… | |
… | |
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 | |
… | |
… | |
77 | on event-based programming, nor will it introduce event-based programming |
77 | on event-based programming, nor will it introduce event-based programming |
78 | with libev. |
78 | with libev. |
79 | |
79 | |
80 | Familiarity with event based programming techniques in general is assumed |
80 | Familiarity with event based programming techniques in general is assumed |
81 | throughout this document. |
81 | throughout this document. |
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82 | |
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83 | =head1 WHAT TO READ WHEN IN A HURRY |
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84 | |
|
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85 | This manual tries to be very detailed, but unfortunately, this also makes |
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86 | it very long. If you just want to know the basics of libev, I suggest |
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87 | reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and |
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88 | look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and |
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89 | C<ev_timer> sections in L<WATCHER TYPES>. |
82 | |
90 | |
83 | =head1 ABOUT LIBEV |
91 | =head1 ABOUT LIBEV |
84 | |
92 | |
85 | Libev is an event loop: you register interest in certain events (such as a |
93 | Libev is an event loop: you register interest in certain events (such as a |
86 | file descriptor being readable or a timeout occurring), and it will manage |
94 | file descriptor being readable or a timeout occurring), and it will manage |
… | |
… | |
124 | this argument. |
132 | this argument. |
125 | |
133 | |
126 | =head2 TIME REPRESENTATION |
134 | =head2 TIME REPRESENTATION |
127 | |
135 | |
128 | Libev represents time as a single floating point number, representing |
136 | Libev represents time as a single floating point number, representing |
129 | the (fractional) number of seconds since the (POSIX) epoch (in practise |
137 | the (fractional) number of seconds since the (POSIX) epoch (in practice |
130 | somewhere near the beginning of 1970, details are complicated, don't |
138 | somewhere near the beginning of 1970, details are complicated, don't |
131 | ask). This type is called C<ev_tstamp>, which is what you should use |
139 | ask). This type is called C<ev_tstamp>, which is what you should use |
132 | too. It usually aliases to the C<double> type in C. When you need to do |
140 | too. It usually aliases to the C<double> type in C. When you need to do |
133 | any calculations on it, you should treat it as some floating point value. |
141 | any calculations on it, you should treat it as some floating point value. |
134 | |
142 | |
… | |
… | |
165 | |
173 | |
166 | =item ev_tstamp ev_time () |
174 | =item ev_tstamp ev_time () |
167 | |
175 | |
168 | Returns the current time as libev would use it. Please note that the |
176 | Returns the current time as libev would use it. Please note that the |
169 | C<ev_now> function is usually faster and also often returns the timestamp |
177 | C<ev_now> function is usually faster and also often returns the timestamp |
170 | you actually want to know. |
178 | you actually want to know. Also interesting is the combination of |
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179 | C<ev_update_now> and C<ev_now>. |
171 | |
180 | |
172 | =item ev_sleep (ev_tstamp interval) |
181 | =item ev_sleep (ev_tstamp interval) |
173 | |
182 | |
174 | Sleep for the given interval: The current thread will be blocked until |
183 | Sleep for the given interval: The current thread will be blocked until |
175 | either it is interrupted or the given time interval has passed. Basically |
184 | either it is interrupted or the given time interval has passed. Basically |
… | |
… | |
192 | as this indicates an incompatible change. Minor versions are usually |
201 | as this indicates an incompatible change. Minor versions are usually |
193 | compatible to older versions, so a larger minor version alone is usually |
202 | compatible to older versions, so a larger minor version alone is usually |
194 | not a problem. |
203 | not a problem. |
195 | |
204 | |
196 | Example: Make sure we haven't accidentally been linked against the wrong |
205 | Example: Make sure we haven't accidentally been linked against the wrong |
197 | version (note, however, that this will not detect ABI mismatches :). |
206 | version (note, however, that this will not detect other ABI mismatches, |
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207 | such as LFS or reentrancy). |
198 | |
208 | |
199 | assert (("libev version mismatch", |
209 | assert (("libev version mismatch", |
200 | ev_version_major () == EV_VERSION_MAJOR |
210 | ev_version_major () == EV_VERSION_MAJOR |
201 | && ev_version_minor () >= EV_VERSION_MINOR)); |
211 | && ev_version_minor () >= EV_VERSION_MINOR)); |
202 | |
212 | |
… | |
… | |
213 | assert (("sorry, no epoll, no sex", |
223 | assert (("sorry, no epoll, no sex", |
214 | ev_supported_backends () & EVBACKEND_EPOLL)); |
224 | ev_supported_backends () & EVBACKEND_EPOLL)); |
215 | |
225 | |
216 | =item unsigned int ev_recommended_backends () |
226 | =item unsigned int ev_recommended_backends () |
217 | |
227 | |
218 | Return the set of all backends compiled into this binary of libev and also |
228 | Return the set of all backends compiled into this binary of libev and |
219 | recommended for this platform. This set is often smaller than the one |
229 | also recommended for this platform, meaning it will work for most file |
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230 | descriptor types. This set is often smaller than the one returned by |
220 | returned by C<ev_supported_backends>, as for example kqueue is broken on |
231 | C<ev_supported_backends>, as for example kqueue is broken on most BSDs |
221 | most BSDs and will not be auto-detected unless you explicitly request it |
232 | and 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 |
233 | you know what you are doing). This is the set of backends that libev will |
223 | libev will probe for if you specify no backends explicitly. |
234 | probe for if you specify no backends explicitly. |
224 | |
235 | |
225 | =item unsigned int ev_embeddable_backends () |
236 | =item unsigned int ev_embeddable_backends () |
226 | |
237 | |
227 | Returns the set of backends that are embeddable in other event loops. This |
238 | Returns the set of backends that are embeddable in other event loops. This |
228 | is the theoretical, all-platform, value. To find which backends |
239 | value is platform-specific but can include backends not available on the |
229 | might be supported on the current system, you would need to look at |
240 | current system. To find which embeddable backends might be supported on |
230 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
241 | the current system, you would need to look at C<ev_embeddable_backends () |
231 | recommended ones. |
242 | & ev_supported_backends ()>, likewise for recommended ones. |
232 | |
243 | |
233 | See the description of C<ev_embed> watchers for more info. |
244 | See the description of C<ev_embed> watchers for more info. |
234 | |
245 | |
235 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT] |
246 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT] |
236 | |
247 | |
… | |
… | |
290 | ... |
301 | ... |
291 | ev_set_syserr_cb (fatal_error); |
302 | ev_set_syserr_cb (fatal_error); |
292 | |
303 | |
293 | =back |
304 | =back |
294 | |
305 | |
295 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
306 | =head1 FUNCTIONS CONTROLLING EVENT LOOPS |
296 | |
307 | |
297 | An event loop is described by a C<struct ev_loop *> (the C<struct> |
308 | An event loop is described by a C<struct ev_loop *> (the C<struct> is |
298 | is I<not> optional in this case, as there is also an C<ev_loop> |
309 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
299 | I<function>). |
310 | libev 3 had an C<ev_loop> function colliding with the struct name). |
300 | |
311 | |
301 | The library knows two types of such loops, the I<default> loop, which |
312 | The library knows two types of such loops, the I<default> loop, which |
302 | supports signals and child events, and dynamically created loops which do |
313 | supports child process events, and dynamically created event loops which |
303 | not. |
314 | do not. |
304 | |
315 | |
305 | =over 4 |
316 | =over 4 |
306 | |
317 | |
307 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
318 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
308 | |
319 | |
309 | This will initialise the default event loop if it hasn't been initialised |
320 | This returns the "default" event loop object, which is what you should |
310 | yet and return it. If the default loop could not be initialised, returns |
321 | normally use when you just need "the event loop". Event loop objects and |
311 | false. If it already was initialised it simply returns it (and ignores the |
322 | the C<flags> parameter are described in more detail in the entry for |
312 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
323 | C<ev_loop_new>. |
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324 | |
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325 | If the default loop is already initialised then this function simply |
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326 | returns it (and ignores the flags. If that is troubling you, check |
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327 | C<ev_backend ()> afterwards). Otherwise it will create it with the given |
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328 | flags, which should almost always be C<0>, unless the caller is also the |
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329 | one calling C<ev_run> or otherwise qualifies as "the main program". |
313 | |
330 | |
314 | If you don't know what event loop to use, use the one returned from this |
331 | If you don't know what event loop to use, use the one returned from this |
315 | function. |
332 | function (or via the C<EV_DEFAULT> macro). |
316 | |
333 | |
317 | Note that this function is I<not> thread-safe, so if you want to use it |
334 | Note that this function is I<not> thread-safe, so if you want to use it |
318 | from multiple threads, you have to lock (note also that this is unlikely, |
335 | from multiple threads, you have to employ some kind of mutex (note also |
319 | as loops cannot be shared easily between threads anyway). |
336 | that this case is unlikely, as loops cannot be shared easily between |
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337 | threads anyway). |
320 | |
338 | |
321 | The default loop is the only loop that can handle C<ev_signal> and |
339 | The default loop is the only loop that can handle C<ev_child> watchers, |
322 | C<ev_child> watchers, and to do this, it always registers a handler |
340 | and to do this, it always registers a handler for C<SIGCHLD>. If this is |
323 | for C<SIGCHLD>. If this is a problem for your application you can either |
341 | a problem for your application you can either create a dynamic loop with |
324 | create a dynamic loop with C<ev_loop_new> that doesn't do that, or you |
342 | C<ev_loop_new> which doesn't do that, or you can simply overwrite the |
325 | can simply overwrite the C<SIGCHLD> signal handler I<after> calling |
343 | C<SIGCHLD> signal handler I<after> calling C<ev_default_init>. |
326 | C<ev_default_init>. |
344 | |
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345 | Example: This is the most typical usage. |
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346 | |
|
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347 | if (!ev_default_loop (0)) |
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348 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
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349 | |
|
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350 | Example: Restrict libev to the select and poll backends, and do not allow |
|
|
351 | environment settings to be taken into account: |
