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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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7 | <meta name="inputfile" content="<standard input>" /> |
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8 | <meta name="outputfile" content="<standard output>" /> |
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13 | <div class="pod"> |
13 | <div class="pod"> |
14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
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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 repeating 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_watch_out_for_pro"><code>ev_child</code> - watch out for process 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> |
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36 | <li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</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_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> |
38 | <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> |
39 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li> |
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40 | <li><a href="#code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</a></li> |
39 | </ul> |
41 | </ul> |
40 | </li> |
42 | </li> |
41 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
43 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
42 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
44 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
43 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
45 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
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|
46 | <li><a href="#MACRO_MAGIC">MACRO MAGIC</a></li> |
44 | <li><a href="#EMBEDDING">EMBEDDING</a> |
47 | <li><a href="#EMBEDDING">EMBEDDING</a> |
45 | <ul><li><a href="#FILESETS">FILESETS</a> |
48 | <ul><li><a href="#FILESETS">FILESETS</a> |
46 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
49 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
47 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
50 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
48 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
51 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
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112 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
115 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
113 | the beginning of 1970, details are complicated, don't ask). This type is |
116 | the beginning of 1970, details are complicated, don't ask). This type is |
114 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
117 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
115 | to the <code>double</code> type in C, and when you need to do any calculations on |
118 | to the <code>double</code> type in C, and when you need to do any calculations on |
116 | it, you should treat it as such.</p> |
119 | it, you should treat it as such.</p> |
117 | |
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118 | |
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119 | |
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120 | |
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121 | |
120 | |
122 | </div> |
121 | </div> |
123 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
122 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
124 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
123 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
125 | <p>These functions can be called anytime, even before initialising the |
124 | <p>These functions can be called anytime, even before initialising the |
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586 | </dd> |
585 | </dd> |
587 | <dt><code>EV_CHILD</code></dt> |
586 | <dt><code>EV_CHILD</code></dt> |
588 | <dd> |
587 | <dd> |
589 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
588 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
590 | </dd> |
589 | </dd> |
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590 | <dt><code>EV_STAT</code></dt> |
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591 | <dd> |
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592 | <p>The path specified in the <code>ev_stat</code> watcher changed its attributes somehow.</p> |
|
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593 | </dd> |
591 | <dt><code>EV_IDLE</code></dt> |
594 | <dt><code>EV_IDLE</code></dt> |
592 | <dd> |
595 | <dd> |
593 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
596 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
594 | </dd> |
597 | </dd> |
595 | <dt><code>EV_PREPARE</code></dt> |
598 | <dt><code>EV_PREPARE</code></dt> |
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600 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
603 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
601 | 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 |
602 | 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 |
603 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
606 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
604 | <code>ev_loop</code> from blocking).</p> |
607 | <code>ev_loop</code> from blocking).</p> |
|
|
608 | </dd> |
|
|
609 | <dt><code>EV_EMBED</code></dt> |
|
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610 | <dd> |
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611 | <p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p> |
|
|
612 | </dd> |
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613 | <dt><code>EV_FORK</code></dt> |
|
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614 | <dd> |
