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Comparing libev/ev.pod (file contents):
Revision 1.431 by root, Fri Nov 22 16:42:10 2013 UTC vs.
Revision 1.433 by root, Fri May 2 07:05:42 2014 UTC

682If you need dynamically allocated loops it is better to use C<ev_loop_new> 682If you need dynamically allocated loops it is better to use C<ev_loop_new>
683and C<ev_loop_destroy>. 683and C<ev_loop_destroy>.
684 684
685=item ev_loop_fork (loop) 685=item ev_loop_fork (loop)
686 686
687This function sets a flag that causes subsequent C<ev_run> iterations to 687This function sets a flag that causes subsequent C<ev_run> iterations
688reinitialise the kernel state for backends that have one. Despite the 688to reinitialise the kernel state for backends that have one. Despite
689name, you can call it anytime, but it makes most sense after forking, in 689the name, you can call it anytime you are allowed to start or stop
690the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the 690watchers (except inside an C<ev_prepare> callback), but it makes most
691sense after forking, in the child process. You I<must> call it (or use
691child before resuming or calling C<ev_run>. 692C<EVFLAG_FORKCHECK>) in the child before resuming or calling C<ev_run>.
692 693
693Again, you I<have> to call it on I<any> loop that you want to re-use after 694Again, you I<have> to call it on I<any> loop that you want to re-use after
694a fork, I<even if you do not plan to use the loop in the parent>. This is 695a fork, I<even if you do not plan to use the loop in the parent>. This is
695because some kernel interfaces *cough* I<kqueue> *cough* do funny things 696because some kernel interfaces *cough* I<kqueue> *cough* do funny things
696during fork. 697during fork.
2393 2394
2394 ev_periodic hourly_tick; 2395 ev_periodic hourly_tick;
2395 ev_periodic_init (&hourly_tick, clock_cb, 2396 ev_periodic_init (&hourly_tick, clock_cb,
2396 fmod (ev_now (loop), 3600.), 3600., 0); 2397 fmod (ev_now (loop), 3600.), 3600., 0);
2397 ev_periodic_start (loop, &hourly_tick); 2398 ev_periodic_start (loop, &hourly_tick);
2398 2399
2399 2400
2400=head2 C<ev_signal> - signal me when a signal gets signalled! 2401=head2 C<ev_signal> - signal me when a signal gets signalled!
2401 2402
2402Signal watchers will trigger an event when the process receives a specific 2403Signal watchers will trigger an event when the process receives a specific
2403signal one or more times. Even though signals are very asynchronous, libev 2404signal one or more times. Even though signals are very asynchronous, libev
2907 2908
2908Prepare and check watchers are often (but not always) used in pairs: 2909Prepare and check watchers are often (but not always) used in pairs:
2909prepare watchers get invoked before the process blocks and check watchers 2910prepare watchers get invoked before the process blocks and check watchers
2910afterwards. 2911afterwards.
2911 2912
2912You I<must not> call C<ev_run> or similar functions that enter 2913You I<must not> call C<ev_run> (or similar functions that enter the
2913the current event loop from either C<ev_prepare> or C<ev_check> 2914current event loop) or C<ev_loop_fork> from either C<ev_prepare> or
2914watchers. Other loops than the current one are fine, however. The 2915C<ev_check> watchers. Other loops than the current one are fine,
2915rationale behind this is that you do not need to check for recursion in 2916however. The rationale behind this is that you do not need to check
2916those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, 2917for recursion in those watchers, i.e. the sequence will always be
2917C<ev_check> so if you have one watcher of each kind they will always be 2918C<ev_prepare>, blocking, C<ev_check> so if you have one watcher of each
2918called in pairs bracketing the blocking call. 2919kind they will always be called in pairs bracketing the blocking call.
2919 2920
2920Their main purpose is to integrate other event mechanisms into libev and 2921Their main purpose is to integrate other event mechanisms into libev and
2921their use is somewhat advanced. They could be used, for example, to track 2922their use is somewhat advanced. They could be used, for example, to track
2922variable changes, implement your own watchers, integrate net-snmp or a 2923variable changes, implement your own watchers, integrate net-snmp or a
2923coroutine library and lots more. They are also occasionally useful if 2924coroutine library and lots more. They are also occasionally useful if
3213used). 3214used).
3214 3215
3215 struct ev_loop *loop_hi = ev_default_init (0); 3216 struct ev_loop *loop_hi = ev_default_init (0);
3216 struct ev_loop *loop_lo = 0; 3217 struct ev_loop *loop_lo = 0;
3217 ev_embed embed; 3218 ev_embed embed;
3218 3219
3219 // see if there is a chance of getting one that works 3220 // see if there is a chance of getting one that works
3220 // (remember that a flags value of 0 means autodetection) 3221 // (remember that a flags value of 0 means autodetection)
3221 loop_lo = ev_embeddable_backends () & ev_recommended_backends () 3222 loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
3222 ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) 3223 ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
3223 : 0; 3224 : 0;
3237C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). 3238C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
3238 3239
3239 struct ev_loop *loop = ev_default_init (0); 3240 struct ev_loop *loop = ev_default_init (0);
3240 struct ev_loop *loop_socket = 0; 3241 struct ev_loop *loop_socket = 0;
3241 ev_embed embed; 3242 ev_embed embed;
3242 3243
3243 if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) 3244 if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
3244 if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) 3245 if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
3245 { 3246 {
3246 ev_embed_init (&embed, 0, loop_socket); 3247 ev_embed_init (&embed, 0, loop_socket);
3247 ev_embed_start (loop, &embed); 3248 ev_embed_start (loop, &embed);
3263and calls it in the wrong process, the fork handlers will be invoked, too, 3264and calls it in the wrong process, the fork handlers will be invoked, too,
3264of course. 3265of course.
3265 3266
3266=head3 The special problem of life after fork - how is it possible? 3267=head3 The special problem of life after fork - how is it possible?
3267 3268
3268Most uses of C<fork()> consist of forking, then some simple calls to set 3269Most uses of C<fork ()> consist of forking, then some simple calls to set
3269up/change the process environment, followed by a call to C<exec()>. This 3270up/change the process environment, followed by a call to C<exec()>. This
3270sequence should be handled by libev without any problems. 3271sequence should be handled by libev without any problems.
3271 3272
3272This changes when the application actually wants to do event handling 3273This changes when the application actually wants to do event handling
3273in the child, or both parent in child, in effect "continuing" after the 3274in the child, or both parent in child, in effect "continuing" after the
4097 void operator() (ev::io &w, int revents) 4098 void operator() (ev::io &w, int revents)
4098 { 4099 {
4099 ... 4100 ...
4100 } 4101 }
4101 } 4102 }
4102 4103
4103 myfunctor f; 4104 myfunctor f;
4104 4105
4105 ev::io w; 4106 ev::io w;
4106 w.set (&f); 4107 w.set (&f);
4107 4108

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