… | |
… | |
2 | |
2 | |
3 | libev - a high performance full-featured event loop written in C |
3 | libev - a high performance full-featured event loop written in C |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
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7 | /* this is the only header you need */ |
7 | #include <ev.h> |
8 | #include <ev.h> |
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9 | |
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10 | /* what follows is a fully working example program */ |
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11 | ev_io stdin_watcher; |
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12 | ev_timer timeout_watcher; |
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13 | |
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14 | /* called when data readable on stdin */ |
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15 | static void |
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16 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
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17 | { |
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18 | /* puts ("stdin ready"); */ |
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19 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
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20 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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21 | } |
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22 | |
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23 | static void |
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24 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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25 | { |
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26 | /* puts ("timeout"); */ |
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27 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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28 | } |
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29 | |
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30 | int |
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31 | main (void) |
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32 | { |
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33 | struct ev_loop *loop = ev_default_loop (0); |
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34 | |
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35 | /* initialise an io watcher, then start it */ |
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36 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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37 | ev_io_start (loop, &stdin_watcher); |
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38 | |
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39 | /* simple non-repeating 5.5 second timeout */ |
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40 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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41 | ev_timer_start (loop, &timeout_watcher); |
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42 | |
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43 | /* loop till timeout or data ready */ |
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44 | ev_loop (loop, 0); |
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45 | |
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46 | return 0; |
|
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47 | } |
8 | |
48 | |
9 | =head1 DESCRIPTION |
49 | =head1 DESCRIPTION |
10 | |
50 | |
11 | Libev is an event loop: you register interest in certain events (such as a |
51 | Libev is an event loop: you register interest in certain events (such as a |
12 | file descriptor being readable or a timeout occuring), and it will manage |
52 | file descriptor being readable or a timeout occuring), and it will manage |
… | |
… | |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
88 | the beginning of 1970, details are complicated, don't ask). This type is |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
89 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
50 | to the C<double> type in C, and when you need to do any calculations on |
90 | to the C<double> type in C, and when you need to do any calculations on |
51 | it, you should treat it as such. |
91 | it, you should treat it as such. |
52 | |
92 | |
53 | |
|
|
54 | =head1 GLOBAL FUNCTIONS |
93 | =head1 GLOBAL FUNCTIONS |
55 | |
94 | |
56 | These functions can be called anytime, even before initialising the |
95 | These functions can be called anytime, even before initialising the |
57 | library in any way. |
96 | library in any way. |
58 | |
97 | |
… | |
… | |
116 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
