… | |
… | |
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); |
… | |
… | |
124 | this argument. |
124 | this argument. |
125 | |
125 | |
126 | =head2 TIME REPRESENTATION |
126 | =head2 TIME REPRESENTATION |
127 | |
127 | |
128 | Libev represents time as a single floating point number, representing |
128 | Libev represents time as a single floating point number, representing |
129 | the (fractional) number of seconds since the (POSIX) epoch (in practise |
129 | the (fractional) number of seconds since the (POSIX) epoch (in practice |
130 | somewhere near the beginning of 1970, details are complicated, don't |
130 | 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 |
131 | 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 |
132 | 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. |
133 | any calculations on it, you should treat it as some floating point value. |
134 | |
134 | |
… | |
… | |
165 | |
165 | |
166 | =item ev_tstamp ev_time () |
166 | =item ev_tstamp ev_time () |
167 | |
167 | |
168 | Returns the current time as libev would use it. Please note that the |
168 | 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 |
169 | C<ev_now> function is usually faster and also often returns the timestamp |
170 | you actually want to know. |
170 | you actually want to know. Also interesting is the combination of |
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171 | C<ev_update_now> and C<ev_now>. |
171 | |
172 | |
172 | =item ev_sleep (ev_tstamp interval) |
173 | =item ev_sleep (ev_tstamp interval) |
173 | |
174 | |
174 | Sleep for the given interval: The current thread will be blocked until |
175 | 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 |
176 | either it is interrupted or the given time interval has passed. Basically |
… | |
… | |
192 | as this indicates an incompatible change. Minor versions are usually |
193 | as this indicates an incompatible change. Minor versions are usually |
193 | compatible to older versions, so a larger minor version alone is usually |
194 | compatible to older versions, so a larger minor version alone is usually |
194 | not a problem. |
195 | not a problem. |
195 | |
196 | |
196 | Example: Make sure we haven't accidentally been linked against the wrong |
197 | Example: Make sure we haven't accidentally been linked against the wrong |
197 | version (note, however, that this will not detect ABI mismatches :). |
198 | version (note, however, that this will not detect other ABI mismatches, |
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199 | such as LFS or reentrancy). |
198 | |
200 | |
199 | assert (("libev version mismatch", |
201 | assert (("libev version mismatch", |
200 | ev_version_major () == EV_VERSION_MAJOR |
202 | ev_version_major () == EV_VERSION_MAJOR |
201 | && ev_version_minor () >= EV_VERSION_MINOR)); |
203 | && ev_version_minor () >= EV_VERSION_MINOR)); |
202 | |
204 | |
… | |
… | |
213 | assert (("sorry, no epoll, no sex", |
215 | assert (("sorry, no epoll, no sex", |
214 | ev_supported_backends () & EVBACKEND_EPOLL)); |
216 | ev_supported_backends () & EVBACKEND_EPOLL)); |
215 | |
217 | |
216 | =item unsigned int ev_recommended_backends () |
218 | =item unsigned int ev_recommended_backends () |
217 | |
219 | |
218 | Return the set of all backends compiled into this binary of libev and also |
220 | 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 |
221 | also recommended for this platform, meaning it will work for most file |
|
|
222 | 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 |
223 | 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 |
224 | 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 |
225 | 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. |
226 | probe for if you specify no backends explicitly. |
224 | |
227 | |
225 | =item unsigned int ev_embeddable_backends () |
228 | =item unsigned int ev_embeddable_backends () |
226 | |
229 | |
227 | Returns the set of backends that are embeddable in other event loops. This |
230 | Returns the set of backends that are embeddable in other event loops. This |
228 | is the theoretical, all-platform, value. To find which backends |
231 | 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 |
232 | current system. To find which embeddable backends might be supported on |
230 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
233 | the current system, you would need to look at C<ev_embeddable_backends () |
231 | recommended ones. |
234 | & ev_supported_backends ()>, likewise for recommended ones. |
232 | |
235 | |
233 | See the description of C<ev_embed> watchers for more info. |
236 | See the description of C<ev_embed> watchers for more info. |
