | play around with an Xlib connection), then you have to seperately re-test |
891 | play around with an Xlib connection), then you have to seperately re-test |
733 | wether a file descriptor is really ready with a known-to-be good interface |
892 | whether a file descriptor is really ready with a known-to-be good interface |
734 | such as poll (fortunately in our Xlib example, Xlib already does this on |
893 | such as poll (fortunately in our Xlib example, Xlib already does this on |
735 | its own, so its quite safe to use). |
894 | its own, so its quite safe to use). |
736 | |
895 | |
737 | =over 4 |
896 | =over 4 |
738 | |
897 | |
… | |
… | |
742 | |
901 | |
743 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
902 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
744 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
903 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
745 | C<EV_READ | EV_WRITE> to receive the given events. |
904 | C<EV_READ | EV_WRITE> to receive the given events. |
746 | |
905 | |
|
|
906 | =item int fd [read-only] |
|
|
907 | |
|
|
908 | The file descriptor being watched. |
|
|
909 | |
|
|
910 | =item int events [read-only] |
|
|
911 | |
|
|
912 | The events being watched. |
|
|
913 | |
747 | =back |
914 | =back |
748 | |
915 | |
749 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
916 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
750 | readable, but only once. Since it is likely line-buffered, you could |
917 | readable, but only once. Since it is likely line-buffered, you could |
751 | attempt to read a whole line in the callback: |
918 | attempt to read a whole line in the callback. |
752 | |
919 | |
753 | static void |
920 | static void |
754 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
921 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
755 | { |
922 | { |
756 | ev_io_stop (loop, w); |
923 | ev_io_stop (loop, w); |
… | |
… | |
808 | =item ev_timer_again (loop) |
975 | =item ev_timer_again (loop) |
809 | |
976 | |
810 | This will act as if the timer timed out and restart it again if it is |
977 | This will act as if the timer timed out and restart it again if it is |
811 | repeating. The exact semantics are: |
978 | repeating. The exact semantics are: |
812 | |
979 | |
|
|
980 | If the timer is pending, its pending status is cleared. |
|
|
981 | |
813 | If the timer is started but nonrepeating, stop it. |
982 | If the timer is started but nonrepeating, stop it (as if it timed out). |
814 | |
983 | |
815 | If the timer is repeating, either start it if necessary (with the repeat |
984 | If the timer is repeating, either start it if necessary (with the |
816 | value), or reset the running timer to the repeat value. |
985 | C<repeat> value), or reset the running timer to the C<repeat> value. |
817 | |
986 | |
818 | This sounds a bit complicated, but here is a useful and typical |
987 | This sounds a bit complicated, but here is a useful and typical |
819 | example: Imagine you have a tcp connection and you want a so-called idle |
988 | example: Imagine you have a tcp connection and you want a so-called idle |
820 | timeout, that is, you want to be called when there have been, say, 60 |
989 | timeout, that is, you want to be called when there have been, say, 60 |
821 | seconds of inactivity on the socket. The easiest way to do this is to |
990 | seconds of inactivity on the socket. The easiest way to do this is to |
822 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
991 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
823 | time you successfully read or write some data. If you go into an idle |
992 | C<ev_timer_again> each time you successfully read or write some data. If |
824 | state where you do not expect data to travel on the socket, you can stop |
993 | you go into an idle state where you do not expect data to travel on the |
825 | the timer, and again will automatically restart it if need be. |
994 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
|
|
995 | automatically restart it if need be. |
|
|
996 | |
|
|
997 | That means you can ignore the C<after> value and C<ev_timer_start> |
|
|
998 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
|
|
999 | |
|
|
1000 | ev_timer_init (timer, callback, 0., 5.); |
|
|
1001 | ev_timer_again (loop, timer); |
|
|
1002 | ... |
|
|
1003 | timer->again = 17.; |
|
|
1004 | ev_timer_again (loop, timer); |
|
|
1005 | ... |
|
|
1006 | timer->again = 10.; |
|
|
1007 | ev_timer_again (loop, timer); |
|
|
1008 | |
|
|
1009 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1010 | you want to modify its timeout value. |
|
|
1011 | |
|
|
1012 | =item ev_tstamp repeat [read-write] |
|
|
1013 | |
|
|
1014 | The current C<repeat> value. Will be used each time the watcher times out |
|
|
1015 | or C<ev_timer_again> is called and determines the next timeout (if any), |
|
|
1016 | which is also when any modifications are taken into account. |
826 | |
1017 | |
827 | =back |
1018 | =back |
828 | |
1019 | |
829 | Example: create a timer that fires after 60 seconds. |
1020 | Example: Create a timer that fires after 60 seconds. |
830 | |
1021 | |
831 | static void |
1022 | static void |
832 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1023 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
833 | { |
1024 | { |
834 | .. one minute over, w is actually stopped right here |
1025 | .. one minute over, w is actually stopped right here |