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615 | <p>The event loop has been resumed in the child process after fork (see |
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616 | <code>ev_fork</code>).</p> |
605 | </dd> |
617 | </dd> |
606 | <dt><code>EV_ERROR</code></dt> |
618 | <dt><code>EV_ERROR</code></dt> |
607 | <dd> |
619 | <dd> |
608 | <p>An unspecified error has occured, the watcher has been stopped. This might |
620 | <p>An unspecified error has occured, the watcher has been stopped. This might |
609 | happen because the watcher could not be properly started because libev |
621 | happen because the watcher could not be properly started because libev |
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… | |
732 | |
744 | |
733 | </div> |
745 | </div> |
734 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
746 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
735 | <div id="WATCHER_TYPES_CONTENT"> |
747 | <div id="WATCHER_TYPES_CONTENT"> |
736 | <p>This section describes each watcher in detail, but will not repeat |
748 | <p>This section describes each watcher in detail, but will not repeat |
737 | information given in the last section.</p> |
749 | information given in the last section. Any initialisation/set macros, |
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750 | functions and members specific to the watcher type are explained.</p> |
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751 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
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752 | while the watcher is active, you can look at the member and expect some |
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753 | sensible content, but you must not modify it (you can modify it while the |
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754 | watcher is stopped to your hearts content), or <i>[read-write]</i>, which |
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755 | means you can expect it to have some sensible content while the watcher |
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756 | is active, but you can also modify it. Modifying it may not do something |
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757 | sensible or take immediate effect (or do anything at all), but libev will |
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758 | not crash or malfunction in any way.</p> |
738 | |
759 | |
739 | |
760 | |
740 | |
761 | |
741 | |
762 | |
742 | |
763 | |
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781 | <dd> |
802 | <dd> |
782 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
803 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
783 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
804 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
784 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
805 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
785 | </dd> |
806 | </dd> |
|
|
807 | <dt>int fd [read-only]</dt> |
|
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808 | <dd> |
|
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809 | <p>The file descriptor being watched.</p> |
|
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810 | </dd> |
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811 | <dt>int events [read-only]</dt> |
|
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812 | <dd> |
|
|
813 | <p>The events being watched.</p> |
|
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814 | </dd> |
786 | </dl> |
815 | </dl> |
787 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
816 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
788 | readable, but only once. Since it is likely line-buffered, you could |
817 | readable, but only once. Since it is likely line-buffered, you could |
789 | attempt to read a whole line in the callback:</p> |
818 | attempt to read a whole line in the callback:</p> |
790 | <pre> static void |
819 | <pre> static void |
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847 | repeating. The exact semantics are:</p> |
876 | repeating. The exact semantics are:</p> |
848 | <p>If the timer is started but nonrepeating, stop it.</p> |
877 | <p>If the timer is started but nonrepeating, stop it.</p> |
849 | <p>If the timer is repeating, either start it if necessary (with the repeat |
878 | <p>If the timer is repeating, either start it if necessary (with the repeat |
850 | value), or reset the running timer to the repeat value.</p> |
879 | value), or reset the running timer to the repeat value.</p> |
851 | <p>This sounds a bit complicated, but here is a useful and typical |
880 | <p>This sounds a bit complicated, but here is a useful and typical |
852 | example: Imagine you have a tcp connection and you want a so-called idle |
881 | example: Imagine you have a tcp connection and you want a so-called |
853 | timeout, that is, you want to be called when there have been, say, 60 |
882 | idle timeout, that is, you want to be called when there have been, |
854 | seconds of inactivity on the socket. The easiest way to do this is to |
883 | say, 60 seconds of inactivity on the socket. The easiest way to do |
855 | configure an <code>ev_timer</code> with after=repeat=60 and calling ev_timer_again each |
884 | this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling |
856 | time you successfully read or write some data. If you go into an idle |
885 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
857 | state where you do not expect data to travel on the socket, you can stop |
886 | you go into an idle state where you do not expect data to travel on the |