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352 | |
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353 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
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354 | |
|
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355 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
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356 | |
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357 | This will create and initialise a new event loop object. If the loop |
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358 | could not be initialised, returns false. |
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359 | |
|
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360 | Note that this function I<is> thread-safe, and one common way to use |
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361 | libev with threads is indeed to create one loop per thread, and using the |
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362 | default loop in the "main" or "initial" thread. |
327 | |
363 | |
328 | The flags argument can be used to specify special behaviour or specific |
364 | The flags argument can be used to specify special behaviour or specific |
329 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
365 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
330 | |
366 | |
331 | The following flags are supported: |
367 | The following flags are supported: |
… | |
… | |
439 | of course I<doesn't>, and epoll just loves to report events for totally |
475 | of course I<doesn't>, and epoll just loves to report events for totally |
440 | I<different> file descriptors (even already closed ones, so one cannot |
476 | I<different> file descriptors (even already closed ones, so one cannot |
441 | even remove them from the set) than registered in the set (especially |
477 | even remove them from the set) than registered in the set (especially |
442 | on SMP systems). Libev tries to counter these spurious notifications by |
478 | on SMP systems). Libev tries to counter these spurious notifications by |
443 | employing an additional generation counter and comparing that against the |
479 | employing an additional generation counter and comparing that against the |
444 | events to filter out spurious ones, recreating the set when required. |
480 | events to filter out spurious ones, recreating the set when required. Last |
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481 | not least, it also refuses to work with some file descriptors which work |
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|
482 | perfectly fine with C<select> (files, many character devices...). |
445 | |
483 | |
446 | While stopping, setting and starting an I/O watcher in the same iteration |
484 | While stopping, setting and starting an I/O watcher in the same iteration |
447 | will result in some caching, there is still a system call per such |
485 | will result in some caching, there is still a system call per such |
448 | incident (because the same I<file descriptor> could point to a different |
486 | incident (because the same I<file descriptor> could point to a different |
449 | I<file description> now), so its best to avoid that. Also, C<dup ()>'ed |
487 | I<file description> now), so its best to avoid that. Also, C<dup ()>'ed |
… | |
… | |
547 | If one or more of the backend flags are or'ed into the flags value, |
585 | If one or more of the backend flags are or'ed into the flags value, |
548 | then only these backends will be tried (in the reverse order as listed |
586 | then only these backends will be tried (in the reverse order as listed |
549 | here). If none are specified, all backends in C<ev_recommended_backends |
587 | here). If none are specified, all backends in C<ev_recommended_backends |
550 | ()> will be tried. |
588 | ()> will be tried. |
551 | |
589 | |
552 | Example: This is the most typical usage. |
|
|
553 | |
|
|
554 | if (!ev_default_loop (0)) |
|
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555 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
|
556 | |
|
|
557 | Example: Restrict libev to the select and poll backends, and do not allow |
|
|
558 | environment settings to be taken into account: |
|
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559 | |
|
|
560 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
|
|
561 | |
|
|
562 | Example: Use whatever libev has to offer, but make sure that kqueue is |
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563 | used if available (warning, breaks stuff, best use only with your own |
|
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564 | private event loop and only if you know the OS supports your types of |
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565 | fds): |
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566 | |
|
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567 | ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
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568 | |
|
|
569 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
|
|
570 | |
|
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571 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
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572 | always distinct from the default loop. |
|
|
573 | |
|
|
574 | Note that this function I<is> thread-safe, and one common way to use |
|
|
575 | libev with threads is indeed to create one loop per thread, and using the |
|
|
576 | default loop in the "main" or "initial" thread. |
|
|
577 | |
|
|
578 | Example: Try to create a event loop that uses epoll and nothing else. |
590 | Example: Try to create a event loop that uses epoll and nothing else. |
579 | |
591 | |
580 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
592 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
581 | if (!epoller) |
593 | if (!epoller) |
582 | fatal ("no epoll found here, maybe it hides under your chair"); |
594 | fatal ("no epoll found here, maybe it hides under your chair"); |
583 | |
595 | |
|
|
596 | Example: Use whatever libev has to offer, but make sure that kqueue is |
|
|
597 | used if available. |
|
|
598 | |
|
|
599 | struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
|
600 | |
584 | =item ev_default_destroy () |
601 | =item ev_loop_destroy (loop) |
585 | |
602 | |
586 | Destroys the default loop (frees all memory and kernel state etc.). None |
603 | Destroys an event loop object (frees all memory and kernel state |
587 | of the active event watchers will be stopped in the normal sense, so |
604 | etc.). None of the active event watchers will be stopped in the normal |
588 | e.g. C<ev_is_active> might still return true. It is your responsibility to |
605 | sense, so e.g. C<ev_is_active> might still return true. It is your |
589 | either stop all watchers cleanly yourself I<before> calling this function, |
606 | responsibility to either stop all watchers cleanly yourself I<before> |
590 | or cope with the fact afterwards (which is usually the easiest thing, you |
607 | calling this function, or cope with the fact afterwards (which is usually |
591 | can just ignore the watchers and/or C<free ()> them for example). |
608 | the easiest thing, you can just ignore the watchers and/or C<free ()> them |
|
|
609 | for example). |
592 | |
610 | |
593 | Note that certain global state, such as signal state (and installed signal |
611 | Note that certain global state, such as signal state (and installed signal |
594 | handlers), will not be freed by this function, and related watchers (such |
612 | handlers), will not be freed by this function, and related watchers (such |
595 | as signal and child watchers) would need to be stopped manually. |
613 | as signal and child watchers) would need to be stopped manually. |
596 | |
614 | |
597 | In general it is not advisable to call this function except in the |
615 | This function is normally used on loop objects allocated by |
598 | rare occasion where you really need to free e.g. the signal handling |
616 | C<ev_loop_new>, but it can also be used on the default loop returned by |
|
|
617 | C<ev_default_loop>, in which case it is not thread-safe. |
|
|
618 | |
|
|
619 | Note that it is not advisable to call this function on the default loop |
|
|
620 | except in the rare occasion where you really need to free it's resources. |
599 | pipe fds. If you need dynamically allocated loops it is better to use |
621 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
600 | C<ev_loop_new> and C<ev_loop_destroy>. |
622 | and C<ev_loop_destroy>. |
601 | |
623 | |
602 | =item ev_loop_destroy (loop) |
624 | =item ev_loop_fork (loop) |
603 | |
625 | |
604 | Like C<ev_default_destroy>, but destroys an event loop created by an |
|
|
605 | earlier call to C<ev_loop_new>. |
|
|
606 | |
|
|
607 | =item ev_default_fork () |
|
|
608 | |
|
|
609 | This function sets a flag that causes subsequent C<ev_loop> iterations |
626 | This function sets a flag that causes subsequent C<ev_run> iterations to |
610 | to reinitialise the kernel state for backends that have one. Despite the |
627 | reinitialise the kernel state for backends that have one. Despite the |
611 | name, you can call it anytime, but it makes most sense after forking, in |
628 | name, you can call it anytime, but it makes most sense after forking, in |
612 | the child process (or both child and parent, but that again makes little |
629 | the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the |
613 | sense). You I<must> call it in the child before using any of the libev |
630 | child before resuming or calling C<ev_run>. |
614 | functions, and it will only take effect at the next C<ev_loop> iteration. |
|
|
615 | |
631 | |
616 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
632 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
617 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
633 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
618 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
634 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
619 | during fork. |
635 | during fork. |
620 | |
636 | |
621 | On the other hand, you only need to call this function in the child |
637 | On the other hand, you only need to call this function in the child |
622 | process if and only if you want to use the event loop in the child. If you |
638 | process if and only if you want to use the event loop in the child. If |
623 | just fork+exec or create a new loop in the child, you don't have to call |
639 | you just fork+exec or create a new loop in the child, you don't have to |
624 | it at all. |
640 | call it at all (in fact, C<epoll> is so badly broken that it makes a |
|
|
641 | difference, but libev will usually detect this case on its own and do a |
|
|
642 | costly reset of the backend). |
625 | |
643 | |
626 | The function itself is quite fast and it's usually not a problem to call |
644 | The function itself is quite fast and it's usually not a problem to call |
627 | it just in case after a fork. To make this easy, the function will fit in |
645 | it just in case after a fork. |
628 | quite nicely into a call to C<pthread_atfork>: |
|
|
629 | |
646 | |
|
|
647 | Example: Automate calling C<ev_loop_fork> on the default loop when |
|
|
648 | using pthreads. |
|
|
649 | |
|
|
650 | static void |
|
|
651 | post_fork_child (void) |
|
|
652 | { |
|
|
653 | ev_loop_fork (EV_DEFAULT); |
|
|
654 | } |
|
|
655 | |
|
|
656 | ... |
630 | pthread_atfork (0, 0, ev_default_fork); |
657 | pthread_atfork (0, 0, post_fork_child); |
631 | |
|
|
632 | =item ev_loop_fork (loop) |
|
|
633 | |
|
|
634 | Like C<ev_default_fork>, but acts on an event loop created by |
|
|
635 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
|
|
636 | after fork that you want to re-use in the child, and how you keep track of |
|
|
637 | them is entirely your own problem. |
|
|
638 | |
658 | |
639 | =item int ev_is_default_loop (loop) |
659 | =item int ev_is_default_loop (loop) |
640 | |
660 | |
641 | Returns true when the given loop is, in fact, the default loop, and false |
661 | Returns true when the given loop is, in fact, the default loop, and false |
642 | otherwise. |