155 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
117 | recommended ones. |
156 | recommended ones. |
118 | |
157 | |
119 | See the description of C<ev_embed> watchers for more info. |
158 | See the description of C<ev_embed> watchers for more info. |
120 | |
159 | |
121 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
160 | =item ev_set_allocator (void *(*cb)(void *ptr, size_t size)) |
122 | |
161 | |
123 | Sets the allocation function to use (the prototype is similar to the |
162 | Sets the allocation function to use (the prototype and semantics are |
124 | realloc C function, the semantics are identical). It is used to allocate |
163 | identical to the realloc C function). It is used to allocate and free |
125 | and free memory (no surprises here). If it returns zero when memory |
164 | memory (no surprises here). If it returns zero when memory needs to be |
126 | needs to be allocated, the library might abort or take some potentially |
165 | allocated, the library might abort or take some potentially destructive |
127 | destructive action. The default is your system realloc function. |
166 | action. The default is your system realloc function. |
128 | |
167 | |
129 | You could override this function in high-availability programs to, say, |
168 | You could override this function in high-availability programs to, say, |
130 | free some memory if it cannot allocate memory, to use a special allocator, |
169 | free some memory if it cannot allocate memory, to use a special allocator, |
131 | or even to sleep a while and retry until some memory is available. |
170 | or even to sleep a while and retry until some memory is available. |
132 | |
171 | |
133 | Example: replace the libev allocator with one that waits a bit and then |
172 | Example: replace the libev allocator with one that waits a bit and then |
134 | retries: better than mine). |
173 | retries: better than mine). |
135 | |
174 | |
136 | static void * |
175 | static void * |
137 | persistent_realloc (void *ptr, long size) |
176 | persistent_realloc (void *ptr, size_t size) |
138 | { |
177 | { |
139 | for (;;) |
178 | for (;;) |
140 | { |
179 | { |
141 | void *newptr = realloc (ptr, size); |
180 | void *newptr = realloc (ptr, size); |
142 | |
181 | |
… | |
… | |
545 | |
584 | |
546 | =item C<EV_CHILD> |
585 | =item C<EV_CHILD> |
547 | |
586 | |
548 | The pid specified in the C<ev_child> watcher has received a status change. |
587 | The pid specified in the C<ev_child> watcher has received a status change. |
549 | |
588 | |
|
|
589 | =item C<EV_STAT> |
|
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590 | |
|
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591 | The path specified in the C<ev_stat> watcher changed its attributes somehow. |
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592 | |
550 | =item C<EV_IDLE> |
593 | =item C<EV_IDLE> |
551 | |
594 | |
552 | The C<ev_idle> watcher has determined that you have nothing better to do. |
595 | The C<ev_idle> watcher has determined that you have nothing better to do. |
553 | |
596 | |
554 | =item C<EV_PREPARE> |
597 | =item C<EV_PREPARE> |
… | |
… | |
561 | received events. Callbacks of both watcher types can start and stop as |
604 | received events. Callbacks of both watcher types can start and stop as |
562 | many watchers as they want, and all of them will be taken into account |
605 | many watchers as they want, and all of them will be taken into account |
563 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
606 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
564 | C<ev_loop> from blocking). |
607 | C<ev_loop> from blocking). |
565 | |
608 | |
|
|
609 | =item C<EV_EMBED> |
|
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610 | |
|
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611 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
|
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612 | |
|
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613 | =item C<EV_FORK> |
|
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614 | |
|
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615 | The event loop has been resumed in the child process after fork (see |
|
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616 | C<ev_fork>). |
|
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617 | |
566 | =item C<EV_ERROR> |
618 | =item C<EV_ERROR> |
567 | |
619 | |
568 | An unspecified error has occured, the watcher has been stopped. This might |
620 | An unspecified error has occured, the watcher has been stopped. This might |
569 | happen because the watcher could not be properly started because libev |
621 | happen because the watcher could not be properly started because libev |
570 | ran out of memory, a file descriptor was found to be closed or any other |
