… | |
… | |
260 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
260 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
261 | |
261 | |
262 | If you don't know what event loop to use, use the one returned from this |
262 | If you don't know what event loop to use, use the one returned from this |
263 | function. |
263 | function. |
264 | |
264 | |
|
|
265 | The default loop is the only loop that can handle C<ev_signal> and |
|
|
266 | C<ev_child> watchers, and to do this, it always registers a handler |
|
|
267 | for C<SIGCHLD>. If this is a problem for your app you can either |
|
|
268 | create a dynamic loop with C<ev_loop_new> that doesn't do that, or you |
|
|
269 | can simply overwrite the C<SIGCHLD> signal handler I<after> calling |
|
|
270 | C<ev_default_init>. |
|
|
271 | |
265 | The flags argument can be used to specify special behaviour or specific |
272 | The flags argument can be used to specify special behaviour or specific |
266 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
273 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
267 | |
274 | |
268 | The following flags are supported: |
275 | The following flags are supported: |
269 | |
276 | |
… | |
… | |
403 | While this backend scales well, it requires one system call per active |
410 | While this backend scales well, it requires one system call per active |
404 | file descriptor per loop iteration. For small and medium numbers of file |
411 | file descriptor per loop iteration. For small and medium numbers of file |
405 | descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend |
412 | descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend |
406 | might perform better. |
413 | might perform better. |
407 | |
414 | |
|
|
415 | On the positive side, ignoring the spurious readyness notifications, this |
|
|
416 | backend actually performed to specification in all tests and is fully |
|
|
417 | embeddable, which is a rare feat among the OS-specific backends. |
|
|
418 | |
408 | =item C<EVBACKEND_ALL> |
419 | =item C<EVBACKEND_ALL> |
409 | |
420 | |
410 | Try all backends (even potentially broken ones that wouldn't be tried |
421 | Try all backends (even potentially broken ones that wouldn't be tried |
411 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
422 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
412 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
423 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
… | |
… | |
414 | It is definitely not recommended to use this flag. |
425 | It is definitely not recommended to use this flag. |
415 | |
426 | |
416 | =back |
427 | =back |
417 | |
428 | |
418 | If one or more of these are ored into the flags value, then only these |
429 | If one or more of these are ored into the flags value, then only these |
419 | backends will be tried (in the reverse order as given here). If none are |
430 | backends will be tried (in the reverse order as listed here). If none are |
420 | specified, most compiled-in backend will be tried, usually in reverse |
431 | specified, all backends in C<ev_recommended_backends ()> will be tried. |
421 | order of their flag values :) |
|
|
422 | |
432 | |
423 | The most typical usage is like this: |
433 | The most typical usage is like this: |
424 | |
434 | |
425 | if (!ev_default_loop (0)) |
435 | if (!ev_default_loop (0)) |
426 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
436 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
… | |
… | |
473 | Like C<ev_default_destroy>, but destroys an event loop created by an |
483 | Like C<ev_default_destroy>, but destroys an event loop created by an |
474 | earlier call to C<ev_loop_new>. |
484 | earlier call to C<ev_loop_new>. |
475 | |
485 | |
476 | =item ev_default_fork () |
486 | =item ev_default_fork () |
477 | |
487 | |
|
|
488 | This function sets a flag that causes subsequent C<ev_loop> iterations |
478 | This function reinitialises the kernel state for backends that have |
489 | to reinitialise the kernel state for backends that have one. Despite the |
479 | one. Despite the name, you can call it anytime, but it makes most sense |
