… | |
… | |
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); |
… | |
… | |
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 | |
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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> is |
308 | An event loop is described by a C<struct ev_loop *> (the C<struct> is |
298 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
309 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
299 | libev 3 had an C<ev_loop> function colliding with the struct name). |
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 event loops |
313 | supports child process events, and dynamically created event loops which |
303 | which do 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 |
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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: |
… | |
… | |
427 | epoll scales either O(1) or O(active_fds). |
463 | epoll scales either O(1) or O(active_fds). |
428 | |
464 | |
429 | The epoll mechanism deserves honorable mention as the most misdesigned |
465 | The epoll mechanism deserves honorable mention as the most misdesigned |
430 | of the more advanced event mechanisms: mere annoyances include silently |
466 | of the more advanced event mechanisms: mere annoyances include silently |
431 | dropping file descriptors, requiring a system call per change per file |
467 | dropping file descriptors, requiring a system call per change per file |
432 | descriptor (and unnecessary guessing of parameters), problems with dup and |
468 | descriptor (and unnecessary guessing of parameters), problems with dup, |
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469 | returning before the timeout value, resulting in additional iterations |
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470 | (and only giving 5ms accuracy while select on the same platform gives |
433 | so on. The biggest issue is fork races, however - if a program forks then |
471 | 0.1ms) and so on. The biggest issue is fork races, however - if a program |
434 | I<both> parent and child process have to recreate the epoll set, which can |
472 | forks then I<both> parent and child process have to recreate the epoll |
435 | take considerable time (one syscall per file descriptor) and is of course |
473 | set, which can take considerable time (one syscall per file descriptor) |
436 | hard to detect. |
474 | and is of course hard to detect. |
437 | |
475 | |
438 | Epoll is also notoriously buggy - embedding epoll fds I<should> work, but |
476 | Epoll is also notoriously buggy - embedding epoll fds I<should> work, but |
439 | of course I<doesn't>, and epoll just loves to report events for totally |
477 | 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 |
478 | I<different> file descriptors (even already closed ones, so one cannot |
441 | even remove them from the set) than registered in the set (especially |
479 | even remove them from the set) than registered in the set (especially |
… | |
… | |
443 | employing an additional generation counter and comparing that against the |
481 | employing an additional generation counter and comparing that against the |
444 | events to filter out spurious ones, recreating the set when required. Last |
482 | events to filter out spurious ones, recreating the set when required. Last |
445 | not least, it also refuses to work with some file descriptors which work |
483 | not least, it also refuses to work with some file descriptors which work |
446 | perfectly fine with C<select> (files, many character devices...). |
484 | perfectly fine with C<select> (files, many character devices...). |
447 | |
485 | |
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486 | Epoll is truly the train wreck analog among event poll mechanisms. |
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487 | |
448 | While stopping, setting and starting an I/O watcher in the same iteration |
488 | While stopping, setting and starting an I/O watcher in the same iteration |
449 | will result in some caching, there is still a system call per such |
489 | will result in some caching, there is still a system call per such |
450 | incident (because the same I<file descriptor> could point to a different |
490 | incident (because the same I<file descriptor> could point to a different |
451 | I<file description> now), so its best to avoid that. Also, C<dup ()>'ed |
491 | I<file description> now), so its best to avoid that. Also, C<dup ()>'ed |
452 | file descriptors might not work very well if you register events for both |
492 | file descriptors might not work very well if you register events for both |
… | |
… | |
549 | If one or more of the backend flags are or'ed into the flags value, |