234 | |
237 | |
235 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT] |
238 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT] |
236 | |
239 | |
… | |
… | |
290 | ... |
293 | ... |
291 | ev_set_syserr_cb (fatal_error); |
294 | ev_set_syserr_cb (fatal_error); |
292 | |
295 | |
293 | =back |
296 | =back |
294 | |
297 | |
295 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
298 | =head1 FUNCTIONS CONTROLLING EVENT LOOPS |
296 | |
299 | |
297 | An event loop is described by a C<struct ev_loop *> (the C<struct> is |
300 | An event loop is described by a C<struct ev_loop *> (the C<struct> is |
298 | I<not> optional in case unless libev 3 compatibility is disabled, as libev |
301 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
299 | 3 had an C<ev_loop> function colliding with the struct name). |
302 | libev 3 had an C<ev_loop> function colliding with the struct name). |
300 | |
303 | |
301 | The library knows two types of such loops, the I<default> loop, which |
304 | The library knows two types of such loops, the I<default> loop, which |
302 | supports signals and child events, and dynamically created event loops |
305 | supports signals and child events, and dynamically created event loops |
303 | which do not. |
306 | which do not. |
304 | |
307 | |
305 | =over 4 |
308 | =over 4 |
306 | |
309 | |
307 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
310 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
308 | |
311 | |
309 | This will initialise the default event loop if it hasn't been initialised |
312 | 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 |
313 | 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 |
314 | 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). |
315 | C<ev_loop_new>. |
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|
316 | |
|
|
317 | If the default loop is already initialised then this function simply |
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318 | returns it (and ignores the flags. If that is troubling you, check |
|
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319 | C<ev_backend ()> afterwards). Otherwise it will create it with the given |
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320 | flags, which should almost always be C<0>, unless the caller is also the |
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|
321 | one calling C<ev_run> or otherwise qualifies as "the main program". |
313 | |
322 | |
314 | If you don't know what event loop to use, use the one returned from this |
323 | If you don't know what event loop to use, use the one returned from this |
315 | function. |
324 | function (or via the C<EV_DEFAULT> macro). |
316 | |
325 | |
317 | Note that this function is I<not> thread-safe, so if you want to use it |
326 | 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, |
327 | from multiple threads, you have to employ some kind of mutex (note also |
319 | as loops cannot be shared easily between threads anyway). |
328 | that this case is unlikely, as loops cannot be shared easily between |
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|
329 | threads anyway). |
320 | |
330 | |
321 | The default loop is the only loop that can handle C<ev_signal> and |
331 | 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 |
332 | 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 |
333 | 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 |
334 | 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 |
335 | C<SIGCHLD> signal handler I<after> calling C<ev_default_init>. |
326 | C<ev_default_init>. |
336 | |
|
|
337 | Example: This is the most typical usage. |
|
|
338 | |
|
|
339 | if (!ev_default_loop (0)) |
|
|
340 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
|
341 | |
|
|
342 | Example: Restrict libev to the select and poll backends, and do not allow |
|
|
343 | environment settings to be taken into account: |
|
|
344 | |
|
|
345 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
|
|
346 | |
|
|
347 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
|
|
348 | |
|
|
349 | This will create and initialise a new event loop object. If the loop |
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|
350 | could not be initialised, returns false. |
|
|
351 | |
|
|
352 | Note that this function I<is> thread-safe, and one common way to use |
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|
353 | libev with threads is indeed to create one loop per thread, and using the |
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|
354 | default loop in the "main" or "initial" thread. |
327 | |
355 | |
328 | The flags argument can be used to specify special behaviour or specific |