662 | otherwise. |
643 | |
663 | |
644 | =item unsigned int ev_iteration (loop) |
664 | =item unsigned int ev_iteration (loop) |
645 | |
665 | |
646 | Returns the current iteration count for the loop, which is identical to |
666 | Returns the current iteration count for the event loop, which is identical |
647 | the number of times libev did poll for new events. It starts at C<0> and |
667 | to the number of times libev did poll for new events. It starts at C<0> |
648 | happily wraps around with enough iterations. |
668 | and happily wraps around with enough iterations. |
649 | |
669 | |
650 | This value can sometimes be useful as a generation counter of sorts (it |
670 | This value can sometimes be useful as a generation counter of sorts (it |
651 | "ticks" the number of loop iterations), as it roughly corresponds with |
671 | "ticks" the number of loop iterations), as it roughly corresponds with |
652 | C<ev_prepare> and C<ev_check> calls - and is incremented between the |
672 | C<ev_prepare> and C<ev_check> calls - and is incremented between the |
653 | prepare and check phases. |
673 | prepare and check phases. |
654 | |
674 | |
655 | =item unsigned int ev_depth (loop) |
675 | =item unsigned int ev_depth (loop) |
656 | |
676 | |
657 | Returns the number of times C<ev_loop> was entered minus the number of |
677 | Returns the number of times C<ev_run> was entered minus the number of |
658 | times C<ev_loop> was exited, in other words, the recursion depth. |
678 | times C<ev_run> was exited, in other words, the recursion depth. |
659 | |
679 | |
660 | Outside C<ev_loop>, this number is zero. In a callback, this number is |
680 | Outside C<ev_run>, this number is zero. In a callback, this number is |
661 | C<1>, unless C<ev_loop> was invoked recursively (or from another thread), |
681 | C<1>, unless C<ev_run> was invoked recursively (or from another thread), |
662 | in which case it is higher. |
682 | in which case it is higher. |
663 | |
683 | |
664 | Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread |
684 | Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread |
665 | etc.), doesn't count as "exit" - consider this as a hint to avoid such |
685 | etc.), doesn't count as "exit" - consider this as a hint to avoid such |
666 | ungentleman behaviour unless it's really convenient. |
686 | ungentleman-like behaviour unless it's really convenient. |
667 | |
687 | |
668 | =item unsigned int ev_backend (loop) |
688 | =item unsigned int ev_backend (loop) |
669 | |
689 | |
670 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
690 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
671 | use. |
691 | use. |
… | |
… | |
680 | |
700 | |
681 | =item ev_now_update (loop) |
701 | =item ev_now_update (loop) |
682 | |
702 | |
683 | Establishes the current time by querying the kernel, updating the time |
703 | Establishes the current time by querying the kernel, updating the time |
684 | returned by C<ev_now ()> in the progress. This is a costly operation and |
704 | returned by C<ev_now ()> in the progress. This is a costly operation and |
685 | is usually done automatically within C<ev_loop ()>. |
705 | is usually done automatically within C<ev_run ()>. |
686 | |
706 | |
687 | This function is rarely useful, but when some event callback runs for a |
707 | This function is rarely useful, but when some event callback runs for a |
688 | very long time without entering the event loop, updating libev's idea of |
708 | very long time without entering the event loop, updating libev's idea of |
689 | the current time is a good idea. |
709 | the current time is a good idea. |
690 | |
710 | |
… | |
… | |
692 | |
712 | |
693 | =item ev_suspend (loop) |
713 | =item ev_suspend (loop) |
694 | |
714 | |
695 | =item ev_resume (loop) |
715 | =item ev_resume (loop) |
696 | |
716 | |
697 | These two functions suspend and resume a loop, for use when the loop is |
717 | These two functions suspend and resume an event loop, for use when the |
698 | not used for a while and timeouts should not be processed. |
718 | loop is not used for a while and timeouts should not be processed. |
699 | |
719 | |
700 | A typical use case would be an interactive program such as a game: When |
720 | A typical use case would be an interactive program such as a game: When |
701 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
721 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
702 | would be best to handle timeouts as if no time had actually passed while |
722 | would be best to handle timeouts as if no time had actually passed while |
703 | the program was suspended. This can be achieved by calling C<ev_suspend> |
723 | the program was suspended. This can be achieved by calling C<ev_suspend> |
… | |
… | |
714 | without a previous call to C<ev_suspend>. |
734 | without a previous call to C<ev_suspend>. |
715 | |
735 | |
716 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
736 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
717 | event loop time (see C<ev_now_update>). |
737 | event loop time (see C<ev_now_update>). |
718 | |
738 | |
719 | =item ev_loop (loop, int flags) |
739 | =item ev_run (loop, int flags) |
720 | |
740 | |
721 | Finally, this is it, the event handler. This function usually is called |
741 | Finally, this is it, the event handler. This function usually is called |
722 | after you have initialised all your watchers and you want to start |
742 | after you have initialised all your watchers and you want to start |
723 | handling events. |
743 | handling events. It will ask the operating system for any new events, call |
|
|
744 | the watcher callbacks, an then repeat the whole process indefinitely: This |
|
|
745 | is why event loops are called I<loops>. |
724 | |
746 | |
725 | If the flags argument is specified as C<0>, it will not return until |
747 | If the flags argument is specified as C<0>, it will keep handling events |
726 | either no event watchers are active anymore or C<ev_unloop> was called. |
748 | until either no event watchers are active anymore or C<ev_break> was |
|
|
749 | called. |
727 | |
750 | |
728 | Please note that an explicit C<ev_unloop> is usually better than |
751 | Please note that an explicit C<ev_break> is usually better than |
729 | relying on all watchers to be stopped when deciding when a program has |
752 | relying on all watchers to be stopped when deciding when a program has |
730 | finished (especially in interactive programs), but having a program |
753 | finished (especially in interactive programs), but having a program |
731 | that automatically loops as long as it has to and no longer by virtue |
754 | that automatically loops as long as it has to and no longer by virtue |
732 | of relying on its watchers stopping correctly, that is truly a thing of |
755 | of relying on its watchers stopping correctly, that is truly a thing of |
733 | beauty. |
756 | beauty. |
734 | |
757 | |
735 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
758 | A flags value of C<EVRUN_NOWAIT> will look for new events, will handle |
736 | those events and any already outstanding ones, but will not block your |
759 | those events and any already outstanding ones, but will not wait and |
737 | process in case there are no events and will return after one iteration of |
760 | block your process in case there are no events and will return after one |
738 | the loop. |
761 | iteration of the loop. This is sometimes useful to poll and handle new |
|
|
762 | events while doing lengthy calculations, to keep the program responsive. |
739 | |
763 | |
740 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
764 | A flags value of C<EVRUN_ONCE> will look for new events (waiting if |
741 | necessary) and will handle those and any already outstanding ones. It |
765 | necessary) and will handle those and any already outstanding ones. It |
742 | will block your process until at least one new event arrives (which could |
766 | will block your process until at least one new event arrives (which could |
743 | be an event internal to libev itself, so there is no guarantee that a |
767 | be an event internal to libev itself, so there is no guarantee that a |
744 | user-registered callback will be called), and will return after one |
768 | user-registered callback will be called), and will return after one |
745 | iteration of the loop. |
769 | iteration of the loop. |
746 | |
770 | |
747 | This is useful if you are waiting for some external event in conjunction |
771 | This is useful if you are waiting for some external event in conjunction |
748 | with something not expressible using other libev watchers (i.e. "roll your |
772 | with something not expressible using other libev watchers (i.e. "roll your |
749 | own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
773 | own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
750 | usually a better approach for this kind of thing. |
774 | usually a better approach for this kind of thing. |
751 | |
775 | |
752 | Here are the gory details of what C<ev_loop> does: |
776 | Here are the gory details of what C<ev_run> does: |
753 | |
777 | |
|
|
778 | - Increment loop depth. |
|
|
779 | - Reset the ev_break status. |
754 | - Before the first iteration, call any pending watchers. |
780 | - Before the first iteration, call any pending watchers. |
|
|
781 | LOOP: |
755 | * If EVFLAG_FORKCHECK was used, check for a fork. |
782 | - If EVFLAG_FORKCHECK was used, check for a fork. |
756 | - If a fork was detected (by any means), queue and call all fork watchers. |
783 | - If a fork was detected (by any means), queue and call all fork watchers. |
757 | - Queue and call all prepare watchers. |
784 | - Queue and call all prepare watchers. |
|
|
785 | - If ev_break was called, goto FINISH. |
758 | - If we have been forked, detach and recreate the kernel state |
786 | - If we have been forked, detach and recreate the kernel state |
759 | as to not disturb the other process. |
787 | as to not disturb the other process. |
760 | - Update the kernel state with all outstanding changes. |
788 | - Update the kernel state with all outstanding changes. |
761 | - Update the "event loop time" (ev_now ()). |
789 | - Update the "event loop time" (ev_now ()). |
762 | - Calculate for how long to sleep or block, if at all |
790 | - Calculate for how long to sleep or block, if at all |
763 | (active idle watchers, EVLOOP_NONBLOCK or not having |
791 | (active idle watchers, EVRUN_NOWAIT or not having |
764 | any active watchers at all will result in not sleeping). |
792 | any active watchers at all will result in not sleeping). |
765 | - Sleep if the I/O and timer collect interval say so. |
793 | - Sleep if the I/O and timer collect interval say so. |
|
|
794 | - Increment loop iteration counter. |
766 | - Block the process, waiting for any events. |
795 | - Block the process, waiting for any events. |
767 | - Queue all outstanding I/O (fd) events. |
796 | - Queue all outstanding I/O (fd) events. |
768 | - Update the "event loop time" (ev_now ()), and do time jump adjustments. |
797 | - Update the "event loop time" (ev_now ()), and do time jump adjustments. |
769 | - Queue all expired timers. |
798 | - Queue all expired timers. |
770 | - Queue all expired periodics. |
799 | - Queue all expired periodics. |
771 | - Unless any events are pending now, queue all idle watchers. |
800 | - Queue all idle watchers with priority higher than that of pending events. |
772 | - Queue all check watchers. |
801 | - Queue all check watchers. |
773 | - Call all queued watchers in reverse order (i.e. check watchers first). |
802 | - 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 |
803 | Signals and child watchers are implemented as I/O watchers, and will |
775 | be handled here by queueing them when their watcher gets executed. |
804 | be handled here by queueing them when their watcher gets executed. |
776 | - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
805 | - If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
777 | were used, or there are no active watchers, return, otherwise |
806 | were used, or there are no active watchers, goto FINISH, otherwise |
778 | continue with step *. |
807 | continue with step LOOP. |
|
|
808 | FINISH: |
|
|