589 | If one or more of the backend flags are or'ed into the flags value, |
550 | then only these backends will be tried (in the reverse order as listed |
590 | then only these backends will be tried (in the reverse order as listed |
551 | here). If none are specified, all backends in C<ev_recommended_backends |
591 | here). If none are specified, all backends in C<ev_recommended_backends |
552 | ()> will be tried. |
592 | ()> will be tried. |
553 | |
593 | |
554 | Example: This is the most typical usage. |
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|
555 | |
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556 | if (!ev_default_loop (0)) |
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557 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
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|
558 | |
|
|
559 | Example: Restrict libev to the select and poll backends, and do not allow |
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560 | environment settings to be taken into account: |
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561 | |
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562 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
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563 | |
|
|
564 | Example: Use whatever libev has to offer, but make sure that kqueue is |
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565 | used if available (warning, breaks stuff, best use only with your own |
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566 | private event loop and only if you know the OS supports your types of |
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567 | fds): |
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568 | |
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569 | ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
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570 | |
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571 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
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572 | |
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573 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
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574 | always distinct from the default loop. |
|
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575 | |
|
|
576 | Note that this function I<is> thread-safe, and one common way to use |
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577 | libev with threads is indeed to create one loop per thread, and using the |
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578 | default loop in the "main" or "initial" thread. |
|
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579 | |
|
|
580 | Example: Try to create a event loop that uses epoll and nothing else. |
594 | Example: Try to create a event loop that uses epoll and nothing else. |
581 | |
595 | |
582 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
596 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
583 | if (!epoller) |
597 | if (!epoller) |
584 | fatal ("no epoll found here, maybe it hides under your chair"); |
598 | fatal ("no epoll found here, maybe it hides under your chair"); |
585 | |
599 | |
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600 | Example: Use whatever libev has to offer, but make sure that kqueue is |
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601 | used if available. |
|
|
602 | |
|
|
603 | struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
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604 | |
586 | =item ev_default_destroy () |
605 | =item ev_loop_destroy (loop) |
587 | |
606 | |
588 | Destroys the default loop (frees all memory and kernel state etc.). None |
607 | Destroys an event loop object (frees all memory and kernel state |
589 | of the active event watchers will be stopped in the normal sense, so |
608 | etc.). None of the active event watchers will be stopped in the normal |
590 | e.g. C<ev_is_active> might still return true. It is your responsibility to |
609 | sense, so e.g. C<ev_is_active> might still return true. It is your |
591 | either stop all watchers cleanly yourself I<before> calling this function, |
610 | responsibility to either stop all watchers cleanly yourself I<before> |
592 | or cope with the fact afterwards (which is usually the easiest thing, you |
611 | calling this function, or cope with the fact afterwards (which is usually |
593 | can just ignore the watchers and/or C<free ()> them for example). |
612 | the easiest thing, you can just ignore the watchers and/or C<free ()> them |
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613 | for example). |
594 | |
614 | |
595 | Note that certain global state, such as signal state (and installed signal |