490 | name, you can call it anytime, but it makes most sense after forking, in |
480 | after forking, in either the parent or child process (or both, but that |
491 | the child process (or both child and parent, but that again makes little |
481 | again makes little sense). |
492 | sense). You I<must> call it in the child before using any of the libev |
|
|
493 | functions, and it will only take effect at the next C<ev_loop> iteration. |
482 | |
494 | |
483 | You I<must> call this function in the child process after forking if and |
495 | On the other hand, you only need to call this function in the child |
484 | only if you want to use the event library in both processes. If you just |
496 | process if and only if you want to use the event library in the child. If |
485 | fork+exec, you don't have to call it. |
497 | you just fork+exec, you don't have to call it at all. |
486 | |
498 | |
487 | The function itself is quite fast and it's usually not a problem to call |
499 | The function itself is quite fast and it's usually not a problem to call |
488 | it just in case after a fork. To make this easy, the function will fit in |
500 | it just in case after a fork. To make this easy, the function will fit in |
489 | quite nicely into a call to C<pthread_atfork>: |
501 | quite nicely into a call to C<pthread_atfork>: |
490 | |
502 | |
491 | pthread_atfork (0, 0, ev_default_fork); |
503 | pthread_atfork (0, 0, ev_default_fork); |
492 | |
|
|
493 | At the moment, C<EVBACKEND_SELECT> and C<EVBACKEND_POLL> are safe to use |
|
|
494 | without calling this function, so if you force one of those backends you |
|
|
495 | do not need to care. |
|
|
496 | |
504 | |
497 | =item ev_loop_fork (loop) |
505 | =item ev_loop_fork (loop) |
498 | |
506 | |
499 | Like C<ev_default_fork>, but acts on an event loop created by |
507 | Like C<ev_default_fork>, but acts on an event loop created by |
500 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
508 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
… | |
… | |
551 | usually a better approach for this kind of thing. |
559 | usually a better approach for this kind of thing. |
552 | |
560 | |
553 | Here are the gory details of what C<ev_loop> does: |
561 | Here are the gory details of what C<ev_loop> does: |
554 | |
562 | |
555 | - Before the first iteration, call any pending watchers. |
563 | - Before the first iteration, call any pending watchers. |
556 | * If there are no active watchers (reference count is zero), return. |
564 | * If EVFLAG_FORKCHECK was used, check for a fork. |
557 | - Queue all prepare watchers and then call all outstanding watchers. |
565 | - If a fork was detected, queue and call all fork watchers. |
|
|
566 | - Queue and call all prepare watchers. |
558 | - If we have been forked, recreate the kernel state. |
567 | - If we have been forked, recreate the kernel state. |
559 | - Update the kernel state with all outstanding changes. |
568 | - Update the kernel state with all outstanding changes. |
560 | - Update the "event loop time". |
569 | - Update the "event loop time". |
561 | - Calculate for how long to block. |
570 | - Calculate for how long to sleep or block, if at all |
|
|
571 | (active idle watchers, EVLOOP_NONBLOCK or not having |
|
|
572 | any active watchers at all will result in not sleeping). |
|
|
573 | - Sleep if the I/O and timer collect interval say so. |
562 | - Block the process, waiting for any events. |
574 | - Block the process, waiting for any events. |
563 | - Queue all outstanding I/O (fd) events. |
575 | - Queue all outstanding I/O (fd) events. |
564 | - Update the "event loop time" and do time jump handling. |
576 | - Update the "event loop time" and do time jump handling. |
565 | - Queue all outstanding timers. |
577 | - Queue all outstanding timers. |
566 | - Queue all outstanding periodics. |
578 | - Queue all outstanding periodics. |
567 | - If no events are pending now, queue all idle watchers. |
579 | - If no events are pending now, queue all idle watchers. |
568 | - Queue all check watchers. |
580 | - Queue all check watchers. |
569 | - Call all queued watchers in reverse order (i.e. check watchers first). |
581 | - Call all queued watchers in reverse order (i.e. check watchers first). |
570 | Signals and child watchers are implemented as I/O watchers, and will |
582 | Signals and child watchers are implemented as I/O watchers, and will |
571 | be handled here by queueing them when their watcher gets executed. |
583 | be handled here by queueing them when their watcher gets executed. |
572 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
584 | - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
573 | were used, return, otherwise continue with step *. |
585 | were used, or there are no active watchers, return, otherwise |
|
|
586 | continue with step *. |
574 | |
587 | |
575 | Example: Queue some jobs and then loop until no events are outsanding |
588 | Example: Queue some jobs and then loop until no events are outstanding |
576 | anymore. |
589 | anymore. |
577 | |
590 | |
578 | ... queue jobs here, make sure they register event watchers as long |
591 | ... queue jobs here, make sure they register event watchers as long |
579 | ... as they still have work to do (even an idle watcher will do..) |
592 | ... as they still have work to do (even an idle watcher will do..) |
580 | ev_loop (my_loop, 0); |
593 | ev_loop (my_loop, 0); |
… | |
… | |
584 | |
597 | |
585 | Can be used to make a call to C<ev_loop> return early (but only after it |
598 | Can be used to make a call to C<ev_loop> return early (but only after it |
586 | has processed all outstanding events). The C<how> argument must be either |
599 | has processed all outstanding events). The C<how> argument must be either |
587 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
600 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
588 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
601 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
|
|
602 | |
|
|
603 | This "unloop state" will be cleared when entering C<ev_loop> again. |
589 | |
604 | |
590 | =item ev_ref (loop) |
605 | =item ev_ref (loop) |
591 | |
606 | |
592 | =item ev_unref (loop) |
607 | =item ev_unref (loop) |
593 | |
608 | |
… | |
… | |
598 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
613 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
599 | example, libev itself uses this for its internal signal pipe: It is not |
614 | example, libev itself uses this for its internal signal pipe: It is not |
600 | visible to the libev user and should not keep C<ev_loop> from exiting if |
615 | visible to the libev user and should not keep C<ev_loop> from exiting if |
601 | no event watchers registered by it are active. It is also an excellent |
616 | no event watchers registered by it are active. It is also an excellent |
602 | way to do this for generic recurring timers or from within third-party |
617 | way to do this for generic recurring timers or from within third-party |
603 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
618 | libraries. Just remember to I<unref after start> and I<ref before stop> |
|
|
619 | (but only if the watcher wasn't active before, or was active before, |
|
|
620 | respectively). |
604 | |
621 | |
605 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
622 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
606 | running when nothing else is active. |
623 | running when nothing else is active. |
607 | |
624 | |
608 | struct ev_signal exitsig; |
625 | struct ev_signal exitsig; |
… | |
… | |
756 | |
773 | |
757 | =item C<EV_FORK> |
774 | =item C<EV_FORK> |
758 | |
775 | |
759 | The event loop has been resumed in the child process after fork (see |
776 | The event loop has been resumed in the child process after fork (see |
760 | C<ev_fork>). |
777 | C<ev_fork>). |
|
|
778 | |
|
|
779 | =item C<EV_ASYNC> |
|
|
780 | |
|
|
781 | The given async watcher has been asynchronously notified (see C<ev_async>). |
761 | |
782 | |
762 | =item C<EV_ERROR> |
783 | =item C<EV_ERROR> |
763 | |
784 | |
764 | An unspecified error has occured, the watcher has been stopped. This might |