809 | - Reset the ev_break status iff it was EVBREAK_ONE. |
|
|
810 | - Decrement the loop depth. |
|
|
811 | - Return. |
779 | |
812 | |
780 | Example: Queue some jobs and then loop until no events are outstanding |
813 | Example: Queue some jobs and then loop until no events are outstanding |
781 | anymore. |
814 | anymore. |
782 | |
815 | |
783 | ... queue jobs here, make sure they register event watchers as long |
816 | ... 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..) |
817 | ... as they still have work to do (even an idle watcher will do..) |
785 | ev_loop (my_loop, 0); |
818 | ev_run (my_loop, 0); |
786 | ... jobs done or somebody called unloop. yeah! |
819 | ... jobs done or somebody called unloop. yeah! |
787 | |
820 | |
788 | =item ev_unloop (loop, how) |
821 | =item ev_break (loop, how) |
789 | |
822 | |
790 | Can be used to make a call to C<ev_loop> return early (but only after it |
823 | Can be used to make a call to C<ev_run> return early (but only after it |
791 | has processed all outstanding events). The C<how> argument must be either |
824 | has processed all outstanding events). The C<how> argument must be either |
792 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
825 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
793 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
826 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
794 | |
827 | |
795 | This "unloop state" will be cleared when entering C<ev_loop> again. |
828 | This "break state" will be cleared when entering C<ev_run> again. |
796 | |
829 | |
797 | It is safe to call C<ev_unloop> from outside any C<ev_loop> calls. |
830 | It is safe to call C<ev_break> from outside any C<ev_run> calls, too. |
798 | |
831 | |
799 | =item ev_ref (loop) |
832 | =item ev_ref (loop) |
800 | |
833 | |
801 | =item ev_unref (loop) |
834 | =item ev_unref (loop) |
802 | |
835 | |
803 | Ref/unref can be used to add or remove a reference count on the event |
836 | Ref/unref can be used to add or remove a reference count on the event |
804 | loop: Every watcher keeps one reference, and as long as the reference |
837 | loop: Every watcher keeps one reference, and as long as the reference |
805 | count is nonzero, C<ev_loop> will not return on its own. |
838 | count is nonzero, C<ev_run> will not return on its own. |
806 | |
839 | |
807 | This is useful when you have a watcher that you never intend to |
840 | This is useful when you have a watcher that you never intend to |
808 | unregister, but that nevertheless should not keep C<ev_loop> from |
841 | unregister, but that nevertheless should not keep C<ev_run> from |
809 | returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> |
842 | returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> |
810 | before stopping it. |
843 | before stopping it. |
811 | |
844 | |
812 | As an example, libev itself uses this for its internal signal pipe: It |
845 | As an example, libev itself uses this for its internal signal pipe: It |
813 | is not visible to the libev user and should not keep C<ev_loop> from |
846 | is not visible to the libev user and should not keep C<ev_run> from |
814 | exiting if no event watchers registered by it are active. It is also an |
847 | exiting if no event watchers registered by it are active. It is also an |
815 | excellent way to do this for generic recurring timers or from within |
848 | excellent way to do this for generic recurring timers or from within |
816 | third-party libraries. Just remember to I<unref after start> and I<ref |
849 | third-party libraries. Just remember to I<unref after start> and I<ref |
817 | before stop> (but only if the watcher wasn't active before, or was active |
850 | before stop> (but only if the watcher wasn't active before, or was active |
818 | before, respectively. Note also that libev might stop watchers itself |
851 | before, respectively. Note also that libev might stop watchers itself |
819 | (e.g. non-repeating timers) in which case you have to C<ev_ref> |
852 | (e.g. non-repeating timers) in which case you have to C<ev_ref> |
820 | in the callback). |
853 | in the callback). |
821 | |
854 | |
822 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
855 | Example: Create a signal watcher, but keep it from keeping C<ev_run> |
823 | running when nothing else is active. |
856 | running when nothing else is active. |
824 | |
857 | |
825 | ev_signal exitsig; |
858 | ev_signal exitsig; |
826 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
859 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
827 | ev_signal_start (loop, &exitsig); |
860 | ev_signal_start (loop, &exitsig); |
… | |
… | |
890 | ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
923 | ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
891 | |
924 | |
892 | =item ev_invoke_pending (loop) |
925 | =item ev_invoke_pending (loop) |
893 | |
926 | |
894 | This call will simply invoke all pending watchers while resetting their |
927 | This call will simply invoke all pending watchers while resetting their |
895 | pending state. Normally, C<ev_loop> does this automatically when required, |
928 | pending state. Normally, C<ev_run> does this automatically when required, |
896 | but when overriding the invoke callback this call comes handy. |
929 | but when overriding the invoke callback this call comes handy. This |
|
|
930 | function can be invoked from a watcher - this can be useful for example |
|
|
931 | when you want to do some lengthy calculation and want to pass further |
|
|
932 | event handling to another thread (you still have to make sure only one |
|
|
933 | thread executes within C<ev_invoke_pending> or C<ev_run> of course). |
897 | |
934 | |
898 | =item int ev_pending_count (loop) |
935 | =item int ev_pending_count (loop) |
899 | |
936 | |
900 | Returns the number of pending watchers - zero indicates that no watchers |
937 | Returns the number of pending watchers - zero indicates that no watchers |
901 | are pending. |
938 | are pending. |
902 | |
939 | |
903 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
940 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
904 | |
941 | |
905 | This overrides the invoke pending functionality of the loop: Instead of |
942 | This overrides the invoke pending functionality of the loop: Instead of |
906 | invoking all pending watchers when there are any, C<ev_loop> will call |
943 | invoking all pending watchers when there are any, C<ev_run> will call |
907 | this callback instead. This is useful, for example, when you want to |
944 | this callback instead. This is useful, for example, when you want to |
908 | invoke the actual watchers inside another context (another thread etc.). |
945 | invoke the actual watchers inside another context (another thread etc.). |
909 | |
946 | |
910 | If you want to reset the callback, use C<ev_invoke_pending> as new |
947 | If you want to reset the callback, use C<ev_invoke_pending> as new |
911 | callback. |
948 | callback. |
… | |
… | |
914 | |
951 | |
915 | Sometimes you want to share the same loop between multiple threads. This |
952 | Sometimes you want to share the same loop between multiple threads. This |
916 | can be done relatively simply by putting mutex_lock/unlock calls around |
953 | can be done relatively simply by putting mutex_lock/unlock calls around |
917 | each call to a libev function. |
954 | each call to a libev function. |
918 | |
955 | |
919 | However, C<ev_loop> can run an indefinite time, so it is not feasible to |
956 | However, C<ev_run> can run an indefinite time, so it is not feasible |
920 | wait for it to return. One way around this is to wake up the loop via |
957 | to wait for it to return. One way around this is to wake up the event |
921 | C<ev_unloop> and C<av_async_send>, another way is to set these I<release> |
958 | loop via C<ev_break> and C<av_async_send>, another way is to set these |
922 | and I<acquire> callbacks on the loop. |
959 | I<release> and I<acquire> callbacks on the loop. |
923 | |
960 | |
924 | When set, then C<release> will be called just before the thread is |
961 | When set, then C<release> will be called just before the thread is |
925 | suspended waiting for new events, and C<acquire> is called just |
962 | suspended waiting for new events, and C<acquire> is called just |
926 | afterwards. |
963 | afterwards. |
927 | |
964 | |
… | |
… | |
930 | |
967 | |
931 | While event loop modifications are allowed between invocations of |
968 | While event loop modifications are allowed between invocations of |
932 | C<release> and C<acquire> (that's their only purpose after all), no |
969 | C<release> and C<acquire> (that's their only purpose after all), no |
933 | modifications done will affect the event loop, i.e. adding watchers will |
970 | modifications done will affect the event loop, i.e. adding watchers will |
934 | have no effect on the set of file descriptors being watched, or the time |
971 | have no effect on the set of file descriptors being watched, or the time |
935 | waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it |
972 | waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it |
936 | to take note of any changes you made. |
973 | to take note of any changes you made. |
937 | |
974 | |
938 | In theory, threads executing C<ev_loop> will be async-cancel safe between |
975 | In theory, threads executing C<ev_run> will be async-cancel safe between |
939 | invocations of C<release> and C<acquire>. |
976 | invocations of C<release> and C<acquire>. |
940 | |
977 | |
941 | See also the locking example in the C<THREADS> section later in this |
978 | See also the locking example in the C<THREADS> section later in this |
942 | document. |
979 | document. |
943 | |
980 | |
… | |
… | |
952 | These two functions can be used to associate arbitrary data with a loop, |
989 | These two functions can be used to associate arbitrary data with a loop, |
953 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
990 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
954 | C<acquire> callbacks described above, but of course can be (ab-)used for |
991 | C<acquire> callbacks described above, but of course can be (ab-)used for |
955 | any other purpose as well. |
992 | any other purpose as well. |
956 | |
993 | |
957 | =item ev_loop_verify (loop) |
994 | =item ev_verify (loop) |
958 | |
995 | |
959 | This function only does something when C<EV_VERIFY> support has been |
996 | This function only does something when C<EV_VERIFY> support has been |
960 | compiled in, which is the default for non-minimal builds. It tries to go |
997 | compiled in, which is the default for non-minimal builds. It tries to go |
961 | through all internal structures and checks them for validity. If anything |
998 | through all internal structures and checks them for validity. If anything |
962 | is found to be inconsistent, it will print an error message to standard |
999 | is found to be inconsistent, it will print an error message to standard |
… | |
… | |
973 | |
1010 | |
974 | In the following description, uppercase C<TYPE> in names stands for the |
1011 | In the following description, uppercase C<TYPE> in names stands for the |
975 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
1012 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
976 | watchers and C<ev_io_start> for I/O watchers. |
1013 | watchers and C<ev_io_start> for I/O watchers. |
977 | |
1014 | |
978 | A watcher is a structure that you create and register to record your |
1015 | A watcher is an opaque structure that you allocate and register to record |
979 | interest in some event. For instance, if you want to wait for STDIN to |
1016 | your interest in some event. To make a concrete example, imagine you want |
980 | become readable, you would create an C<ev_io> watcher for that: |
1017 | to wait for STDIN to become readable, you would create an C<ev_io> watcher |
|
|
1018 | for that: |
981 | |
1019 | |
982 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
1020 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
983 | { |
1021 | { |
984 | ev_io_stop (w); |
1022 | ev_io_stop (w); |
985 | ev_unloop (loop, EVUNLOOP_ALL); |
1023 | ev_break (loop, EVBREAK_ALL); |
986 | } |
1024 | } |
987 | |
1025 | |