615 | Note that certain global state, such as signal state (and installed signal |
596 | handlers), will not be freed by this function, and related watchers (such |
616 | handlers), will not be freed by this function, and related watchers (such |
597 | as signal and child watchers) would need to be stopped manually. |
617 | as signal and child watchers) would need to be stopped manually. |
598 | |
618 | |
599 | In general it is not advisable to call this function except in the |
619 | This function is normally used on loop objects allocated by |
600 | rare occasion where you really need to free e.g. the signal handling |
620 | C<ev_loop_new>, but it can also be used on the default loop returned by |
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621 | C<ev_default_loop>, in which case it is not thread-safe. |
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622 | |
|
|
623 | Note that it is not advisable to call this function on the default loop |
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624 | except in the rare occasion where you really need to free it's resources. |
601 | pipe fds. If you need dynamically allocated loops it is better to use |
625 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
602 | C<ev_loop_new> and C<ev_loop_destroy>. |
626 | and C<ev_loop_destroy>. |
603 | |
627 | |
604 | =item ev_loop_destroy (loop) |
628 | =item ev_loop_fork (loop) |
605 | |
629 | |
606 | Like C<ev_default_destroy>, but destroys an event loop created by an |
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|
607 | earlier call to C<ev_loop_new>. |
|
|
608 | |
|
|
609 | =item ev_default_fork () |
|
|
610 | |
|
|
611 | This function sets a flag that causes subsequent C<ev_run> iterations |
630 | This function sets a flag that causes subsequent C<ev_run> iterations to |
612 | to reinitialise the kernel state for backends that have one. Despite the |
631 | reinitialise the kernel state for backends that have one. Despite the |
613 | name, you can call it anytime, but it makes most sense after forking, in |
632 | name, you can call it anytime, but it makes most sense after forking, in |
614 | the child process (or both child and parent, but that again makes little |
633 | the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the |
615 | sense). You I<must> call it in the child before using any of the libev |
634 | child before resuming or calling C<ev_run>. |
616 | functions, and it will only take effect at the next C<ev_run> iteration. |
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|
617 | |
635 | |
618 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
636 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
619 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
637 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
620 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
638 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
621 | during fork. |
639 | during fork. |
… | |
… | |
626 | call it at all (in fact, C<epoll> is so badly broken that it makes a |
644 | call it at all (in fact, C<epoll> is so badly broken that it makes a |
627 | difference, but libev will usually detect this case on its own and do a |
645 | difference, but libev will usually detect this case on its own and do a |
628 | costly reset of the backend). |
646 | costly reset of the backend). |
629 | |
647 | |
630 | The function itself is quite fast and it's usually not a problem to call |
648 | The function itself is quite fast and it's usually not a problem to call |
631 | it just in case after a fork. To make this easy, the function will fit in |
649 | it just in case after a fork. |
632 | quite nicely into a call to C<pthread_atfork>: |
|
|
633 | |
650 | |
|
|
651 | Example: Automate calling C<ev_loop_fork> on the default loop when |
|
|
652 | using pthreads. |
|
|
653 | |
|
|
654 | static void |
|
|
655 | post_fork_child (void) |
|
|
656 | { |
|
|
657 | ev_loop_fork (EV_DEFAULT); |
|
|
658 | } |
|
|
659 | |
|
|
660 | ... |
634 | pthread_atfork (0, 0, ev_default_fork); |
661 | pthread_atfork (0, 0, post_fork_child); |
635 | |
|
|
636 | =item ev_loop_fork (loop) |
|
|
637 | |
|
|
638 | Like C<ev_default_fork>, but acts on an event loop created by |
|
|
639 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
|
|
640 | after fork that you want to re-use in the child, and how you keep track of |
|
|
641 | them is entirely your own problem. |
|
|
642 | |
662 | |
643 | =item int ev_is_default_loop (loop) |
663 | =item int ev_is_default_loop (loop) |
644 | |
664 | |
645 | Returns true when the given loop is, in fact, the default loop, and false |
665 | Returns true when the given loop is, in fact, the default loop, and false |
