| … | |
… | |
| 682 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
682 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
| 683 | and C<ev_loop_destroy>. |
683 | and C<ev_loop_destroy>. |
| 684 | |
684 | |
| 685 | =item ev_loop_fork (loop) |
685 | =item ev_loop_fork (loop) |
| 686 | |
686 | |
| 687 | This function sets a flag that causes subsequent C<ev_run> iterations to |
687 | This function sets a flag that causes subsequent C<ev_run> iterations |
| 688 | reinitialise the kernel state for backends that have one. Despite the |
688 | to reinitialise the kernel state for backends that have one. Despite |
| 689 | name, you can call it anytime, but it makes most sense after forking, in |
689 | the name, you can call it anytime you are allowed to start or stop |
| 690 | the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the |
690 | watchers (except inside an C<ev_prepare> callback), but it makes most |
|
|
691 | sense after forking, in the child process. You I<must> call it (or use |
| 691 | child before resuming or calling C<ev_run>. |
692 | C<EVFLAG_FORKCHECK>) in the child before resuming or calling C<ev_run>. |
| 692 | |
693 | |
| 693 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
694 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
| 694 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
695 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
| 695 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
696 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
| 696 | during fork. |
697 | during fork. |
| … | |
… | |
| 2907 | |
2908 | |
| 2908 | Prepare and check watchers are often (but not always) used in pairs: |
2909 | Prepare and check watchers are often (but not always) used in pairs: |
| 2909 | prepare watchers get invoked before the process blocks and check watchers |
2910 | prepare watchers get invoked before the process blocks and check watchers |
| 2910 | afterwards. |
2911 | afterwards. |
| 2911 | |
2912 | |
| 2912 | You I<must not> call C<ev_run> or similar functions that enter |
2913 | You I<must not> call C<ev_run> (or similar functions that enter the |
| 2913 | the current event loop from either C<ev_prepare> or C<ev_check> |
2914 | current event loop) or C<ev_loop_fork> from either C<ev_prepare> or |
| 2914 | watchers. Other loops than the current one are fine, however. The |
2915 | C<ev_check> watchers. Other loops than the current one are fine, |
| 2915 | rationale behind this is that you do not need to check for recursion in |
2916 | however. The rationale behind this is that you do not need to check |
| 2916 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2917 | for recursion in those watchers, i.e. the sequence will always be |
| 2917 | C<ev_check> so if you have one watcher of each kind they will always be |
2918 | C<ev_prepare>, blocking, C<ev_check> so if you have one watcher of each |
| 2918 | called in pairs bracketing the blocking call. |
2919 | kind they will always be called in pairs bracketing the blocking call. |
| 2919 | |
2920 | |
| 2920 | Their main purpose is to integrate other event mechanisms into libev and |
2921 | Their main purpose is to integrate other event mechanisms into libev and |
| 2921 | their use is somewhat advanced. They could be used, for example, to track |
2922 | their use is somewhat advanced. They could be used, for example, to track |
| 2922 | variable changes, implement your own watchers, integrate net-snmp or a |
2923 | variable changes, implement your own watchers, integrate net-snmp or a |
| 2923 | coroutine library and lots more. They are also occasionally useful if |
2924 | coroutine library and lots more. They are also occasionally useful if |
| … | |
… | |
| 3263 | and calls it in the wrong process, the fork handlers will be invoked, too, |
3264 | and calls it in the wrong process, the fork handlers will be invoked, too, |
| 3264 | of course. |
3265 | of 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 | |
| 3268 | Most uses of C<fork()> consist of forking, then some simple calls to set |
3269 | Most uses of C<fork ()> consist of forking, then some simple calls to set |
| 3269 | up/change the process environment, followed by a call to C<exec()>. This |
3270 | up/change the process environment, followed by a call to C<exec()>. This |
| 3270 | sequence should be handled by libev without any problems. |
3271 | sequence should be handled by libev without any problems. |
| 3271 | |
3272 | |
| 3272 | This changes when the application actually wants to do event handling |
3273 | This changes when the application actually wants to do event handling |
| 3273 | in the child, or both parent in child, in effect "continuing" after the |
3274 | in the child, or both parent in child, in effect "continuing" after the |