356 | 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>). |
357 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
330 | |
358 | |
331 | The following flags are supported: |
359 | The following flags are supported: |
… | |
… | |
549 | If one or more of the backend flags are or'ed into the flags value, |
577 | 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 |
578 | 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 |
579 | here). If none are specified, all backends in C<ev_recommended_backends |
552 | ()> will be tried. |
580 | ()> will be tried. |
553 | |
581 | |
554 | Example: This is the most typical usage. |
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|
555 | |
|
|
556 | if (!ev_default_loop (0)) |
|
|
557 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
|
558 | |
|
|
559 | Example: Restrict libev to the select and poll backends, and do not allow |
|
|
560 | environment settings to be taken into account: |
|
|
561 | |
|
|
562 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
|
|
563 | |
|
|
564 | Example: Use whatever libev has to offer, but make sure that kqueue is |
|
|
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 | |
|
|
571 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
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|
572 | |
|
|
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. |
|
|
575 | |
|
|
576 | Note that this function I<is> thread-safe, and one common way to use |
|
|
577 | libev with threads is indeed to create one loop per thread, and using the |
|
|
578 | default loop in the "main" or "initial" thread. |
|
|
579 | |
|
|
580 | Example: Try to create a event loop that uses epoll and nothing else. |
582 | Example: Try to create a event loop that uses epoll and nothing else. |
581 | |
583 | |
582 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
584 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
583 | if (!epoller) |
585 | if (!epoller) |
584 | fatal ("no epoll found here, maybe it hides under your chair"); |
586 | fatal ("no epoll found here, maybe it hides under your chair"); |
585 | |
587 | |
|
|
588 | Example: Use whatever libev has to offer, but make sure that kqueue is |
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|
589 | used if available. |
|
|
590 | |
|
|
591 | struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
|
592 | |
586 | =item ev_default_destroy () |
593 | =item ev_loop_destroy (loop) |
587 | |
594 | |
588 | Destroys the default loop (frees all memory and kernel state etc.). None |
595 | 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 |
596 | 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 |
597 | 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, |
598 | responsibility to either stop all watchers cleanly yourself I<before> |
592 | or cope with the fact afterwards (which is usually the easiest thing, you |
599 | 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). |
600 | the easiest thing, you can just ignore the watchers and/or C<free ()> them |
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|
601 | for example). |
594 | |
602 | |
595 | Note that certain global state, such as signal state (and installed signal |
603 | 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 |
604 | handlers), will not be freed by this function, and related watchers (such |
597 | as signal and child watchers) would need to be stopped manually. |
605 | as signal and child watchers) would need to be stopped manually. |
598 | |
606 | |
599 | In general it is not advisable to call this function except in the |
607 | This function is normally used on loop objects allocated by |
600 | rare occasion where you really need to free e.g. the signal handling |
608 | C<ev_loop_new>, but it can also be used on the default loop returned by |
|
|
609 | C<ev_default_loop>, in which case it is not thread-safe. |
|
|
610 | |
|
|
611 | Note that it is not advisable to call this function on the default loop |
|
|
612 | 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 |
613 | 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>. |
614 | and C<ev_loop_destroy>. |
603 | |
615 | |
604 | =item ev_loop_destroy (loop) |
616 | =item ev_loop_fork (loop) |
605 | |
617 | |
606 | Like C<ev_default_destroy>, but destroys an event loop created by an |
|
|
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 |
618 | 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 |
619 | 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 |
620 | 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 |
621 | 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 |
622 | child before resuming or calling C<ev_run>. |