646 | otherwise. |
666 | otherwise. |
… | |
… | |
807 | Can be used to make a call to C<ev_run> return early (but only after it |
827 | Can be used to make a call to C<ev_run> return early (but only after it |
808 | has processed all outstanding events). The C<how> argument must be either |
828 | has processed all outstanding events). The C<how> argument must be either |
809 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
829 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
810 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
830 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
811 | |
831 | |
812 | This "unloop state" will be cleared when entering C<ev_run> again. |
832 | This "break state" will be cleared when entering C<ev_run> again. |
813 | |
833 | |
814 | It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO## |
834 | It is safe to call C<ev_break> from outside any C<ev_run> calls, too. |
815 | |
835 | |
816 | =item ev_ref (loop) |
836 | =item ev_ref (loop) |
817 | |
837 | |
818 | =item ev_unref (loop) |
838 | =item ev_unref (loop) |
819 | |
839 | |
… | |
… | |
1104 | =item C<EV_FORK> |
1124 | =item C<EV_FORK> |
1105 | |
1125 | |
1106 | The event loop has been resumed in the child process after fork (see |
1126 | The event loop has been resumed in the child process after fork (see |
1107 | C<ev_fork>). |
1127 | C<ev_fork>). |
1108 | |
1128 | |
|
|
1129 | =item C<EV_CLEANUP> |
|
|
1130 | |
|
|
1131 | The event loop is about to be destroyed (see C<ev_cleanup>). |
|
|
1132 | |
1109 | =item C<EV_ASYNC> |
1133 | =item C<EV_ASYNC> |
1110 | |
1134 | |
1111 | The given async watcher has been asynchronously notified (see C<ev_async>). |
1135 | The given async watcher has been asynchronously notified (see C<ev_async>). |
1112 | |
1136 | |
1113 | =item C<EV_CUSTOM> |
1137 | =item C<EV_CUSTOM> |
… | |
… | |
1134 | programs, though, as the fd could already be closed and reused for another |
1158 | programs, though, as the fd could already be closed and reused for another |
1135 | thing, so beware. |
1159 | thing, so beware. |
1136 | |
1160 | |
1137 | =back |
1161 | =back |
1138 | |
1162 | |
1139 | =head2 WATCHER STATES |
|
|
1140 | |
|
|
1141 | There are various watcher states mentioned throughout this manual - |
|
|
1142 | active, pending and so on. In this section these states and the rules to |
|
|
1143 | transition between them will be described in more detail - and while these |
|
|
1144 | rules might look complicated, they usually do "the right thing". |
|
|
1145 | |
|
|
1146 | =over 4 |
|
|
1147 | |
|
|
1148 | =item initialiased |
|
|
1149 | |
|
|
1150 | Before a watcher can be registered with the event looop it has to be |
|
|
1151 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
|
|
1152 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
|
|
1153 | |
|
|
1154 | In this state it is simply some block of memory that is suitable for use |
|
|
1155 | in an event loop. It can be moved around, freed, reused etc. at will. |
|
|
1156 | |
|
|
1157 | =item started/running/active |
|
|
1158 | |
|
|
1159 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
|
|
1160 | property of the event loop, and is actively waiting for events. While in |
|
|
1161 | this state it cannot be accessed (except in a few documented ways), moved, |
|
|
1162 | freed or anything else - the only legal thing is to keep a pointer to it, |
|
|
1163 | and call libev functions on it that are documented to work on active watchers. |
|
|
1164 | |
|
|
1165 | =item pending |
|
|
1166 | |
|
|
1167 | If a watcher is active and libev determines that an event it is interested |
|
|
1168 | in has occurred (such as a timer expiring), it will become pending. It will |
|
|
1169 | stay in this pending state until either it is stopped or its callback is |
|
|
1170 | about to be invoked, so it is not normally pending inside the watcher |
|
|
1171 | callback. |
|
|
1172 | |
|
|
1173 | The watcher might or might not be active while it is pending (for example, |
|
|
1174 | an expired non-repeating timer can be pending but no longer active). If it |
|
|
1175 | is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>), |
|
|
1176 | but it is still property of the event loop at this time, so cannot be |
|
|
1177 | moved, freed or reused. And if it is active the rules described in the |
|
|
1178 | previous item still apply. |
|
|
1179 | |
|
|
1180 | It is also possible to feed an event on a watcher that is not active (e.g. |
|
|
1181 | via C<ev_feed_event>), in which case it becomes pending without being |
|
|
1182 | active. |
|
|
1183 | |
|
|
1184 | =item stopped |
|
|
1185 | |
|
|
1186 | A watcher can be stopped implicitly by libev (in which case it might still |
|
|
1187 | be pending), or explicitly by calling its C<ev_TYPE_stop> function. The |
|
|
1188 | latter will clear any pending state the watcher might be in, regardless |
|
|
1189 | of whether it was active or not, so stopping a watcher explicitly before |
|
|
1190 | freeing it is often a good idea. |
|
|
1191 | |
|
|
1192 | While stopped (and not pending) the watcher is essentially in the |
|
|
1193 | initialised state, that is it can be reused, moved, modified in any way |
|
|
1194 | you wish. |
|
|
1195 | |
|
|
1196 | =back |
|
|
1197 | |
|
|
1198 | =head2 GENERIC WATCHER FUNCTIONS |
1163 | =head2 GENERIC WATCHER FUNCTIONS |
1199 | |
1164 | |
1200 | =over 4 |
1165 | =over 4 |
1201 | |
1166 | |
1202 | =item C<ev_init> (ev_TYPE *watcher, callback) |
1167 | =item C<ev_init> (ev_TYPE *watcher, callback) |
… | |
… | |
1343 | |
1308 | |
1344 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1309 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1345 | functions that do not need a watcher. |
1310 | functions that do not need a watcher. |
1346 | |
1311 | |
1347 | =back |
1312 | =back |
1348 | |
|
|
1349 | |
1313 | |
1350 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
1314 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
1351 | |
1315 | |
1352 | Each watcher has, by default, a member C<void *data> that you can change |
1316 | Each watcher has, by default, a member C<void *data> that you can change |
1353 | and read at any time: libev will completely ignore it. This can be used |
1317 | and read at any time: libev will completely ignore it. This can be used |
… | |
… | |
1409 | t2_cb (EV_P_ ev_timer *w, int revents) |
1373 | t2_cb (EV_P_ ev_timer *w, int revents) |
1410 | { |
1374 | { |
1411 | struct my_biggy big = (struct my_biggy *) |
1375 | struct my_biggy big = (struct my_biggy *) |
1412 | (((char *)w) - offsetof (struct my_biggy, t2)); |
1376 | (((char *)w) - offsetof (struct my_biggy, t2)); |
1413 | } |
1377 | } |
|
|
1378 | |
|
|
1379 | =head2 WATCHER STATES |
|
|
1380 | |
|
|
1381 | There are various watcher states mentioned throughout this manual - |
|
|
1382 | active, pending and so on. In this section these states and the rules to |
|
|
1383 | transition between them will be described in more detail - and while these |
|
|
1384 | rules might look complicated, they usually do "the right thing". |
|
|
1385 | |
|
|
1386 | =over 4 |
|
|
1387 | |
|
|
1388 | =item initialiased |
|
|
1389 | |
|
|
1390 | Before a watcher can be registered with the event looop it has to be |
|
|
1391 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
|
|
1392 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
|
|
1393 | |
|
|
1394 | In this state it is simply some block of memory that is suitable for use |
|
|
1395 | in an event loop. It can be moved around, freed, reused etc. at will. |
|
|
1396 | |
|
|
1397 | =item started/running/active |
|
|
1398 | |
|
|
1399 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
|
|
1400 | property of the event loop, and is actively waiting for events. While in |
|
|
1401 | this state it cannot be accessed (except in a few documented ways), moved, |
|
|
1402 | freed or anything else - the only legal thing is to keep a pointer to it, |
|
|
1403 | and call libev functions on it that are documented to work on active watchers. |
|
|
1404 | |
|
|
1405 | =item pending |
|
|
1406 | |
|
|
1407 | If a watcher is active and libev determines that an event it is interested |
|
|
1408 | in has occurred (such as a timer expiring), it will become pending. It will |
|
|
1409 | stay in this pending state until either it is stopped or its callback is |
|
|
1410 | about to be invoked, so it is not normally pending inside the watcher |
|
|
1411 | callback. |
|
|
1412 | |
|
|
1413 | The watcher might or might not be active while it is pending (for example, |
|
|
1414 | an expired non-repeating timer can be pending but no longer active). If it |
|
|
1415 | is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>), |
|
|
1416 | but it is still property of the event loop at this time, so cannot be |
|
|
1417 | moved, freed or reused. And if it is active the rules described in the |
|
|
1418 | previous item still apply. |
|
|
1419 | |
|
|
1420 | It is also possible to feed an event on a watcher that is not active (e.g. |
|
|
1421 | via C<ev_feed_event>), in which case it becomes pending without being |
|
|
1422 | active. |
|
|
1423 | |
|
|
1424 | =item stopped |
|
|
1425 | |
|
|
1426 | A watcher can be stopped implicitly by libev (in which case it might still |
|
|
1427 | be pending), or explicitly by calling its C<ev_TYPE_stop> function. The |
|
|
1428 | latter will clear any pending state the watcher might be in, regardless |
|
|
1429 | of whether it was active or not, so stopping a watcher explicitly before |