858 | the timer, and again will automatically restart it if need be.</p> |
887 | socket, you can stop the timer, and again will automatically restart it if |
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888 | need be.</p> |
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889 | <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether |
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890 | and only ever use the <code>repeat</code> value:</p> |
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891 | <pre> ev_timer_init (timer, callback, 0., 5.); |
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892 | ev_timer_again (loop, timer); |
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893 | ... |
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894 | timer->again = 17.; |
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895 | ev_timer_again (loop, timer); |
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896 | ... |
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897 | timer->again = 10.; |
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898 | ev_timer_again (loop, timer); |
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899 | |
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900 | </pre> |
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901 | <p>This is more efficient then stopping/starting the timer eahc time you want |
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902 | to modify its timeout value.</p> |
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903 | </dd> |
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904 | <dt>ev_tstamp repeat [read-write]</dt> |
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905 | <dd> |
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906 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
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907 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
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908 | which is also when any modifications are taken into account.</p> |
859 | </dd> |
909 | </dd> |
860 | </dl> |
910 | </dl> |
861 | <p>Example: create a timer that fires after 60 seconds.</p> |
911 | <p>Example: create a timer that fires after 60 seconds.</p> |
862 | <pre> static void |
912 | <pre> static void |
863 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
913 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
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… | |
981 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
1031 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
982 | when you changed some parameters or the reschedule callback would return |
1032 | when you changed some parameters or the reschedule callback would return |
983 | a different time than the last time it was called (e.g. in a crond like |
1033 | a different time than the last time it was called (e.g. in a crond like |
984 | program when the crontabs have changed).</p> |
1034 | program when the crontabs have changed).</p> |
985 | </dd> |
1035 | </dd> |
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1036 | <dt>ev_tstamp interval [read-write]</dt> |
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1037 | <dd> |
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1038 | <p>The current interval value. Can be modified any time, but changes only |
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1039 | take effect when the periodic timer fires or <code>ev_periodic_again</code> is being |
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1040 | called.</p> |
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1041 | </dd> |
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1042 | <dt>ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]</dt> |
|
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1043 | <dd> |
|
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1044 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
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1045 | switched off. Can be changed any time, but changes only take effect when |
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1046 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
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1047 | </dd> |
986 | </dl> |
1048 | </dl> |
987 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1049 | <p>Example: call a callback every hour, or, more precisely, whenever the |
988 | system clock is divisible by 3600. The callback invocation times have |
1050 | system clock is divisible by 3600. The callback invocation times have |
989 | potentially a lot of jittering, but good long-term stability.</p> |
1051 | potentially a lot of jittering, but good long-term stability.</p> |
990 | <pre> static void |
1052 | <pre> static void |
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1039 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1101 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1040 | <dd> |
1102 | <dd> |
1041 | <p>Configures the watcher to trigger on the given signal number (usually one |
1103 | <p>Configures the watcher to trigger on the given signal number (usually one |
1042 | of the <code>SIGxxx</code> constants).</p> |
1104 | of the <code>SIGxxx</code> constants).</p> |
1043 | </dd> |
1105 | </dd> |
|
|
1106 | <dt>int signum [read-only]</dt> |
|
|
1107 | <dd> |
|
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1108 | <p>The signal the watcher watches out for.</p> |
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1109 | </dd> |
1044 | </dl> |
1110 | </dl> |
1045 | |
1111 | |
1046 | |
1112 | |
1047 | |
1113 | |
1048 | |
1114 | |
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1061 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1127 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1062 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1128 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1063 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1129 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1064 | process causing the status change.</p> |
1130 | process causing the status change.</p> |
1065 | </dd> |
1131 | </dd> |
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1132 | <dt>int pid [read-only]</dt> |
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|
1133 | <dd> |
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1134 | <p>The process id this watcher watches out for, or <code>0</code>, meaning any process id.</p> |
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1135 | </dd> |
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|
1136 | <dt>int rpid [read-write]</dt> |
|
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1137 | <dd> |
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1138 | <p>The process id that detected a status change.</p> |
|
|
1139 | </dd> |
|
|
1140 | <dt>int rstatus [read-write]</dt> |
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|
1141 | <dd> |
|
|
1142 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
|
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1143 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
|
|
1144 | </dd> |
1066 | </dl> |
1145 | </dl> |
1067 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1146 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1068 | <pre> static void |
1147 | <pre> static void |
1069 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1148 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1070 | { |
1149 | { |
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… | |
1072 | } |
1151 | } |
1073 | |
1152 | |
1074 | struct ev_signal signal_watcher; |
1153 | struct ev_signal signal_watcher; |
1075 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1154 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1076 | ev_signal_start (loop, &sigint_cb); |
1155 | ev_signal_start (loop, &sigint_cb); |
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1156 | |
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1157 | |
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1158 | |
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1159 | |
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1160 | </pre> |
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1161 | |
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1162 | </div> |
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1163 | <h2 id="code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</h2> |
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1164 | <div id="code_ev_stat_code_did_the_file_attri-2"> |
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1165 | <p>This watches a filesystem path for attribute changes. That is, it calls |
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1166 | <code>stat</code> regularly (or when the OS says it changed) and sees if it changed |
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1167 | compared to the last time, invoking the callback if it did.</p> |
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1168 | <p>The path does not need to exist: changing from "path exists" to "path does |
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1169 | not exist" is a status change like any other. The condition "path does |
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1170 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
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1171 | otherwise always forced to be at least one) and all the other fields of |
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1172 | the stat buffer having unspecified contents.</p> |
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1173 | <p>Since there is no standard to do this, the portable implementation simply |
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1174 | calls <code>stat (2)</code> regulalry on the path to see if it changed somehow. You |
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1175 | can specify a recommended polling interval for this case. If you specify |
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1176 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
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1177 | unspecified default</i> value will be used (which you can expect to be around |
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1178 | five seconds, although this might change dynamically). Libev will also |
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1179 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
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1180 | usually overkill.</p> |
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|
1181 | <p>This watcher type is not meant for massive numbers of stat watchers, |
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1182 | as even with OS-supported change notifications, this can be |
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1183 | resource-intensive.</p> |
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|
1184 | <p>At the time of this writing, no specific OS backends are implemented, but |
|
|
1185 | if demand increases, at least a kqueue and inotify backend will be added.</p> |
|
|
1186 | <dl> |
|
|
1187 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
|
|
1188 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
|
|
1189 | <dd> |
|
|
1190 | <p>Configures the watcher to wait for status changes of the given |
|
|
1191 | <code>path</code>. The <code>interval</code> is a hint on how quickly a change is expected to |
|
|
1192 | be detected and should normally be specified as <code>0</code> to let libev choose |
|
|
1193 | a suitable value. The memory pointed to by <code>path</code> must point to the same |
|
|
1194 | path for as long as the watcher is active.</p> |
|
|
1195 | <p>The callback will be receive <code>EV_STAT</code> when a change was detected, |
|
|
1196 | relative to the attributes at the time the watcher was started (or the |
|
|
1197 | last change was detected).</p> |
|
|
1198 | </dd> |
|
|
1199 | <dt>ev_stat_stat (ev_stat *)</dt> |
|
|
1200 | <dd> |
|
|
1201 | <p>Updates the stat buffer immediately with new values. If you change the |
|
|
1202 | watched path in your callback, you could call this fucntion to avoid |
|
|
1203 | detecting this change (while introducing a race condition). Can also be |
|
|
1204 | useful simply to find out the new values.</p> |
|
|
1205 | </dd> |
|
|
1206 | <dt>ev_statdata attr [read-only]</dt> |
|
|
1207 | <dd> |
|
|
1208 | <p>The most-recently detected attributes of the file. Although the type is of |
|
|
1209 | <code>ev_statdata</code>, this is usually the (or one of the) <code>struct stat</code> types |
|
|
1210 | suitable for your system. If the <code>st_nlink</code> member is <code>0</code>, then there |
|
|
1211 | was some error while <code>stat</code>ing the file.</p> |
|
|
1212 | </dd> |
|
|
1213 | <dt>ev_statdata prev [read-only]</dt> |
|
|
1214 | <dd> |
|
|
1215 | <p>The previous attributes of the file. The callback gets invoked whenever |
|
|
1216 | <code>prev</code> != <code>attr</code>.</p> |
|
|
1217 | </dd> |
|
|
1218 | <dt>ev_tstamp interval [read-only]</dt> |
|
|
1219 | <dd> |
|
|
1220 | <p>The specified interval.</p> |
|
|
1221 | </dd> |
|
|
1222 | <dt>const char *path [read-only]</dt> |
|
|
1223 | <dd> |
|
|
1224 | <p>The filesystem path that is being watched.</p> |
|
|
1225 | </dd> |
|
|
1226 | </dl> |
|
|
1227 | <p>Example: Watch <code>/etc/passwd</code> for attribute changes.</p> |
|
|
1228 | <pre> static void |
|
|
1229 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1230 | { |
|
|
1231 | /* /etc/passwd changed in some way */ |
|
|
1232 | if (w->attr.st_nlink) |
|
|
1233 | { |
|
|
1234 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1235 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1236 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1237 | } |
|
|
1238 | else |
|
|
1239 | /* you shalt not abuse printf for puts */ |
|
|
1240 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1241 | "if this is windows, they already arrived\n"); |
|
|
1242 | } |
|
|
1243 | |
|
|
1244 | ... |
|
|
1245 | ev_stat passwd; |
|
|
1246 | |
|
|
1247 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1248 | ev_stat_start (loop, &passwd); |
1077 | |
1249 | |
1078 | |
1250 | |
1079 | |
1251 | |
1080 | |
1252 | |
1081 | </pre> |
1253 | </pre> |
… | |
… | |
1303 | <dt>ev_embed_sweep (loop, ev_embed *)</dt> |
1475 | <dt>ev_embed_sweep (loop, ev_embed *)</dt> |
1304 | <dd> |
1476 | <dd> |
1305 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1477 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1306 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1478 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1307 | apropriate way for embedded loops.</p> |
1479 | apropriate way for embedded loops.</p> |
|
|
1480 | </dd> |
|
|
1481 | <dt>struct ev_loop *loop [read-only]</dt> |
|
|
1482 | <dd> |
|
|
1483 | <p>The embedded event loop.</p> |
|
|
1484 | </dd> |
|
|
1485 | </dl> |
|
|
1486 | |
|
|
1487 | |
|
|
1488 | |
|
|
1489 | |
|
|
1490 | |
|
|
1491 | </div> |
|
|
1492 | <h2 id="code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</h2> |
|
|
1493 | <div id="code_ev_fork_code_the_audacity_to_re-2"> |
|
|
1494 | <p>Fork watchers are called when a <code>fork ()</code> was detected (usually because |
|
|
1495 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1496 | <code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the |
|
|
1497 | event loop blocks next and before <code>ev_check</code> watchers are being called, |
|
|
1498 | and only in the child after the fork. If whoever good citizen calling |
|
|
1499 | <code>ev_default_fork</code> cheats and calls it in the wrong process, the fork |
|
|
1500 | handlers will be invoked, too, of course.</p> |
|
|
1501 | <dl> |
|
|
1502 | <dt>ev_fork_init (ev_signal *, callback)</dt> |
|
|
1503 | <dd> |
|
|
1504 | <p>Initialises and configures the fork watcher - it has no parameters of any |
|
|
1505 | kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless, |
|
|
1506 | believe me.</p> |
1308 | </dd> |
1507 | </dd> |
1309 | </dl> |
1508 | </dl> |
1310 | |
1509 | |
1311 | |
1510 | |
1312 | |
1511 | |
… | |
… | |
1462 | </dd> |
1661 | </dd> |
1463 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1662 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1464 | <dd> |
1663 | <dd> |
1465 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1664 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1466 | </dd> |
1665 | </dd> |
|
|
1666 | <dt>w->update () <code>ev::stat</code> only</dt> |
|
|
1667 | <dd> |
|
|
1668 | <p>Invokes <code>ev_stat_stat</code>.</p> |
|
|
1669 | </dd> |
1467 | </dl> |
1670 | </dl> |
1468 | </p> |
1671 | </p> |
1469 | </dd> |
1672 | </dd> |
1470 | </dl> |
1673 | </dl> |
1471 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
1674 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1482 | : io (this, &myclass::io_cb), |
1685 | : io (this, &myclass::io_cb), |
1483 | idle (this, &myclass::idle_cb) |
1686 | idle (this, &myclass::idle_cb) |
1484 | { |
1687 | { |
1485 | io.start (fd, ev::READ); |
1688 | io.start (fd, ev::READ); |
1486 | } |
1689 | } |
|
|
1690 | |
|
|
1691 | |
|
|
1692 | |
|
|
1693 | |
|
|
1694 | </pre> |
|
|
1695 | |
|
|
1696 | </div> |
|
|
1697 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> |
|
|
1698 | <div id="MACRO_MAGIC_CONTENT"> |
|
|
1699 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1700 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
|
|
1701 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
|
|
1702 | <p>To make it easier to write programs that cope with either variant, the |
|
|
1703 | following macros are defined:</p> |
|
|
1704 | <dl> |
|
|
1705 | <dt><code>EV_A</code>, <code>EV_A_</code></dt> |
|
|
1706 | <dd> |
|
|
1707 | <p>This provides the loop <i>argument</i> for functions, if one is required ("ev |
|
|
1708 | loop argument"). The <code>EV_A</code> form is used when this is the sole argument, |
|
|
1709 | <code>EV_A_</code> is used when other arguments are following. Example:</p> |
|
|
1710 | <pre> ev_unref (EV_A); |
|
|
1711 | ev_timer_add (EV_A_ watcher); |
|
|
1712 | ev_loop (EV_A_ 0); |
|
|
1713 | |
|
|
1714 | </pre> |
|
|
1715 | <p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope, |
|
|
1716 | which is often provided by the following macro.</p> |
|
|
1717 | </dd> |
|
|
1718 | <dt><code>EV_P</code>, <code>EV_P_</code></dt> |
|
|
1719 | <dd> |
|
|
1720 | <p>This provides the loop <i>parameter</i> for functions, if one is required ("ev |
|
|
1721 | loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter, |
|
|
1722 | <code>EV_P_</code> is used when other parameters are following. Example:</p> |
|
|
1723 | <pre> // this is how ev_unref is being declared |
|
|
1724 | static void ev_unref (EV_P); |
|
|
1725 | |
|
|
1726 | // this is how you can declare your typical callback |
|
|
1727 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1728 | |
|
|
1729 | </pre> |
|
|
1730 | <p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite |
|
|
1731 | suitable for use with <code>EV_A</code>.</p> |
|
|
1732 | </dd> |
|
|
1733 | <dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt> |
|
|
1734 | <dd> |
|
|
1735 | <p>Similar to the other two macros, this gives you the value of the default |
|
|
1736 | loop, if multiple loops are supported ("ev loop default").</p> |
|
|
1737 | </dd> |
|
|
1738 | </dl> |
|
|
1739 | <p>Example: Declare and initialise a check watcher, working regardless of |
|
|
1740 | wether multiple loops are supported or not.</p> |
|
|
1741 | <pre> static void |
|
|
1742 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1743 | { |
|
|
1744 | ev_check_stop (EV_A_ w); |
|
|
1745 | } |
|
|
1746 | |
|
|
1747 | ev_check check; |
|
|
1748 | ev_check_init (&check, check_cb); |
|
|
1749 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1750 | ev_loop (EV_DEFAULT_ 0); |
|
|
1751 | |
|
|
1752 | |
|
|
1753 | |
1487 | |
1754 | |
1488 | </pre> |
1755 | </pre> |
1489 | |
1756 | |
1490 | </div> |
1757 | </div> |
1491 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1758 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
… | |
… | |
1702 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
1969 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
1703 | additional independent event loops. Otherwise there will be no support |
1970 | additional independent event loops. Otherwise there will be no support |
1704 | for multiple event loops and there is no first event loop pointer |
1971 | for multiple event loops and there is no first event loop pointer |
1705 | argument. Instead, all functions act on the single default loop.</p> |
1972 | argument. Instead, all functions act on the single default loop.</p> |
1706 | </dd> |
1973 | </dd> |
1707 | <dt>EV_PERIODICS</dt> |
1974 | <dt>EV_PERIODIC_ENABLE</dt> |
1708 | <dd> |
1975 | <dd> |
1709 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported, |
1976 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If |
1710 | otherwise not. This saves a few kb of code.</p> |
1977 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
|
|
1978 | code.</p> |
|
|
1979 | </dd> |
|
|
1980 | <dt>EV_EMBED_ENABLE</dt> |
|
|
1981 | <dd> |
|
|
1982 | <p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If |
|
|
1983 | defined to be <code>0</code>, then they are not.</p> |
|
|
1984 | </dd> |
|
|
1985 | <dt>EV_STAT_ENABLE</dt> |
|
|
1986 | <dd> |
|
|
1987 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
|
|
1988 | defined to be <code>0</code>, then they are not.</p> |
|
|
1989 | </dd> |
|
|
1990 | <dt>EV_FORK_ENABLE</dt> |
|
|
1991 | <dd> |
|
|
1992 | <p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If |
|
|
1993 | defined to be <code>0</code>, then they are not.</p> |
|
|
1994 | </dd> |
|
|
1995 | <dt>EV_MINIMAL</dt> |
|
|
1996 | <dd> |
|
|
1997 | <p>If you need to shave off some kilobytes of code at the expense of some |
|
|
1998 | speed, define this symbol to <code>1</code>. Currently only used for gcc to override |
|
|
1999 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
1711 | </dd> |
2000 | </dd> |
1712 | <dt>EV_COMMON</dt> |
2001 | <dt>EV_COMMON</dt> |
1713 | <dd> |
2002 | <dd> |
1714 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2003 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
1715 | this macro to a something else you can include more and other types of |
2004 | this macro to a something else you can include more and other types of |