… | |
… | |
836 | |
1027 | |
837 | struct ev_timer mytimer; |
1028 | struct ev_timer mytimer; |
838 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1029 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
839 | ev_timer_start (loop, &mytimer); |
1030 | ev_timer_start (loop, &mytimer); |
840 | |
1031 | |
841 | Example: create a timeout timer that times out after 10 seconds of |
1032 | Example: Create a timeout timer that times out after 10 seconds of |
842 | inactivity. |
1033 | inactivity. |
843 | |
1034 | |
844 | static void |
1035 | static void |
845 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1036 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
846 | { |
1037 | { |
… | |
… | |
957 | Simply stops and restarts the periodic watcher again. This is only useful |
1148 | Simply stops and restarts the periodic watcher again. This is only useful |
958 | when you changed some parameters or the reschedule callback would return |
1149 | when you changed some parameters or the reschedule callback would return |
959 | a different time than the last time it was called (e.g. in a crond like |
1150 | a different time than the last time it was called (e.g. in a crond like |
960 | program when the crontabs have changed). |
1151 | program when the crontabs have changed). |
961 | |
1152 | |
|
|
1153 | =item ev_tstamp interval [read-write] |
|
|
1154 | |
|
|
1155 | The current interval value. Can be modified any time, but changes only |
|
|
1156 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
|
|
1157 | called. |
|
|
1158 | |
|
|
1159 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
|
|
1160 | |
|
|
1161 | The current reschedule callback, or C<0>, if this functionality is |
|
|
1162 | switched off. Can be changed any time, but changes only take effect when |
|
|
1163 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1164 | |
962 | =back |
1165 | =back |
963 | |
1166 | |
964 | Example: call a callback every hour, or, more precisely, whenever the |
1167 | Example: Call a callback every hour, or, more precisely, whenever the |
965 | system clock is divisible by 3600. The callback invocation times have |
1168 | system clock is divisible by 3600. The callback invocation times have |
966 | potentially a lot of jittering, but good long-term stability. |
1169 | potentially a lot of jittering, but good long-term stability. |
967 | |
1170 | |
968 | static void |
1171 | static void |
969 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1172 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
973 | |
1176 | |
974 | struct ev_periodic hourly_tick; |
1177 | struct ev_periodic hourly_tick; |
975 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1178 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
976 | ev_periodic_start (loop, &hourly_tick); |
1179 | ev_periodic_start (loop, &hourly_tick); |
977 | |
1180 | |
978 | Example: the same as above, but use a reschedule callback to do it: |
1181 | Example: The same as above, but use a reschedule callback to do it: |
979 | |
1182 | |
980 | #include <math.h> |
1183 | #include <math.h> |
981 | |
1184 | |
982 | static ev_tstamp |
1185 | static ev_tstamp |
983 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1186 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
985 | return fmod (now, 3600.) + 3600.; |
1188 | return fmod (now, 3600.) + 3600.; |
986 | } |
1189 | } |
987 | |
1190 | |
988 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1191 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
989 | |
1192 | |
990 | Example: call a callback every hour, starting now: |
1193 | Example: Call a callback every hour, starting now: |
991 | |
1194 | |
992 | struct ev_periodic hourly_tick; |
1195 | struct ev_periodic hourly_tick; |
993 | ev_periodic_init (&hourly_tick, clock_cb, |
1196 | ev_periodic_init (&hourly_tick, clock_cb, |
994 | fmod (ev_now (loop), 3600.), 3600., 0); |
1197 | fmod (ev_now (loop), 3600.), 3600., 0); |
995 | ev_periodic_start (loop, &hourly_tick); |
1198 | ev_periodic_start (loop, &hourly_tick); |
… | |
… | |
1016 | =item ev_signal_set (ev_signal *, int signum) |
1219 | =item ev_signal_set (ev_signal *, int signum) |
1017 | |
1220 | |
1018 | Configures the watcher to trigger on the given signal number (usually one |
1221 | Configures the watcher to trigger on the given signal number (usually one |
1019 | of the C<SIGxxx> constants). |
1222 | of the C<SIGxxx> constants). |
1020 | |
1223 | |
|
|
1224 | =item int signum [read-only] |
|
|
1225 | |
|
|
1226 | The signal the watcher watches out for. |
|
|
1227 | |
1021 | =back |
1228 | =back |
1022 | |
1229 | |
1023 | |
1230 | |
1024 | =head2 C<ev_child> - watch out for process status changes |
1231 | =head2 C<ev_child> - watch out for process status changes |
1025 | |
1232 | |
… | |
… | |
1037 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1244 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1038 | the status word (use the macros from C<sys/wait.h> and see your systems |
1245 | the status word (use the macros from C<sys/wait.h> and see your systems |
1039 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1246 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1040 | process causing the status change. |
1247 | process causing the status change. |
1041 | |
1248 | |
|
|
1249 | =item int pid [read-only] |
|
|
1250 | |
|
|
