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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 |
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… | |
396 | |
398 | |
397 | If this flag bit is or'ed into the flag value (or the program runs setuid |
399 | 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 |
400 | or setgid) then libev will I<not> look at the environment variable |
399 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
401 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
400 | override the flags completely if it is found in the environment. This is |
402 | 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 |
403 | useful to try out specific backends to test their performance, to work |
402 | around bugs. |
404 | around bugs, or to make libev threadsafe (accessing environment variables |
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405 | cannot be done in a threadsafe way, but usually it works if no other |
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406 | thread modifies them). |
403 | |
407 | |
404 | =item C<EVFLAG_FORKCHECK> |
408 | =item C<EVFLAG_FORKCHECK> |
405 | |
409 | |
406 | Instead of calling C<ev_loop_fork> manually after a fork, you can also |
410 | 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. |
411 | make libev check for a fork in each iteration by enabling this flag. |
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684 | reinitialise the kernel state for backends that have one. Despite the |
688 | reinitialise the kernel state for backends that have one. Despite the |
685 | name, you can call it anytime, but it makes most sense after forking, in |
689 | name, you can call it anytime, but it makes most sense after forking, in |
686 | the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the |
690 | the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the |
687 | child before resuming or calling C<ev_run>. |
691 | child before resuming or calling C<ev_run>. |
688 | |
692 | |
689 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
693 | 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 |
694 | 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 |
695 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
692 | during fork. |
696 | during fork. |
693 | |
697 | |
694 | On the other hand, you only need to call this function in the child |
698 | On the other hand, you only need to call this function in the child |
… | |
… | |
2389 | |
2393 | |
2390 | ev_periodic hourly_tick; |
2394 | ev_periodic hourly_tick; |
2391 | ev_periodic_init (&hourly_tick, clock_cb, |
2395 | ev_periodic_init (&hourly_tick, clock_cb, |
2392 | fmod (ev_now (loop), 3600.), 3600., 0); |
2396 | fmod (ev_now (loop), 3600.), 3600., 0); |
2393 | ev_periodic_start (loop, &hourly_tick); |
2397 | ev_periodic_start (loop, &hourly_tick); |
2394 | |
2398 | |
2395 | |
2399 | |
2396 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
2400 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
2397 | |
2401 | |
2398 | Signal watchers will trigger an event when the process receives a specific |
2402 | 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 |
2403 | signal one or more times. Even though signals are very asynchronous, libev |
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2409 | only within the same loop, i.e. you can watch for C<SIGINT> in your |
2413 | 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 |
2414 | 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 |
2415 | 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. |
2416 | the moment, C<SIGCHLD> is permanently tied to the default loop. |
2413 | |
2417 | |
2414 | When the first watcher gets started will libev actually register something |
2418 | 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 |
2419 | register something with the kernel. It thus coexists with your own signal |
2416 | you don't register any with libev for the same signal). |
2420 | handlers as long as you don't register any with libev for the same signal. |
2417 | |
2421 | |
2418 | If possible and supported, libev will install its handlers with |
2422 | If possible and supported, libev will install its handlers with |
2419 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
2423 | 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 |
2424 | 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 |
2425 | interrupted by signals you can block all signals in an C<ev_check> watcher |
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… | |
2606 | |
2610 | |
2607 | =head2 C<ev_stat> - did the file attributes just change? |
2611 | =head2 C<ev_stat> - did the file attributes just change? |
2608 | |
2612 | |
2609 | This watches a file system path for attribute changes. That is, it calls |
2613 | 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) |
2614 | 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 |
2615 | and sees if it changed compared to the last time, invoking the callback |
2612 | it did. |
2616 | if it did. Starting the watcher C<stat>'s the file, so only changes that |
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2617 | happen after the watcher has been started will be reported. |
2613 | |
2618 | |