|
|
1430 | freeing it is often a good idea. |
|
|
1431 | |
|
|
1432 | While stopped (and not pending) the watcher is essentially in the |
|
|
1433 | initialised state, that is it can be reused, moved, modified in any way |
|
|
1434 | you wish. |
|
|
1435 | |
|
|
1436 | =back |
1414 | |
1437 | |
1415 | =head2 WATCHER PRIORITY MODELS |
1438 | =head2 WATCHER PRIORITY MODELS |
1416 | |
1439 | |
1417 | Many event loops support I<watcher priorities>, which are usually small |
1440 | Many event loops support I<watcher priorities>, which are usually small |
1418 | integers that influence the ordering of event callback invocation |
1441 | integers that influence the ordering of event callback invocation |
… | |
… | |
3072 | disadvantage of having to use multiple event loops (which do not support |
3095 | disadvantage of having to use multiple event loops (which do not support |
3073 | signal watchers). |
3096 | signal watchers). |
3074 | |
3097 | |
3075 | When this is not possible, or you want to use the default loop for |
3098 | When this is not possible, or you want to use the default loop for |
3076 | other reasons, then in the process that wants to start "fresh", call |
3099 | other reasons, then in the process that wants to start "fresh", call |
3077 | C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying |
3100 | C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>. |
3078 | the default loop will "orphan" (not stop) all registered watchers, so you |
3101 | Destroying the default loop will "orphan" (not stop) all registered |
3079 | have to be careful not to execute code that modifies those watchers. Note |
3102 | watchers, so you have to be careful not to execute code that modifies |
3080 | also that in that case, you have to re-register any signal watchers. |
3103 | those watchers. Note also that in that case, you have to re-register any |
|
|
3104 | signal watchers. |
3081 | |
3105 | |
3082 | =head3 Watcher-Specific Functions and Data Members |
3106 | =head3 Watcher-Specific Functions and Data Members |
3083 | |
3107 | |
3084 | =over 4 |
3108 | =over 4 |
3085 | |
3109 | |
3086 | =item ev_fork_init (ev_signal *, callback) |
3110 | =item ev_fork_init (ev_fork *, callback) |
3087 | |
3111 | |
3088 | Initialises and configures the fork watcher - it has no parameters of any |
3112 | Initialises and configures the fork watcher - it has no parameters of any |
3089 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
3113 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
3090 | believe me. |
3114 | really. |
3091 | |
3115 | |
3092 | =back |
3116 | =back |
|
|
3117 | |
|
|
3118 | |
|
|
3119 | =head2 C<ev_cleanup> - even the best things end |
|
|
3120 | |
|
|
3121 | Cleanup watchers are called just before the event loop is being destroyed |
|
|
3122 | by a call to C<ev_loop_destroy>. |
|
|
3123 | |
|
|
3124 | While there is no guarantee that the event loop gets destroyed, cleanup |
|
|
3125 | watchers provide a convenient method to install cleanup hooks for your |
|
|
3126 | program, worker threads and so on - you just to make sure to destroy the |
|
|
3127 | loop when you want them to be invoked. |
|
|
3128 | |
|
|
3129 | Cleanup watchers are invoked in the same way as any other watcher. Unlike |
|
|
3130 | all other watchers, they do not keep a reference to the event loop (which |
|
|
3131 | makes a lot of sense if you think about it). Like all other watchers, you |
|
|
3132 | can call libev functions in the callback, except C<ev_cleanup_start>. |
|
|
3133 | |
|
|
3134 | =head3 Watcher-Specific Functions and Data Members |
|
|
3135 | |
|
|
3136 | =over 4 |
|
|
3137 | |
|
|
3138 | =item ev_cleanup_init (ev_cleanup *, callback) |
|
|
3139 | |
|
|
3140 | Initialises and configures the cleanup watcher - it has no parameters of |
|
|
3141 | any kind. There is a C<ev_cleanup_set> macro, but using it is utterly |
|
|
3142 | pointless, I assure you. |
|
|
3143 | |
|
|
3144 | =back |
|
|
3145 | |
|
|
3146 | Example: Register an atexit handler to destroy the default loop, so any |
|
|
3147 | cleanup functions are called. |
|
|
3148 | |
|
|
3149 | static void |
|
|
3150 | program_exits (void) |
|
|
3151 | { |
|
|
3152 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
3153 | } |
|
|
3154 | |
|
|
3155 | ... |
|
|
3156 | atexit (program_exits); |
3093 | |
3157 | |
3094 | |
3158 | |
3095 | =head2 C<ev_async> - how to wake up an event loop |
3159 | =head2 C<ev_async> - how to wake up an event loop |
3096 | |
3160 | |
3097 | In general, you cannot use an C<ev_run> from multiple threads or other |
3161 | In general, you cannot use an C<ev_run> from multiple threads or other |
… | |
… | |
4704 | structure (guaranteed by POSIX but not by ISO C for example), but it also |
4768 | structure (guaranteed by POSIX but not by ISO C for example), but it also |
4705 | assumes that the same (machine) code can be used to call any watcher |
4769 | assumes that the same (machine) code can be used to call any watcher |
4706 | callback: The watcher callbacks have different type signatures, but libev |
4770 | callback: The watcher callbacks have different type signatures, but libev |
4707 | calls them using an C<ev_watcher *> internally. |
4771 | calls them using an C<ev_watcher *> internally. |
4708 | |
4772 | |
|
|
4773 | =item pointer accesses must be thread-atomic |
|
|
4774 | |
|
|
4775 | Accessing a pointer value must be atomic, it must both be readable and |
|
|
4776 | writable in one piece - this is the case on all current architectures. |
|
|
4777 | |
4709 | =item C<sig_atomic_t volatile> must be thread-atomic as well |
4778 | =item C<sig_atomic_t volatile> must be thread-atomic as well |
4710 | |
4779 | |
4711 | The type C<sig_atomic_t volatile> (or whatever is defined as |
4780 | The type C<sig_atomic_t volatile> (or whatever is defined as |
4712 | C<EV_ATOMIC_T>) must be atomic with respect to accesses from different |
4781 | C<EV_ATOMIC_T>) must be atomic with respect to accesses from different |
4713 | threads. This is not part of the specification for C<sig_atomic_t>, but is |
4782 | threads. This is not part of the specification for C<sig_atomic_t>, but is |
… | |
… | |
4819 | =back |
4888 | =back |
4820 | |
4889 | |
4821 | |
4890 | |
4822 | =head1 PORTING FROM LIBEV 3.X TO 4.X |
4891 | =head1 PORTING FROM LIBEV 3.X TO 4.X |
4823 | |
4892 | |
4824 | The major version 4 introduced some minor incompatible changes to the API. |
4893 | The major version 4 introduced some incompatible changes to the API. |
4825 | |
4894 | |
4826 | At the moment, the C<ev.h> header file tries to implement superficial |
4895 | At the moment, the C<ev.h> header file provides compatibility definitions |
4827 | compatibility, so most programs should still compile. Those might be |
4896 | for all changes, so most programs should still compile. The compatibility |
4828 | removed in later versions of libev, so better update early than late. |
4897 | layer might be removed in later versions of libev, so better update to the |
|
|
4898 | new API early than late. |
4829 | |
4899 | |
4830 | =over 4 |
4900 | =over 4 |
|
|
4901 | |
|
|
4902 | =item C<EV_COMPAT3> backwards compatibility mechanism |
|
|
4903 | |
|
|
4904 | The backward compatibility mechanism can be controlled by |
|
|
4905 | C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> |
|
|
4906 | section. |
|
|
4907 | |
|
|
4908 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
|
|
4909 | |
|
|
4910 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
|
|
4911 | |
|
|
4912 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
4913 | ev_loop_fork (EV_DEFAULT); |
4831 | |
4914 | |
4832 | =item function/symbol renames |
4915 | =item function/symbol renames |
4833 | |
4916 | |
4834 | A number of functions and symbols have been renamed: |
4917 | A number of functions and symbols have been renamed: |
4835 | |
4918 | |
… | |
… | |
4854 | ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme |
4937 | ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme |
4855 | as all other watcher types. Note that C<ev_loop_fork> is still called |
4938 | as all other watcher types. Note that C<ev_loop_fork> is still called |
4856 | C<ev_loop_fork> because it would otherwise clash with the C<ev_fork> |
4939 | C<ev_loop_fork> because it would otherwise clash with the C<ev_fork> |
4857 | typedef. |
4940 | typedef. |
4858 | |
4941 | |
4859 | =item C<EV_COMPAT3> backwards compatibility mechanism |
|
|
4860 | |
|
|
4861 | The backward compatibility mechanism can be controlled by |
|
|
4862 | C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> |
|
|
4863 | section. |
|
|
4864 | |
|
|
4865 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4942 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4866 | |
4943 | |
4867 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4944 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4868 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |
4945 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |
4869 | and work, but the library code will of course be larger. |
4946 | and work, but the library code will of course be larger. |
… | |
… | |
4943 | |
5020 | |
4944 | =back |
5021 | =back |
4945 | |
5022 | |
4946 | =head1 AUTHOR |
5023 | =head1 AUTHOR |
4947 | |
5024 | |
4948 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. |
5025 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael |
|
|
5026 | Magnusson and Emanuele Giaquinta. |
4949 | |
5027 | |