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4 | <head> |
4 | <head> |
5 | <title>libev</title> |
5 | <title>libev</title> |
6 | <meta name="description" content="Pod documentation for libev" /> |
6 | <meta name="description" content="Pod documentation for libev" /> |
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14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
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21 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
21 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
22 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
22 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
23 | <li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li> |
23 | <li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li> |
24 | <li><a href="#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</a></li> |
24 | <li><a href="#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</a></li> |
25 | <li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a> |
25 | <li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a> |
26 | <ul><li><a href="#SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS">SUMMARY OF GENERIC WATCHER FUNCTIONS</a></li> |
26 | <ul><li><a href="#GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</a></li> |
27 | <li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li> |
27 | <li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li> |
28 | </ul> |
28 | </ul> |
29 | </li> |
29 | </li> |
30 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
30 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
31 | <ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</a></li> |
31 | <ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a></li> |
32 | <li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</a></li> |
32 | <li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li> |
33 | <li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</a></li> |
33 | <li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a></li> |
34 | <li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</a></li> |
34 | <li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li> |
35 | <li><a href="#code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</a></li> |
35 | <li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a></li> |
36 | <li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</a></li> |
36 | <li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</a></li> |
37 | <li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</a></li> |
37 | <li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</a></li> |
38 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</a></li> |
38 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li> |
39 | </ul> |
39 | </ul> |
40 | </li> |
40 | </li> |
41 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
41 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
42 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
42 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
43 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
43 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
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513 | |
513 | |
514 | </pre> |
514 | </pre> |
515 | </dd> |
515 | </dd> |
516 | </dl> |
516 | </dl> |
517 | |
517 | |
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518 | |
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519 | |
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520 | |
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521 | |
518 | </div> |
522 | </div> |
519 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
523 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
520 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
524 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
521 | <p>A watcher is a structure that you create and register to record your |
525 | <p>A watcher is a structure that you create and register to record your |
522 | interest in some event. For instance, if you want to wait for STDIN to |
526 | interest in some event. For instance, if you want to wait for STDIN to |
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612 | programs, though, so beware.</p> |
616 | programs, though, so beware.</p> |
613 | </dd> |
617 | </dd> |
614 | </dl> |
618 | </dl> |
615 | |
619 | |
616 | </div> |
620 | </div> |
617 | <h2 id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS">SUMMARY OF GENERIC WATCHER FUNCTIONS</h2> |
621 | <h2 id="GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</h2> |
618 | <div id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS-2"> |
622 | <div id="GENERIC_WATCHER_FUNCTIONS_CONTENT"> |
619 | <p>In the following description, <code>TYPE</code> stands for the watcher type, |
623 | <p>In the following description, <code>TYPE</code> stands for the watcher type, |
620 | e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p> |
624 | e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p> |
621 | <dl> |
625 | <dl> |
622 | <dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt> |
626 | <dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt> |
623 | <dd> |
627 | <dd> |
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627 | the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the |
631 | the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the |
628 | type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro |
632 | type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro |
629 | which rolls both calls into one.</p> |
633 | which rolls both calls into one.</p> |
630 | <p>You can reinitialise a watcher at any time as long as it has been stopped |
634 | <p>You can reinitialise a watcher at any time as long as it has been stopped |
631 | (or never started) and there are no pending events outstanding.</p> |
635 | (or never started) and there are no pending events outstanding.</p> |
632 | <p>The callbakc is always of type <code>void (*)(ev_loop *loop, ev_TYPE *watcher, |
636 | <p>The callback is always of type <code>void (*)(ev_loop *loop, ev_TYPE *watcher, |
633 | int revents)</code>.</p> |
637 | int revents)</code>.</p> |
634 | </dd> |
638 | </dd> |
635 | <dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt> |
639 | <dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt> |
636 | <dd> |
640 | <dd> |
637 | <p>This macro initialises the type-specific parts of a watcher. You need to |
641 | <p>This macro initialises the type-specific parts of a watcher. You need to |
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734 | |
738 | |
735 | |
739 | |
736 | |
740 | |
737 | |
741 | |
738 | </div> |
742 | </div> |
739 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2> |
743 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</h2> |
740 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
744 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
741 | <p>I/O watchers check whether a file descriptor is readable or writable |
745 | <p>I/O watchers check whether a file descriptor is readable or writable |
742 | in each iteration of the event loop (This behaviour is called |
746 | in each iteration of the event loop, or, more precisely, when reading |
743 | level-triggering because you keep receiving events as long as the |
747 | would not block the process and writing would at least be able to write |
744 | condition persists. Remember you can stop the watcher if you don't want to |
748 | some data. This behaviour is called level-triggering because you keep |
745 | act on the event and neither want to receive future events).</p> |
749 | receiving events as long as the condition persists. Remember you can stop |
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750 | the watcher if you don't want to act on the event and neither want to |
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751 | receive future events.</p> |
746 | <p>In general you can register as many read and/or write event watchers per |
752 | <p>In general you can register as many read and/or write event watchers per |
747 | fd as you want (as long as you don't confuse yourself). Setting all file |
753 | fd as you want (as long as you don't confuse yourself). Setting all file |
748 | descriptors to non-blocking mode is also usually a good idea (but not |
754 | descriptors to non-blocking mode is also usually a good idea (but not |
749 | required if you know what you are doing).</p> |
755 | required if you know what you are doing).</p> |
750 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
756 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
751 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
757 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
752 | descriptors correctly if you register interest in two or more fds pointing |
758 | descriptors correctly if you register interest in two or more fds pointing |
753 | to the same underlying file/socket etc. description (that is, they share |
759 | to the same underlying file/socket/etc. description (that is, they share |
754 | the same underlying "file open").</p> |
760 | the same underlying "file open").</p> |
755 | <p>If you must do this, then force the use of a known-to-be-good backend |
761 | <p>If you must do this, then force the use of a known-to-be-good backend |
756 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
762 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
757 | <code>EVBACKEND_POLL</code>).</p> |
763 | <code>EVBACKEND_POLL</code>).</p> |
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|
764 | <p>Another thing you have to watch out for is that it is quite easy to |
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765 | receive "spurious" readyness notifications, that is your callback might |
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766 | be called with <code>EV_READ</code> but a subsequent <code>read</code>(2) will actually block |
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767 | because there is no data. Not only are some backends known to create a |
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768 | lot of those (for example solaris ports), it is very easy to get into |
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769 | this situation even with a relatively standard program structure. Thus |
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770 | it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning |
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771 | <code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p> |
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772 | <p>If you cannot run the fd in non-blocking mode (for example you should not |
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773 | play around with an Xlib connection), then you have to seperately re-test |
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774 | wether a file descriptor is really ready with a known-to-be good interface |
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775 | such as poll (fortunately in our Xlib example, Xlib already does this on |
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776 | its own, so its quite safe to use).</p> |
758 | <dl> |
777 | <dl> |
759 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
778 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
760 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
779 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
761 | <dd> |
780 | <dd> |
762 | <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive |
781 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
763 | events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ | |
782 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
764 | EV_WRITE</code> to receive the given events.</p> |
783 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
765 | <p>Please note that most of the more scalable backend mechanisms (for example |
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766 | epoll and solaris ports) can result in spurious readyness notifications |
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767 | for file descriptors, so you practically need to use non-blocking I/O (and |
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768 | treat callback invocation as hint only), or retest separately with a safe |
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769 | interface before doing I/O (XLib can do this), or force the use of either |
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770 | <code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this |
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771 | problem. Also note that it is quite easy to have your callback invoked |
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772 | when the readyness condition is no longer valid even when employing |
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773 | typical ways of handling events, so its a good idea to use non-blocking |
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774 | I/O unconditionally.</p> |
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775 | </dd> |
784 | </dd> |
776 | </dl> |
785 | </dl> |
777 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
786 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
778 | readable, but only once. Since it is likely line-buffered, you could |
787 | readable, but only once. Since it is likely line-buffered, you could |
779 | attempt to read a whole line in the callback:</p> |
788 | attempt to read a whole line in the callback:</p> |
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795 | |
804 | |
796 | |
805 | |
797 | </pre> |
806 | </pre> |
798 | |
807 | |
799 | </div> |
808 | </div> |
800 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2> |
809 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</h2> |
801 | <div id="code_ev_timer_code_relative_and_opti-2"> |
810 | <div id="code_ev_timer_code_relative_and_opti-2"> |
802 | <p>Timer watchers are simple relative timers that generate an event after a |
811 | <p>Timer watchers are simple relative timers that generate an event after a |
803 | given time, and optionally repeating in regular intervals after that.</p> |
812 | given time, and optionally repeating in regular intervals after that.</p> |
804 | <p>The timers are based on real time, that is, if you register an event that |
813 | <p>The timers are based on real time, that is, if you register an event that |
805 | times out after an hour and you reset your system clock to last years |
814 | times out after an hour and you reset your system clock to last years |
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881 | |
890 | |
882 | |
891 | |
883 | </pre> |
892 | </pre> |
884 | |
893 | |
885 | </div> |
894 | </div> |
886 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2> |
895 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</h2> |
887 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
896 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
888 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
897 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
889 | (and unfortunately a bit complex).</p> |
898 | (and unfortunately a bit complex).</p> |
890 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
899 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
891 | but on wallclock time (absolute time). You can tell a periodic watcher |
900 | but on wallclock time (absolute time). You can tell a periodic watcher |
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1010 | |
1019 | |
1011 | |
1020 | |
1012 | </pre> |
1021 | </pre> |
1013 | |
1022 | |
1014 | </div> |
1023 | </div> |
1015 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2> |
1024 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</h2> |
1016 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
1025 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
1017 | <p>Signal watchers will trigger an event when the process receives a specific |
1026 | <p>Signal watchers will trigger an event when the process receives a specific |
1018 | signal one or more times. Even though signals are very asynchronous, libev |
1027 | signal one or more times. Even though signals are very asynchronous, libev |
1019 | will try it's best to deliver signals synchronously, i.e. as part of the |
1028 | will try it's best to deliver signals synchronously, i.e. as part of the |
1020 | normal event processing, like any other event.</p> |
1029 | normal event processing, like any other event.</p> |
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1036 | |
1045 | |
1037 | |
1046 | |
1038 | |
1047 | |
1039 | |
1048 | |
1040 | </div> |
1049 | </div> |
1041 | <h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2> |
1050 | <h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2> |
1042 | <div id="code_ev_child_code_wait_for_pid_stat-2"> |
1051 | <div id="code_ev_child_code_watch_out_for_pro-2"> |
1043 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
1052 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
1044 | some child status changes (most typically when a child of yours dies).</p> |
1053 | some child status changes (most typically when a child of yours dies).</p> |
1045 | <dl> |
1054 | <dl> |
1046 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
1055 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
1047 | <dt>ev_child_set (ev_child *, int pid)</dt> |
1056 | <dt>ev_child_set (ev_child *, int pid)</dt> |
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1069 | |
1078 | |
1070 | |
1079 | |
1071 | </pre> |
1080 | </pre> |
1072 | |
1081 | |
1073 | </div> |
1082 | </div> |
1074 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2> |
1083 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2> |
1075 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1084 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1076 | <p>Idle watchers trigger events when there are no other events are pending |
1085 | <p>Idle watchers trigger events when there are no other events are pending |
1077 | (prepare, check and other idle watchers do not count). That is, as long |
1086 | (prepare, check and other idle watchers do not count). That is, as long |
1078 | as your process is busy handling sockets or timeouts (or even signals, |
1087 | as your process is busy handling sockets or timeouts (or even signals, |
1079 | imagine) it will not be triggered. But when your process is idle all idle |
1088 | imagine) it will not be triggered. But when your process is idle all idle |
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1112 | |
1121 | |
1113 | |
1122 | |
1114 | </pre> |
1123 | </pre> |
1115 | |
1124 | |
1116 | </div> |
1125 | </div> |
1117 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2> |
1126 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2> |
1118 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1127 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1119 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1128 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1120 | prepare watchers get invoked before the process blocks and check watchers |
1129 | prepare watchers get invoked before the process blocks and check watchers |
1121 | afterwards.</p> |
1130 | afterwards.</p> |
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1131 | <p>You <i>must not</i> call <code>ev_loop</code> or similar functions that enter |
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1132 | the current event loop from either <code>ev_prepare</code> or <code>ev_check</code> |
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1133 | watchers. Other loops than the current one are fine, however. The |
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1134 | rationale behind this is that you do not need to check for recursion in |
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1135 | those watchers, i.e. the sequence will always be <code>ev_prepare</code>, blocking, |
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1136 | <code>ev_check</code> so if you have one watcher of each kind they will always be |
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1137 | called in pairs bracketing the blocking call.</p> |
1122 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1138 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1123 | their use is somewhat advanced. This could be used, for example, to track |
1139 | their use is somewhat advanced. This could be used, for example, to track |
1124 | variable changes, implement your own watchers, integrate net-snmp or a |
1140 | variable changes, implement your own watchers, integrate net-snmp or a |
1125 | coroutine library and lots more.</p> |
1141 | coroutine library and lots more. They are also occasionally useful if |
|
|
1142 | you cache some data and want to flush it before blocking (for example, |
|
|
1143 | in X programs you might want to do an <code>XFlush ()</code> in an <code>ev_prepare</code> |
|
|
1144 | watcher).</p> |
1126 | <p>This is done by examining in each prepare call which file descriptors need |
1145 | <p>This is done by examining in each prepare call which file descriptors need |
1127 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1146 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1128 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1147 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1129 | provide just this functionality). Then, in the check watcher you check for |
1148 | provide just this functionality). Then, in the check watcher you check for |
1130 | any events that occured (by checking the pending status of all watchers |
1149 | any events that occured (by checking the pending status of all watchers |
… | |
… | |
1146 | <p>Initialises and configures the prepare or check watcher - they have no |
1165 | <p>Initialises and configures the prepare or check watcher - they have no |
1147 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1166 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1148 | macros, but using them is utterly, utterly and completely pointless.</p> |
1167 | macros, but using them is utterly, utterly and completely pointless.</p> |
1149 | </dd> |
1168 | </dd> |
1150 | </dl> |
1169 | </dl> |
1151 | <p>Example: *TODO*.</p> |
1170 | <p>Example: To include a library such as adns, you would add IO watchers |
|
|
1171 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1172 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1173 | pseudo-code only of course:</p> |
|
|
1174 | <pre> static ev_io iow [nfd]; |
|
|
1175 | static ev_timer tw; |
1152 | |
1176 | |
|
|
1177 | static void |
|
|
1178 | io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1179 | { |
|
|
1180 | // set the relevant poll flags |
|
|
1181 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1182 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1183 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1184 | } |
1153 | |
1185 | |
|
|
1186 | // create io watchers for each fd and a timer before blocking |
|
|
1187 | static void |
|
|
1188 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1189 | { |
|
|
1190 | int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1191 | // actual code will need to loop here and realloc etc. |
|
|
1192 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1154 | |
1193 | |
|
|
1194 | /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1195 | ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1196 | ev_timer_start (loop, &tw); |
1155 | |
1197 | |
|
|
1198 | // create on ev_io per pollfd |
|
|
1199 | for (int i = 0; i < nfd; ++i) |
|
|
1200 | { |
|
|
1201 | ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1202 | ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1203 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1156 | |
1204 | |
|
|
1205 | fds [i].revents = 0; |
|
|
1206 | iow [i].data = fds + i; |
|
|
1207 | ev_io_start (loop, iow + i); |
|
|
1208 | } |
|
|
1209 | } |
|
|
1210 | |
|
|
1211 | // stop all watchers after blocking |
|
|
1212 | static void |
|
|
1213 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1214 | { |
|
|
1215 | ev_timer_stop (loop, &tw); |
|
|
1216 | |
|
|
1217 | for (int i = 0; i < nfd; ++i) |
|
|
1218 | ev_io_stop (loop, iow + i); |
|
|
1219 | |
|
|
1220 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1221 | } |
|
|
1222 | |
|
|
1223 | |
|
|
1224 | |
|
|
1225 | |
|
|
1226 | </pre> |
|
|
1227 | |
1157 | </div> |
1228 | </div> |
1158 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</h2> |
1229 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1159 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1230 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1160 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1231 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1161 | into another (currently only <code>ev_io</code> events are supported in the embedded |
1232 | into another (currently only <code>ev_io</code> events are supported in the embedded |
1162 | loop, other types of watchers might be handled in a delayed or incorrect |
1233 | loop, other types of watchers might be handled in a delayed or incorrect |
1163 | fashion and must not be used).</p> |
1234 | fashion and must not be used).</p> |
… | |
… | |
1460 | ev_vars.h |
1531 | ev_vars.h |
1461 | ev_wrap.h |
1532 | ev_wrap.h |
1462 | |
1533 | |
1463 | ev_win32.c required on win32 platforms only |
1534 | ev_win32.c required on win32 platforms only |
1464 | |
1535 | |
1465 | ev_select.c only when select backend is enabled (which is is by default) |
1536 | ev_select.c only when select backend is enabled (which is by default) |
1466 | ev_poll.c only when poll backend is enabled (disabled by default) |
1537 | ev_poll.c only when poll backend is enabled (disabled by default) |
1467 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1538 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1468 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1539 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1469 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1540 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1470 | |
1541 | |
1471 | </pre> |
1542 | </pre> |
1472 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
1543 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
1473 | to compile a single file.</p> |
1544 | to compile this single file.</p> |
1474 | |
1545 | |
1475 | </div> |
1546 | </div> |
1476 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
1547 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
1477 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
1548 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
1478 | <p>To include the libevent compatibility API, also include:</p> |
1549 | <p>To include the libevent compatibility API, also include:</p> |
… | |
… | |
1493 | </div> |
1564 | </div> |
1494 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
1565 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
1495 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
1566 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
1496 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
1567 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
1497 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
1568 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
1498 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> off. <cite>ev.c</cite> will then include |
1569 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> undefined. <cite>ev.c</cite> will then |
1499 | <cite>config.h</cite> and configure itself accordingly.</p> |
1570 | include <cite>config.h</cite> and configure itself accordingly.</p> |
1500 | <p>For this of course you need the m4 file:</p> |
1571 | <p>For this of course you need the m4 file:</p> |
1501 | <pre> libev.m4 |
1572 | <pre> libev.m4 |
1502 | |
1573 | |
1503 | </pre> |
1574 | </pre> |
1504 | |
1575 | |
… | |
… | |
1647 | SV *self; /* contains this struct */ \ |
1718 | SV *self; /* contains this struct */ \ |
1648 | SV *cb_sv, *fh /* note no trailing ";" */ |
1719 | SV *cb_sv, *fh /* note no trailing ";" */ |
1649 | |
1720 | |
1650 | </pre> |
1721 | </pre> |
1651 | </dd> |
1722 | </dd> |
1652 | <dt>EV_CB_DECLARE(type)</dt> |
1723 | <dt>EV_CB_DECLARE (type)</dt> |
1653 | <dt>EV_CB_INVOKE(watcher,revents)</dt> |
1724 | <dt>EV_CB_INVOKE (watcher, revents)</dt> |
1654 | <dt>ev_set_cb(ev,cb)</dt> |
1725 | <dt>ev_set_cb (ev, cb)</dt> |
1655 | <dd> |
1726 | <dd> |
1656 | <p>Can be used to change the callback member declaration in each watcher, |
1727 | <p>Can be used to change the callback member declaration in each watcher, |
1657 | and the way callbacks are invoked and set. Must expand to a struct member |
1728 | and the way callbacks are invoked and set. Must expand to a struct member |
1658 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
1729 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
1659 | their default definitions. One possible use for overriding these is to |
1730 | their default definitions. One possible use for overriding these is to |
1660 | avoid the ev_loop pointer as first argument in all cases, or to use method |
1731 | avoid the <code>struct ev_loop *</code> as first argument in all cases, or to use |
1661 | calls instead of plain function calls in C++.</p> |
1732 | method calls instead of plain function calls in C++.</p> |
1662 | |
1733 | |
1663 | </div> |
1734 | </div> |
1664 | <h2 id="EXAMPLES">EXAMPLES</h2> |
1735 | <h2 id="EXAMPLES">EXAMPLES</h2> |
1665 | <div id="EXAMPLES_CONTENT"> |
1736 | <div id="EXAMPLES_CONTENT"> |
1666 | <p>For a real-world example of a program the includes libev |
1737 | <p>For a real-world example of a program the includes libev |