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Revision 1.425 by root, Tue Jan 22 03:53:01 2013 UTC vs.
Revision 1.432 by root, Sat Apr 26 14:28:48 2014 UTC

1=encoding utf-8
2
1=head1 NAME 3=head1 NAME
2 4
3libev - a high performance full-featured event loop written in C 5libev - a high performance full-featured event loop written in C
4 6
5=head1 SYNOPSIS 7=head1 SYNOPSIS
396 398
397If this flag bit is or'ed into the flag value (or the program runs setuid 399If this flag bit is or'ed into the flag value (or the program runs setuid
398or setgid) then libev will I<not> look at the environment variable 400or setgid) then libev will I<not> look at the environment variable
399C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will 401C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
400override the flags completely if it is found in the environment. This is 402override the flags completely if it is found in the environment. This is
401useful to try out specific backends to test their performance, or to work 403useful to try out specific backends to test their performance, to work
402around bugs. 404around bugs, or to make libev threadsafe (accessing environment variables
405cannot be done in a threadsafe way, but usually it works if no other
406thread modifies them).
403 407
404=item C<EVFLAG_FORKCHECK> 408=item C<EVFLAG_FORKCHECK>
405 409
406Instead of calling C<ev_loop_fork> manually after a fork, you can also 410Instead of calling C<ev_loop_fork> manually after a fork, you can also
407make libev check for a fork in each iteration by enabling this flag. 411make libev check for a fork in each iteration by enabling this flag.
684reinitialise the kernel state for backends that have one. Despite the 688reinitialise the kernel state for backends that have one. Despite the
685name, you can call it anytime, but it makes most sense after forking, in 689name, you can call it anytime, but it makes most sense after forking, in
686the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the 690the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
687child before resuming or calling C<ev_run>. 691child before resuming or calling C<ev_run>.
688 692
689Again, you I<have> to call it on I<any> loop that you want to re-use after 693Again, you I<have> to call it on I<any> loop that you want to re-use after
690a fork, I<even if you do not plan to use the loop in the parent>. This is 694a fork, I<even if you do not plan to use the loop in the parent>. This is
691because some kernel interfaces *cough* I<kqueue> *cough* do funny things 695because some kernel interfaces *cough* I<kqueue> *cough* do funny things
692during fork. 696during fork.
693 697
694On the other hand, you only need to call this function in the child 698On 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
2398Signal watchers will trigger an event when the process receives a specific 2402Signal watchers will trigger an event when the process receives a specific
2399signal one or more times. Even though signals are very asynchronous, libev 2403signal one or more times. Even though signals are very asynchronous, libev
2409only within the same loop, i.e. you can watch for C<SIGINT> in your 2413only within the same loop, i.e. you can watch for C<SIGINT> in your
2410default loop and for C<SIGIO> in another loop, but you cannot watch for 2414default loop and for C<SIGIO> in another loop, but you cannot watch for
2411C<SIGINT> in both the default loop and another loop at the same time. At 2415C<SIGINT> in both the default loop and another loop at the same time. At
2412the moment, C<SIGCHLD> is permanently tied to the default loop. 2416the moment, C<SIGCHLD> is permanently tied to the default loop.
2413 2417
2414When the first watcher gets started will libev actually register something 2418Only after the first watcher for a signal is started will libev actually
2415with the kernel (thus it coexists with your own signal handlers as long as 2419register something with the kernel. It thus coexists with your own signal
2416you don't register any with libev for the same signal). 2420handlers as long as you don't register any with libev for the same signal.
2417 2421
2418If possible and supported, libev will install its handlers with 2422If possible and supported, libev will install its handlers with
2419C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should 2423C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2420not be unduly interrupted. If you have a problem with system calls getting 2424not be unduly interrupted. If you have a problem with system calls getting
2421interrupted by signals you can block all signals in an C<ev_check> watcher 2425interrupted by signals you can block all signals in an C<ev_check> watcher
3209used). 3213used).