785 | An unspecified error has occured, the watcher has been stopped. This might |
765 | happen because the watcher could not be properly started because libev |
786 | happen because the watcher could not be properly started because libev |
… | |
… | |
1421 | |
1442 | |
1422 | =head3 Watcher-Specific Functions and Data Members |
1443 | =head3 Watcher-Specific Functions and Data Members |
1423 | |
1444 | |
1424 | =over 4 |
1445 | =over 4 |
1425 | |
1446 | |
1426 | =item ev_child_init (ev_child *, callback, int pid) |
1447 | =item ev_child_init (ev_child *, callback, int pid, int trace) |
1427 | |
1448 | |
1428 | =item ev_child_set (ev_child *, int pid) |
1449 | =item ev_child_set (ev_child *, int pid, int trace) |
1429 | |
1450 | |
1430 | Configures the watcher to wait for status changes of process C<pid> (or |
1451 | Configures the watcher to wait for status changes of process C<pid> (or |
1431 | I<any> process if C<pid> is specified as C<0>). The callback can look |
1452 | I<any> process if C<pid> is specified as C<0>). The callback can look |
1432 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1453 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1433 | the status word (use the macros from C<sys/wait.h> and see your systems |
1454 | the status word (use the macros from C<sys/wait.h> and see your systems |
1434 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1455 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1435 | process causing the status change. |
1456 | process causing the status change. C<trace> must be either C<0> (only |
|
|
1457 | activate the watcher when the process terminates) or C<1> (additionally |
|
|
1458 | activate the watcher when the process is stopped or continued). |
1436 | |
1459 | |
1437 | =item int pid [read-only] |
1460 | =item int pid [read-only] |
1438 | |
1461 | |
1439 | The process id this watcher watches out for, or C<0>, meaning any process id. |
1462 | The process id this watcher watches out for, or C<0>, meaning any process id. |
1440 | |
1463 | |
… | |
… | |
1676 | static void |
1699 | static void |
1677 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1700 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1678 | { |
1701 | { |
1679 | free (w); |
1702 | free (w); |
1680 | // now do something you wanted to do when the program has |
1703 | // now do something you wanted to do when the program has |
1681 | // no longer asnything immediate to do. |
1704 | // no longer anything immediate to do. |
1682 | } |
1705 | } |
1683 | |
1706 | |
1684 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1707 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1685 | ev_idle_init (idle_watcher, idle_cb); |
1708 | ev_idle_init (idle_watcher, idle_cb); |
1686 | ev_idle_start (loop, idle_cb); |
1709 | ev_idle_start (loop, idle_cb); |
… | |
… | |
2027 | believe me. |
2050 | believe me. |
2028 | |
2051 | |
2029 | =back |
2052 | =back |
2030 | |
2053 | |
2031 | |
2054 | |
|
|
2055 | =head2 C<ev_async> - how to wake up another event loop |
|
|
2056 | |
|
|
2057 | In general, you cannot use an C<ev_loop> from multiple threads or other |
|
|
2058 | asynchronous sources such as signal handlers (as opposed to multiple event |
|
|
2059 | loops - those are of course safe to use in different threads). |
|
|
2060 | |
|
|
2061 | Sometimes, however, you need to wake up another event loop you do not |
|
|
2062 | control, for example because it belongs to another thread. This is what |
|
|
2063 | C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you |
|
|
2064 | can signal it by calling C<ev_async_send>, which is thread- and signal |
|
|
2065 | safe. |
|
|
2066 | |
|
|
2067 | This functionality is very similar to C<ev_signal> watchers, as signals, |
|
|
2068 | too, are asynchronous in nature, and signals, too, will be compressed |
|
|
2069 | (i.e. the number of callback invocations may be less than the number of |
|
|
2070 | C<ev_async_sent> calls). |
|
|
2071 | |
|
|
2072 | Unlike C<ev_signal> watchers, C<ev_async> works with any event loop, not |
|
|
2073 | just the default loop. |
|
|
2074 | |