616 | functions, and it will only take effect at the next C<ev_run> iteration. |
|
|
617 | |
623 | |
618 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
624 | 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 |
625 | 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 |
626 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
621 | during fork. |
627 | during fork. |
… | |
… | |
626 | call it at all (in fact, C<epoll> is so badly broken that it makes a |
632 | 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 |
633 | difference, but libev will usually detect this case on its own and do a |
628 | costly reset of the backend). |
634 | costly reset of the backend). |
629 | |
635 | |
630 | The function itself is quite fast and it's usually not a problem to call |
636 | 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 |
637 | it just in case after a fork. |
632 | quite nicely into a call to C<pthread_atfork>: |
|
|
633 | |
638 | |
|
|
639 | Example: Automate calling C<ev_loop_fork> on the default loop when |
|
|
640 | using pthreads. |
|
|
641 | |
|
|
642 | static void |
|
|
643 | post_fork_child (void) |
|
|
644 | { |
|
|
645 | ev_loop_fork (EV_DEFAULT); |
|
|
646 | } |
|
|
647 | |
|
|
648 | ... |
634 | pthread_atfork (0, 0, ev_default_fork); |
649 | 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 | |
650 | |
643 | =item int ev_is_default_loop (loop) |
651 | =item int ev_is_default_loop (loop) |
644 | |
652 | |
645 | Returns true when the given loop is, in fact, the default loop, and false |
653 | Returns true when the given loop is, in fact, the default loop, and false |
646 | otherwise. |
654 | otherwise. |
… | |
… | |
908 | |
916 | |
909 | =item ev_invoke_pending (loop) |
917 | =item ev_invoke_pending (loop) |
910 | |
918 | |
911 | This call will simply invoke all pending watchers while resetting their |
919 | This call will simply invoke all pending watchers while resetting their |
912 | pending state. Normally, C<ev_run> does this automatically when required, |
920 | pending state. Normally, C<ev_run> does this automatically when required, |
913 | but when overriding the invoke callback this call comes handy. |
921 | but when overriding the invoke callback this call comes handy. This |
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|
922 | function can be invoked from a watcher - this can be useful for example |
|
|
923 | when you want to do some lengthy calculation and want to pass further |
|
|
924 | event handling to another thread (you still have to make sure only one |
|
|
925 | thread executes within C<ev_invoke_pending> or C<ev_run> of course). |
914 | |
926 | |
915 | =item int ev_pending_count (loop) |
927 | =item int ev_pending_count (loop) |
916 | |
928 | |
917 | Returns the number of pending watchers - zero indicates that no watchers |
929 | Returns the number of pending watchers - zero indicates that no watchers |
918 | are pending. |
930 | are pending. |
… | |
… | |
990 | |
1002 | |
991 | In the following description, uppercase C<TYPE> in names stands for the |
1003 | In the following description, uppercase C<TYPE> in names stands for the |
992 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
1004 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
993 | watchers and C<ev_io_start> for I/O watchers. |
1005 | watchers and C<ev_io_start> for I/O watchers. |
994 | |
1006 | |
995 | A watcher is a structure that you create and register to record your |
1007 | A watcher is an opaque structure that you allocate and register to record |
996 | interest in some event. For instance, if you want to wait for STDIN to |
1008 | your interest in some event. To make a concrete example, imagine you want |
997 | become readable, you would create an C<ev_io> watcher for that: |
1009 | to wait for STDIN to become readable, you would create an C<ev_io> watcher |
|
|
1010 | for that: |
998 | |
1011 | |
999 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
1012 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
1000 | { |
1013 | { |
1001 | ev_io_stop (w); |
1014 | ev_io_stop (w); |
1002 | ev_break (loop, EVBREAK_ALL); |
1015 | ev_break (loop, EVBREAK_ALL); |
… | |
… | |
1017 | stack). |
1030 | stack). |
1018 | |
1031 | |
1019 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1032 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1020 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1033 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1021 | |
1034 | |
1022 | Each watcher structure must be initialised by a call to C<ev_init |
1035 | Each watcher structure must be initialised by a call to C<ev_init (watcher |
1023 | (watcher *, callback)>, which expects a callback to be provided. This |