3210 3214
3211 struct ev_loop *loop_hi = ev_default_init (0); 3215 struct ev_loop *loop_hi = ev_default_init (0);
3212 struct ev_loop *loop_lo = 0; 3216 struct ev_loop *loop_lo = 0;
3213 ev_embed embed; 3217 ev_embed embed;
3214 3218
3215 // see if there is a chance of getting one that works 3219 // see if there is a chance of getting one that works
3216 // (remember that a flags value of 0 means autodetection) 3220 // (remember that a flags value of 0 means autodetection)
3217 loop_lo = ev_embeddable_backends () & ev_recommended_backends () 3221 loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
3218 ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) 3222 ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
3219 : 0; 3223 : 0;
3233C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). 3237C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
3234 3238
3235 struct ev_loop *loop = ev_default_init (0); 3239 struct ev_loop *loop = ev_default_init (0);
3236 struct ev_loop *loop_socket = 0; 3240 struct ev_loop *loop_socket = 0;
3237 ev_embed embed; 3241 ev_embed embed;
3238 3242
3239 if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) 3243 if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
3240 if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) 3244 if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
3241 { 3245 {
3242 ev_embed_init (&embed, 0, loop_socket); 3246 ev_embed_init (&embed, 0, loop_socket);
3243 ev_embed_start (loop, &embed); 3247 ev_embed_start (loop, &embed);
3980Libev comes with some simplistic wrapper classes for C++ that mainly allow 3984Libev comes with some simplistic wrapper classes for C++ that mainly allow
3981you to use some convenience methods to start/stop watchers and also change 3985you to use some convenience methods to start/stop watchers and also change
3982the callback model to a model using method callbacks on objects. 3986the callback model to a model using method callbacks on objects.
3983 3987
3984To use it, 3988To use it,
3985 3989
3986 #include <ev++.h> 3990 #include <ev++.h>
3987 3991
3988This automatically includes F<ev.h> and puts all of its definitions (many 3992This automatically includes F<ev.h> and puts all of its definitions (many
3989of them macros) into the global namespace. All C++ specific things are 3993of them macros) into the global namespace. All C++ specific things are
3990put into the C<ev> namespace. It should support all the same embedding 3994put into the C<ev> namespace. It should support all the same embedding
4093 void operator() (ev::io &w, int revents) 4097 void operator() (ev::io &w, int revents)
4094 { 4098 {
4095 ... 4099 ...
4096 } 4100 }
4097 } 4101 }
4098 4102
4099 myfunctor f; 4103 myfunctor f;
4100 4104
4101 ev::io w; 4105 ev::io w;
4102 w.set (&f); 4106 w.set (&f);
4103 4107
4618different cpus (or different cpu cores). This reduces dependencies 4622different cpus (or different cpu cores). This reduces dependencies
4619and makes libev faster. 4623and makes libev faster.
4620 4624
4621=item EV_NO_THREADS 4625=item EV_NO_THREADS
4622 4626
4623If defined to be C<1>, libev will assume that it will never be called 4627If defined to be C<1>, libev will assume that it will never be called from
4624from different threads, which is a stronger assumption than C<EV_NO_SMP>, 4628different threads (that includes signal handlers), which is a stronger
4625above. This reduces dependencies and makes libev faster. 4629assumption than C<EV_NO_SMP>, above. This reduces dependencies and makes
4630libev faster.
4626 4631
4627=item EV_ATOMIC_T 4632=item EV_ATOMIC_T
4628 4633
4629Libev requires an integer type (suitable for storing C<0> or C<1>) whose 4634Libev requires an integer type (suitable for storing C<0> or C<1>) whose
4630access is atomic with respect to other threads or signal contexts. No 4635access is atomic with respect to other threads or signal contexts. No
5426=over 4 5431=over 4
5427 5432
5428=item C<EV_COMPAT3> backwards compatibility mechanism 5433=item C<EV_COMPAT3> backwards compatibility mechanism
5429 5434
5430The backward compatibility mechanism can be controlled by 5435The backward compatibility mechanism can be controlled by
5431C<EV_COMPAT3>. See L</PREPROCESSOR SYMBOLS/MACROS> in the L</EMBEDDING> 5436C<EV_COMPAT3>. See L</"PREPROCESSOR SYMBOLS/MACROS"> in the L</EMBEDDING>
5432section. 5437section.
5433 5438
5434=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
5435 5440
5436These calls can be replaced easily by their C<ev_loop_xxx> counterparts: 5441These calls can be replaced easily by their C<ev_loop_xxx> counterparts:

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