|
|
2075 | =head3 Queueing |
|
|
2076 | |
|
|
2077 | C<ev_async> does not support queueing of data in any way. The reason |
|
|
2078 | is that the author does not know of a simple (or any) algorithm for a |
|
|
2079 | multiple-writer-single-reader queue that works in all cases and doesn't |
|
|
2080 | need elaborate support such as pthreads. |
|
|
2081 | |
|
|
2082 | That means that if you want to queue data, you have to provide your own |
|
|
2083 | queue. But at least I can tell you would implement locking around your |
|
|
2084 | queue: |
|
|
2085 | |
|
|
2086 | =over 4 |
|
|
2087 | |
|
|
2088 | =item queueing from a signal handler context |
|
|
2089 | |
|
|
2090 | To implement race-free queueing, you simply add to the queue in the signal |
|
|
2091 | handler but you block the signal handler in the watcher callback. Here is an example that does that for |
|
|
2092 | some fictitiuous SIGUSR1 handler: |
|
|
2093 | |
|
|
2094 | static ev_async mysig; |
|
|
2095 | |
|
|
2096 | static void |
|
|
2097 | sigusr1_handler (void) |
|
|
2098 | { |
|
|
2099 | sometype data; |
|
|
2100 | |
|
|
2101 | // no locking etc. |
|
|
2102 | queue_put (data); |
|
|
2103 | ev_async_send (DEFAULT_ &mysig); |
|
|
2104 | } |
|
|
2105 | |
|
|
2106 | static void |
|
|
2107 | mysig_cb (EV_P_ ev_async *w, int revents) |
|
|
2108 | { |
|
|
2109 | sometype data; |
|
|
2110 | sigset_t block, prev; |
|
|
2111 | |
|
|
2112 | sigemptyset (&block); |
|
|
2113 | sigaddset (&block, SIGUSR1); |
|
|
2114 | sigprocmask (SIG_BLOCK, &block, &prev); |
|
|
2115 | |
|
|
2116 | while (queue_get (&data)) |
|
|
2117 | process (data); |
|
|
2118 | |
|
|
2119 | if (sigismember (&prev, SIGUSR1) |
|
|
2120 | sigprocmask (SIG_UNBLOCK, &block, 0); |
|
|
2121 | } |
|
|
2122 | |
|
|
2123 | (Note: pthreads in theory requires you to use C<pthread_setmask> |
|
|
2124 | instead of C<sigprocmask> when you use threads, but libev doesn't do it |
|
|
2125 | either...). |
|
|
2126 | |
|
|
2127 | =item queueing from a thread context |
|
|
2128 | |
|
|
2129 | The strategy for threads is different, as you cannot (easily) block |
|
|
2130 | threads but you can easily preempt them, so to queue safely you need to |
|
|
2131 | employ a traditional mutex lock, such as in this pthread example: |
|
|
2132 | |
|
|
2133 | static ev_async mysig; |
|
|
2134 | static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER; |
|
|
2135 | |
|
|
2136 | static void |
|
|
2137 | otherthread (void) |
|
|
2138 | { |
|
|
2139 | // only need to lock the actual queueing operation |
|
|
2140 | pthread_mutex_lock (&mymutex); |
|
|
2141 | queue_put (data); |
|
|
2142 | pthread_mutex_unlock (&mymutex); |
|
|
2143 | |
|
|
2144 | ev_async_send (DEFAULT_ &mysig); |
|
|
2145 | } |
|
|
2146 | |
|
|
2147 | static void |
|
|
2148 | mysig_cb (EV_P_ ev_async *w, int revents) |
|
|
2149 | { |
|
|
2150 | pthread_mutex_lock (&mymutex); |
|
|
2151 | |
|
|
2152 | while (queue_get (&data)) |
|
|
2153 | process (data); |
|
|
2154 | |
|
|
2155 | pthread_mutex_unlock (&mymutex); |
|
|
2156 | } |
|
|
2157 | |
|
|
2158 | =back |
|
|
2159 | |
|
|
2160 | |
|
|
2161 | =head3 Watcher-Specific Functions and Data Members |
|
|
2162 | |
|
|
2163 | =over 4 |
|
|
2164 | |
|
|
2165 | =item ev_async_init (ev_async *, callback) |
|
|
2166 | |
|
|
2167 | Initialises and configures the async watcher - it has no parameters of any |
|
|
2168 | kind. There is a C<ev_asynd_set> macro, but using it is utterly pointless, |
|
|
2169 | believe me. |
|
|
2170 | |
|
|
2171 | =item ev_async_send (loop, ev_async *) |
|
|
2172 | |
|
|
2173 | Sends/signals/activates the given C<ev_async> watcher, that is, feeds |
|
|
2174 | an C<EV_ASYNC> event on the watcher into the event loop. Unlike |
|
|
2175 | C<ev_feed_event>, this call is safe to do in other threads, signal or |
|
|
2176 | similar contexts (see the dicusssion of C<EV_ATOMIC_T> in the embedding |
|
|
2177 | section below on what exactly this means). |
|
|
2178 | |
|
|
2179 | This call incurs the overhead of a syscall only once per loop iteration, |
|
|
2180 | so while the overhead might be noticable, it doesn't apply to repeated |