622 | ran out of memory, a file descriptor was found to be closed or any other |
… | |
… | |
689 | |
741 | |
690 | |
742 | |
691 | =head1 WATCHER TYPES |
743 | =head1 WATCHER TYPES |
692 | |
744 | |
693 | This section describes each watcher in detail, but will not repeat |
745 | This section describes each watcher in detail, but will not repeat |
694 | information given in the last section. |
746 | information given in the last section. Any initialisation/set macros, |
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|
747 | functions and members specific to the watcher type are explained. |
|
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748 | |
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|
749 | Members are additionally marked with either I<[read-only]>, meaning that, |
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750 | while the watcher is active, you can look at the member and expect some |
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|
751 | sensible content, but you must not modify it (you can modify it while the |
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752 | watcher is stopped to your hearts content), or I<[read-write]>, which |
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753 | means you can expect it to have some sensible content while the watcher |
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754 | is active, but you can also modify it. Modifying it may not do something |
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755 | sensible or take immediate effect (or do anything at all), but libev will |
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756 | not crash or malfunction in any way. |
695 | |
757 | |
696 | |
758 | |
697 | =head2 C<ev_io> - is this file descriptor readable or writable? |
759 | =head2 C<ev_io> - is this file descriptor readable or writable? |
698 | |
760 | |
699 | I/O watchers check whether a file descriptor is readable or writable |
761 | I/O watchers check whether a file descriptor is readable or writable |
… | |
… | |
742 | |
804 | |
743 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
805 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
744 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
806 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
745 | C<EV_READ | EV_WRITE> to receive the given events. |
807 | C<EV_READ | EV_WRITE> to receive the given events. |
746 | |
808 | |
|
|
809 | =item int fd [read-only] |
|
|
810 | |
|
|
811 | The file descriptor being watched. |
|
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812 | |
|
|
813 | =item int events [read-only] |
|
|
814 | |
|
|
815 | The events being watched. |
|
|
816 | |
747 | =back |
817 | =back |
748 | |
818 | |
749 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
819 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
750 | readable, but only once. Since it is likely line-buffered, you could |
820 | readable, but only once. Since it is likely line-buffered, you could |
751 | attempt to read a whole line in the callback: |
821 | attempt to read a whole line in the callback: |
… | |
… | |
814 | |
884 | |
815 | If the timer is repeating, either start it if necessary (with the repeat |
885 | If the timer is repeating, either start it if necessary (with the repeat |
816 | value), or reset the running timer to the repeat value. |
886 | value), or reset the running timer to the repeat value. |
817 | |
887 | |
818 | This sounds a bit complicated, but here is a useful and typical |
888 | This sounds a bit complicated, but here is a useful and typical |
819 | example: Imagine you have a tcp connection and you want a so-called idle |
889 | example: Imagine you have a tcp connection and you want a so-called |
820 | timeout, that is, you want to be called when there have been, say, 60 |
890 | idle timeout, that is, you want to be called when there have been, |
821 | seconds of inactivity on the socket. The easiest way to do this is to |
891 | say, 60 seconds of inactivity on the socket. The easiest way to do |
822 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
892 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
823 | time you successfully read or write some data. If you go into an idle |
893 | C<ev_timer_again> each time you successfully read or write some data. If |
824 | state where you do not expect data to travel on the socket, you can stop |
894 | you go into an idle state where you do not expect data to travel on the |
825 | the timer, and again will automatically restart it if need be. |
895 | socket, you can stop the timer, and again will automatically restart it if |
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896 | need be. |
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897 | |
|
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898 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