1036 | *, callback)>, which expects a callback to be provided. This callback is |
1024 | callback gets invoked each time the event occurs (or, in the case of I/O |
1037 | invoked each time the event occurs (or, in the case of I/O watchers, each |
1025 | watchers, each time the event loop detects that the file descriptor given |
1038 | time the event loop detects that the file descriptor given is readable |
1026 | is readable and/or writable). |
1039 | and/or writable). |
1027 | |
1040 | |
1028 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1041 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1029 | macro to configure it, with arguments specific to the watcher type. There |
1042 | macro to configure it, with arguments specific to the watcher type. There |
1030 | is also a macro to combine initialisation and setting in one call: C<< |
1043 | is also a macro to combine initialisation and setting in one call: C<< |
1031 | ev_TYPE_init (watcher *, callback, ...) >>. |
1044 | ev_TYPE_init (watcher *, callback, ...) >>. |
… | |
… | |
1099 | =item C<EV_FORK> |
1112 | =item C<EV_FORK> |
1100 | |
1113 | |
1101 | The event loop has been resumed in the child process after fork (see |
1114 | The event loop has been resumed in the child process after fork (see |
1102 | C<ev_fork>). |
1115 | C<ev_fork>). |
1103 | |
1116 | |
|
|
1117 | =item C<EV_CLEANUP> |
|
|
1118 | |
|
|
1119 | The event loop is abotu to be destroyed (see C<ev_cleanup>). |
|
|
1120 | |
1104 | =item C<EV_ASYNC> |
1121 | =item C<EV_ASYNC> |
1105 | |
1122 | |
1106 | The given async watcher has been asynchronously notified (see C<ev_async>). |
1123 | The given async watcher has been asynchronously notified (see C<ev_async>). |
1107 | |
1124 | |
1108 | =item C<EV_CUSTOM> |
1125 | =item C<EV_CUSTOM> |
… | |
… | |
1126 | example it might indicate that a fd is readable or writable, and if your |
1143 | example it might indicate that a fd is readable or writable, and if your |
1127 | callbacks is well-written it can just attempt the operation and cope with |
1144 | callbacks is well-written it can just attempt the operation and cope with |
1128 | the error from read() or write(). This will not work in multi-threaded |
1145 | the error from read() or write(). This will not work in multi-threaded |
1129 | programs, though, as the fd could already be closed and reused for another |
1146 | programs, though, as the fd could already be closed and reused for another |
1130 | thing, so beware. |
1147 | thing, so beware. |
|
|
1148 | |
|
|
1149 | =back |
|
|
1150 | |
|
|
1151 | =head2 WATCHER STATES |
|
|
1152 | |
|
|
1153 | There are various watcher states mentioned throughout this manual - |
|
|
1154 | active, pending and so on. In this section these states and the rules to |
|
|
1155 | transition between them will be described in more detail - and while these |
|
|
1156 | rules might look complicated, they usually do "the right thing". |
|
|
1157 | |
|
|
1158 | =over 4 |
|
|
1159 | |
|
|
1160 | =item initialiased |
|
|
1161 | |
|
|
1162 | Before a watcher can be registered with the event looop it has to be |
|
|
1163 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
|
|
1164 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
|
|
1165 | |
|
|
1166 | In this state it is simply some block of memory that is suitable for use |
|
|
1167 | in an event loop. It can be moved around, freed, reused etc. at will. |
|
|
1168 | |
|
|
1169 | =item started/running/active |
|
|
1170 | |
|
|
1171 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
|
|
1172 | property of the event loop, and is actively waiting for events. While in |
|
|
1173 | this state it cannot be accessed (except in a few documented ways), moved, |
|
|
1174 | freed or anything else - the only legal thing is to keep a pointer to it, |
|
|
1175 | and call libev functions on it that are documented to work on active watchers. |
|
|
1176 | |
|
|
1177 | =item pending |
|
|
1178 | |
|
|
1179 | If a watcher is active and libev determines that an event it is interested |
|
|
1180 | in has occurred (such as a timer expiring), it will become pending. It will |
|
|
1181 | stay in this pending state until either it is stopped or its callback is |
|
|
1182 | about to be invoked, so it is not normally pending inside the watcher |
|
|
1183 | callback. |
|
|
1184 | |
|
|
1185 | The watcher might or might not be active while it is pending (for example, |
|
|
1186 | an expired non-repeating timer can be pending but no longer active). If it |
|
|
1187 | is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>), |
|
|
1188 | but it is still property of the event loop at this time, so cannot be |