2614 | The path does not need to exist: changing from "path exists" to "path does |
2619 | 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 |
2620 | 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 |
2621 | 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 |
2622 | C<st_nlink> field being zero (which is otherwise always forced to be at |
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… | |
3208 | used). |
3213 | used). |
3209 | |
3214 | |
3210 | struct ev_loop *loop_hi = ev_default_init (0); |
3215 | struct ev_loop *loop_hi = ev_default_init (0); |
3211 | struct ev_loop *loop_lo = 0; |
3216 | struct ev_loop *loop_lo = 0; |
3212 | ev_embed embed; |
3217 | ev_embed embed; |
3213 | |
3218 | |
3214 | // see if there is a chance of getting one that works |
3219 | // see if there is a chance of getting one that works |
3215 | // (remember that a flags value of 0 means autodetection) |
3220 | // (remember that a flags value of 0 means autodetection) |
3216 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3221 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3217 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3222 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3218 | : 0; |
3223 | : 0; |
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3232 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
3237 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
3233 | |
3238 | |
3234 | struct ev_loop *loop = ev_default_init (0); |
3239 | struct ev_loop *loop = ev_default_init (0); |
3235 | struct ev_loop *loop_socket = 0; |
3240 | struct ev_loop *loop_socket = 0; |
3236 | ev_embed embed; |
3241 | ev_embed embed; |
3237 | |
3242 | |
3238 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3243 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3239 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3244 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3240 | { |
3245 | { |
3241 | ev_embed_init (&embed, 0, loop_socket); |
3246 | ev_embed_init (&embed, 0, loop_socket); |
3242 | ev_embed_start (loop, &embed); |
3247 | ev_embed_start (loop, &embed); |
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3979 | Libev comes with some simplistic wrapper classes for C++ that mainly allow |
3984 | 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 |
3985 | 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. |
3986 | the callback model to a model using method callbacks on objects. |
3982 | |
3987 | |
3983 | To use it, |
3988 | To use it, |
3984 | |
3989 | |
3985 | #include <ev++.h> |
3990 | #include <ev++.h> |
3986 | |
3991 | |
3987 | This automatically includes F<ev.h> and puts all of its definitions (many |
3992 | 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 |
3993 | 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 |
3994 | put into the C<ev> namespace. It should support all the same embedding |
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4092 | void operator() (ev::io &w, int revents) |
4097 | void operator() (ev::io &w, int revents) |
4093 | { |
4098 | { |
4094 | ... |
4099 | ... |
4095 | } |
4100 | } |
4096 | } |
4101 | } |
4097 | |
4102 | |
4098 | myfunctor f; |
4103 | myfunctor f; |
4099 | |
4104 | |
4100 | ev::io w; |
4105 | ev::io w; |
4101 | w.set (&f); |
4106 | w.set (&f); |
4102 | |
4107 | |
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4617 | different cpus (or different cpu cores). This reduces dependencies |
4622 | different cpus (or different cpu cores). This reduces dependencies |
4618 | and makes libev faster. |
4623 | and makes libev faster. |
4619 | |
4624 | |
4620 | =item EV_NO_THREADS |
4625 | =item EV_NO_THREADS |
4621 | |
4626 | |
4622 | If defined to be C<1>, libev will assume that it will never be called |
4627 | 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>, |
4628 | different threads (that includes signal handlers), which is a stronger |
4624 | above. This reduces dependencies and makes libev faster. |
4629 | assumption than C<EV_NO_SMP>, above. This reduces dependencies and makes |
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4630 | libev faster. |
4625 | |
4631 | |
4626 | =item EV_ATOMIC_T |
4632 | =item EV_ATOMIC_T |
4627 | |
4633 | |
4628 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
4634 | 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 |
4635 | access is atomic with respect to other threads or signal contexts. No |
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5425 | =over 4 |
5431 | =over 4 |
5426 | |
5432 | |
5427 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5433 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5428 | |
5434 | |
5429 | The backward compatibility mechanism can be controlled by |
5435 | The backward compatibility mechanism can be controlled by |
5430 | C<EV_COMPAT3>. See L</PREPROCESSOR SYMBOLS/MACROS> in the L</EMBEDDING> |
5436 | C<EV_COMPAT3>. See L</"PREPROCESSOR SYMBOLS/MACROS"> in the L</EMBEDDING> |
5431 | section. |
5437 | section. |
5432 | |
5438 | |
5433 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5439 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5434 | |
5440 | |
5435 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
5441 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |