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1 | =encoding utf-8 |
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2 | |
1 | =head1 NAME |
3 | =head1 NAME |
2 | |
4 | |
3 | libev - a high performance full-featured event loop written in C |
5 | libev - a high performance full-featured event loop written in C |
4 | |
6 | |
5 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
… | |
… | |
263 | |
265 | |
264 | You could override this function in high-availability programs to, say, |
266 | You could override this function in high-availability programs to, say, |
265 | free some memory if it cannot allocate memory, to use a special allocator, |
267 | free some memory if it cannot allocate memory, to use a special allocator, |
266 | or even to sleep a while and retry until some memory is available. |
268 | or even to sleep a while and retry until some memory is available. |
267 | |
269 | |
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270 | Example: The following is the C<realloc> function that libev itself uses |
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271 | which should work with C<realloc> and C<free> functions of all kinds and |
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272 | is probably a good basis for your own implementation. |
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273 | |
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274 | static void * |
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275 | ev_realloc_emul (void *ptr, long size) EV_NOEXCEPT |
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276 | { |
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277 | if (size) |
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278 | return realloc (ptr, size); |
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279 | |
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280 | free (ptr); |
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281 | return 0; |
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282 | } |
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283 | |
268 | Example: Replace the libev allocator with one that waits a bit and then |
284 | Example: Replace the libev allocator with one that waits a bit and then |
269 | retries (example requires a standards-compliant C<realloc>). |
285 | retries. |
270 | |
286 | |
271 | static void * |
287 | static void * |
272 | persistent_realloc (void *ptr, size_t size) |
288 | persistent_realloc (void *ptr, size_t size) |
273 | { |
289 | { |
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290 | if (!size) |
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291 | { |
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292 | free (ptr); |
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293 | return 0; |
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294 | } |
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295 | |
274 | for (;;) |
296 | for (;;) |
275 | { |
297 | { |
276 | void *newptr = realloc (ptr, size); |
298 | void *newptr = realloc (ptr, size); |
277 | |
299 | |
278 | if (newptr) |
300 | if (newptr) |
… | |
… | |
396 | |
418 | |
397 | If this flag bit is or'ed into the flag value (or the program runs setuid |
419 | If this flag bit is or'ed into the flag value (or the program runs setuid |
398 | or setgid) then libev will I<not> look at the environment variable |
420 | or setgid) then libev will I<not> look at the environment variable |
399 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
421 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
400 | override the flags completely if it is found in the environment. This is |
422 | override the flags completely if it is found in the environment. This is |
401 | useful to try out specific backends to test their performance, or to work |
423 | useful to try out specific backends to test their performance, to work |
402 | around bugs. |
424 | around bugs, or to make libev threadsafe (accessing environment variables |
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425 | cannot be done in a threadsafe way, but usually it works if no other |
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426 | thread modifies them). |
403 | |
427 | |
404 | =item C<EVFLAG_FORKCHECK> |
428 | =item C<EVFLAG_FORKCHECK> |
405 | |
429 | |
406 | Instead of calling C<ev_loop_fork> manually after a fork, you can also |
430 | Instead of calling C<ev_loop_fork> manually after a fork, you can also |
407 | make libev check for a fork in each iteration by enabling this flag. |
431 | make libev check for a fork in each iteration by enabling this flag. |
408 | |
432 | |
409 | This works by calling C<getpid ()> on every iteration of the loop, |
433 | This works by calling C<getpid ()> on every iteration of the loop, |
410 | and thus this might slow down your event loop if you do a lot of loop |
434 | and thus this might slow down your event loop if you do a lot of loop |
411 | iterations and little real work, but is usually not noticeable (on my |
435 | iterations and little real work, but is usually not noticeable (on my |
412 | GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence |
436 | GNU/Linux system for example, C<getpid> is actually a simple 5-insn |
413 | without a system call and thus I<very> fast, but my GNU/Linux system also has |
437 | sequence without a system call and thus I<very> fast, but my GNU/Linux |
414 | C<pthread_atfork> which is even faster). |
438 | system also has C<pthread_atfork> which is even faster). (Update: glibc |
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439 | versions 2.25 apparently removed the C<getpid> optimisation again). |
415 | |
440 | |
416 | The big advantage of this flag is that you can forget about fork (and |
441 | The big advantage of this flag is that you can forget about fork (and |
417 | forget about forgetting to tell libev about forking) when you use this |
442 | forget about forgetting to tell libev about forking, although you still |
418 | flag. |
443 | have to ignore C<SIGPIPE>) when you use this flag. |
419 | |
444 | |
420 | This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS> |
445 | This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS> |
421 | environment variable. |
446 | environment variable. |
422 | |
447 | |
423 | =item C<EVFLAG_NOINOTIFY> |
448 | =item C<EVFLAG_NOINOTIFY> |
… | |
… | |
678 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
703 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
679 | and C<ev_loop_destroy>. |
704 | and C<ev_loop_destroy>. |
680 | |
705 | |
681 | =item ev_loop_fork (loop) |
706 | =item ev_loop_fork (loop) |
682 | |
707 | |
683 | This function sets a flag that causes subsequent C<ev_run> iterations to |
708 | This function sets a flag that causes subsequent C<ev_run> iterations |
684 | reinitialise the kernel state for backends that have one. Despite the |
709 | to reinitialise the kernel state for backends that have one. Despite |
685 | name, you can call it anytime, but it makes most sense after forking, in |
710 | the name, you can call it anytime you are allowed to start or stop |
686 | the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the |
711 | watchers (except inside an C<ev_prepare> callback), but it makes most |
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712 | sense after forking, in the child process. You I<must> call it (or use |
687 | child before resuming or calling C<ev_run>. |
713 | C<EVFLAG_FORKCHECK>) in the child before resuming or calling C<ev_run>. |
688 | |
714 | |
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715 | In addition, if you want to reuse a loop (via this function or |
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716 | C<EVFLAG_FORKCHECK>), you I<also> have to ignore C<SIGPIPE>. |
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717 | |
689 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
718 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
690 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
719 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
691 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
720 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
692 | during fork. |
721 | during fork. |
693 | |
722 | |
694 | On the other hand, you only need to call this function in the child |
723 | On the other hand, you only need to call this function in the child |
… | |
… | |
2024 | |
2053 | |
2025 | The relative timeouts are calculated relative to the C<ev_now ()> |
2054 | The relative timeouts are calculated relative to the C<ev_now ()> |
2026 | time. This is usually the right thing as this timestamp refers to the time |
2055 | time. This is usually the right thing as this timestamp refers to the time |
2027 | of the event triggering whatever timeout you are modifying/starting. If |
2056 | of the event triggering whatever timeout you are modifying/starting. If |
2028 | you suspect event processing to be delayed and you I<need> to base the |
2057 | you suspect event processing to be delayed and you I<need> to base the |
2029 | timeout on the current time, use something like this to adjust for this: |
2058 | timeout on the current time, use something like the following to adjust |
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2059 | for it: |
2030 | |
2060 | |
2031 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
2061 | ev_timer_set (&timer, after + (ev_time () - ev_now ()), 0.); |
2032 | |
2062 | |
2033 | If the event loop is suspended for a long time, you can also force an |
2063 | If the event loop is suspended for a long time, you can also force an |
2034 | update of the time returned by C<ev_now ()> by calling C<ev_now_update |
2064 | update of the time returned by C<ev_now ()> by calling C<ev_now_update |
2035 | ()>. |
2065 | ()>, although that will push the event time of all outstanding events |
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2066 | further into the future. |
2036 | |
2067 | |
2037 | =head3 The special problem of unsynchronised clocks |
2068 | =head3 The special problem of unsynchronised clocks |
2038 | |
2069 | |
2039 | Modern systems have a variety of clocks - libev itself uses the normal |
2070 | Modern systems have a variety of clocks - libev itself uses the normal |
2040 | "wall clock" clock and, if available, the monotonic clock (to avoid time |
2071 | "wall clock" clock and, if available, the monotonic clock (to avoid time |
… | |
… | |
2103 | |
2134 | |
2104 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
2135 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
2105 | |
2136 | |
2106 | =item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat) |
2137 | =item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat) |
2107 | |
2138 | |
2108 | Configure the timer to trigger after C<after> seconds. If C<repeat> |
2139 | Configure the timer to trigger after C<after> seconds (fractional and |
2109 | is C<0.>, then it will automatically be stopped once the timeout is |
2140 | negative values are supported). If C<repeat> is C<0.>, then it will |
2110 | reached. If it is positive, then the timer will automatically be |
2141 | automatically be stopped once the timeout is reached. If it is positive, |
2111 | configured to trigger again C<repeat> seconds later, again, and again, |
2142 | then the timer will automatically be configured to trigger again C<repeat> |
2112 | until stopped manually. |
2143 | seconds later, again, and again, until stopped manually. |
2113 | |
2144 | |
2114 | The timer itself will do a best-effort at avoiding drift, that is, if |
2145 | The timer itself will do a best-effort at avoiding drift, that is, if |
2115 | you configure a timer to trigger every 10 seconds, then it will normally |
2146 | you configure a timer to trigger every 10 seconds, then it will normally |
2116 | trigger at exactly 10 second intervals. If, however, your program cannot |
2147 | trigger at exactly 10 second intervals. If, however, your program cannot |
2117 | keep up with the timer (because it takes longer than those 10 seconds to |
2148 | keep up with the timer (because it takes longer than those 10 seconds to |
… | |
… | |
2199 | Periodic watchers are also timers of a kind, but they are very versatile |
2230 | Periodic watchers are also timers of a kind, but they are very versatile |
2200 | (and unfortunately a bit complex). |
2231 | (and unfortunately a bit complex). |
2201 | |
2232 | |
2202 | Unlike C<ev_timer>, periodic watchers are not based on real time (or |
2233 | Unlike C<ev_timer>, periodic watchers are not based on real time (or |
2203 | relative time, the physical time that passes) but on wall clock time |
2234 | relative time, the physical time that passes) but on wall clock time |
2204 | (absolute time, the thing you can read on your calender or clock). The |
2235 | (absolute time, the thing you can read on your calendar or clock). The |
2205 | difference is that wall clock time can run faster or slower than real |
2236 | difference is that wall clock time can run faster or slower than real |
2206 | time, and time jumps are not uncommon (e.g. when you adjust your |
2237 | time, and time jumps are not uncommon (e.g. when you adjust your |
2207 | wrist-watch). |
2238 | wrist-watch). |
2208 | |
2239 | |
2209 | You can tell a periodic watcher to trigger after some specific point |
2240 | You can tell a periodic watcher to trigger after some specific point |
… | |
… | |
2214 | C<ev_timer>, which would still trigger roughly 10 seconds after starting |
2245 | C<ev_timer>, which would still trigger roughly 10 seconds after starting |
2215 | it, as it uses a relative timeout). |