1251 | The process id this watcher watches out for, or C<0>, meaning any process id. |
|
|
1252 | |
|
|
1253 | =item int rpid [read-write] |
|
|
1254 | |
|
|
1255 | The process id that detected a status change. |
|
|
1256 | |
|
|
1257 | =item int rstatus [read-write] |
|
|
1258 | |
|
|
1259 | The process exit/trace status caused by C<rpid> (see your systems |
|
|
1260 | C<waitpid> and C<sys/wait.h> documentation for details). |
|
|
1261 | |
1042 | =back |
1262 | =back |
1043 | |
1263 | |
1044 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1264 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1045 | |
1265 | |
1046 | static void |
1266 | static void |
1047 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1267 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1048 | { |
1268 | { |
1049 | ev_unloop (loop, EVUNLOOP_ALL); |
1269 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
1052 | struct ev_signal signal_watcher; |
1272 | struct ev_signal signal_watcher; |
1053 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1273 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1054 | ev_signal_start (loop, &sigint_cb); |
1274 | ev_signal_start (loop, &sigint_cb); |
1055 | |
1275 | |
1056 | |
1276 | |
|
|
1277 | =head2 C<ev_stat> - did the file attributes just change? |
|
|
1278 | |
|
|
1279 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1280 | C<stat> regularly (or when the OS says it changed) and sees if it changed |
|
|
1281 | compared to the last time, invoking the callback if it did. |
|
|
1282 | |
|
|
1283 | The path does not need to exist: changing from "path exists" to "path does |
|
|
1284 | not exist" is a status change like any other. The condition "path does |
|
|
1285 | not exist" is signified by the C<st_nlink> field being zero (which is |
|
|
1286 | otherwise always forced to be at least one) and all the other fields of |
|
|
1287 | the stat buffer having unspecified contents. |
|
|
1288 | |
|
|
1289 | The path I<should> be absolute and I<must not> end in a slash. If it is |
|
|
1290 | relative and your working directory changes, the behaviour is undefined. |
|
|
1291 | |
|
|
1292 | Since there is no standard to do this, the portable implementation simply |
|
|
1293 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
|
|
1294 | can specify a recommended polling interval for this case. If you specify |
|
|
1295 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
|
|
1296 | unspecified default> value will be used (which you can expect to be around |
|
|
1297 | five seconds, although this might change dynamically). Libev will also |
|
|
1298 | impose a minimum interval which is currently around C<0.1>, but thats |
|
|
1299 | usually overkill. |
|
|
1300 | |
|
|
1301 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1302 | as even with OS-supported change notifications, this can be |
|
|
1303 | resource-intensive. |
|
|
1304 | |
|
|
1305 | At the time of this writing, only the Linux inotify interface is |
|
|
1306 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1307 | reader). Inotify will be used to give hints only and should not change the |
|
|
1308 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
|
|
1309 | to fall back to regular polling again even with inotify, but changes are |
|
|
1310 | usually detected immediately, and if the file exists there will be no |
|
|
1311 | polling. |
|
|
1312 | |
|
|
1313 | =over 4 |
|
|
1314 | |
|
|
1315 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
|
|
1316 | |
|
|
1317 | =item ev_stat_set (ev_stat *, const char *path, ev_tstamp interval) |
|
|
1318 | |
|
|
1319 | Configures the watcher to wait for status changes of the given |
|
|
1320 | C<path>. The C<interval> is a hint on how quickly a change is expected to |
|
|
1321 | be detected and should normally be specified as C<0> to let libev choose |
|
|
1322 | a suitable value. The memory pointed to by C<path> must point to the same |
|
|
1323 | path for as long as the watcher is active. |
|
|
1324 | |
|
|
1325 | The callback will be receive C<EV_STAT> when a change was detected, |
|
|
1326 | relative to the attributes at the time the watcher was started (or the |
|
|
1327 | last change was detected). |
|
|
1328 | |
|
|
1329 | =item ev_stat_stat (ev_stat *) |
|
|
1330 | |
|
|
1331 | Updates the stat buffer immediately with new values. If you change the |
|
|
1332 | watched path in your callback, you could call this fucntion to avoid |
|
|
1333 | detecting this change (while introducing a race condition). Can also be |
|
|
1334 | useful simply to find out the new values. |
|
|
1335 | |
|
|
1336 | =item ev_statdata attr [read-only] |
|
|
1337 | |
|
|
1338 | The most-recently detected attributes of the file. Although the type is of |
|
|
1339 | C<ev_statdata>, this is usually the (or one of the) C<struct stat> types |
|
|
1340 | suitable for your system. If the C<st_nlink> member is C<0>, then there |
|
|
1341 | was some error while C<stat>ing the file. |
|
|
1342 | |
|
|
1343 | =item ev_statdata prev [read-only] |
|
|
1344 | |
|
|
1345 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1346 | C<prev> != C<attr>. |
|
|
1347 | |
|
|
1348 | =item ev_tstamp interval [read-only] |
|
|
1349 | |
|
|
1350 | The specified interval. |
|
|
1351 | |
|
|
1352 | =item const char *path [read-only] |
|
|
1353 | |
|
|
1354 | The filesystem path that is being watched. |
|
|
1355 | |
|
|
1356 | =back |
|
|
1357 | |
|
|
1358 | Example: Watch C</etc/passwd> for attribute changes. |
|
|
1359 | |
|
|
1360 | static void |
|
|
1361 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1362 | { |
|
|
1363 | /* /etc/passwd changed in some way */ |
|
|
1364 | if (w->attr.st_nlink) |
|
|
1365 | { |
|
|
1366 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1367 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1368 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1369 | } |
|
|
1370 | else |
|
|
1371 | /* you shalt not abuse printf for puts */ |
|
|
1372 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1373 | "if this is windows, they already arrived\n"); |
|
|
1374 | } |
|
|
1375 | |
|
|
1376 | ... |
|
|
1377 | ev_stat passwd; |
|
|
1378 | |
|
|
1379 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1380 | ev_stat_start (loop, &passwd); |
|
|
1381 | |
|
|
1382 | |
1057 | =head2 C<ev_idle> - when you've got nothing better to do... |
1383 | =head2 C<ev_idle> - when you've got nothing better to do... |
1058 | |
1384 | |
1059 | Idle watchers trigger events when there are no other events are pending |
1385 | Idle watchers trigger events when no other events of the same or higher |
1060 | (prepare, check and other idle watchers do not count). That is, as long |
1386 | priority are pending (prepare, check and other idle watchers do not |
1061 | as your process is busy handling sockets or timeouts (or even signals, |
1387 | count). |
1062 | imagine) it will not be triggered. But when your process is idle all idle |
1388 | |
1063 | watchers are being called again and again, once per event loop iteration - |
1389 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1390 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1391 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1392 | are pending), the idle watchers are being called once per event loop |
1064 | until stopped, that is, or your process receives more events and becomes |
1393 | iteration - until stopped, that is, or your process receives more events |
1065 | busy. |
1394 | and becomes busy again with higher priority stuff. |
1066 | |
1395 | |
1067 | The most noteworthy effect is that as long as any idle watchers are |
1396 | The most noteworthy effect is that as long as any idle watchers are |
1068 | active, the process will not block when waiting for new events. |
1397 | active, the process will not block when waiting for new events. |
1069 | |
1398 | |
1070 | Apart from keeping your process non-blocking (which is a useful |
1399 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1080 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1409 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1081 | believe me. |
1410 | believe me. |
1082 | |
1411 | |
1083 | =back |
1412 | =back |
1084 | |
1413 | |
1085 | Example: dynamically allocate an C<ev_idle>, start it, and in the |
1414 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1086 | callback, free it. Alos, use no error checking, as usual. |
1415 | callback, free it. Also, use no error checking, as usual. |
1087 | |
1416 | |
1088 | static void |
1417 | static void |
1089 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1418 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1090 | { |
1419 | { |
1091 | free (w); |
1420 | free (w); |
… | |
… | |
1160 | |
1489 | |
1161 | static void |
1490 | static void |
1162 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1491 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1163 | { |
1492 | { |
1164 | // set the relevant poll flags |
1493 | // set the relevant poll flags |
|
|
1494 | // could also call adns_processreadable etc. here |
1165 | struct pollfd *fd = (struct pollfd *)w->data; |
1495 | struct pollfd *fd = (struct pollfd *)w->data; |
1166 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1496 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1167 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1497 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1168 | } |
1498 | } |
1169 | |
1499 | |
1170 | // create io watchers for each fd and a timer before blocking |
1500 | // create io watchers for each fd and a timer before blocking |
1171 | static void |
1501 | static void |
1172 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1502 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1173 | { |
1503 | { |
1174 | int timeout = 3600000;truct pollfd fds [nfd]; |
1504 | int timeout = 3600000; |
|
|
1505 | struct pollfd fds [nfd]; |
1175 | // actual code will need to loop here and realloc etc. |
1506 | // actual code will need to loop here and realloc etc. |
1176 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1507 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1177 | |
1508 | |
1178 | /* the callback is illegal, but won't be called as we stop during check */ |
1509 | /* the callback is illegal, but won't be called as we stop during check */ |
1179 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1510 | ev_timer_init (&tw, 0, timeout * 1e-3); |
… | |
… | |
1291 | |
1622 | |
1292 | Make a single, non-blocking sweep over the embedded loop. This works |
1623 | Make a single, non-blocking sweep over the embedded loop. This works |
1293 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1624 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1294 | apropriate way for embedded loops. |
1625 | apropriate way for embedded loops. |
1295 | |
1626 | |
|
|
1627 | =item struct ev_loop *loop [read-only] |
|
|
1628 | |
|
|
1629 | The embedded event loop. |
|
|
1630 | |
|
|
1631 | =back |
|
|
1632 | |
|
|
1633 | |
|
|
1634 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
|
|
1635 | |
|
|
1636 | Fork watchers are called when a C<fork ()> was detected (usually because |
|
|
1637 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1638 | C<ev_default_fork> or C<ev_loop_fork>). The invocation is done before the |
|
|
1639 | event loop blocks next and before C<ev_check> watchers are being called, |
|
|
1640 | and only in the child after the fork. If whoever good citizen calling |
|
|
1641 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
|
|
1642 | handlers will be invoked, too, of course. |
|
|
1643 | |
|
|
1644 | =over 4 |
|
|
1645 | |
|
|
1646 | =item ev_fork_init (ev_signal *, callback) |
|
|
1647 | |
|
|
1648 | Initialises and configures the fork watcher - it has no parameters of any |
|
|
1649 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
|
|
1650 | believe me. |
|
|
1651 | |
1296 | =back |
1652 | =back |
1297 | |
1653 | |
1298 | |
1654 | |
1299 | =head1 OTHER FUNCTIONS |
1655 | =head1 OTHER FUNCTIONS |
1300 | |
1656 | |
… | |
… | |
1388 | |
1744 | |
1389 | To use it, |
1745 | To use it, |
1390 | |
1746 | |
1391 | #include <ev++.h> |
1747 | #include <ev++.h> |
1392 | |
1748 | |
1393 | (it is not installed by default). This automatically includes F<ev.h> |
1749 | This automatically includes F<ev.h> and puts all of its definitions (many |
1394 | and puts all of its definitions (many of them macros) into the global |
1750 | of them macros) into the global namespace. All C++ specific things are |
1395 | namespace. All C++ specific things are put into the C<ev> namespace. |
1751 | put into the C<ev> namespace. It should support all the same embedding |
|
|
1752 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
1396 | |
1753 | |
1397 | It should support all the same embedding options as F<ev.h>, most notably |
1754 | Care has been taken to keep the overhead low. The only data member the C++ |
1398 | C<EV_MULTIPLICITY>. |
1755 | classes add (compared to plain C-style watchers) is the event loop pointer |
|
|
1756 | that the watcher is associated with (or no additional members at all if |
|
|
1757 | you disable C<EV_MULTIPLICITY> when embedding libev). |
|
|
1758 | |
|
|
1759 | Currently, functions, and static and non-static member functions can be |
|
|
1760 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1761 | need one additional pointer for context. If you need support for other |
|
|
1762 | types of functors please contact the author (preferably after implementing |
|
|
1763 | it). |
1399 | |
1764 | |
1400 | Here is a list of things available in the C<ev> namespace: |
1765 | Here is a list of things available in the C<ev> namespace: |
1401 | |
1766 | |
1402 | =over 4 |
1767 | =over 4 |
1403 | |
1768 | |
… | |
… | |
1419 | |
1784 | |
1420 | All of those classes have these methods: |
1785 | All of those classes have these methods: |
1421 | |
1786 | |
1422 | =over 4 |
1787 | =over 4 |
1423 | |
1788 | |
1424 | =item ev::TYPE::TYPE (object *, object::method *) |
1789 | =item ev::TYPE::TYPE () |
1425 | |
1790 | |
1426 | =item ev::TYPE::TYPE (object *, object::method *, struct ev_loop *) |
1791 | =item ev::TYPE::TYPE (struct ev_loop *) |
1427 | |
1792 | |
1428 | =item ev::TYPE::~TYPE |
1793 | =item ev::TYPE::~TYPE |
1429 | |
1794 | |
1430 | The constructor takes a pointer to an object and a method pointer to |
1795 | The constructor (optionally) takes an event loop to associate the watcher |
1431 | the event handler callback to call in this class. The constructor calls |
1796 | with. If it is omitted, it will use C<EV_DEFAULT>. |
1432 | C<ev_init> for you, which means you have to call the C<set> method |
1797 | |
1433 | before starting it. If you do not specify a loop then the constructor |
1798 | The constructor calls C<ev_init> for you, which means you have to call the |
1434 | automatically associates the default loop with this watcher. |
1799 | C<set> method before starting it. |
|
|
1800 | |
|
|
1801 | It will not set a callback, however: You have to call the templated C<set> |
|
|
1802 | method to set a callback before you can start the watcher. |
|
|
1803 | |
|
|
1804 | (The reason why you have to use a method is a limitation in C++ which does |
|
|
1805 | not allow explicit template arguments for constructors). |
1435 | |
1806 | |
1436 | The destructor automatically stops the watcher if it is active. |
1807 | The destructor automatically stops the watcher if it is active. |
|
|
1808 | |
|
|
1809 | =item w->set<class, &class::method> (object *) |
|
|
1810 | |
|
|
1811 | This method sets the callback method to call. The method has to have a |
|
|
1812 | signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as |
|
|
1813 | first argument and the C<revents> as second. The object must be given as |
|
|
1814 | parameter and is stored in the C<data> member of the watcher. |
|
|
1815 | |
|
|
1816 | This method synthesizes efficient thunking code to call your method from |
|
|
1817 | the C callback that libev requires. If your compiler can inline your |
|
|
1818 | callback (i.e. it is visible to it at the place of the C<set> call and |
|
|
1819 | your compiler is good :), then the method will be fully inlined into the |
|
|
1820 | thunking function, making it as fast as a direct C callback. |