|
|
1189 | moved, freed or reused. And if it is active the rules described in the |
|
|
1190 | previous item still apply. |
|
|
1191 | |
|
|
1192 | It is also possible to feed an event on a watcher that is not active (e.g. |
|
|
1193 | via C<ev_feed_event>), in which case it becomes pending without being |
|
|
1194 | active. |
|
|
1195 | |
|
|
1196 | =item stopped |
|
|
1197 | |
|
|
1198 | A watcher can be stopped implicitly by libev (in which case it might still |
|
|
1199 | be pending), or explicitly by calling its C<ev_TYPE_stop> function. The |
|
|
1200 | latter will clear any pending state the watcher might be in, regardless |
|
|
1201 | of whether it was active or not, so stopping a watcher explicitly before |
|
|
1202 | freeing it is often a good idea. |
|
|
1203 | |
|
|
1204 | While stopped (and not pending) the watcher is essentially in the |
|
|
1205 | initialised state, that is it can be reused, moved, modified in any way |
|
|
1206 | you wish. |
1131 | |
1207 | |
1132 | =back |
1208 | =back |
1133 | |
1209 | |
1134 | =head2 GENERIC WATCHER FUNCTIONS |
1210 | =head2 GENERIC WATCHER FUNCTIONS |
1135 | |
1211 | |
… | |
… | |
3008 | disadvantage of having to use multiple event loops (which do not support |
3084 | disadvantage of having to use multiple event loops (which do not support |
3009 | signal watchers). |
3085 | signal watchers). |
3010 | |
3086 | |
3011 | When this is not possible, or you want to use the default loop for |
3087 | When this is not possible, or you want to use the default loop for |
3012 | other reasons, then in the process that wants to start "fresh", call |
3088 | other reasons, then in the process that wants to start "fresh", call |
3013 | C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying |
3089 | C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>. |
3014 | the default loop will "orphan" (not stop) all registered watchers, so you |
3090 | Destroying the default loop will "orphan" (not stop) all registered |
3015 | have to be careful not to execute code that modifies those watchers. Note |
3091 | watchers, so you have to be careful not to execute code that modifies |
3016 | also that in that case, you have to re-register any signal watchers. |
3092 | those watchers. Note also that in that case, you have to re-register any |
|
|
3093 | signal watchers. |
3017 | |
3094 | |
3018 | =head3 Watcher-Specific Functions and Data Members |
3095 | =head3 Watcher-Specific Functions and Data Members |
3019 | |
3096 | |
3020 | =over 4 |
3097 | =over 4 |
3021 | |
3098 | |
3022 | =item ev_fork_init (ev_signal *, callback) |
3099 | =item ev_fork_init (ev_fork *, callback) |
3023 | |
3100 | |
3024 | Initialises and configures the fork watcher - it has no parameters of any |
3101 | Initialises and configures the fork watcher - it has no parameters of any |
3025 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
3102 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
3026 | believe me. |
3103 | believe me. |
3027 | |
3104 | |
3028 | =back |
3105 | =back |
|
|
3106 | |
|
|
3107 | |
|
|
3108 | =head2 C<ev_cleanup> - even the best things end |
|
|
3109 | |
|
|
3110 | Cleanup watchers are called just before the event loop is being destroyed |
|
|
3111 | by a call to C<ev_loop_destroy>. |
|
|
3112 | |
|
|
3113 | While there is no guarantee that the event loop gets destroyed, cleanup |
|
|
3114 | watchers provide a convenient method to install cleanup hooks for your |
|
|
3115 | program, worker threads and so on - you just to make sure to destroy the |
|
|
3116 | loop when you want them to be invoked. |
|
|
3117 | |
|
|
3118 | Cleanup watchers are invoked in the same way as any other watcher. Unlike |
|
|
3119 | all other watchers, they do not keep a reference to the event loop (which |
|
|
3120 | makes a lot of sense if you think about it). Like all other watchers, you |
|
|
3121 | can call libev functions in the callback, except C<ev_cleanup_start>. |
|
|
3122 | |
|
|
3123 | =head3 Watcher-Specific Functions and Data Members |
|
|
3124 | |
|
|
3125 | =over 4 |
|
|
3126 | |
|
|
3127 | =item ev_cleanup_init (ev_cleanup *, callback) |
|
|
3128 | |
|
|
3129 | Initialises and configures the cleanup watcher - it has no parameters of |
|
|
3130 | any kind. There is a C<ev_cleanup_set> macro, but using it is utterly |
|
|
3131 | pointless, believe me. |
|
|
3132 | |
|
|
3133 | =back |
|
|
3134 | |
|
|
3135 | Example: Register an atexit handler to destroy the default loop, so any |
|
|
3136 | cleanup functions are called. |
|
|
3137 | |
|
|
3138 | static void |
|
|
3139 | program_exits (void) |
|
|
3140 | { |
|
|
3141 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
3142 | } |
|
|
3143 | |
|
|
3144 | ... |
|
|
3145 | atexit (program_exits); |
3029 | |
3146 | |
3030 | |
3147 | |
3031 | =head2 C<ev_async> - how to wake up an event loop |
3148 | =head2 C<ev_async> - how to wake up an event loop |
3032 | |
3149 | |
3033 | In general, you cannot use an C<ev_run> from multiple threads or other |
3150 | In general, you cannot use an C<ev_run> from multiple threads or other |
… | |
… | |
4467 | =head3 C<kqueue> is buggy |
4584 | =head3 C<kqueue> is buggy |
4468 | |
4585 | |
4469 | The kqueue syscall is broken in all known versions - most versions support |
4586 | The kqueue syscall is broken in all known versions - most versions support |
4470 | only sockets, many support pipes. |
4587 | only sockets, many support pipes. |
4471 | |
4588 | |
4472 | Libev tries to work around this by not using C<kqueue> by default on |
4589 | Libev tries to work around this by not using C<kqueue> by default on this |
4473 | this rotten platform, but of course you can still ask for it when creating |
4590 | rotten platform, but of course you can still ask for it when creating a |
4474 | a loop. |
4591 | loop - embedding a socket-only kqueue loop into a select-based one is |
|
|
4592 | probably going to work well. |
4475 | |
4593 | |
4476 | =head3 C<poll> is buggy |
4594 | =head3 C<poll> is buggy |
4477 | |
4595 | |
4478 | Instead of fixing C<kqueue>, Apple replaced their (working) C<poll> |
4596 | Instead of fixing C<kqueue>, Apple replaced their (working) C<poll> |
4479 | implementation by something calling C<kqueue> internally around the 10.5.6 |
4597 | implementation by something calling C<kqueue> internally around the 10.5.6 |
… | |
… | |
4498 | |
4616 | |
4499 | =head3 C<errno> reentrancy |
4617 | =head3 C<errno> reentrancy |
4500 | |
4618 | |
4501 | The default compile environment on Solaris is unfortunately so |
4619 | The default compile environment on Solaris is unfortunately so |
4502 | thread-unsafe that you can't even use components/libraries compiled |
4620 | thread-unsafe that you can't even use components/libraries compiled |
4503 | without C<-D_REENTRANT> (as long as they use C<errno>), which, of course, |
4621 | without C<-D_REENTRANT> in a threaded program, which, of course, isn't |
4504 | isn't defined by default. |
4622 | defined by default. A valid, if stupid, implementation choice. |
4505 | |
4623 | |
4506 | If you want to use libev in threaded environments you have to make sure |
4624 | If you want to use libev in threaded environments you have to make sure |
4507 | it's compiled with C<_REENTRANT> defined. |
4625 | it's compiled with C<_REENTRANT> defined. |
4508 | |
4626 | |
4509 | =head3 Event port backend |
4627 | =head3 Event port backend |
4510 | |
4628 | |
4511 | The scalable event interface for Solaris is called "event ports". Unfortunately, |
4629 | The scalable event interface for Solaris is called "event |
4512 | this mechanism is very buggy. If you run into high CPU usage, your program |
4630 | ports". Unfortunately, this mechanism is very buggy in all major |
|
|
4631 | releases. If you run into high CPU usage, your program freezes or you get |
4513 | freezes or you get a large number of spurious wakeups, make sure you have |
4632 | a large number of spurious wakeups, make sure you have all the relevant |
4514 | all the relevant and latest kernel patches applied. No, I don't know which |
4633 | and latest kernel patches applied. No, I don't know which ones, but there |
4515 | ones, but there are multiple ones. |
4634 | are multiple ones to apply, and afterwards, event ports actually work |
|
|
4635 | great. |
4516 | |
4636 | |
4517 | If you can't get it to work, you can try running the program by setting |
4637 | If you can't get it to work, you can try running the program by setting |
4518 | the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and |
4638 | the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and |
4519 | C<select> backends. |
4639 | C<select> backends. |
4520 | |
4640 | |
4521 | =head2 AIX POLL BUG |
4641 | =head2 AIX POLL BUG |
4522 | |
4642 | |
4523 | AIX unfortunately has a broken C<poll.h> header. Libev works around |
4643 | AIX unfortunately has a broken C<poll.h> header. Libev works around |
4524 | this by trying to avoid the poll backend altogether (i.e. it's not even |
4644 | this by trying to avoid the poll backend altogether (i.e. it's not even |
4525 | compiled in), which normally isn't a big problem as C<select> works fine |
4645 | compiled in), which normally isn't a big problem as C<select> works fine |
4526 | with large bitsets, and AIX is dead anyway. |
4646 | with large bitsets on AIX, and AIX is dead anyway. |
4527 | |
4647 | |
4528 | =head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS |
4648 | =head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS |
4529 | |
4649 | |
4530 | =head3 General issues |
4650 | =head3 General issues |
4531 | |
4651 | |
… | |
… | |
4760 | compatibility, so most programs should still compile. Those might be |
4880 | compatibility, so most programs should still compile. Those might be |
4761 | removed in later versions of libev, so better update early than late. |
4881 | removed in later versions of libev, so better update early than late. |
4762 | |
4882 | |
4763 | =over 4 |
4883 | =over 4 |
4764 | |
4884 | |
|
|
4885 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
|
|
4886 | |
|
|
4887 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
|
|
4888 | |
|
|
4889 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
4890 | ev_loop_fork (EV_DEFAULT); |
|
|
4891 | |
4765 | =item function/symbol renames |
4892 | =item function/symbol renames |
4766 | |
4893 | |
4767 | A number of functions and symbols have been renamed: |
4894 | A number of functions and symbols have been renamed: |
4768 | |
4895 | |
4769 | ev_loop => ev_run |
4896 | ev_loop => ev_run |
… | |
… | |
4808 | |
4935 | |
4809 | =over 4 |
4936 | =over 4 |
4810 | |
4937 | |
4811 | =item active |
4938 | =item active |
4812 | |
4939 | |
4813 | A watcher is active as long as it has been started (has been attached to |
4940 | A watcher is active as long as it has been started and not yet stopped. |
4814 | an event loop) but not yet stopped (disassociated from the event loop). |
4941 | See L<WATCHER STATES> for details. |
4815 | |
4942 | |
4816 | =item application |
4943 | =item application |
4817 | |
4944 | |
4818 | In this document, an application is whatever is using libev. |
4945 | In this document, an application is whatever is using libev. |
|
|
4946 | |
|
|
4947 | =item backend |
|
|
4948 | |
|
|
4949 | The part of the code dealing with the operating system interfaces. |
4819 | |
4950 | |
4820 | =item callback |
4951 | =item callback |
4821 | |
4952 | |
4822 | The address of a function that is called when some event has been |
4953 | The address of a function that is called when some event has been |
4823 | detected. Callbacks are being passed the event loop, the watcher that |
4954 | detected. Callbacks are being passed the event loop, the watcher that |
4824 | received the event, and the actual event bitset. |
4955 | received the event, and the actual event bitset. |
4825 | |
4956 | |
4826 | =item callback invocation |
4957 | =item callback/watcher invocation |
4827 | |
4958 | |
4828 | The act of calling the callback associated with a watcher. |
4959 | The act of calling the callback associated with a watcher. |
4829 | |
4960 | |
4830 | =item event |
4961 | =item event |
4831 | |
4962 | |
… | |
… | |
4850 | The model used to describe how an event loop handles and processes |
4981 | The model used to describe how an event loop handles and processes |
4851 | watchers and events. |
4982 | watchers and events. |
4852 | |
4983 | |
4853 | =item pending |
4984 | =item pending |
4854 | |
4985 | |
4855 | A watcher is pending as soon as the corresponding event has been detected, |
4986 | A watcher is pending as soon as the corresponding event has been |
4856 | and stops being pending as soon as the watcher will be invoked or its |
4987 | detected. See L<WATCHER STATES> for details. |
4857 | pending status is explicitly cleared by the application. |
|
|
4858 | |
|
|
4859 | A watcher can be pending, but not active. Stopping a watcher also clears |
|
|
4860 | its pending status. |
|
|
4861 | |
4988 | |
4862 | =item real time |
4989 | =item real time |
4863 | |
4990 | |
4864 | The physical time that is observed. It is apparently strictly monotonic :) |
4991 | The physical time that is observed. It is apparently strictly monotonic :) |
4865 | |
4992 | |
… | |
… | |
4872 | =item watcher |
4999 | =item watcher |
4873 | |
5000 | |
4874 | A data structure that describes interest in certain events. Watchers need |
5001 | A data structure that describes interest in certain events. Watchers need |
4875 | to be started (attached to an event loop) before they can receive events. |
5002 | to be started (attached to an event loop) before they can receive events. |
4876 | |
5003 | |
4877 | =item watcher invocation |
|
|
4878 | |
|
|
4879 | The act of calling the callback associated with a watcher. |
|
|
4880 | |
|
|
4881 | =back |
5004 | =back |
4882 | |
5005 | |
4883 | =head1 AUTHOR |
5006 | =head1 AUTHOR |
4884 | |
5007 | |
4885 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. |
5008 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. |