2246 | it, as it uses a relative timeout). |
2216 | |
2247 | |
2217 | C<ev_periodic> watchers can also be used to implement vastly more complex |
2248 | C<ev_periodic> watchers can also be used to implement vastly more complex |
2218 | timers, such as triggering an event on each "midnight, local time", or |
2249 | timers, such as triggering an event on each "midnight, local time", or |
2219 | other complicated rules. This cannot be done with C<ev_timer> watchers, as |
2250 | other complicated rules. This cannot easily be done with C<ev_timer> |
2220 | those cannot react to time jumps. |
2251 | watchers, as those cannot react to time jumps. |
2221 | |
2252 | |
2222 | As with timers, the callback is guaranteed to be invoked only when the |
2253 | As with timers, the callback is guaranteed to be invoked only when the |
2223 | point in time where it is supposed to trigger has passed. If multiple |
2254 | point in time where it is supposed to trigger has passed. If multiple |
2224 | timers become ready during the same loop iteration then the ones with |
2255 | timers become ready during the same loop iteration then the ones with |
2225 | earlier time-out values are invoked before ones with later time-out values |
2256 | earlier time-out values are invoked before ones with later time-out values |
… | |
… | |
2311 | |
2342 | |
2312 | NOTE: I<< This callback must always return a time that is higher than or |
2343 | NOTE: I<< This callback must always return a time that is higher than or |
2313 | equal to the passed C<now> value >>. |
2344 | equal to the passed C<now> value >>. |
2314 | |
2345 | |
2315 | This can be used to create very complex timers, such as a timer that |
2346 | This can be used to create very complex timers, such as a timer that |
2316 | triggers on "next midnight, local time". To do this, you would calculate the |
2347 | triggers on "next midnight, local time". To do this, you would calculate |
2317 | next midnight after C<now> and return the timestamp value for this. How |
2348 | the next midnight after C<now> and return the timestamp value for |
2318 | you do this is, again, up to you (but it is not trivial, which is the main |
2349 | this. Here is a (completely untested, no error checking) example on how to |
2319 | reason I omitted it as an example). |
2350 | do this: |
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2351 | |
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2352 | #include <time.h> |
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2353 | |
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2354 | static ev_tstamp |
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2355 | my_rescheduler (ev_periodic *w, ev_tstamp now) |
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2356 | { |
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2357 | time_t tnow = (time_t)now; |
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2358 | struct tm tm; |
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2359 | localtime_r (&tnow, &tm); |
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2360 | |
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2361 | tm.tm_sec = tm.tm_min = tm.tm_hour = 0; // midnight current day |
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2362 | ++tm.tm_mday; // midnight next day |
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2363 | |
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2364 | return mktime (&tm); |
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2365 | } |
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2366 | |
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2367 | Note: this code might run into trouble on days that have more then two |
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2368 | midnights (beginning and end). |
2320 | |
2369 | |
2321 | =back |
2370 | =back |
2322 | |
2371 | |
2323 | =item ev_periodic_again (loop, ev_periodic *) |
2372 | =item ev_periodic_again (loop, ev_periodic *) |
2324 | |
2373 | |
… | |
… | |
2389 | |
2438 | |
2390 | ev_periodic hourly_tick; |
2439 | ev_periodic hourly_tick; |
2391 | ev_periodic_init (&hourly_tick, clock_cb, |
2440 | ev_periodic_init (&hourly_tick, clock_cb, |
2392 | fmod (ev_now (loop), 3600.), 3600., 0); |
2441 | fmod (ev_now (loop), 3600.), 3600., 0); |
2393 | ev_periodic_start (loop, &hourly_tick); |
2442 | ev_periodic_start (loop, &hourly_tick); |
2394 | |
2443 | |
2395 | |
2444 | |
2396 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
2445 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
2397 | |
2446 | |