|
|
2181 | calls to C<ev_async_send>. |
|
|
2182 | |
|
|
2183 | =back |
|
|
2184 | |
|
|
2185 | |
2032 | =head1 OTHER FUNCTIONS |
2186 | =head1 OTHER FUNCTIONS |
2033 | |
2187 | |
2034 | There are some other functions of possible interest. Described. Here. Now. |
2188 | There are some other functions of possible interest. Described. Here. Now. |
2035 | |
2189 | |
2036 | =over 4 |
2190 | =over 4 |
… | |
… | |
2263 | Example: Define a class with an IO and idle watcher, start one of them in |
2417 | Example: Define a class with an IO and idle watcher, start one of them in |
2264 | the constructor. |
2418 | the constructor. |
2265 | |
2419 | |
2266 | class myclass |
2420 | class myclass |
2267 | { |
2421 | { |
2268 | ev_io io; void io_cb (ev::io &w, int revents); |
2422 | ev::io io; void io_cb (ev::io &w, int revents); |
2269 | ev_idle idle void idle_cb (ev::idle &w, int revents); |
2423 | ev:idle idle void idle_cb (ev::idle &w, int revents); |
2270 | |
2424 | |
2271 | myclass (); |
2425 | myclass (int fd) |
2272 | } |
|
|
2273 | |
|
|
2274 | myclass::myclass (int fd) |
|
|
2275 | { |
2426 | { |
2276 | io .set <myclass, &myclass::io_cb > (this); |
2427 | io .set <myclass, &myclass::io_cb > (this); |
2277 | idle.set <myclass, &myclass::idle_cb> (this); |
2428 | idle.set <myclass, &myclass::idle_cb> (this); |
2278 | |
2429 | |
2279 | io.start (fd, ev::READ); |
2430 | io.start (fd, ev::READ); |
|
|
2431 | } |
2280 | } |
2432 | }; |
2281 | |
2433 | |
2282 | |
2434 | |
2283 | =head1 MACRO MAGIC |
2435 | =head1 MACRO MAGIC |
2284 | |
2436 | |
2285 | Libev can be compiled with a variety of options, the most fundamantal |
2437 | Libev can be compiled with a variety of options, the most fundamantal |
… | |
… | |
2541 | |
2693 | |
2542 | If defined to be C<1>, libev will compile in support for the Linux inotify |
2694 | If defined to be C<1>, libev will compile in support for the Linux inotify |
2543 | interface to speed up C<ev_stat> watchers. Its actual availability will |
2695 | interface to speed up C<ev_stat> watchers. Its actual availability will |
2544 | be detected at runtime. |
2696 | be detected at runtime. |
2545 | |
2697 | |
|
|
2698 | =item EV_ATOMIC_T |
|
|
2699 | |
|
|
2700 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
|
|
2701 | access is atomic with respect to other threads or signal contexts. No such |
|
|
2702 | type is easily found in the C language, so you can provide your own type |
|
|
2703 | that you know is safe for your purposes. It is used both for signal handler "locking" |
|
|
2704 | as well as for signal and thread safety in C<ev_async> watchers. |
|
|
2705 | |
|
|
2706 | In the absense of this define, libev will use C<sig_atomic_t volatile> |
|
|
2707 | (from F<signal.h>), which is usually good enough on most platforms. |
|
|
2708 | |
2546 | =item EV_H |
2709 | =item EV_H |
2547 | |
2710 | |
2548 | The name of the F<ev.h> header file used to include it. The default if |
2711 | The name of the F<ev.h> header file used to include it. The default if |
2549 | undefined is C<"ev.h"> in F<event.h> and F<ev.c>. This can be used to |
2712 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
2550 | virtually rename the F<ev.h> header file in case of conflicts. |
2713 | used to virtually rename the F<ev.h> header file in case of conflicts. |
2551 | |
2714 | |
2552 | =item EV_CONFIG_H |
2715 | =item EV_CONFIG_H |
2553 | |
2716 | |
2554 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2717 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2555 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2718 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2556 | C<EV_H>, above. |
2719 | C<EV_H>, above. |
2557 | |
2720 | |
2558 | =item EV_EVENT_H |
2721 | =item EV_EVENT_H |
2559 | |
2722 | |
2560 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2723 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2561 | of how the F<event.h> header can be found, the dfeault is C<"event.h">. |
2724 | of how the F<event.h> header can be found, the default is C<"event.h">. |
2562 | |
2725 | |
2563 | =item EV_PROTOTYPES |