988 | struct ev_loop *loop = ev_default_loop (0); |
1026 | struct ev_loop *loop = ev_default_loop (0); |
989 | |
1027 | |
990 | ev_io stdin_watcher; |
1028 | ev_io stdin_watcher; |
991 | |
1029 | |
992 | ev_init (&stdin_watcher, my_cb); |
1030 | ev_init (&stdin_watcher, my_cb); |
993 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
1031 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
994 | ev_io_start (loop, &stdin_watcher); |
1032 | ev_io_start (loop, &stdin_watcher); |
995 | |
1033 | |
996 | ev_loop (loop, 0); |
1034 | ev_run (loop, 0); |
997 | |
1035 | |
998 | As you can see, you are responsible for allocating the memory for your |
1036 | As you can see, you are responsible for allocating the memory for your |
999 | watcher structures (and it is I<usually> a bad idea to do this on the |
1037 | watcher structures (and it is I<usually> a bad idea to do this on the |
1000 | stack). |
1038 | stack). |
1001 | |
1039 | |
1002 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1040 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1003 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1041 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1004 | |
1042 | |
1005 | Each watcher structure must be initialised by a call to C<ev_init |
1043 | Each watcher structure must be initialised by a call to C<ev_init (watcher |
1006 | (watcher *, callback)>, which expects a callback to be provided. This |
1044 | *, callback)>, which expects a callback to be provided. This callback is |
1007 | callback gets invoked each time the event occurs (or, in the case of I/O |
1045 | invoked each time the event occurs (or, in the case of I/O watchers, each |
1008 | watchers, each time the event loop detects that the file descriptor given |
1046 | time the event loop detects that the file descriptor given is readable |
1009 | is readable and/or writable). |
1047 | and/or writable). |
1010 | |
1048 | |
1011 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1049 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1012 | macro to configure it, with arguments specific to the watcher type. There |
1050 | macro to configure it, with arguments specific to the watcher type. There |
1013 | is also a macro to combine initialisation and setting in one call: C<< |
1051 | is also a macro to combine initialisation and setting in one call: C<< |
1014 | ev_TYPE_init (watcher *, callback, ...) >>. |
1052 | ev_TYPE_init (watcher *, callback, ...) >>. |
… | |
… | |
1065 | |
1103 | |
1066 | =item C<EV_PREPARE> |
1104 | =item C<EV_PREPARE> |
1067 | |
1105 | |
1068 | =item C<EV_CHECK> |
1106 | =item C<EV_CHECK> |
1069 | |
1107 | |
1070 | All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts |
1108 | All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts |
1071 | to gather new events, and all C<ev_check> watchers are invoked just after |
1109 | to gather new events, and all C<ev_check> watchers are invoked just after |
1072 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
1110 | C<ev_run> has gathered them, but before it invokes any callbacks for any |
1073 | received events. Callbacks of both watcher types can start and stop as |
1111 | received events. Callbacks of both watcher types can start and stop as |
1074 | many watchers as they want, and all of them will be taken into account |
1112 | many 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 |
1113 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
1076 | C<ev_loop> from blocking). |
1114 | C<ev_run> from blocking). |
1077 | |
1115 | |
1078 | =item C<EV_EMBED> |
1116 | =item C<EV_EMBED> |
1079 | |
1117 | |
1080 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1118 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1081 | |
1119 | |
1082 | =item C<EV_FORK> |
1120 | =item C<EV_FORK> |
1083 | |
1121 | |
1084 | The event loop has been resumed in the child process after fork (see |
1122 | The event loop has been resumed in the child process after fork (see |
1085 | C<ev_fork>). |
1123 | C<ev_fork>). |
|
|
1124 | |
|
|
1125 | =item C<EV_CLEANUP> |
|
|
1126 | |
|
|
1127 | The event loop is about to be destroyed (see C<ev_cleanup>). |
1086 | |
1128 | |
1087 | =item C<EV_ASYNC> |
1129 | =item C<EV_ASYNC> |
1088 | |
1130 | |
1089 | The given async watcher has been asynchronously notified (see C<ev_async>). |
1131 | The given async watcher has been asynchronously notified (see C<ev_async>). |
1090 | |
1132 | |
… | |
… | |
1262 | |
1304 | |
1263 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1305 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1264 | functions that do not need a watcher. |
1306 | functions that do not need a watcher. |
1265 | |
1307 | |
1266 | =back |
1308 | =back |
1267 | |
|
|
1268 | |
1309 | |
1269 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
1310 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
1270 | |
1311 | |
1271 | Each watcher has, by default, a member C<void *data> that you can change |
1312 | Each watcher has, by default, a member C<void *data> that you can change |
1272 | and read at any time: libev will completely ignore it. This can be used |
1313 | and read at any time: libev will completely ignore it. This can be used |
… | |
… | |
1328 | t2_cb (EV_P_ ev_timer *w, int revents) |
1369 | t2_cb (EV_P_ ev_timer *w, int revents) |
1329 | { |
1370 | { |
1330 | struct my_biggy big = (struct my_biggy *) |
1371 | struct my_biggy big = (struct my_biggy *) |
1331 | (((char *)w) - offsetof (struct my_biggy, t2)); |
1372 | (((char *)w) - offsetof (struct my_biggy, t2)); |
1332 | } |
1373 | } |
|
|
1374 | |
|
|
1375 | =head2 WATCHER STATES |
|
|
1376 | |
|
|
1377 | There are various watcher states mentioned throughout this manual - |
|
|
1378 | active, pending and so on. In this section these states and the rules to |
|
|
1379 | transition between them will be described in more detail - and while these |
|
|
1380 | rules might look complicated, they usually do "the right thing". |
|
|
1381 | |
|
|
1382 | =over 4 |
|
|
1383 | |
|
|
1384 | =item initialiased |
|
|
1385 | |
|
|
1386 | Before a watcher can be registered with the event looop it has to be |
|
|
1387 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
|
|
1388 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
|
|
1389 | |
|
|
1390 | In this state it is simply some block of memory that is suitable for use |
|
|
1391 | in an event loop. It can be moved around, freed, reused etc. at will. |
|
|
1392 | |
|
|
1393 | =item started/running/active |
|
|
1394 | |
|
|
1395 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
|
|
1396 | property of the event loop, and is actively waiting for events. While in |
|
|
1397 | this state it cannot be accessed (except in a few documented ways), moved, |
|
|
1398 | freed or anything else - the only legal thing is to keep a pointer to it, |
|
|
1399 | and call libev functions on it that are documented to work on active watchers. |
|
|
1400 | |
|
|
1401 | =item pending |
|
|
1402 | |
|
|
1403 | If a watcher is active and libev determines that an event it is interested |
|
|
1404 | in has occurred (such as a timer expiring), it will become pending. It will |
|
|
1405 | stay in this pending state until either it is stopped or its callback is |
|
|
1406 | about to be invoked, so it is not normally pending inside the watcher |
|
|
1407 | callback. |
|
|
1408 | |
|
|
1409 | The watcher might or might not be active while it is pending (for example, |
|
|
1410 | an expired non-repeating timer can be pending but no longer active). If it |
|
|
1411 | is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>), |
|
|
1412 | but it is still property of the event loop at this time, so cannot be |
|
|
1413 | moved, freed or reused. And if it is active the rules described in the |
|
|
1414 | previous item still apply. |
|
|
1415 | |
|
|
1416 | It is also possible to feed an event on a watcher that is not active (e.g. |
|
|
1417 | via C<ev_feed_event>), in which case it becomes pending without being |
|
|
1418 | active. |
|
|
1419 | |
|
|
1420 | =item stopped |
|
|
1421 | |
|
|
1422 | A watcher can be stopped implicitly by libev (in which case it might still |
|
|
1423 | be pending), or explicitly by calling its C<ev_TYPE_stop> function. The |
|
|
1424 | latter will clear any pending state the watcher might be in, regardless |
|
|
1425 | of whether it was active or not, so stopping a watcher explicitly before |
|
|
1426 | freeing it is often a good idea. |
|
|
1427 | |
|
|
1428 | While stopped (and not pending) the watcher is essentially in the |
|
|
1429 | initialised state, that is it can be reused, moved, modified in any way |
|
|
1430 | you wish. |
|
|
1431 | |
|
|
1432 | =back |
1333 | |
1433 | |
1334 | =head2 WATCHER PRIORITY MODELS |
1434 | =head2 WATCHER PRIORITY MODELS |
1335 | |
1435 | |
1336 | Many event loops support I<watcher priorities>, which are usually small |
1436 | Many event loops support I<watcher priorities>, which are usually small |
1337 | integers that influence the ordering of event callback invocation |
1437 | integers that influence the ordering of event callback invocation |
… | |
… | |
1622 | ... |
1722 | ... |
1623 | struct ev_loop *loop = ev_default_init (0); |
1723 | struct ev_loop *loop = ev_default_init (0); |
1624 | ev_io stdin_readable; |
1724 | ev_io stdin_readable; |
1625 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1725 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1626 | ev_io_start (loop, &stdin_readable); |
1726 | ev_io_start (loop, &stdin_readable); |
1627 | ev_loop (loop, 0); |
1727 | ev_run (loop, 0); |
1628 | |
1728 | |
1629 | |
1729 | |
1630 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1730 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1631 | |
1731 | |
1632 | Timer watchers are simple relative timers that generate an event after a |
1732 | Timer watchers are simple relative timers that generate an event after a |
… | |
… | |
1641 | The callback is guaranteed to be invoked only I<after> its timeout has |
1741 | The callback is guaranteed to be invoked only I<after> its timeout has |
1642 | passed (not I<at>, so on systems with very low-resolution clocks this |
1742 | passed (not I<at>, so on systems with very low-resolution clocks this |
1643 | might introduce a small delay). If multiple timers become ready during the |
1743 | might introduce a small delay). If multiple timers become ready during the |
1644 | same loop iteration then the ones with earlier time-out values are invoked |
1744 | same loop iteration then the ones with earlier time-out values are invoked |
1645 | before ones of the same priority with later time-out values (but this is |
1745 | before ones of the same priority with later time-out values (but this is |
1646 | no longer true when a callback calls C<ev_loop> recursively). |
1746 | no longer true when a callback calls C<ev_run> recursively). |
1647 | |
1747 | |
1648 | =head3 Be smart about timeouts |
1748 | =head3 Be smart about timeouts |
1649 | |
1749 | |
1650 | Many real-world problems involve some kind of timeout, usually for error |
1750 | Many real-world problems involve some kind of timeout, usually for error |
1651 | recovery. A typical example is an HTTP request - if the other side hangs, |
1751 | recovery. A typical example is an HTTP request - if the other side hangs, |
… | |
… | |
1822 | |
1922 | |
1823 | =head3 The special problem of time updates |
1923 | =head3 The special problem of time updates |
1824 | |
1924 | |
1825 | Establishing the current time is a costly operation (it usually takes at |
1925 | Establishing the current time is a costly operation (it usually takes at |
1826 | least two system calls): EV therefore updates its idea of the current |
1926 | least two system calls): EV therefore updates its idea of the current |
1827 | time only before and after C<ev_loop> collects new events, which causes a |
1927 | time only before and after C<ev_run> collects new events, which causes a |
1828 | growing difference between C<ev_now ()> and C<ev_time ()> when handling |
1928 | growing difference between C<ev_now ()> and C<ev_time ()> when handling |
1829 | lots of events in one iteration. |
1929 | lots of events in one iteration. |
1830 | |
1930 | |
1831 | The relative timeouts are calculated relative to the C<ev_now ()> |
1931 | The relative timeouts are calculated relative to the C<ev_now ()> |
1832 | time. This is usually the right thing as this timestamp refers to the time |
1932 | time. This is usually the right thing as this timestamp refers to the time |
… | |
… | |
1949 | } |
2049 | } |
1950 | |
2050 | |
1951 | ev_timer mytimer; |
2051 | ev_timer mytimer; |
1952 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
2052 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1953 | ev_timer_again (&mytimer); /* start timer */ |
2053 | ev_timer_again (&mytimer); /* start timer */ |
1954 | ev_loop (loop, 0); |
2054 | ev_run (loop, 0); |
1955 | |
2055 | |
1956 | // and in some piece of code that gets executed on any "activity": |
2056 | // and in some piece of code that gets executed on any "activity": |
1957 | // reset the timeout to start ticking again at 10 seconds |
2057 | // reset the timeout to start ticking again at 10 seconds |
1958 | ev_timer_again (&mytimer); |
2058 | ev_timer_again (&mytimer); |
1959 | |
2059 | |
… | |
… | |
1985 | |
2085 | |
1986 | As with timers, the callback is guaranteed to be invoked only when the |
2086 | As with timers, the callback is guaranteed to be invoked only when the |
1987 | point in time where it is supposed to trigger has passed. If multiple |
2087 | point in time where it is supposed to trigger has passed. If multiple |
1988 | timers become ready during the same loop iteration then the ones with |
2088 | timers become ready during the same loop iteration then the ones with |
1989 | earlier time-out values are invoked before ones with later time-out values |
2089 | earlier 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). |
2090 | (but this is no longer true when a callback calls C<ev_run> recursively). |
1991 | |
2091 | |
1992 | =head3 Watcher-Specific Functions and Data Members |
2092 | =head3 Watcher-Specific Functions and Data Members |
1993 | |
2093 | |
1994 | =over 4 |
2094 | =over 4 |
1995 | |
2095 | |
… | |
… | |
2233 | Example: Try to exit cleanly on SIGINT. |
2333 | Example: Try to exit cleanly on SIGINT. |
2234 | |
2334 | |
2235 | static void |
2335 | static void |
2236 | sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2336 | sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2237 | { |
2337 | { |
2238 | ev_unloop (loop, EVUNLOOP_ALL); |
2338 | ev_break (loop, EVBREAK_ALL); |
2239 | } |
2339 | } |
2240 | |
2340 | |
2241 | ev_signal signal_watcher; |
2341 | ev_signal signal_watcher; |
2242 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2342 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2243 | ev_signal_start (loop, &signal_watcher); |
2343 | ev_signal_start (loop, &signal_watcher); |
… | |
… | |
2629 | |
2729 | |
2630 | Prepare and check watchers are usually (but not always) used in pairs: |
2730 | Prepare and check watchers are usually (but not always) used in pairs: |
2631 | prepare watchers get invoked before the process blocks and check watchers |
2731 | prepare watchers get invoked before the process blocks and check watchers |
2632 | afterwards. |
2732 | afterwards. |
2633 | |
2733 | |
2634 | You I<must not> call C<ev_loop> or similar functions that enter |
2734 | You I<must not> call C<ev_run> or similar functions that enter |
2635 | the current event loop from either C<ev_prepare> or C<ev_check> |
2735 | the current event loop from either C<ev_prepare> or C<ev_check> |
2636 | watchers. Other loops than the current one are fine, however. The |
2736 | watchers. Other loops than the current one are fine, however. The |
2637 | rationale behind this is that you do not need to check for recursion in |
2737 | rationale behind this is that you do not need to check for recursion in |
2638 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2738 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2639 | C<ev_check> so if you have one watcher of each kind they will always be |
2739 | C<ev_check> so if you have one watcher of each kind they will always be |
… | |
… | |
2807 | |
2907 | |
2808 | if (timeout >= 0) |
2908 | if (timeout >= 0) |
2809 | // create/start timer |
2909 | // create/start timer |
2810 | |
2910 | |
2811 | // poll |
2911 | // poll |
2812 | ev_loop (EV_A_ 0); |
2912 | ev_run (EV_A_ 0); |
2813 | |
2913 | |
2814 | // stop timer again |
2914 | // stop timer again |
2815 | if (timeout >= 0) |
2915 | if (timeout >= 0) |
2816 | ev_timer_stop (EV_A_ &to); |
2916 | ev_timer_stop (EV_A_ &to); |
2817 | |
2917 | |
… | |
… | |
2895 | if you do not want that, you need to temporarily stop the embed watcher). |
2995 | if you do not want that, you need to temporarily stop the embed watcher). |
2896 | |
2996 | |
2897 | =item ev_embed_sweep (loop, ev_embed *) |
2997 | =item ev_embed_sweep (loop, ev_embed *) |
2898 | |
2998 | |
2899 | Make a single, non-blocking sweep over the embedded loop. This works |
2999 | Make a single, non-blocking sweep over the embedded loop. This works |
2900 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
3000 | similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most |
2901 | appropriate way for embedded loops. |
3001 | appropriate way for embedded loops. |
2902 | |
3002 | |
2903 | =item struct ev_loop *other [read-only] |
3003 | =item struct ev_loop *other [read-only] |
2904 | |
3004 | |
2905 | The embedded event loop. |
3005 | The embedded event loop. |
… | |
… | |
2991 | disadvantage of having to use multiple event loops (which do not support |
3091 | disadvantage of having to use multiple event loops (which do not support |
2992 | signal watchers). |
3092 | signal watchers). |
2993 | |
3093 | |
2994 | When this is not possible, or you want to use the default loop for |
3094 | When this is not possible, or you want to use the default loop for |
2995 | other reasons, then in the process that wants to start "fresh", call |
3095 | other reasons, then in the process that wants to start "fresh", call |
2996 | C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying |
3096 | C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>. |
2997 | the default loop will "orphan" (not stop) all registered watchers, so you |
3097 | Destroying the default loop will "orphan" (not stop) all registered |
2998 | have to be careful not to execute code that modifies those watchers. Note |
3098 | watchers, so you have to be careful not to execute code that modifies |
2999 | also that in that case, you have to re-register any signal watchers. |
3099 | those watchers. Note also that in that case, you have to re-register any |
|
|
3100 | signal watchers. |
3000 | |
3101 | |
3001 | =head3 Watcher-Specific Functions and Data Members |
3102 | =head3 Watcher-Specific Functions and Data Members |
3002 | |
3103 | |
3003 | =over 4 |
3104 | =over 4 |
3004 | |
3105 | |
3005 | =item ev_fork_init (ev_signal *, callback) |
3106 | =item ev_fork_init (ev_fork *, callback) |
3006 | |
3107 | |
3007 | Initialises and configures the fork watcher - it has no parameters of any |
3108 | Initialises and configures the fork watcher - it has no parameters of any |
3008 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
3109 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
3009 | believe me. |
3110 | really. |
3010 | |
3111 | |
3011 | =back |
3112 | =back |
3012 | |
3113 | |
3013 | |
3114 | |
|
|
3115 | =head2 C<ev_cleanup> - even the best things end |
|
|
3116 | |
|
|
3117 | Cleanup watchers are called just before the event loop is being destroyed |
|
|
3118 | by a call to C<ev_loop_destroy>. |
|
|
3119 | |
|
|
3120 | While there is no guarantee that the event loop gets destroyed, cleanup |
|
|
3121 | watchers provide a convenient method to install cleanup hooks for your |
|
|
3122 | program, worker threads and so on - you just to make sure to destroy the |
|
|
3123 | loop when you want them to be invoked. |
|
|
3124 | |
|
|
3125 | Cleanup watchers are invoked in the same way as any other watcher. Unlike |
|
|
3126 | all other watchers, they do not keep a reference to the event loop (which |
|
|
3127 | makes a lot of sense if you think about it). Like all other watchers, you |
|
|
3128 | can call libev functions in the callback, except C<ev_cleanup_start>. |
|
|
3129 | |
|
|
3130 | =head3 Watcher-Specific Functions and Data Members |
|
|
3131 | |
|
|
3132 | =over 4 |
|
|
3133 | |
|
|
3134 | =item ev_cleanup_init (ev_cleanup *, callback) |
|
|
3135 | |
|
|
3136 | Initialises and configures the cleanup watcher - it has no parameters of |
|
|
3137 | any kind. There is a C<ev_cleanup_set> macro, but using it is utterly |
|
|
3138 | pointless, I assure you. |
|
|
3139 | |
|
|
3140 | =back |
|
|
3141 | |
|
|
3142 | Example: Register an atexit handler to destroy the default loop, so any |
|
|
3143 | cleanup functions are called. |
|
|
3144 | |
|
|
3145 | static void |
|
|
3146 | program_exits (void) |
|
|
3147 | { |
|
|
3148 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
3149 | } |
|
|
3150 | |
|
|
3151 | ... |
|
|
3152 | atexit (program_exits); |
|
|
3153 | |
|
|
3154 | |
3014 | =head2 C<ev_async> - how to wake up an event loop |
3155 | =head2 C<ev_async> - how to wake up an event loop |
3015 | |
3156 | |
3016 | In general, you cannot use an C<ev_loop> from multiple threads or other |
3157 | In general, you cannot use an C<ev_run> from multiple threads or other |
3017 | asynchronous sources such as signal handlers (as opposed to multiple event |
3158 | asynchronous sources such as signal handlers (as opposed to multiple event |
3018 | loops - those are of course safe to use in different threads). |
3159 | loops - those are of course safe to use in different threads). |
3019 | |
3160 | |
3020 | Sometimes, however, you need to wake up an event loop you do not control, |
3161 | Sometimes, however, you need to wake up an event loop you do not control, |
3021 | for example because it belongs to another thread. This is what C<ev_async> |
3162 | for example because it belongs to another thread. This is what C<ev_async> |
… | |
… | |
3389 | Associates a different C<struct ev_loop> with this watcher. You can only |
3530 | Associates a different C<struct ev_loop> with this watcher. You can only |
3390 | do this when the watcher is inactive (and not pending either). |
3531 | do this when the watcher is inactive (and not pending either). |
3391 | |
3532 | |
3392 | =item w->set ([arguments]) |
3533 | =item w->set ([arguments]) |
3393 | |
3534 | |
3394 | Basically the same as C<ev_TYPE_set>, with the same arguments. Must be |
3535 | Basically the same as C<ev_TYPE_set>, with the same arguments. Either this |
3395 | called at least once. Unlike the C counterpart, an active watcher gets |
3536 | method or a suitable start method must be called at least once. Unlike the |
3396 | automatically stopped and restarted when reconfiguring it with this |
3537 | C counterpart, an active watcher gets automatically stopped and restarted |
3397 | method. |
3538 | when reconfiguring it with this method. |
3398 | |
3539 | |
3399 | =item w->start () |
3540 | =item w->start () |
3400 | |
3541 | |
3401 | Starts the watcher. Note that there is no C<loop> argument, as the |
3542 | Starts the watcher. Note that there is no C<loop> argument, as the |
3402 | constructor already stores the event loop. |
3543 | constructor already stores the event loop. |
3403 | |
3544 | |
|
|
3545 | =item w->start ([arguments]) |
|
|
3546 | |
|
|
3547 | Instead of calling C<set> and C<start> methods separately, it is often |
|
|
3548 | convenient to wrap them in one call. Uses the same type of arguments as |
|
|
3549 | the configure C<set> method of the watcher. |
|
|
3550 | |
3404 | =item w->stop () |
3551 | =item w->stop () |
3405 | |
3552 | |
3406 | Stops the watcher if it is active. Again, no C<loop> argument. |
3553 | Stops the watcher if it is active. Again, no C<loop> argument. |
3407 | |
3554 | |
3408 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
3555 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
… | |
… | |
3420 | |
3567 | |
3421 | =back |
3568 | =back |
3422 | |
3569 | |
3423 | =back |
3570 | =back |
3424 | |
3571 | |
3425 | Example: Define a class with an IO and idle watcher, start one of them in |
3572 | Example: Define a class with two I/O and idle watchers, start the I/O |
3426 | the constructor. |
3573 | watchers in the constructor. |
3427 | |
3574 | |
3428 | class myclass |
3575 | class myclass |
3429 | { |
3576 | { |
3430 | ev::io io ; void io_cb (ev::io &w, int revents); |
3577 | ev::io io ; void io_cb (ev::io &w, int revents); |
|
|
3578 | ev::io2 io2 ; void io2_cb (ev::io &w, int revents); |
3431 | ev::idle idle; void idle_cb (ev::idle &w, int revents); |
3579 | ev::idle idle; void idle_cb (ev::idle &w, int revents); |
3432 | |
3580 | |
3433 | myclass (int fd) |
3581 | myclass (int fd) |
3434 | { |
3582 | { |
3435 | io .set <myclass, &myclass::io_cb > (this); |
3583 | io .set <myclass, &myclass::io_cb > (this); |
|
|
3584 | io2 .set <myclass, &myclass::io2_cb > (this); |
3436 | idle.set <myclass, &myclass::idle_cb> (this); |
3585 | idle.set <myclass, &myclass::idle_cb> (this); |
3437 | |
3586 | |
3438 | io.start (fd, ev::READ); |
3587 | io.set (fd, ev::WRITE); // configure the watcher |
|
|
3588 | io.start (); // start it whenever convenient |
|
|
3589 | |
|
|
3590 | io2.start (fd, ev::READ); // set + start in one call |
3439 | } |
3591 | } |
3440 | }; |
3592 | }; |
3441 | |
3593 | |
3442 | |
3594 | |
3443 | =head1 OTHER LANGUAGE BINDINGS |
3595 | =head1 OTHER LANGUAGE BINDINGS |
… | |
… | |
3517 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
3669 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
3518 | C<EV_A_> is used when other arguments are following. Example: |
3670 | C<EV_A_> is used when other arguments are following. Example: |
3519 | |
3671 | |
3520 | ev_unref (EV_A); |
3672 | ev_unref (EV_A); |
3521 | ev_timer_add (EV_A_ watcher); |
3673 | ev_timer_add (EV_A_ watcher); |
3522 | ev_loop (EV_A_ 0); |
3674 | ev_run (EV_A_ 0); |
3523 | |
3675 | |
3524 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
3676 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
3525 | which is often provided by the following macro. |
3677 | which is often provided by the following macro. |
3526 | |
3678 | |
3527 | =item C<EV_P>, C<EV_P_> |
3679 | =item C<EV_P>, C<EV_P_> |
… | |
… | |
3567 | } |
3719 | } |
3568 | |
3720 | |
3569 | ev_check check; |
3721 | ev_check check; |
3570 | ev_check_init (&check, check_cb); |
3722 | ev_check_init (&check, check_cb); |
3571 | ev_check_start (EV_DEFAULT_ &check); |
3723 | ev_check_start (EV_DEFAULT_ &check); |
3572 | ev_loop (EV_DEFAULT_ 0); |
3724 | ev_run (EV_DEFAULT_ 0); |
3573 | |
3725 | |
3574 | =head1 EMBEDDING |
3726 | =head1 EMBEDDING |
3575 | |
3727 | |
3576 | Libev can (and often is) directly embedded into host |
3728 | Libev can (and often is) directly embedded into host |
3577 | applications. Examples of applications that embed it include the Deliantra |
3729 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
3668 | to a compiled library. All other symbols change the ABI, which means all |
3820 | to a compiled library. All other symbols change the ABI, which means all |
3669 | users of libev and the libev code itself must be compiled with compatible |
3821 | users of libev and the libev code itself must be compiled with compatible |
3670 | settings. |
3822 | settings. |
3671 | |
3823 | |
3672 | =over 4 |
3824 | =over 4 |
|
|
3825 | |
|
|
3826 | =item EV_COMPAT3 (h) |
|
|
3827 | |
|
|
3828 | Backwards compatibility is a major concern for libev. This is why this |
|
|
3829 | release of libev comes with wrappers for the functions and symbols that |
|
|
3830 | have been renamed between libev version 3 and 4. |
|
|
3831 | |
|
|
3832 | You can disable these wrappers (to test compatibility with future |
|
|
3833 | versions) by defining C<EV_COMPAT3> to C<0> when compiling your |
|
|
3834 | sources. This has the additional advantage that you can drop the C<struct> |
|
|
3835 | from C<struct ev_loop> declarations, as libev will provide an C<ev_loop> |
|
|
3836 | typedef in that case. |
|
|
3837 | |
|
|
3838 | In some future version, the default for C<EV_COMPAT3> will become C<0>, |
|
|
3839 | and in some even more future version the compatibility code will be |
|
|
3840 | removed completely. |
3673 | |
3841 | |
3674 | =item EV_STANDALONE (h) |
3842 | =item EV_STANDALONE (h) |
3675 | |
3843 | |
3676 | Must always be C<1> if you do not use autoconf configuration, which |
3844 | Must always be C<1> if you do not use autoconf configuration, which |
3677 | keeps libev from including F<config.h>, and it also defines dummy |
3845 | keeps libev from including F<config.h>, and it also defines dummy |
… | |
… | |
4027 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
4195 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
4028 | will be C<0>. |
4196 | will be C<0>. |
4029 | |
4197 | |
4030 | =item EV_VERIFY |
4198 | =item EV_VERIFY |
4031 | |
4199 | |
4032 | Controls how much internal verification (see C<ev_loop_verify ()>) will |
4200 | Controls how much internal verification (see C<ev_verify ()>) will |
4033 | be done: If set to C<0>, no internal verification code will be compiled |
4201 | be done: If set to C<0>, no internal verification code will be compiled |
4034 | in. If set to C<1>, then verification code will be compiled in, but not |
4202 | in. If set to C<1>, then verification code will be compiled in, but not |
4035 | called. If set to C<2>, then the internal verification code will be |
4203 | called. If set to C<2>, then the internal verification code will be |
4036 | called once per loop, which can slow down libev. If set to C<3>, then the |
4204 | called once per loop, which can slow down libev. If set to C<3>, then the |
4037 | verification code will be called very frequently, which will slow down |
4205 | verification code will be called very frequently, which will slow down |
… | |
… | |
4252 | userdata *u = ev_userdata (EV_A); |
4420 | userdata *u = ev_userdata (EV_A); |
4253 | pthread_mutex_lock (&u->lock); |
4421 | pthread_mutex_lock (&u->lock); |
4254 | } |
4422 | } |
4255 | |
4423 | |
4256 | The event loop thread first acquires the mutex, and then jumps straight |
4424 | The event loop thread first acquires the mutex, and then jumps straight |
4257 | into C<ev_loop>: |
4425 | into C<ev_run>: |
4258 | |
4426 | |
4259 | void * |
4427 | void * |
4260 | l_run (void *thr_arg) |
4428 | l_run (void *thr_arg) |
4261 | { |
4429 | { |
4262 | struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4430 | struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4263 | |
4431 | |
4264 | l_acquire (EV_A); |
4432 | l_acquire (EV_A); |
4265 | pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4433 | pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4266 | ev_loop (EV_A_ 0); |
4434 | ev_run (EV_A_ 0); |
4267 | l_release (EV_A); |
4435 | l_release (EV_A); |
4268 | |
4436 | |
4269 | return 0; |
4437 | return 0; |
4270 | } |
4438 | } |
4271 | |
4439 | |
… | |
… | |
4323 | |
4491 | |
4324 | =head3 COROUTINES |
4492 | =head3 COROUTINES |
4325 | |
4493 | |
4326 | Libev is very accommodating to coroutines ("cooperative threads"): |
4494 | Libev is very accommodating to coroutines ("cooperative threads"): |
4327 | libev fully supports nesting calls to its functions from different |
4495 | libev fully supports nesting calls to its functions from different |
4328 | coroutines (e.g. you can call C<ev_loop> on the same loop from two |
4496 | coroutines (e.g. you can call C<ev_run> on the same loop from two |
4329 | different coroutines, and switch freely between both coroutines running |
4497 | different coroutines, and switch freely between both coroutines running |
4330 | the loop, as long as you don't confuse yourself). The only exception is |
4498 | the loop, as long as you don't confuse yourself). The only exception is |
4331 | that you must not do this from C<ev_periodic> reschedule callbacks. |
4499 | that you must not do this from C<ev_periodic> reschedule callbacks. |
4332 | |
4500 | |
4333 | Care has been taken to ensure that libev does not keep local state inside |
4501 | Care has been taken to ensure that libev does not keep local state inside |
4334 | C<ev_loop>, and other calls do not usually allow for coroutine switches as |
4502 | C<ev_run>, and other calls do not usually allow for coroutine switches as |
4335 | they do not call any callbacks. |
4503 | they do not call any callbacks. |
4336 | |
4504 | |
4337 | =head2 COMPILER WARNINGS |
4505 | =head2 COMPILER WARNINGS |
4338 | |
4506 | |
4339 | Depending on your compiler and compiler settings, you might get no or a |
4507 | Depending on your compiler and compiler settings, you might get no or a |
… | |
… | |
4423 | =head3 C<kqueue> is buggy |
4591 | =head3 C<kqueue> is buggy |
4424 | |
4592 | |
4425 | The kqueue syscall is broken in all known versions - most versions support |
4593 | The kqueue syscall is broken in all known versions - most versions support |
4426 | only sockets, many support pipes. |
4594 | only sockets, many support pipes. |
4427 | |
4595 | |
|
|
4596 | Libev tries to work around this by not using C<kqueue> by default on this |
|
|
4597 | rotten platform, but of course you can still ask for it when creating a |
|
|
4598 | loop - embedding a socket-only kqueue loop into a select-based one is |
|
|
4599 | probably going to work well. |
|
|
4600 | |
4428 | =head3 C<poll> is buggy |
4601 | =head3 C<poll> is buggy |
4429 | |
4602 | |
4430 | Instead of fixing C<kqueue>, Apple replaced their (working) C<poll> |
4603 | Instead of fixing C<kqueue>, Apple replaced their (working) C<poll> |
4431 | implementation by something calling C<kqueue> internally around the 10.5.6 |
4604 | implementation by something calling C<kqueue> internally around the 10.5.6 |
4432 | release, so now C<kqueue> I<and> C<poll> are broken. |
4605 | release, so now C<kqueue> I<and> C<poll> are broken. |
4433 | |
4606 | |
4434 | Libev tries to work around this by neither using C<kqueue> nor C<poll> by |
4607 | Libev tries to work around this by not using C<poll> by default on |
4435 | default on this rotten platform, but of course you cna still ask for them |
4608 | this rotten platform, but of course you can still ask for it when creating |
4436 | when creating a loop. |
4609 | a loop. |
4437 | |
4610 | |
4438 | =head3 C<select> is buggy |
4611 | =head3 C<select> is buggy |
4439 | |
4612 | |
4440 | All that's left is C<select>, and of course Apple found a way to fuck this |
4613 | All that's left is C<select>, and of course Apple found a way to fuck this |
4441 | one up as well: On OS/X, C<select> actively limits the number of file |
4614 | one up as well: On OS/X, C<select> actively limits the number of file |
4442 | descriptors you can pass in to 1024 - your program suddenyl crashes when |
4615 | descriptors you can pass in to 1024 - your program suddenly crashes when |
4443 | you use more. |
4616 | you use more. |
4444 | |
4617 | |
4445 | There is an undocumented "workaround" for this - defining |
4618 | There is an undocumented "workaround" for this - defining |
4446 | C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should> |
4619 | C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should> |
4447 | work on OS/X. |
4620 | work on OS/X. |
… | |
… | |
4450 | |
4623 | |
4451 | =head3 C<errno> reentrancy |
4624 | =head3 C<errno> reentrancy |
4452 | |
4625 | |
4453 | The default compile environment on Solaris is unfortunately so |
4626 | The default compile environment on Solaris is unfortunately so |
4454 | thread-unsafe that you can't even use components/libraries compiled |
4627 | thread-unsafe that you can't even use components/libraries compiled |
4455 | without C<-D_REENTRANT> (as long as they use C<errno>), which, of course, |
4628 | without C<-D_REENTRANT> in a threaded program, which, of course, isn't |
4456 | isn't defined by default. |
4629 | defined by default. A valid, if stupid, implementation choice. |
4457 | |
4630 | |
4458 | If you want to use libev in threaded environments you have to make sure |
4631 | If you want to use libev in threaded environments you have to make sure |
4459 | it's compiled with C<_REENTRANT> defined. |
4632 | it's compiled with C<_REENTRANT> defined. |
4460 | |
4633 | |
4461 | =head3 Event port backend |
4634 | =head3 Event port backend |
4462 | |
4635 | |
4463 | The scalable event interface for Solaris is called "event ports". Unfortunately, |
4636 | The scalable event interface for Solaris is called "event |