2398 | Signal watchers will trigger an event when the process receives a specific |
2447 | Signal watchers will trigger an event when the process receives a specific |
2399 | signal one or more times. Even though signals are very asynchronous, libev |
2448 | signal one or more times. Even though signals are very asynchronous, libev |
… | |
… | |
2409 | only within the same loop, i.e. you can watch for C<SIGINT> in your |
2458 | only within the same loop, i.e. you can watch for C<SIGINT> in your |
2410 | default loop and for C<SIGIO> in another loop, but you cannot watch for |
2459 | default loop and for C<SIGIO> in another loop, but you cannot watch for |
2411 | C<SIGINT> in both the default loop and another loop at the same time. At |
2460 | C<SIGINT> in both the default loop and another loop at the same time. At |
2412 | the moment, C<SIGCHLD> is permanently tied to the default loop. |
2461 | the moment, C<SIGCHLD> is permanently tied to the default loop. |
2413 | |
2462 | |
2414 | When the first watcher gets started will libev actually register something |
2463 | Only after the first watcher for a signal is started will libev actually |
2415 | with the kernel (thus it coexists with your own signal handlers as long as |
2464 | register something with the kernel. It thus coexists with your own signal |
2416 | you don't register any with libev for the same signal). |
2465 | handlers as long as you don't register any with libev for the same signal. |
2417 | |
2466 | |
2418 | If possible and supported, libev will install its handlers with |
2467 | If possible and supported, libev will install its handlers with |
2419 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
2468 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
2420 | not be unduly interrupted. If you have a problem with system calls getting |
2469 | not be unduly interrupted. If you have a problem with system calls getting |
2421 | interrupted by signals you can block all signals in an C<ev_check> watcher |
2470 | interrupted by signals you can block all signals in an C<ev_check> watcher |
… | |
… | |
2606 | |
2655 | |
2607 | =head2 C<ev_stat> - did the file attributes just change? |
2656 | =head2 C<ev_stat> - did the file attributes just change? |
2608 | |
2657 | |
2609 | This watches a file system path for attribute changes. That is, it calls |
2658 | This watches a file system path for attribute changes. That is, it calls |
2610 | C<stat> on that path in regular intervals (or when the OS says it changed) |
2659 | C<stat> on that path in regular intervals (or when the OS says it changed) |
2611 | and sees if it changed compared to the last time, invoking the callback if |
2660 | and sees if it changed compared to the last time, invoking the callback |
2612 | it did. |
2661 | if it did. Starting the watcher C<stat>'s the file, so only changes that |
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2662 | happen after the watcher has been started will be reported. |
2613 | |
2663 | |
2614 | The path does not need to exist: changing from "path exists" to "path does |
2664 | The path does not need to exist: changing from "path exists" to "path does |
2615 | not exist" is a status change like any other. The condition "path does not |
2665 | not exist" is a status change like any other. The condition "path does not |
2616 | exist" (or more correctly "path cannot be stat'ed") is signified by the |
2666 | exist" (or more correctly "path cannot be stat'ed") is signified by the |
2617 | C<st_nlink> field being zero (which is otherwise always forced to be at |
2667 | C<st_nlink> field being zero (which is otherwise always forced to be at |
… | |
… | |
2902 | |
2952 | |
2903 | Prepare and check watchers are often (but not always) used in pairs: |
2953 | Prepare and check watchers are often (but not always) used in pairs: |
2904 | prepare watchers get invoked before the process blocks and check watchers |
2954 | prepare watchers get invoked before the process blocks and check watchers |
2905 | afterwards. |
2955 | afterwards. |
2906 | |
2956 | |
2907 | You I<must not> call C<ev_run> or similar functions that enter |
2957 | You I<must not> call C<ev_run> (or similar functions that enter the |
2908 | the current event loop from either C<ev_prepare> or C<ev_check> |
2958 | current event loop) or C<ev_loop_fork> from either C<ev_prepare> or |
2909 | watchers. Other loops than the current one are fine, however. The |
2959 | C<ev_check> watchers. Other loops than the current one are fine, |
2910 | rationale behind this is that you do not need to check for recursion in |
2960 | however. The rationale behind this is that you do not need to check |
2911 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2961 | for recursion in those watchers, i.e. the sequence will always be |
2912 | C<ev_check> so if you have one watcher of each kind they will always be |
2962 | C<ev_prepare>, blocking, C<ev_check> so if you have one watcher of each |
2913 | called in pairs bracketing the blocking call. |
2963 | kind they will always be called in pairs bracketing the blocking call. |
2914 | |
2964 | |
2915 | Their main purpose is to integrate other event mechanisms into libev and |
2965 | Their main purpose is to integrate other event mechanisms into libev and |
2916 | their use is somewhat advanced. They could be used, for example, to track |
2966 | their use is somewhat advanced. They could be used, for example, to track |
2917 | variable changes, implement your own watchers, integrate net-snmp or a |
2967 | variable changes, implement your own watchers, integrate net-snmp or a |
2918 | coroutine library and lots more. They are also occasionally useful if |
2968 | coroutine library and lots more. They are also occasionally useful if |
… | |
… | |
3208 | used). |
3258 | used). |
3209 | |
3259 | |
3210 | struct ev_loop *loop_hi = ev_default_init (0); |
3260 | struct ev_loop *loop_hi = ev_default_init (0); |
3211 | struct ev_loop *loop_lo = 0; |
3261 | struct ev_loop *loop_lo = 0; |
3212 | ev_embed embed; |
3262 | ev_embed embed; |
3213 | |
3263 | |
3214 | // see if there is a chance of getting one that works |
3264 | // see if there is a chance of getting one that works |
3215 | // (remember that a flags value of 0 means autodetection) |
3265 | // (remember that a flags value of 0 means autodetection) |
3216 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3266 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3217 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3267 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3218 | : 0; |
3268 | : 0; |
… | |
… | |
3232 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
3282 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
3233 | |
3283 | |
3234 | struct ev_loop *loop = ev_default_init (0); |
3284 | struct ev_loop *loop = ev_default_init (0); |
3235 | struct ev_loop *loop_socket = 0; |
3285 | struct ev_loop *loop_socket = 0; |
3236 | ev_embed embed; |
3286 | ev_embed embed; |
3237 | |
3287 | |
3238 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3288 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3239 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3289 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3240 | { |
3290 | { |
3241 | ev_embed_init (&embed, 0, loop_socket); |
3291 | ev_embed_init (&embed, 0, loop_socket); |
3242 | ev_embed_start (loop, &embed); |
3292 | ev_embed_start (loop, &embed); |
… | |
… | |
3258 | and calls it in the wrong process, the fork handlers will be invoked, too, |
3308 | and calls it in the wrong process, the fork handlers will be invoked, too, |
3259 | of course. |
3309 | of course. |
3260 | |
3310 | |
3261 | =head3 The special problem of life after fork - how is it possible? |
3311 | =head3 The special problem of life after fork - how is it possible? |
3262 | |
3312 | |
3263 | Most uses of C<fork()> consist of forking, then some simple calls to set |
3313 | Most uses of C<fork ()> consist of forking, then some simple calls to set |
3264 | up/change the process environment, followed by a call to C<exec()>. This |
3314 | up/change the process environment, followed by a call to C<exec()>. This |
3265 | sequence should be handled by libev without any problems. |
3315 | sequence should be handled by libev without any problems. |
3266 | |
3316 | |
3267 | This changes when the application actually wants to do event handling |
3317 | This changes when the application actually wants to do event handling |
3268 | in the child, or both parent in child, in effect "continuing" after the |
3318 | in the child, or both parent in child, in effect "continuing" after the |
… | |
… | |
3506 | |
3556 | |
3507 | There are some other functions of possible interest. Described. Here. Now. |
3557 | There are some other functions of possible interest. Described. Here. Now. |
3508 | |
3558 | |
3509 | =over 4 |
3559 | =over 4 |
3510 | |
3560 | |
3511 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) |
3561 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback, arg) |
3512 | |
3562 | |
3513 | This function combines a simple timer and an I/O watcher, calls your |
3563 | This function combines a simple timer and an I/O watcher, calls your |
3514 | callback on whichever event happens first and automatically stops both |
3564 | callback on whichever event happens first and automatically stops both |
3515 | watchers. This is useful if you want to wait for a single event on an fd |
3565 | watchers. This is useful if you want to wait for a single event on an fd |
3516 | or timeout without having to allocate/configure/start/stop/free one or |
3566 | or timeout without having to allocate/configure/start/stop/free one or |
… | |
… | |
3892 | To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two |
3942 | To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two |
3893 | files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: |
3943 | files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: |
3894 | |
3944 | |
3895 | // my_ev.h |
3945 | // my_ev.h |
3896 | #define EV_CB_DECLARE(type) struct my_coro *cb; |
3946 | #define EV_CB_DECLARE(type) struct my_coro *cb; |
3897 | #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb); |
3947 | #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb) |
3898 | #include "../libev/ev.h" |
3948 | #include "../libev/ev.h" |
3899 | |
3949 | |
3900 | // my_ev.c |
3950 | // my_ev.c |
3901 | #define EV_H "my_ev.h" |
3951 | #define EV_H "my_ev.h" |
3902 | #include "../libev/ev.c" |
3952 | #include "../libev/ev.c" |
… | |
… | |
3948 | The normal C API should work fine when used from C++: both ev.h and the |
3998 | The normal C API should work fine when used from C++: both ev.h and the |
3949 | libev sources can be compiled as C++. Therefore, code that uses the C API |
3999 | libev sources can be compiled as C++. Therefore, code that uses the C API |
3950 | will work fine. |
4000 | will work fine. |
3951 | |
4001 | |
3952 | Proper exception specifications might have to be added to callbacks passed |
4002 | Proper exception specifications might have to be added to callbacks passed |
3953 | to libev: exceptions may be thrown only from watcher callbacks, all |
4003 | to libev: exceptions may be thrown only from watcher callbacks, all other |
3954 | other callbacks (allocator, syserr, loop acquire/release and periodic |
4004 | callbacks (allocator, syserr, loop acquire/release and periodic reschedule |
3955 | reschedule callbacks) must not throw exceptions, and might need a C<throw |
4005 | callbacks) must not throw exceptions, and might need a C<noexcept> |
3956 | ()> specification. If you have code that needs to be compiled as both C |
4006 | specification. If you have code that needs to be compiled as both C and |
3957 | and C++ you can use the C<EV_THROW> macro for this: |
4007 | C++ you can use the C<EV_NOEXCEPT> macro for this: |
3958 | |
4008 | |
3959 | static void |
4009 | static void |
3960 | fatal_error (const char *msg) EV_THROW |
4010 | fatal_error (const char *msg) EV_NOEXCEPT |
3961 | { |
4011 | { |
3962 | perror (msg); |
4012 | perror (msg); |
3963 | abort (); |
4013 | abort (); |
3964 | } |
4014 | } |
3965 | |
4015 | |
… | |
… | |
3979 | Libev comes with some simplistic wrapper classes for C++ that mainly allow |
4029 | Libev comes with some simplistic wrapper classes for C++ that mainly allow |
3980 | you to use some convenience methods to start/stop watchers and also change |
4030 | you to use some convenience methods to start/stop watchers and also change |
3981 | the callback model to a model using method callbacks on objects. |
4031 | the callback model to a model using method callbacks on objects. |
3982 | |
4032 | |
3983 | To use it, |
4033 | To use it, |
3984 | |
4034 | |
3985 | #include <ev++.h> |
4035 | #include <ev++.h> |
3986 | |
4036 | |
3987 | This automatically includes F<ev.h> and puts all of its definitions (many |
4037 | This automatically includes F<ev.h> and puts all of its definitions (many |
3988 | of them macros) into the global namespace. All C++ specific things are |
4038 | of them macros) into the global namespace. All C++ specific things are |
3989 | put into the C<ev> namespace. It should support all the same embedding |
4039 | put into the C<ev> namespace. It should support all the same embedding |
… | |
… | |
4092 | void operator() (ev::io &w, int revents) |
4142 | void operator() (ev::io &w, int revents) |
4093 | { |
4143 | { |
4094 | ... |
4144 | ... |
4095 | } |
4145 | } |
4096 | } |
4146 | } |
4097 | |
4147 | |
4098 | myfunctor f; |
4148 | myfunctor f; |
4099 | |
4149 | |
4100 | ev::io w; |
4150 | ev::io w; |
4101 | w.set (&f); |
4151 | w.set (&f); |
4102 | |
4152 | |