|
|
1821 | |
|
|
1822 | Example: simple class declaration and watcher initialisation |
|
|
1823 | |
|
|
1824 | struct myclass |
|
|
1825 | { |
|
|
1826 | void io_cb (ev::io &w, int revents) { } |
|
|
1827 | } |
|
|
1828 | |
|
|
1829 | myclass obj; |
|
|
1830 | ev::io iow; |
|
|
1831 | iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1832 | |
|
|
1833 | =item w->set (void (*function)(watcher &w, int), void *data = 0) |
|
|
1834 | |
|
|
1835 | Also sets a callback, but uses a static method or plain function as |
|
|
1836 | callback. The optional C<data> argument will be stored in the watcher's |
|
|
1837 | C<data> member and is free for you to use. |
|
|
1838 | |
|
|
1839 | See the method-C<set> above for more details. |
1437 | |
1840 | |
1438 | =item w->set (struct ev_loop *) |
1841 | =item w->set (struct ev_loop *) |
1439 | |
1842 | |
1440 | Associates a different C<struct ev_loop> with this watcher. You can only |
1843 | Associates a different C<struct ev_loop> with this watcher. You can only |
1441 | do this when the watcher is inactive (and not pending either). |
1844 | do this when the watcher is inactive (and not pending either). |
1442 | |
1845 | |
1443 | =item w->set ([args]) |
1846 | =item w->set ([args]) |
1444 | |
1847 | |
1445 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1848 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1446 | called at least once. Unlike the C counterpart, an active watcher gets |
1849 | called at least once. Unlike the C counterpart, an active watcher gets |
1447 | automatically stopped and restarted. |
1850 | automatically stopped and restarted when reconfiguring it with this |
|
|
1851 | method. |
1448 | |
1852 | |
1449 | =item w->start () |
1853 | =item w->start () |
1450 | |
1854 | |
1451 | Starts the watcher. Note that there is no C<loop> argument as the |
1855 | Starts the watcher. Note that there is no C<loop> argument, as the |
1452 | constructor already takes the loop. |
1856 | constructor already stores the event loop. |
1453 | |
1857 | |
1454 | =item w->stop () |
1858 | =item w->stop () |
1455 | |
1859 | |
1456 | Stops the watcher if it is active. Again, no C<loop> argument. |
1860 | Stops the watcher if it is active. Again, no C<loop> argument. |
1457 | |
1861 | |
… | |
… | |
1462 | |
1866 | |
1463 | =item w->sweep () C<ev::embed> only |
1867 | =item w->sweep () C<ev::embed> only |
1464 | |
1868 | |
1465 | Invokes C<ev_embed_sweep>. |
1869 | Invokes C<ev_embed_sweep>. |
1466 | |
1870 | |
|
|
1871 | =item w->update () C<ev::stat> only |
|
|
1872 | |
|
|
1873 | Invokes C<ev_stat_stat>. |
|
|
1874 | |
1467 | =back |
1875 | =back |
1468 | |
1876 | |
1469 | =back |
1877 | =back |
1470 | |
1878 | |
1471 | Example: Define a class with an IO and idle watcher, start one of them in |
1879 | Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1478 | |
1886 | |
1479 | myclass (); |
1887 | myclass (); |
1480 | } |
1888 | } |
1481 | |
1889 | |
1482 | myclass::myclass (int fd) |
1890 | myclass::myclass (int fd) |
1483 | : io (this, &myclass::io_cb), |
|
|
1484 | idle (this, &myclass::idle_cb) |
|
|
1485 | { |
1891 | { |
|
|
1892 | io .set <myclass, &myclass::io_cb > (this); |
|
|
1893 | idle.set <myclass, &myclass::idle_cb> (this); |
|
|
1894 | |
1486 | io.start (fd, ev::READ); |
1895 | io.start (fd, ev::READ); |
1487 | } |
1896 | } |
|
|
1897 | |
|
|
1898 | |
|
|
1899 | =head1 MACRO MAGIC |
|
|
1900 | |
|
|
1901 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1902 | C<EV_MULTIPLICITY>. This option determines whether (most) functions and |
|
|
1903 | callbacks have an initial C<struct ev_loop *> argument. |
|
|
1904 | |
|
|
1905 | To make it easier to write programs that cope with either variant, the |
|
|
1906 | following macros are defined: |
|
|
1907 | |
|
|
1908 | =over 4 |
|
|
1909 | |
|
|
1910 | =item C<EV_A>, C<EV_A_> |
|
|
1911 | |
|
|
1912 | This provides the loop I<argument> for functions, if one is required ("ev |
|
|
1913 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
|
|
1914 | C<EV_A_> is used when other arguments are following. Example: |
|
|
1915 | |
|
|
1916 | ev_unref (EV_A); |
|
|
1917 | ev_timer_add (EV_A_ watcher); |
|
|
1918 | ev_loop (EV_A_ 0); |
|
|
1919 | |
|
|
1920 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
|
|
1921 | which is often provided by the following macro. |
|
|
1922 | |
|
|
1923 | =item C<EV_P>, C<EV_P_> |
|
|
1924 | |
|
|
1925 | This provides the loop I<parameter> for functions, if one is required ("ev |
|
|
1926 | loop parameter"). The C<EV_P> form is used when this is the sole parameter, |
|
|
1927 | C<EV_P_> is used when other parameters are following. Example: |
|
|
1928 | |
|
|
1929 | // this is how ev_unref is being declared |
|
|
1930 | static void ev_unref (EV_P); |
|
|
1931 | |
|
|
1932 | // this is how you can declare your typical callback |
|
|
1933 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1934 | |
|
|
1935 | It declares a parameter C<loop> of type C<struct ev_loop *>, quite |
|
|
1936 | suitable for use with C<EV_A>. |
|
|
1937 | |
|
|
1938 | =item C<EV_DEFAULT>, C<EV_DEFAULT_> |
|
|
1939 | |
|
|
1940 | Similar to the other two macros, this gives you the value of the default |
|
|
1941 | loop, if multiple loops are supported ("ev loop default"). |
|
|
1942 | |
|
|
1943 | =back |
|
|
1944 | |
|
|
1945 | Example: Declare and initialise a check watcher, utilising the above |
