… | |
… | |
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); |
… | |
… | |
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. Also interetsing is the combination of |
170 | you actually want to know. Also interesting is the combination of |
171 | C<ev_update_now> and C<ev_now>. |
171 | C<ev_update_now> and C<ev_now>. |
172 | |
172 | |
173 | =item ev_sleep (ev_tstamp interval) |
173 | =item ev_sleep (ev_tstamp interval) |
174 | |
174 | |
175 | 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 |
… | |
… | |
193 | as this indicates an incompatible change. Minor versions are usually |
193 | as this indicates an incompatible change. Minor versions are usually |
194 | 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 |
195 | not a problem. |
195 | not a problem. |
196 | |
196 | |
197 | 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 |
198 | version (note, however, that this will not detect ABI mismatches :). |
198 | version (note, however, that this will not detect other ABI mismatches, |
|
|
199 | such as LFS or reentrancy). |
199 | |
200 | |
200 | assert (("libev version mismatch", |
201 | assert (("libev version mismatch", |
201 | ev_version_major () == EV_VERSION_MAJOR |
202 | ev_version_major () == EV_VERSION_MAJOR |
202 | && ev_version_minor () >= EV_VERSION_MINOR)); |
203 | && ev_version_minor () >= EV_VERSION_MINOR)); |
203 | |
204 | |
… | |
… | |
292 | ... |
293 | ... |
293 | ev_set_syserr_cb (fatal_error); |
294 | ev_set_syserr_cb (fatal_error); |
294 | |
295 | |
295 | =back |
296 | =back |
296 | |
297 | |
297 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
298 | =head1 FUNCTIONS CONTROLLING EVENT LOOPS |
298 | |
299 | |
299 | 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 |
300 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
301 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
301 | libev 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). |
302 | |
303 | |
… | |
… | |
306 | |
307 | |
307 | =over 4 |
308 | =over 4 |
308 | |
309 | |
309 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
310 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
310 | |
311 | |
311 | 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 |
312 | 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 |
313 | 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 |
314 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
315 | C<ev_loop_new>. |
|
|
316 | |
|
|
317 | If the default loop is already initialised then this function simply |
|
|
318 | returns it (and ignores the flags. If that is troubling you, check |
|
|
319 | C<ev_backend ()> afterwards). Otherwise it will create it with the given |
|
|
320 | flags, which should almost always be C<0>, unless the caller is also the |
|
|
321 | one calling C<ev_run> or otherwise qualifies as "the main program". |
315 | |
322 | |
316 | 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 |
317 | function. |
324 | function (or via the C<EV_DEFAULT> macro). |
318 | |
325 | |
319 | 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 |
320 | 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 |
321 | as loops cannot be shared easily between threads anyway). |
328 | that this case is unlikely, as loops cannot be shared easily between |
|
|
329 | threads anyway). |
322 | |
330 | |
323 | 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, |
324 | 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 |
325 | 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 |
326 | 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 |
327 | can simply overwrite the C<SIGCHLD> signal handler I<after> calling |
335 | C<SIGCHLD> signal handler I<after> calling C<ev_default_init>. |
328 | 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 |
|
|
350 | could not be initialised, returns false. |
|
|
351 | |
|
|
352 | Note that this function I<is> thread-safe, and one common way to use |
|
|
353 | libev with threads is indeed to create one loop per thread, and using the |
|
|
354 | default loop in the "main" or "initial" thread. |
329 | |
355 | |
330 | 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 |
331 | 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>). |
332 | |
358 | |
333 | The following flags are supported: |
359 | The following flags are supported: |
… | |
… | |
551 | 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, |
552 | 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 |
553 | 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 |
554 | ()> will be tried. |
580 | ()> will be tried. |
555 | |
581 | |
556 | Example: This is the most typical usage. |
|
|
557 | |
|
|
558 | if (!ev_default_loop (0)) |
|
|
559 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
|
560 | |
|
|
561 | Example: Restrict libev to the select and poll backends, and do not allow |
|
|
562 | environment settings to be taken into account: |
|
|
563 | |
|
|
564 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
|
|
565 | |
|
|
566 | Example: Use whatever libev has to offer, but make sure that kqueue is |
|
|
567 | used if available (warning, breaks stuff, best use only with your own |
|
|
568 | private event loop and only if you know the OS supports your types of |
|
|
569 | fds): |
|
|
570 | |
|
|
571 | ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
|
572 | |
|
|
573 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
|
|
574 | |
|
|
575 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
|
|
576 | always distinct from the default loop. |
|
|
577 | |
|
|
578 | Note that this function I<is> thread-safe, and one common way to use |
|
|
579 | libev with threads is indeed to create one loop per thread, and using the |
|
|
580 | default loop in the "main" or "initial" thread. |
|
|
581 | |
|
|
582 | 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. |
583 | |
583 | |
584 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
584 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
585 | if (!epoller) |
585 | if (!epoller) |
586 | fatal ("no epoll found here, maybe it hides under your chair"); |
586 | fatal ("no epoll found here, maybe it hides under your chair"); |
587 | |
587 | |
|
|
588 | Example: Use whatever libev has to offer, but make sure that kqueue is |
|
|
589 | used if available. |
|
|
590 | |
|
|
591 | struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
|
592 | |
588 | =item ev_default_destroy () |
593 | =item ev_loop_destroy (loop) |
589 | |
594 | |
590 | Destroys the default loop (frees all memory and kernel state etc.). None |
595 | Destroys an event loop object (frees all memory and kernel state |
591 | 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 |
592 | 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 |
593 | either stop all watchers cleanly yourself I<before> calling this function, |
598 | responsibility to either stop all watchers cleanly yourself I<before> |
594 | 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 |
595 | 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 |
|
|
601 | for example). |
596 | |
602 | |
597 | 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 |
598 | 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 |
599 | as signal and child watchers) would need to be stopped manually. |
605 | as signal and child watchers) would need to be stopped manually. |
600 | |
606 | |
601 | In general it is not advisable to call this function except in the |
607 | This function is normally used on loop objects allocated by |
602 | 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. |
603 | 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> |
604 | C<ev_loop_new> and C<ev_loop_destroy>. |
614 | and C<ev_loop_destroy>. |
605 | |
615 | |
606 | =item ev_loop_destroy (loop) |
616 | =item ev_loop_fork (loop) |
607 | |
617 | |
608 | Like C<ev_default_destroy>, but destroys an event loop created by an |
|
|
609 | earlier call to C<ev_loop_new>. |
|
|
610 | |
|
|
611 | =item ev_default_fork () |
|
|
612 | |
|
|
613 | 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 |
614 | to reinitialise the kernel state for backends that have one. Despite the |
619 | reinitialise the kernel state for backends that have one. Despite the |
615 | 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 |
616 | 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 |
617 | sense). You I<must> call it in the child before using any of the libev |
622 | child before resuming or calling C<ev_run>. |
618 | functions, and it will only take effect at the next C<ev_run> iteration. |
|
|
619 | |
623 | |
620 | 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 |
621 | 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 |
622 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
626 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
623 | during fork. |
627 | during fork. |
… | |
… | |
628 | 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 |
629 | 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 |
630 | costly reset of the backend). |
634 | costly reset of the backend). |
631 | |
635 | |
632 | 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 |
633 | it just in case after a fork. To make this easy, the function will fit in |
637 | it just in case after a fork. |
634 | quite nicely into a call to C<pthread_atfork>: |
|
|
635 | |
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 | ... |
636 | pthread_atfork (0, 0, ev_default_fork); |
649 | pthread_atfork (0, 0, post_fork_child); |
637 | |
|
|
638 | =item ev_loop_fork (loop) |
|
|
639 | |
|
|
640 | Like C<ev_default_fork>, but acts on an event loop created by |
|
|
641 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
|
|
642 | after fork that you want to re-use in the child, and how you keep track of |
|
|
643 | them is entirely your own problem. |
|
|
644 | |
650 | |
645 | =item int ev_is_default_loop (loop) |
651 | =item int ev_is_default_loop (loop) |
646 | |
652 | |
647 | 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 |
648 | otherwise. |
654 | otherwise. |
… | |
… | |
1106 | =item C<EV_FORK> |
1112 | =item C<EV_FORK> |
1107 | |
1113 | |
1108 | 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 |
1109 | C<ev_fork>). |
1115 | C<ev_fork>). |
1110 | |
1116 | |
|
|
1117 | =item C<EV_CLEANUP> |
|
|
1118 | |
|
|
1119 | The event loop is abotu to be destroyed (see C<ev_cleanup>). |
|
|
1120 | |
1111 | =item C<EV_ASYNC> |
1121 | =item C<EV_ASYNC> |
1112 | |
1122 | |
1113 | 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>). |
1114 | |
1124 | |
1115 | =item C<EV_CUSTOM> |
1125 | =item C<EV_CUSTOM> |
… | |
… | |
3074 | 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 |
3075 | signal watchers). |
3085 | signal watchers). |
3076 | |
3086 | |
3077 | 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 |
3078 | 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 |
3079 | C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying |
3089 | C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>. |
3080 | the default loop will "orphan" (not stop) all registered watchers, so you |
3090 | Destroying the default loop will "orphan" (not stop) all registered |
3081 | 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 |
3082 | 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. |
3083 | |
3094 | |
3084 | =head3 Watcher-Specific Functions and Data Members |
3095 | =head3 Watcher-Specific Functions and Data Members |
3085 | |
3096 | |
3086 | =over 4 |
3097 | =over 4 |
3087 | |
3098 | |
3088 | =item ev_fork_init (ev_signal *, callback) |
3099 | =item ev_fork_init (ev_fork *, callback) |
3089 | |
3100 | |
3090 | 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 |
3091 | 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, |
3092 | believe me. |
3103 | believe me. |
3093 | |
3104 | |
3094 | =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 they are registered |
|
|
3111 | with is being destroyed. |
|
|
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 | =head3 Watcher-Specific Functions and Data Members |
|
|
3119 | |
|
|
3120 | =over 4 |
|
|
3121 | |
|
|
3122 | =item ev_cleanup_init (ev_cleanup *, callback) |
|
|
3123 | |
|
|
3124 | Initialises and configures the cleanup watcher - it has no parameters of |
|
|
3125 | any kind. There is a C<ev_cleanup_set> macro, but using it is utterly |
|
|
3126 | pointless, believe me. |
|
|
3127 | |
|
|
3128 | =back |
|
|
3129 | |
|
|
3130 | Example: Register an atexit handler to destroy the default loop, so any |
|
|
3131 | cleanup functions are called. |
|
|
3132 | |
|
|
3133 | static void |
|
|
3134 | program_exits (void) |
|
|
3135 | { |
|
|
3136 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
3137 | } |
|
|
3138 | |
|
|
3139 | ... |
|
|
3140 | atexit (program_exits); |
3095 | |
3141 | |
3096 | |
3142 | |
3097 | =head2 C<ev_async> - how to wake up an event loop |
3143 | =head2 C<ev_async> - how to wake up an event loop |
3098 | |
3144 | |
3099 | In general, you cannot use an C<ev_run> from multiple threads or other |
3145 | In general, you cannot use an C<ev_run> from multiple threads or other |
… | |
… | |
4829 | compatibility, so most programs should still compile. Those might be |
4875 | compatibility, so most programs should still compile. Those might be |
4830 | removed in later versions of libev, so better update early than late. |
4876 | removed in later versions of libev, so better update early than late. |
4831 | |
4877 | |
4832 | =over 4 |
4878 | =over 4 |
4833 | |
4879 | |
|
|
4880 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
|
|
4881 | |
|
|
4882 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
|
|
4883 | |
|
|
4884 | ev_loop_destroy (EV_DEFAULT_UC); |
|
|
4885 | ev_loop_fork (EV_DEFAULT); |
|
|
4886 | |
4834 | =item function/symbol renames |
4887 | =item function/symbol renames |
4835 | |
4888 | |
4836 | A number of functions and symbols have been renamed: |
4889 | A number of functions and symbols have been renamed: |
4837 | |
4890 | |
4838 | ev_loop => ev_run |
4891 | ev_loop => ev_run |