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|
899 | and only ever use the C<repeat> value: |
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900 | |
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901 | ev_timer_init (timer, callback, 0., 5.); |
|
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902 | ev_timer_again (loop, timer); |
|
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903 | ... |
|
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904 | timer->again = 17.; |
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905 | ev_timer_again (loop, timer); |
|
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906 | ... |
|
|
907 | timer->again = 10.; |
|
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908 | ev_timer_again (loop, timer); |
|
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909 | |
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910 | This is more efficient then stopping/starting the timer eahc time you want |
|
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911 | to modify its timeout value. |
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912 | |
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|
913 | =item ev_tstamp repeat [read-write] |
|
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914 | |
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915 | The current C<repeat> value. Will be used each time the watcher times out |
|
|
916 | or C<ev_timer_again> is called and determines the next timeout (if any), |
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917 | which is also when any modifications are taken into account. |
826 | |
918 | |
827 | =back |
919 | =back |
828 | |
920 | |
829 | Example: create a timer that fires after 60 seconds. |
921 | Example: create a timer that fires after 60 seconds. |
830 | |
922 | |
… | |
… | |
957 | Simply stops and restarts the periodic watcher again. This is only useful |
1049 | Simply stops and restarts the periodic watcher again. This is only useful |
958 | when you changed some parameters or the reschedule callback would return |
1050 | when you changed some parameters or the reschedule callback would return |
959 | a different time than the last time it was called (e.g. in a crond like |
1051 | a different time than the last time it was called (e.g. in a crond like |
960 | program when the crontabs have changed). |
1052 | program when the crontabs have changed). |
961 | |
1053 | |
|
|
1054 | =item ev_tstamp interval [read-write] |
|
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1055 | |
|
|
1056 | The current interval value. Can be modified any time, but changes only |
|
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1057 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
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1058 | called. |
|
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1059 | |
|
|
1060 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
|
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1061 | |
|
|
1062 | The current reschedule callback, or C<0>, if this functionality is |
|
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1063 | switched off. Can be changed any time, but changes only take effect when |
|
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1064 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
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1065 | |
962 | =back |
1066 | =back |
963 | |
1067 | |
964 | Example: call a callback every hour, or, more precisely, whenever the |
1068 | Example: call a callback every hour, or, more precisely, whenever the |
965 | system clock is divisible by 3600. The callback invocation times have |
1069 | system clock is divisible by 3600. The callback invocation times have |
966 | potentially a lot of jittering, but good long-term stability. |
1070 | potentially a lot of jittering, but good long-term stability. |
… | |
… | |
1016 | =item ev_signal_set (ev_signal *, int signum) |
1120 | =item ev_signal_set (ev_signal *, int signum) |
1017 | |
1121 | |
1018 | Configures the watcher to trigger on the given signal number (usually one |
1122 | Configures the watcher to trigger on the given signal number (usually one |
1019 | of the C<SIGxxx> constants). |
1123 | of the C<SIGxxx> constants). |
1020 | |
1124 | |
|
|
1125 | =item int signum [read-only] |
|
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1126 | |
|
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1127 | The signal the watcher watches out for. |
|
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1128 | |
1021 | =back |
1129 | =back |
1022 | |
1130 | |
1023 | |
1131 | |
1024 | =head2 C<ev_child> - watch out for process status changes |
1132 | =head2 C<ev_child> - watch out for process status changes |
1025 | |
1133 | |
… | |
… | |
1037 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1145 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1038 | the status word (use the macros from C<sys/wait.h> and see your systems |
1146 | the status word (use the macros from C<sys/wait.h> and see your systems |
1039 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1147 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1040 | process causing the status change. |
1148 | process causing the status change. |
1041 | |
1149 | |
|
|
1150 | =item int pid [read-only] |
|
|
1151 | |
|
|
1152 | The process id this watcher watches out for, or C<0>, meaning any process id. |
|
|
1153 | |
|
|
1154 | =item int rpid [read-write] |
|
|
1155 | |
|
|
1156 | The process id that detected a status change. |
|
|
1157 | |
|
|
1158 | =item int rstatus [read-write] |
|
|
1159 | |
|
|
1160 | The process exit/trace status caused by C<rpid> (see your systems |
|
|
1161 | C<waitpid> and C<sys/wait.h> documentation for details). |
|
|
1162 | |
1042 | =back |
1163 | =back |
1043 | |
1164 | |
1044 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1165 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1045 | |
1166 | |
1046 | static void |
1167 | static void |
… | |
… | |
1050 | } |
1171 | } |
1051 | |
1172 | |
1052 | struct ev_signal signal_watcher; |
1173 | struct ev_signal signal_watcher; |
1053 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1174 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1054 | ev_signal_start (loop, &sigint_cb); |
1175 | ev_signal_start (loop, &sigint_cb); |
|
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1176 | |
|
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1177 | |
|
|
1178 | =head2 C<ev_stat> - did the file attributes just change? |
|
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1179 | |
|
|
1180 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1181 | C<stat> regularly (or when the OS says it changed) and sees if it changed |
|
|
1182 | compared to the last time, invoking the callback if it did. |
|
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1183 | |
|
|
1184 | The path does not need to exist: changing from "path exists" to "path does |
|
|
1185 | not exist" is a status change like any other. The condition "path does |
|
|
1186 | not exist" is signified by the C<st_nlink> field being zero (which is |
|
|
1187 | otherwise always forced to be at least one) and all the other fields of |
|
|
1188 | the stat buffer having unspecified contents. |
|
|
1189 | |
|
|
1190 | Since there is no standard to do this, the portable implementation simply |
|
|
1191 | calls C<stat (2)> regulalry on the path to see if it changed somehow. You |
|
|
1192 | can specify a recommended polling interval for this case. If you specify |
|
|
1193 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
|
|
1194 | unspecified default> value will be used (which you can expect to be around |
|
|
1195 | five seconds, although this might change dynamically). Libev will also |
|
|
1196 | impose a minimum interval which is currently around C<0.1>, but thats |
|
|
1197 | usually overkill. |
|
|
1198 | |
|
|
1199 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1200 | as even with OS-supported change notifications, this can be |
|
|
1201 | resource-intensive. |
|
|
1202 | |
|
|
1203 | At the time of this writing, no specific OS backends are implemented, but |
|
|
1204 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1205 | |
|
|
1206 | =over 4 |
|
|
1207 | |
|
|
1208 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
|
|
1209 | |
|
|
1210 | =item ev_stat_set (ev_stat *, const char *path, ev_tstamp interval) |
|
|
1211 | |
|
|
1212 | Configures the watcher to wait for status changes of the given |
|
|
1213 | C<path>. The C<interval> is a hint on how quickly a change is expected to |
|
|
1214 | be detected and should normally be specified as C<0> to let libev choose |
|
|
1215 | a suitable value. The memory pointed to by C<path> must point to the same |
|
|
1216 | path for as long as the watcher is active. |
|
|
1217 | |
|
|
1218 | The callback will be receive C<EV_STAT> when a change was detected, |
|
|
1219 | relative to the attributes at the time the watcher was started (or the |
|
|
1220 | last change was detected). |
|
|
1221 | |
|
|
1222 | =item ev_stat_stat (ev_stat *) |
|
|
1223 | |
|
|
1224 | Updates the stat buffer immediately with new values. If you change the |
|
|
1225 | watched path in your callback, you could call this fucntion to avoid |
|
|
1226 | detecting this change (while introducing a race condition). Can also be |
|
|
1227 | useful simply to find out the new values. |
|
|
1228 | |
|
|
1229 | =item ev_statdata attr [read-only] |
|
|
1230 | |
|
|
1231 | The most-recently detected attributes of the file. Although the type is of |
|
|
1232 | C<ev_statdata>, this is usually the (or one of the) C<struct stat> types |
|
|
1233 | suitable for your system. If the C<st_nlink> member is C<0>, then there |
|
|
1234 | was some error while C<stat>ing the file. |
|
|
1235 | |
|
|
1236 | =item ev_statdata prev [read-only] |
|
|
1237 | |
|
|
1238 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1239 | C<prev> != C<attr>. |
|
|
1240 | |
|
|
1241 | =item ev_tstamp interval [read-only] |
|
|
1242 | |
|
|
1243 | The specified interval. |
|
|
1244 | |
|
|
1245 | =item const char *path [read-only] |
|
|
1246 | |
|
|
1247 | The filesystem path that is being watched. |
|
|
1248 | |
|
|
1249 | =back |
|
|
1250 | |
|
|
1251 | Example: Watch C</etc/passwd> for attribute changes. |
|
|
1252 | |
|
|
1253 | static void |
|
|
1254 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1255 | { |
|
|
1256 | /* /etc/passwd changed in some way */ |
|
|
1257 | if (w->attr.st_nlink) |
|
|
1258 | { |
|
|
1259 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1260 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1261 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1262 | } |
|
|
1263 | else |
|
|
1264 | /* you shalt not abuse printf for puts */ |
|
|
1265 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1266 | "if this is windows, they already arrived\n"); |
|
|
1267 | } |
|
|
1268 | |
|
|
1269 | ... |
|
|
1270 | ev_stat passwd; |
|
|
1271 | |
|
|
1272 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1273 | ev_stat_start (loop, &passwd); |
1055 | |
1274 | |
1056 | |
1275 | |
1057 | =head2 C<ev_idle> - when you've got nothing better to do... |
1276 | =head2 C<ev_idle> - when you've got nothing better to do... |
1058 | |
1277 | |
1059 | Idle watchers trigger events when there are no other events are pending |
1278 | Idle watchers trigger events when there are no other events are pending |
… | |
… | |
1292 | |
1511 | |
1293 | Make a single, non-blocking sweep over the embedded loop. This works |
1512 | Make a single, non-blocking sweep over the embedded loop. This works |
1294 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1513 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1295 | apropriate way for embedded loops. |
1514 | apropriate way for embedded loops. |
1296 | |
1515 | |
|
|
1516 | =item struct ev_loop *loop [read-only] |
|
|
1517 | |
|
|
1518 | The embedded event loop. |
|
|
1519 | |
|
|
1520 | =back |
|
|
1521 | |
|
|
1522 | |
|
|
1523 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
|
|
1524 | |
|
|
1525 | Fork watchers are called when a C<fork ()> was detected (usually because |
|
|
1526 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1527 | C<ev_default_fork> or C<ev_loop_fork>). The invocation is done before the |
|
|
1528 | event loop blocks next and before C<ev_check> watchers are being called, |
|
|
1529 | and only in the child after the fork. If whoever good citizen calling |
|
|
1530 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
|
|
1531 | handlers will be invoked, too, of course. |
|
|
1532 | |
|
|
1533 | =over 4 |
|
|
1534 | |
|
|
1535 | =item ev_fork_init (ev_signal *, callback) |
|
|
1536 | |
|
|
1537 | Initialises and configures the fork watcher - it has no parameters of any |
|
|
1538 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
|
|
1539 | believe me. |
|
|
1540 | |
1297 | =back |
1541 | =back |
1298 | |
1542 | |
1299 | |
1543 | |
1300 | =head1 OTHER FUNCTIONS |
1544 | =head1 OTHER FUNCTIONS |
1301 | |
1545 | |
… | |
… | |
1463 | |
1707 | |
1464 | =item w->sweep () C<ev::embed> only |
1708 | =item w->sweep () C<ev::embed> only |
1465 | |
1709 | |
1466 | Invokes C<ev_embed_sweep>. |
1710 | Invokes C<ev_embed_sweep>. |
1467 | |
1711 | |
|
|
1712 | =item w->update () C<ev::stat> only |
|
|
1713 | |
|
|
1714 | Invokes C<ev_stat_stat>. |
|
|
1715 | |
1468 | =back |
1716 | =back |
1469 | |
1717 | |
1470 | =back |
1718 | =back |
1471 | |
1719 | |
1472 | Example: Define a class with an IO and idle watcher, start one of them in |
1720 | Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1484 | : io (this, &myclass::io_cb), |
1732 | : io (this, &myclass::io_cb), |
1485 | idle (this, &myclass::idle_cb) |
1733 | idle (this, &myclass::idle_cb) |
1486 | { |
1734 | { |
1487 | io.start (fd, ev::READ); |
1735 | io.start (fd, ev::READ); |
1488 | } |
1736 | } |
|
|
1737 | |
|
|
1738 | |
|
|
1739 | =head1 MACRO MAGIC |
|
|
1740 | |
|
|
1741 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1742 | C<EV_MULTIPLICITY>. This option determines wether (most) functions and |
|
|
1743 | callbacks have an initial C<struct ev_loop *> argument. |
|
|
1744 | |
|
|
1745 | To make it easier to write programs that cope with either variant, the |
|
|
1746 | following macros are defined: |
|
|
1747 | |
|
|
1748 | =over 4 |
|
|
1749 | |
|
|
1750 | =item C<EV_A>, C<EV_A_> |
|
|
1751 | |
|
|
1752 | This provides the loop I<argument> for functions, if one is required ("ev |
|
|
1753 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
|
|
1754 | C<EV_A_> is used when other arguments are following. Example: |
|
|
1755 | |
|
|
1756 | ev_unref (EV_A); |
|
|
1757 | ev_timer_add (EV_A_ watcher); |
|
|
1758 | ev_loop (EV_A_ 0); |
|
|
1759 | |
|
|
1760 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
|
|
1761 | which is often provided by the following macro. |
|
|
1762 | |
|
|
1763 | =item C<EV_P>, C<EV_P_> |
|
|
1764 | |
|
|
1765 | This provides the loop I<parameter> for functions, if one is required ("ev |
|
|
1766 | loop parameter"). The C<EV_P> form is used when this is the sole parameter, |
|
|
1767 | C<EV_P_> is used when other parameters are following. Example: |
|
|
1768 | |
|
|
1769 | // this is how ev_unref is being declared |
|
|
1770 | static void ev_unref (EV_P); |
|
|
1771 | |
|
|
1772 | // this is how you can declare your typical callback |
|
|
1773 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1774 | |
|
|
1775 | It declares a parameter C<loop> of type C<struct ev_loop *>, quite |
|
|
1776 | suitable for use with C<EV_A>. |
|
|
1777 | |
|
|
1778 | =item C<EV_DEFAULT>, C<EV_DEFAULT_> |
|
|
1779 | |
|
|
1780 | Similar to the other two macros, this gives you the value of the default |
|
|
1781 | loop, if multiple loops are supported ("ev loop default"). |
|
|
1782 | |
|
|
1783 | =back |
|
|
1784 | |
|
|
1785 | Example: Declare and initialise a check watcher, working regardless of |
|
|
1786 | wether multiple loops are supported or not. |
|
|
1787 | |
|
|
1788 | static void |
|
|
1789 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1790 | { |
|
|
1791 | ev_check_stop (EV_A_ w); |
|
|
1792 | } |
|
|
1793 | |
|
|
1794 | ev_check check; |
|
|
1795 | ev_check_init (&check, check_cb); |
|
|
1796 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1797 | ev_loop (EV_DEFAULT_ 0); |
|
|
1798 | |
1489 | |
1799 | |
1490 | =head1 EMBEDDING |
1800 | =head1 EMBEDDING |
1491 | |
1801 | |
1492 | Libev can (and often is) directly embedded into host |
1802 | Libev can (and often is) directly embedded into host |
1493 | applications. Examples of applications that embed it include the Deliantra |
1803 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1700 | will have the C<struct ev_loop *> as first argument, and you can create |
2010 | will have the C<struct ev_loop *> as first argument, and you can create |
1701 | additional independent event loops. Otherwise there will be no support |
2011 | additional independent event loops. Otherwise there will be no support |
1702 | for multiple event loops and there is no first event loop pointer |
2012 | for multiple event loops and there is no first event loop pointer |
1703 | argument. Instead, all functions act on the single default loop. |
2013 | argument. Instead, all functions act on the single default loop. |
1704 | |
2014 | |
1705 | =item EV_PERIODICS |
2015 | =item EV_PERIODIC_ENABLE |
1706 | |
2016 | |
1707 | If undefined or defined to be C<1>, then periodic timers are supported, |
2017 | If undefined or defined to be C<1>, then periodic timers are supported. If |
1708 | otherwise not. This saves a few kb of code. |
2018 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2019 | code. |
|
|
2020 | |
|
|
2021 | =item EV_EMBED_ENABLE |
|
|
2022 | |
|
|
2023 | If undefined or defined to be C<1>, then embed watchers are supported. If |
|
|
2024 | defined to be C<0>, then they are not. |
|
|
2025 | |
|
|
2026 | =item EV_STAT_ENABLE |
|
|
2027 | |
|
|
2028 | If undefined or defined to be C<1>, then stat watchers are supported. If |
|
|
2029 | defined to be C<0>, then they are not. |
|
|
2030 | |
|
|
2031 | =item EV_FORK_ENABLE |
|
|
2032 | |
|
|
2033 | If undefined or defined to be C<1>, then fork watchers are supported. If |
|
|
2034 | defined to be C<0>, then they are not. |
|
|
2035 | |
|
|
2036 | =item EV_MINIMAL |
|
|
2037 | |
|
|
2038 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2039 | speed, define this symbol to C<1>. Currently only used for gcc to override |
|
|
2040 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2041 | |
|
|
2042 | =item EV_PID_HASHSIZE |
|
|
2043 | |
|
|
2044 | C<ev_child> watchers use a small hash table to distribute workload by |
|
|
2045 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
|
|
2046 | than enough. If you need to manage thousands of children you might want to |
|
|
2047 | increase this value. |
1709 | |
2048 | |
1710 | =item EV_COMMON |
2049 | =item EV_COMMON |
1711 | |
2050 | |
1712 | By default, all watchers have a C<void *data> member. By redefining |
2051 | By default, all watchers have a C<void *data> member. By redefining |
1713 | this macro to a something else you can include more and other types of |
2052 | this macro to a something else you can include more and other types of |