|
|
1946 | macros so it will work regardless of whether multiple loops are supported |
|
|
1947 | or not. |
|
|
1948 | |
|
|
1949 | static void |
|
|
1950 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1951 | { |
|
|
1952 | ev_check_stop (EV_A_ w); |
|
|
1953 | } |
|
|
1954 | |
|
|
1955 | ev_check check; |
|
|
1956 | ev_check_init (&check, check_cb); |
|
|
1957 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1958 | ev_loop (EV_DEFAULT_ 0); |
1488 | |
1959 | |
1489 | =head1 EMBEDDING |
1960 | =head1 EMBEDDING |
1490 | |
1961 | |
1491 | Libev can (and often is) directly embedded into host |
1962 | Libev can (and often is) directly embedded into host |
1492 | applications. Examples of applications that embed it include the Deliantra |
1963 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1532 | ev_vars.h |
2003 | ev_vars.h |
1533 | ev_wrap.h |
2004 | ev_wrap.h |
1534 | |
2005 | |
1535 | ev_win32.c required on win32 platforms only |
2006 | ev_win32.c required on win32 platforms only |
1536 | |
2007 | |
1537 | ev_select.c only when select backend is enabled (which is by default) |
2008 | ev_select.c only when select backend is enabled (which is enabled by default) |
1538 | ev_poll.c only when poll backend is enabled (disabled by default) |
2009 | ev_poll.c only when poll backend is enabled (disabled by default) |
1539 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2010 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1540 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2011 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1541 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
2012 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1542 | |
2013 | |
… | |
… | |
1667 | |
2138 | |
1668 | =item EV_USE_DEVPOLL |
2139 | =item EV_USE_DEVPOLL |
1669 | |
2140 | |
1670 | reserved for future expansion, works like the USE symbols above. |
2141 | reserved for future expansion, works like the USE symbols above. |
1671 | |
2142 | |
|
|
2143 | =item EV_USE_INOTIFY |
|
|
2144 | |
|
|
2145 | If defined to be C<1>, libev will compile in support for the Linux inotify |
|
|
2146 | interface to speed up C<ev_stat> watchers. Its actual availability will |
|
|
2147 | be detected at runtime. |
|
|
2148 | |
1672 | =item EV_H |
2149 | =item EV_H |
1673 | |
2150 | |
1674 | The name of the F<ev.h> header file used to include it. The default if |
2151 | The name of the F<ev.h> header file used to include it. The default if |
1675 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
2152 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
1676 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
2153 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
… | |
… | |
1699 | will have the C<struct ev_loop *> as first argument, and you can create |
2176 | will have the C<struct ev_loop *> as first argument, and you can create |
1700 | additional independent event loops. Otherwise there will be no support |
2177 | additional independent event loops. Otherwise there will be no support |
1701 | for multiple event loops and there is no first event loop pointer |
2178 | for multiple event loops and there is no first event loop pointer |
1702 | argument. Instead, all functions act on the single default loop. |
2179 | argument. Instead, all functions act on the single default loop. |
1703 | |
2180 | |
|
|
2181 | =item EV_MINPRI |
|
|
2182 | |
|
|
2183 | =item EV_MAXPRI |
|
|
2184 | |
|
|
2185 | The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to |
|
|
2186 | C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can |
|
|
2187 | provide for more priorities by overriding those symbols (usually defined |
|
|
2188 | to be C<-2> and C<2>, respectively). |
|
|
2189 | |
|
|
2190 | When doing priority-based operations, libev usually has to linearly search |
|
|
2191 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2192 | and time, so using the defaults of five priorities (-2 .. +2) is usually |
|
|
2193 | fine. |
|
|
2194 | |
|
|
2195 | If your embedding app does not need any priorities, defining these both to |
|
|
2196 | C<0> will save some memory and cpu. |
|
|
2197 | |
1704 | =item EV_PERIODICS |
2198 | =item EV_PERIODIC_ENABLE |
1705 | |
2199 | |
1706 | If undefined or defined to be C<1>, then periodic timers are supported, |
2200 | If undefined or defined to be C<1>, then periodic timers are supported. If |
1707 | otherwise not. This saves a few kb of code. |
2201 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2202 | code. |
|
|
2203 | |
|
|
2204 | =item EV_IDLE_ENABLE |
|
|
2205 | |
|
|
2206 | If undefined or defined to be C<1>, then idle watchers are supported. If |
|
|
2207 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2208 | code. |
|
|
2209 | |
|
|
2210 | =item EV_EMBED_ENABLE |
|
|
2211 | |
|
|
2212 | If undefined or defined to be C<1>, then embed watchers are supported. If |
|
|
2213 | defined to be C<0>, then they are not. |
|
|
2214 | |
|
|
2215 | =item EV_STAT_ENABLE |
|
|
2216 | |
|
|
2217 | If undefined or defined to be C<1>, then stat watchers are supported. If |
|
|
2218 | defined to be C<0>, then they are not. |
|
|
2219 | |
|
|
2220 | =item EV_FORK_ENABLE |
|
|
2221 | |
|
|
2222 | If undefined or defined to be C<1>, then fork watchers are supported. If |
|
|
2223 | defined to be C<0>, then they are not. |
|
|
2224 | |
|
|
2225 | =item EV_MINIMAL |
|
|
2226 | |
|
|