2726 | =item EV_PROTOTYPES |
2564 | |
2727 | |
2565 | If defined to be C<0>, then F<ev.h> will not define any function |
2728 | If defined to be C<0>, then F<ev.h> will not define any function |
2566 | prototypes, but still define all the structs and other symbols. This is |
2729 | prototypes, but still define all the structs and other symbols. This is |
… | |
… | |
2615 | defined to be C<0>, then they are not. |
2778 | defined to be C<0>, then they are not. |
2616 | |
2779 | |
2617 | =item EV_FORK_ENABLE |
2780 | =item EV_FORK_ENABLE |
2618 | |
2781 | |
2619 | If undefined or defined to be C<1>, then fork watchers are supported. If |
2782 | If undefined or defined to be C<1>, then fork watchers are supported. If |
|
|
2783 | defined to be C<0>, then they are not. |
|
|
2784 | |
|
|
2785 | =item EV_ASYNC_ENABLE |
|
|
2786 | |
|
|
2787 | If undefined or defined to be C<1>, then async watchers are supported. If |
2620 | defined to be C<0>, then they are not. |
2788 | defined to be C<0>, then they are not. |
2621 | |
2789 | |
2622 | =item EV_MINIMAL |
2790 | =item EV_MINIMAL |
2623 | |
2791 | |
2624 | If you need to shave off some kilobytes of code at the expense of some |
2792 | If you need to shave off some kilobytes of code at the expense of some |
… | |
… | |
2745 | =item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers) |
2913 | =item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers) |
2746 | |
2914 | |
2747 | That means that changing a timer costs less than removing/adding them |
2915 | That means that changing a timer costs less than removing/adding them |
2748 | as only the relative motion in the event queue has to be paid for. |
2916 | as only the relative motion in the event queue has to be paid for. |
2749 | |
2917 | |
2750 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2918 | =item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1) |
2751 | |
2919 | |
2752 | These just add the watcher into an array or at the head of a list. |
2920 | These just add the watcher into an array or at the head of a list. |
2753 | |
2921 | |
2754 | =item Stopping check/prepare/idle watchers: O(1) |
2922 | =item Stopping check/prepare/idle/fork/async watchers: O(1) |
2755 | |
2923 | |
2756 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2924 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2757 | |
2925 | |
2758 | These watchers are stored in lists then need to be walked to find the |
2926 | These watchers are stored in lists then need to be walked to find the |
2759 | correct watcher to remove. The lists are usually short (you don't usually |
2927 | correct watcher to remove. The lists are usually short (you don't usually |
… | |
… | |
2775 | =item Priority handling: O(number_of_priorities) |
2943 | =item Priority handling: O(number_of_priorities) |
2776 | |
2944 | |
2777 | Priorities are implemented by allocating some space for each |
2945 | Priorities are implemented by allocating some space for each |
2778 | priority. When doing priority-based operations, libev usually has to |
2946 | priority. When doing priority-based operations, libev usually has to |
2779 | linearly search all the priorities, but starting/stopping and activating |
2947 | linearly search all the priorities, but starting/stopping and activating |
2780 | watchers becomes O(1) w.r.t. prioritiy handling. |
2948 | watchers becomes O(1) w.r.t. priority handling. |
|
|
2949 | |
|
|
2950 | =item Sending an ev_async: O(1) |
|
|
2951 | |
|
|
2952 | =item Processing ev_async_send: O(number_of_async_watchers) |
|
|
2953 | |
|
|
2954 | =item Processing signals: O(max_signal_number) |
|
|
2955 | |
|
|
2956 | Sending involves a syscall I<iff> there were no other C<ev_async_send> |
|
|
2957 | calls in the current loop iteration. Checking for async and signal events |
|
|
2958 | involves iterating over all running async watchers or all signal numbers. |
2781 | |
2959 | |
2782 | =back |
2960 | =back |
2783 | |
2961 | |
2784 | |
2962 | |
2785 | =head1 Win32 platform limitations and workarounds |
2963 | =head1 Win32 platform limitations and workarounds |