4464 | this mechanism is very buggy. If you run into high CPU usage, your program |
4637 | ports". Unfortunately, this mechanism is very buggy in all major |
|
|
4638 | releases. If you run into high CPU usage, your program freezes or you get |
4465 | freezes or you get a large number of spurious wakeups, make sure you have |
4639 | a large number of spurious wakeups, make sure you have all the relevant |
4466 | all the relevant and latest kernel patches applied. No, I don't know which |
4640 | and latest kernel patches applied. No, I don't know which ones, but there |
4467 | ones, but there are multiple ones. |
4641 | are multiple ones to apply, and afterwards, event ports actually work |
|
|
4642 | great. |
4468 | |
4643 | |
4469 | If you can't get it to work, you can try running the program with |
4644 | If you can't get it to work, you can try running the program by setting |
4470 | C<LIBEV_FLAGS=3> to only allow C<poll> and C<select> backends. |
4645 | the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and |
|
|
4646 | C<select> backends. |
4471 | |
4647 | |
4472 | =head2 AIX POLL BUG |
4648 | =head2 AIX POLL BUG |
4473 | |
4649 | |
4474 | AIX unfortunately has a broken C<poll.h> header. Libev works around |
4650 | AIX unfortunately has a broken C<poll.h> header. Libev works around |
4475 | this by trying to avoid the poll backend altogether (i.e. it's not even |
4651 | this by trying to avoid the poll backend altogether (i.e. it's not even |
4476 | compiled in), which normally isn't a big problem as C<select> works fine |
4652 | compiled in), which normally isn't a big problem as C<select> works fine |
4477 | with large bitsets, and AIX is dead anyway. |
4653 | with large bitsets on AIX, and AIX is dead anyway. |
4478 | |
4654 | |
4479 | =head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS |
4655 | =head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS |
4480 | |
4656 | |
4481 | =head3 General issues |
4657 | =head3 General issues |
4482 | |
4658 | |
… | |
… | |
4588 | structure (guaranteed by POSIX but not by ISO C for example), but it also |
4764 | structure (guaranteed by POSIX but not by ISO C for example), but it also |
4589 | assumes that the same (machine) code can be used to call any watcher |
4765 | assumes that the same (machine) code can be used to call any watcher |
4590 | callback: The watcher callbacks have different type signatures, but libev |
4766 | callback: The watcher callbacks have different type signatures, but libev |
4591 | calls them using an C<ev_watcher *> internally. |
4767 | calls them using an C<ev_watcher *> internally. |
4592 | |
4768 | |
|
|
4769 | =item pointer accesses must be thread-atomic |
|
|
4770 | |
|
|
4771 | Accessing a pointer value must be atomic, it must both be readable and |
|
|
4772 | writable in one piece - this is the case on all current architectures. |
|
|
4773 | |
4593 | =item C<sig_atomic_t volatile> must be thread-atomic as well |
4774 | =item C<sig_atomic_t volatile> must be thread-atomic as well |
4594 | |
4775 | |
4595 | The type C<sig_atomic_t volatile> (or whatever is defined as |
4776 | The type C<sig_atomic_t volatile> (or whatever is defined as |
4596 | C<EV_ATOMIC_T>) must be atomic with respect to accesses from different |
4777 | C<EV_ATOMIC_T>) must be atomic with respect to accesses from different |
4597 | threads. This is not part of the specification for C<sig_atomic_t>, but is |
4778 | threads. This is not part of the specification for C<sig_atomic_t>, but is |
… | |
… | |
4619 | watchers. |
4800 | watchers. |
4620 | |
4801 | |
4621 | =item C<double> must hold a time value in seconds with enough accuracy |
4802 | =item C<double> must hold a time value in seconds with enough accuracy |
4622 | |
4803 | |
4623 | The type C<double> is used to represent timestamps. It is required to |
4804 | The type C<double> is used to represent timestamps. It is required to |
4624 | have at least 51 bits of mantissa (and 9 bits of exponent), which is good |
4805 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
4625 | enough for at least into the year 4000. This requirement is fulfilled by |
4806 | good enough for at least into the year 4000 with millisecond accuracy |
|
|
4807 | (the design goal for libev). This requirement is overfulfilled by |
4626 | implementations implementing IEEE 754, which is basically all existing |
4808 | implementations using IEEE 754, which is basically all existing ones. With |
4627 | ones. With IEEE 754 doubles, you get microsecond accuracy until at least |
4809 | IEEE 754 doubles, you get microsecond accuracy until at least 2200. |
4628 | 2200. |
|
|
4629 | |
4810 | |
4630 | =back |
4811 | =back |
4631 | |
4812 | |
4632 | If you know of other additional requirements drop me a note. |
4813 | If you know of other additional requirements drop me a note. |
4633 | |
4814 | |
… | |
… | |
4703 | =back |
4884 | =back |
4704 | |
4885 | |
4705 | |
4886 | |
4706 | =head1 PORTING FROM LIBEV 3.X TO 4.X |
4887 | =head1 PORTING FROM LIBEV 3.X TO 4.X |
4707 | |
4888 | |
4708 | The major version 4 introduced some minor incompatible changes to the API. |
4889 | The major version 4 introduced some incompatible changes to the API. |
4709 | |
4890 | |
4710 | At the moment, the C<ev.h> header file tries to implement superficial |
4891 | At the moment, the C<ev.h> header file provides compatibility definitions |
4711 | compatibility, so most programs should still compile. Those might be |
4892 | for all changes, so most programs should still compile. The compatibility |
4712 | removed in later versions of libev, so better update early than late. |
4893 | layer might be removed in later versions of libev, so better update to the |
|
|
4894 | new API early than late. |
4713 | |
4895 | |
4714 | =over 4 |
4896 | =over 4 |
4715 | |
4897 | |
4716 | =item C<ev_loop_count> renamed to C<ev_iteration> |
4898 | =item C<EV_COMPAT3> backwards compatibility mechanism |
4717 | |
4899 | |
4718 | =item C<ev_loop_depth> renamed to C<ev_depth> |
4900 | The backward compatibility mechanism can be controlled by |
|
|
4901 | C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> |
|
|
4902 | section. |
4719 | |
4903 | |
4720 | =item C<ev_loop_verify> renamed to C<ev_verify> |
4904 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
|
|
4905 | |
|
|
4906 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
|
|
4907 | |
|
|
4908 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
4909 | ev_loop_fork (EV_DEFAULT); |
|
|
4910 | |
|
|
4911 | =item function/symbol renames |
|
|
4912 | |
|
|
4913 | A number of functions and symbols have been renamed: |
|
|
4914 | |
|
|
4915 | ev_loop => ev_run |
|
|
4916 | EVLOOP_NONBLOCK => EVRUN_NOWAIT |
|
|
4917 | EVLOOP_ONESHOT => EVRUN_ONCE |
|
|
4918 | |
|
|
4919 | ev_unloop => ev_break |
|
|
4920 | EVUNLOOP_CANCEL => EVBREAK_CANCEL |
|
|
4921 | EVUNLOOP_ONE => EVBREAK_ONE |
|
|
4922 | EVUNLOOP_ALL => EVBREAK_ALL |
|
|
4923 | |
|
|
4924 | EV_TIMEOUT => EV_TIMER |
|
|
4925 | |
|
|
4926 | ev_loop_count => ev_iteration |
|
|
4927 | ev_loop_depth => ev_depth |
|
|
4928 | ev_loop_verify => ev_verify |
4721 | |
4929 | |
4722 | Most functions working on C<struct ev_loop> objects don't have an |
4930 | Most functions working on C<struct ev_loop> objects don't have an |
4723 | C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is |
4931 | C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and |
|
|
4932 | associated constants have been renamed to not collide with the C<struct |
|
|
4933 | ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme |
|
|
4934 | as all other watcher types. Note that C<ev_loop_fork> is still called |
4724 | still called C<ev_loop_fork> because it would otherwise clash with the |
4935 | C<ev_loop_fork> because it would otherwise clash with the C<ev_fork> |
4725 | C<ev_fork> typedef. |
4936 | typedef. |
4726 | |
|
|
4727 | =item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents> |
|
|
4728 | |
|
|
4729 | This is a simple rename - all other watcher types use their name |
|
|
4730 | as revents flag, and now C<ev_timer> does, too. |
|
|
4731 | |
|
|
4732 | Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions |
|
|
4733 | and continue to be present for the foreseeable future, so this is mostly a |
|
|
4734 | documentation change. |
|
|
4735 | |
4937 | |
4736 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4938 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4737 | |
4939 | |
4738 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4940 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4739 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |
4941 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |
… | |
… | |
4746 | |
4948 | |
4747 | =over 4 |
4949 | =over 4 |
4748 | |
4950 | |
4749 | =item active |
4951 | =item active |
4750 | |
4952 | |
4751 | A watcher is active as long as it has been started (has been attached to |
4953 | A watcher is active as long as it has been started and not yet stopped. |
4752 | an event loop) but not yet stopped (disassociated from the event loop). |
4954 | See L<WATCHER STATES> for details. |
4753 | |
4955 | |
4754 | =item application |
4956 | =item application |
4755 | |
4957 | |
4756 | In this document, an application is whatever is using libev. |
4958 | In this document, an application is whatever is using libev. |
|
|
4959 | |
|
|
4960 | =item backend |
|
|
4961 | |
|
|
4962 | The part of the code dealing with the operating system interfaces. |
4757 | |
4963 | |
4758 | =item callback |
4964 | =item callback |
4759 | |
4965 | |
4760 | The address of a function that is called when some event has been |
4966 | The address of a function that is called when some event has been |
4761 | detected. Callbacks are being passed the event loop, the watcher that |
4967 | detected. Callbacks are being passed the event loop, the watcher that |
4762 | received the event, and the actual event bitset. |
4968 | received the event, and the actual event bitset. |
4763 | |
4969 | |
4764 | =item callback invocation |
4970 | =item callback/watcher invocation |
4765 | |
4971 | |
4766 | The act of calling the callback associated with a watcher. |
4972 | The act of calling the callback associated with a watcher. |
4767 | |
4973 | |
4768 | =item event |
4974 | =item event |
4769 | |
4975 | |
… | |
… | |
4788 | The model used to describe how an event loop handles and processes |
4994 | The model used to describe how an event loop handles and processes |
4789 | watchers and events. |
4995 | watchers and events. |
4790 | |
4996 | |
4791 | =item pending |
4997 | =item pending |
4792 | |
4998 | |
4793 | A watcher is pending as soon as the corresponding event has been detected, |
4999 | A watcher is pending as soon as the corresponding event has been |
4794 | and stops being pending as soon as the watcher will be invoked or its |
5000 | detected. See L<WATCHER STATES> for details. |
4795 | pending status is explicitly cleared by the application. |
|
|
4796 | |
|
|
4797 | A watcher can be pending, but not active. Stopping a watcher also clears |
|
|
4798 | its pending status. |
|
|
4799 | |
5001 | |
4800 | =item real time |
5002 | =item real time |
4801 | |
5003 | |
4802 | The physical time that is observed. It is apparently strictly monotonic :) |
5004 | The physical time that is observed. It is apparently strictly monotonic :) |
4803 | |
5005 | |
… | |
… | |
4810 | =item watcher |
5012 | =item watcher |
4811 | |
5013 | |
4812 | A data structure that describes interest in certain events. Watchers need |
5014 | A data structure that describes interest in certain events. Watchers need |
4813 | to be started (attached to an event loop) before they can receive events. |
5015 | to be started (attached to an event loop) before they can receive events. |
4814 | |
5016 | |
4815 | =item watcher invocation |
|
|
4816 | |
|
|
4817 | The act of calling the callback associated with a watcher. |
|
|
4818 | |
|
|
4819 | =back |
5017 | =back |
4820 | |
5018 | |
4821 | =head1 AUTHOR |
5019 | =head1 AUTHOR |
4822 | |
5020 | |
4823 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. |
5021 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael |
|
|
5022 | Magnusson and Emanuele Giaquinta. |
4824 | |
5023 | |