2227 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2228 | speed, define this symbol to C<1>. Currently only used for gcc to override |
|
|
2229 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2230 | |
|
|
2231 | =item EV_PID_HASHSIZE |
|
|
2232 | |
|
|
2233 | C<ev_child> watchers use a small hash table to distribute workload by |
|
|
2234 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
|
|
2235 | than enough. If you need to manage thousands of children you might want to |
|
|
2236 | increase this value (I<must> be a power of two). |
|
|
2237 | |
|
|
2238 | =item EV_INOTIFY_HASHSIZE |
|
|
2239 | |
|
|
2240 | C<ev_staz> watchers use a small hash table to distribute workload by |
|
|
2241 | inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>), |
|
|
2242 | usually more than enough. If you need to manage thousands of C<ev_stat> |
|
|
2243 | watchers you might want to increase this value (I<must> be a power of |
|
|
2244 | two). |
1708 | |
2245 | |
1709 | =item EV_COMMON |
2246 | =item EV_COMMON |
1710 | |
2247 | |
1711 | By default, all watchers have a C<void *data> member. By redefining |
2248 | By default, all watchers have a C<void *data> member. By redefining |
1712 | this macro to a something else you can include more and other types of |
2249 | this macro to a something else you can include more and other types of |
… | |
… | |
1741 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2278 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
1742 | will be compiled. It is pretty complex because it provides its own header |
2279 | will be compiled. It is pretty complex because it provides its own header |
1743 | file. |
2280 | file. |
1744 | |
2281 | |
1745 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2282 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
1746 | that everybody includes and which overrides some autoconf choices: |
2283 | that everybody includes and which overrides some configure choices: |
1747 | |
2284 | |
|
|
2285 | #define EV_MINIMAL 1 |
1748 | #define EV_USE_POLL 0 |
2286 | #define EV_USE_POLL 0 |
1749 | #define EV_MULTIPLICITY 0 |
2287 | #define EV_MULTIPLICITY 0 |
1750 | #define EV_PERIODICS 0 |
2288 | #define EV_PERIODIC_ENABLE 0 |
|
|
2289 | #define EV_STAT_ENABLE 0 |
|
|
2290 | #define EV_FORK_ENABLE 0 |
1751 | #define EV_CONFIG_H <config.h> |
2291 | #define EV_CONFIG_H <config.h> |
|
|
2292 | #define EV_MINPRI 0 |
|
|
2293 | #define EV_MAXPRI 0 |
1752 | |
2294 | |
1753 | #include "ev++.h" |
2295 | #include "ev++.h" |
1754 | |
2296 | |
1755 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2297 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
1756 | |
2298 | |
1757 | #include "ev_cpp.h" |
2299 | #include "ev_cpp.h" |
1758 | #include "ev.c" |
2300 | #include "ev.c" |
1759 | |
2301 | |
|
|
2302 | |
|
|
2303 | =head1 COMPLEXITIES |
|
|
2304 | |
|
|
2305 | In this section the complexities of (many of) the algorithms used inside |
|
|
2306 | libev will be explained. For complexity discussions about backends see the |
|
|
2307 | documentation for C<ev_default_init>. |
|
|
2308 | |
|
|
2309 | All of the following are about amortised time: If an array needs to be |
|
|
2310 | extended, libev needs to realloc and move the whole array, but this |
|
|
2311 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2312 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2313 | it is much faster and asymptotically approaches constant time. |
|
|
2314 | |
|
|
2315 | =over 4 |
|
|
2316 | |
|
|
2317 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
|
|
2318 | |
|
|
2319 | This means that, when you have a watcher that triggers in one hour and |
|
|
2320 | there are 100 watchers that would trigger before that then inserting will |
|
|
2321 | have to skip those 100 watchers. |
|
|
2322 | |
|
|
2323 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
|
|
2324 | |
|
|
2325 | That means that for changing a timer costs less than removing/adding them |
|
|
2326 | as only the relative motion in the event queue has to be paid for. |
|
|
2327 | |
|
|
2328 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
|
|
2329 | |
|
|
2330 | These just add the watcher into an array or at the head of a list. |
|
|
2331 | =item Stopping check/prepare/idle watchers: O(1) |
|
|
2332 | |
|
|
2333 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
|
|
2334 | |
|
|
2335 | These watchers are stored in lists then need to be walked to find the |
|
|
2336 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2337 | have many watchers waiting for the same fd or signal). |
|
|
2338 | |
|
|
2339 | =item Finding the next timer per loop iteration: O(1) |
|
|
2340 | |
|
|
2341 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
|
|
2342 | |
|
|
2343 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2344 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2345 | |
|
|
2346 | =item Activating one watcher: O(1) |
|
|
2347 | |
|
|
2348 | =item Priority handling: O(number_of_priorities) |
|
|
2349 | |
|
|
2350 | Priorities are implemented by allocating some space for each |
|
|
2351 | priority. When doing priority-based operations, libev usually has to |
|
|
2352 | linearly search all the priorities. |
|
|
2353 | |
|
|
2354 | =back |
|
|
2355 | |
|
|
2356 | |
1760 | =head1 AUTHOR |
2357 | =head1 AUTHOR |
1761 | |
2358 | |
1762 | Marc Lehmann <libev@schmorp.de>. |
2359 | Marc Lehmann <libev@schmorp.de>. |
1763 | |
2360 | |