… | |
… | |
4375 | ev_vars.h |
4425 | ev_vars.h |
4376 | ev_wrap.h |
4426 | ev_wrap.h |
4377 | |
4427 | |
4378 | ev_win32.c required on win32 platforms only |
4428 | ev_win32.c required on win32 platforms only |
4379 | |
4429 | |
4380 | ev_select.c only when select backend is enabled (which is enabled by default) |
4430 | ev_select.c only when select backend is enabled |
4381 | ev_poll.c only when poll backend is enabled (disabled by default) |
4431 | ev_poll.c only when poll backend is enabled |
4382 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
4432 | ev_epoll.c only when the epoll backend is enabled |
4383 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
4433 | ev_kqueue.c only when the kqueue backend is enabled |
4384 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
4434 | ev_port.c only when the solaris port backend is enabled |
4385 | |
4435 | |
4386 | F<ev.c> includes the backend files directly when enabled, so you only need |
4436 | F<ev.c> includes the backend files directly when enabled, so you only need |
4387 | to compile this single file. |
4437 | to compile this single file. |
4388 | |
4438 | |
4389 | =head3 LIBEVENT COMPATIBILITY API |
4439 | =head3 LIBEVENT COMPATIBILITY API |
… | |
… | |
4617 | different cpus (or different cpu cores). This reduces dependencies |
4667 | different cpus (or different cpu cores). This reduces dependencies |
4618 | and makes libev faster. |
4668 | and makes libev faster. |
4619 | |
4669 | |
4620 | =item EV_NO_THREADS |
4670 | =item EV_NO_THREADS |
4621 | |
4671 | |
4622 | If defined to be C<1>, libev will assume that it will never be called |
4672 | If defined to be C<1>, libev will assume that it will never be called from |
4623 | from different threads, which is a stronger assumption than C<EV_NO_SMP>, |
4673 | different threads (that includes signal handlers), which is a stronger |
4624 | above. This reduces dependencies and makes libev faster. |
4674 | assumption than C<EV_NO_SMP>, above. This reduces dependencies and makes |
|
|
4675 | libev faster. |
4625 | |
4676 | |
4626 | =item EV_ATOMIC_T |
4677 | =item EV_ATOMIC_T |
4627 | |
4678 | |
4628 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
4679 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
4629 | access is atomic with respect to other threads or signal contexts. No |
4680 | access is atomic with respect to other threads or signal contexts. No |
… | |
… | |
5288 | structure (guaranteed by POSIX but not by ISO C for example), but it also |
5339 | structure (guaranteed by POSIX but not by ISO C for example), but it also |
5289 | assumes that the same (machine) code can be used to call any watcher |
5340 | assumes that the same (machine) code can be used to call any watcher |
5290 | callback: The watcher callbacks have different type signatures, but libev |
5341 | callback: The watcher callbacks have different type signatures, but libev |
5291 | calls them using an C<ev_watcher *> internally. |
5342 | calls them using an C<ev_watcher *> internally. |
5292 | |
5343 | |
|
|
5344 | =item null pointers and integer zero are represented by 0 bytes |
|
|
5345 | |
|
|
5346 | Libev uses C<memset> to initialise structs and arrays to C<0> bytes, and |
|
|
5347 | relies on this setting pointers and integers to null. |
|
|
5348 | |
5293 | =item pointer accesses must be thread-atomic |
5349 | =item pointer accesses must be thread-atomic |
5294 | |
5350 | |
5295 | Accessing a pointer value must be atomic, it must both be readable and |
5351 | Accessing a pointer value must be atomic, it must both be readable and |
5296 | writable in one piece - this is the case on all current architectures. |
5352 | writable in one piece - this is the case on all current architectures. |
5297 | |
5353 | |
… | |
… | |
5425 | =over 4 |
5481 | =over 4 |
5426 | |
5482 | |
5427 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5483 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5428 | |
5484 | |
5429 | The backward compatibility mechanism can be controlled by |
5485 | The backward compatibility mechanism can be controlled by |
5430 | C<EV_COMPAT3>. See L</PREPROCESSOR SYMBOLS/MACROS> in the L</EMBEDDING> |
5486 | C<EV_COMPAT3>. See L</"PREPROCESSOR SYMBOLS/MACROS"> in the L</EMBEDDING> |
5431 | section. |
5487 | section. |
5432 | |
5488 | |
5433 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5489 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5434 | |
5490 | |
5435 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
5491 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |