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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" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
9 | <meta name="created" content="Mon Nov 12 08:58:02 2007" /> |
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13 | <div class="pod"> |
13 | <div class="pod"> |
14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
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26 | </ul> |
26 | </ul> |
27 | </li> |
27 | </li> |
28 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
28 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
29 | <ul><li><a href="#struct_ev_io_is_my_file_descriptor_r">struct ev_io - is my file descriptor readable or writable</a></li> |
29 | <ul><li><a href="#struct_ev_io_is_my_file_descriptor_r">struct ev_io - is my file descriptor readable or writable</a></li> |
30 | <li><a href="#struct_ev_timer_relative_and_optiona">struct ev_timer - relative and optionally recurring timeouts</a></li> |
30 | <li><a href="#struct_ev_timer_relative_and_optiona">struct ev_timer - relative and optionally recurring timeouts</a></li> |
31 | <li><a href="#ev_periodic">ev_periodic</a></li> |
31 | <li><a href="#ev_periodic_to_cron_or_not_to_cron_i">ev_periodic - to cron or not to cron it</a></li> |
32 | <li><a href="#ev_signal_signal_me_when_a_signal_ge">ev_signal - signal me when a signal gets signalled</a></li> |
32 | <li><a href="#ev_signal_signal_me_when_a_signal_ge">ev_signal - signal me when a signal gets signalled</a></li> |
33 | <li><a href="#ev_child_wait_for_pid_status_changes">ev_child - wait for pid status changes</a></li> |
33 | <li><a href="#ev_child_wait_for_pid_status_changes">ev_child - wait for pid status changes</a></li> |
34 | <li><a href="#ev_idle_when_you_ve_got_nothing_bett">ev_idle - when you've got nothing better to do</a></li> |
34 | <li><a href="#ev_idle_when_you_ve_got_nothing_bett">ev_idle - when you've got nothing better to do</a></li> |
35 | <li><a href="#prepare_and_check_your_hooks_into_th">prepare and check - your hooks into the event loop</a></li> |
35 | <li><a href="#prepare_and_check_your_hooks_into_th">prepare and check - your hooks into the event loop</a></li> |
36 | </ul> |
36 | </ul> |
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55 | </div> |
55 | </div> |
56 | <h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
56 | <h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
57 | <div id="DESCRIPTION_CONTENT"> |
57 | <div id="DESCRIPTION_CONTENT"> |
58 | <p>Libev is an event loop: you register interest in certain events (such as a |
58 | <p>Libev is an event loop: you register interest in certain events (such as a |
59 | file descriptor being readable or a timeout occuring), and it will manage |
59 | file descriptor being readable or a timeout occuring), and it will manage |
60 | these event sources and provide your program events.</p> |
60 | these event sources and provide your program with events.</p> |
61 | <p>To do this, it must take more or less complete control over your process |
61 | <p>To do this, it must take more or less complete control over your process |
62 | (or thread) by executing the <i>event loop</i> handler, and will then |
62 | (or thread) by executing the <i>event loop</i> handler, and will then |
63 | communicate events via a callback mechanism.</p> |
63 | communicate events via a callback mechanism.</p> |
64 | <p>You register interest in certain events by registering so-called <i>event |
64 | <p>You register interest in certain events by registering so-called <i>event |
65 | watchers</i>, which are relatively small C structures you initialise with the |
65 | watchers</i>, which are relatively small C structures you initialise with the |
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87 | will not have this argument.</p> |
87 | will not have this argument.</p> |
88 | |
88 | |
89 | </div> |
89 | </div> |
90 | <h1 id="TIME_AND_OTHER_GLOBAL_FUNCTIONS">TIME AND OTHER GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
90 | <h1 id="TIME_AND_OTHER_GLOBAL_FUNCTIONS">TIME AND OTHER GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
91 | <div id="TIME_AND_OTHER_GLOBAL_FUNCTIONS_CONT"> |
91 | <div id="TIME_AND_OTHER_GLOBAL_FUNCTIONS_CONT"> |
92 | <p>Libev represents time as a single floating point number. This type is |
92 | <p>Libev represents time as a single floating point number, representing the |
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93 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
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94 | the beginning of 1970, details are complicated, don't ask). This type is |
93 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
95 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
94 | to the double type in C.</p> |
96 | to the double type in C.</p> |
95 | <dl> |
97 | <dl> |
96 | <dt>ev_tstamp ev_time ()</dt> |
98 | <dt>ev_tstamp ev_time ()</dt> |
97 | <dd> |
99 | <dd> |
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314 | *)</code>), and you can stop watching for events at any time by calling the |
316 | *)</code>), and you can stop watching for events at any time by calling the |
315 | corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p> |
317 | corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p> |
316 | <p>As long as your watcher is active (has been started but not stopped) you |
318 | <p>As long as your watcher is active (has been started but not stopped) you |
317 | must not touch the values stored in it. Most specifically you must never |
319 | must not touch the values stored in it. Most specifically you must never |
318 | reinitialise it or call its set method.</p> |
320 | reinitialise it or call its set method.</p> |
319 | <p>You cna check wether an event is active by calling the <code>ev_is_active |
321 | <p>You cna check whether an event is active by calling the <code>ev_is_active |
320 | (watcher *)</code> macro. To see wether an event is outstanding (but the |
322 | (watcher *)</code> macro. To see whether an event is outstanding (but the |
321 | callback for it has not been called yet) you cna use the <code>ev_is_pending |
323 | callback for it has not been called yet) you cna use the <code>ev_is_pending |
322 | (watcher *)</code> macro.</p> |
324 | (watcher *)</code> macro.</p> |
323 | <p>Each and every callback receives the event loop pointer as first, the |
325 | <p>Each and every callback receives the event loop pointer as first, the |
324 | registered watcher structure as second, and a bitset of received events as |
326 | registered watcher structure as second, and a bitset of received events as |
325 | third argument.</p> |
327 | third argument.</p> |
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420 | information given in the last section.</p> |
422 | information given in the last section.</p> |
421 | |
423 | |
422 | </div> |
424 | </div> |
423 | <h2 id="struct_ev_io_is_my_file_descriptor_r">struct ev_io - is my file descriptor readable or writable</h2> |
425 | <h2 id="struct_ev_io_is_my_file_descriptor_r">struct ev_io - is my file descriptor readable or writable</h2> |
424 | <div id="struct_ev_io_is_my_file_descriptor_r-2"> |
426 | <div id="struct_ev_io_is_my_file_descriptor_r-2"> |
425 | <p>I/O watchers check wether a file descriptor is readable or writable |
427 | <p>I/O watchers check whether a file descriptor is readable or writable |
426 | in each iteration of the event loop (This behaviour is called |
428 | in each iteration of the event loop (This behaviour is called |
427 | level-triggering because you keep receiving events as long as the |
429 | level-triggering because you keep receiving events as long as the |
428 | condition persists. Remember you cna stop the watcher if you don't want to |
430 | condition persists. Remember you cna stop the watcher if you don't want to |
429 | act on the event and neither want to receive future events).</p> |
431 | act on the event and neither want to receive future events).</p> |
430 | <dl> |
432 | <dl> |
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478 | the timer, and again will automatically restart it if need be.</p> |
480 | the timer, and again will automatically restart it if need be.</p> |
479 | </dd> |
481 | </dd> |
480 | </dl> |
482 | </dl> |
481 | |
483 | |
482 | </div> |
484 | </div> |
483 | <h2 id="ev_periodic">ev_periodic</h2> |
485 | <h2 id="ev_periodic_to_cron_or_not_to_cron_i">ev_periodic - to cron or not to cron it</h2> |
484 | <div id="ev_periodic_CONTENT"> |
486 | <div id="ev_periodic_to_cron_or_not_to_cron_i-2"> |
485 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
487 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
486 | (and unfortunately a bit complex).</p> |
488 | (and unfortunately a bit complex).</p> |
487 | <p>Unlike ev_timer's, they are not based on real time (or relative time) |
489 | <p>Unlike ev_timer's, they are not based on real time (or relative time) |
488 | but on wallclock time (absolute time). You can tell a periodic watcher |
490 | but on wallclock time (absolute time). You can tell a periodic watcher |
489 | to trigger "at" some specific point in time. For example, if you tell a |
491 | to trigger "at" some specific point in time. For example, if you tell a |